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The influence of barefoot and shod running on Triceps surae muscle strain characteristics

Posted on March 1, 2016 | Comments Off on The influence of barefoot and shod running on Triceps surae muscle strain characteristics

by Sinclair J1*, Cole T2, Richards J2pdflrg

The Foot and Ankle Online Journal 9 (1): 4

The aim of the current investigation was to determine the effects of barefoot and shod running on the kinematics of the Triceps-Surae muscle group. Twelve male participants ran at 4.0 m.s-1 (± 5%) in both barefoot and shod conditions. Kinematics were measured using an eight-camera motion analysis system. Muscle kinematics from the lateral Gastrocnemius, medial Gastrocnemius and Soleus were obtained using musculoskeletal modelling software (Opensim v3.2).  The results showed that muscle strain for the lateral Gastrocnemius (barefoot = 1.10 & shod = 0.33 %), medial Gastrocnemius (barefoot = 1.07 & shod = 0.32 %) and Soleus (barefoot = 3.43 & shod = 2.18 %) were significantly larger for the barefoot condition. Given the proposed association between the extent of muscle strain and the etiology of chronic muscle strain pathologies, the current investigation shows that running barefoot may place runners at greater risk from Triceps-Surae strain injuries.

Key words: Biomechanics, barefoot, shod, Triceps-Surae

ISSN 1941-6806
doi: 10.3827/faoj.2016.0901.0004

1 – Centre for Applied Sport Exercise and Nutritional Sciences, School of Sport & Wellbeing, College of Health & Wellbeing, University of Central Lancashire, UK.
2 – Allied Health Research Unit, School of Health, College of Health & Wellbeing, University of Central Lancashire, UK.
* Correspondence: Dr. Jonathan Sinclair, jksinclair@uclan.ac.uk

Engaging in recreational and competitive distance running has been shown to provide a number of health benefits [1]. Despite this runners are highly susceptible to chronic injuries [2], with an occurrence rate of around 80 % over the course of one year [3]. A large number of strategies have been investigated in biomechanical research with the specific aim of attenuating the risk of running injuries.

One such conservative strategy is to choose running shoes with appropriate mechanical characteristics; the properties of running shoes have been proposed as a mechanism by which chronic injuries can be controlled [4]. Recently barefoot running has been the focus of much attention in biomechanics research.

The popularity and attention paid to barefoot footwear is due the proposition that running barefoot may be able to reduce the incidence of chronic running injuries [5, 6].

The findings from biomechanical research into the kinetics and kinematics of running barefoot in comparison to shod have been equivocal. Sinclair et al. [7] examined the effects of barefoot and shod running on kinetics, kinematics and tibial accelerations during the stance phase. Their kinematic observations showed that the ankle was significantly more plantarflexed at footstrike in the barefoot condition. In addition it was also shown the running barefoot was associated with significantly greater tibial accelerations and vertical rates of loading. Sinclair et al. [8] similarly investigated the effects of barefoot and shod conditions on running kinetics and kinematics. Their kinematic findings showed that barefoot running was associated with a more plantarflexed ankle position at footstrike and also a greater peak eversion angle. The kinetic findings indicated that barefoot running demonstrated a significantly greater vertical rate of loading. When comparing the kinetics and sagittal plane kinematics of running barefoot and shod, Lieberman et al [5] demonstrated firstly that the ankle was significantly more plantarflexed at footstrike in the barefoot condition. However, their kinetic observations showed that the vertical rate of loading was larger when running with shoes. Similarly, Squadrone & Gallozzi, [9] showed that running barefoot was associated with increased plantarflexion at footstrike but with subsequent reductions in peak vertical impact forces.

In addition, with the development more accurate musculoskeletal models more recent research has been able to investigate the loads experienced by specific musculoskeletal structures. Bonacci et al, [10] showed that running barefoot was associated with significant reductions in patellofemoral loading in comparison to shod. Sinclair, [11] similarly demonstrated that patellofemoral loading was significantly reduced when running barefoot but that running without shoes mediated subsequent increases in the loads borne by the Achilles tendon. Finally, Sinclair et al, [12] investigated the effects of barefoot and shod running on limb and joint stiffness characteristics during the stance phase. They showed that limb and knee stiffness were greater when running barefoot but that ankle stiffness was greater when running shod.

There is currently a paucity of biomechanical research investigating muscle mechanics during barefoot and shod running. Sinclair et al, [13] investigated the effects of barefoot and shod running on lower limb muscle forces during the stance phase of running. Their observations showed that peak forces from the Rectus femoris, Vastus medialis, Vastus lateralis and Tibialis anterior were significantly larger in the shod condition whereas Gastrocnemius forces were significantly larger during barefoot running. Similarly, Sinclair, [14] studied the effects of running barefoot and shod on peak and mean foot muscle forces. The findings confirmed that peak and mean forces from the Flexor digitorum longus, Flexor hallucis longus, Peroneus longus muscles were significantly larger when running barefoot, whereas peak and average forces of the Extensor digitorum longus and Extensor hallucis longus muscles were significantly larger when running shod.

There has yet to be any published research investigating Triceps Surae muscle mechanics during barefoot and shod running. Anecdotal evidence of calf pain and stiffness has been reported by runners who seek to conduct their training without shoes. Furthermore, the prospective investigation of Altman & Davis [15] showed that calf injuries may be more prominent in barefoot runners in comparison to those who train shod. This indicates that an investigation into the mechanics of the Tricep-surae (calf) muscle group during barefoot and shod running would be of both practical and clinical significance to both clinicians and runners themselves.

Therefore the aim of the current investigation was to determine the effects of barefoot and shod running on the kinematics of the Triceps Surae muscle group. A study of this nature may aid our understanding of muscle function during barefoot running. The current work tests the hypothesis that the magnitude of strain experienced by the Triceps Surae muscles will be significantly larger when running barefoot.

Methods

Participants

Twelve male runners (age 23.58 ± 2.88 years, height 1.77 ± 0.10 cm and body mass 79.40 ± 5.87 kg) volunteered to take part in this study. All runners were free from musculoskeletal pathology at the time of data collection. Participants provided written informed consent in accordance with the principles outlined in the Declaration of Helsinki. Each runner was considered to be exhibit a natural rearfoot strike pattern as they exhibited an impact peak in their vertical ground reaction force curve when wearing conventional footwear. The procedure was approved by the University of Central Lancashire ethical committee.

Procedure

Participants ran at a velocity of 4.0 m.s-1 ±5%, striking an embedded force platform (Kistler, Kistler Instruments Ltd., Alton, Hampshire) with their right (dominant) foot [16]. The velocity of running was monitored using infrared timing gates (Newtest, Oy Koulukatu, Finland). The stance phase was defined as the duration over which 20 N or greater of vertical force was applied to the force platform [17]. All runners completed five successful trials in each footwear condition.

Kinematic information was captured at 250 Hz using an eight camera optoelectric motion analysis system (QualisysTM Medical AB, Goteburg, Sweden). To define the anatomical frames of the trunk, pelvis, thighs, shanks and feet retroreflective markers were placed at the C7, T12 and xiphoid process landmarks and also positioned bilaterally onto the acromion process, iliac crest, anterior superior iliac spine, posterior super iliac spine, medial and lateral malleoli, medial and lateral femoral epicondyles and greater trochanter. Carbon-fiber tracking clusters comprising of four non-linear retroreflective markers were positioned bilaterally onto the thigh and shank segments. Static calibration trials were obtained with the participant in the anatomical position in order for the positions of the anatomical markers to be referenced in relation to the tracking clusters/markers.

Data processing

Marker trajectories were filtered 12 Hz using a low pass Butterworth 4th order zero-lag filter and analyzed using Visual 3D (C-Motion, Germantown, MD, USA. All information was normalized to 100 % of the stance phase. For the current study angular kinematics of the ankle joint were examined. Kinematic measures from the ankle were extracted for statistical analysis were 1) angle at footstrike and 2) relative peak range of motion from footstrike to peak angle.

OpenSim software was used to quantify muscle-tendon lengths during the stance phase of running [18]. Muscle kinematics were quantified using the gait2392 model using OpenSim v3.2. This model corresponds to the eight segments exported from Visual 3D and features ninety two muscles, eighty six of which are centered around the lower extremities and six are associated with the pelvis and trunk. The muscle properties were modelled using the Hill recommendations based on the associations between force-velocity-length [19]. These muscle properties were then scaled based on each participant’s height and body mass based on the recommendations of Delp et al, [20]. Muscle-tendon lengths are determined by the positions of their proximal and distal muscles muscle origins. The muscle–tendon units which were evaluated as part of the current research were the lateral Gastrocnemius, medial Gastrocnemius, and Soleus. Muscle kinematic parameters that were extracted for statistical analysis were 1) eccentric strain (representative of the maximum increase in muscle length divided by the length at footstrike and 2) peak lengthening velocity.

In addition to this we also estimated the total muscle strain experienced per mile (% x mile) by multiplying the muscle strain magnitude by the number of steps required to complete one mile. The number of steps required to complete one mile was calculated using the step length. Step length was obtained by taking the difference in the horizontal position of the foot between the right and left legs at footstrike [21, 22].

Statistical analyses

Descriptive statistics (means, standard deviations and 95% confidence intervals) were obtained for each footwear condition. Shapiro-Wilk tests were used to screen the data for normality. Footwear mediated differences in foot muscle kinetics were examined using paired samples t-tests. All statistical actions were conducted using SPSS v22.0 (SPSS Inc, Chicago, USA).

Results

Figures 1-3 and table 1 show ankle joint and muscle kinematics as a function of barefoot and shod running conditions. The results show that the different running conditions significantly influence both joint and muscle kinematics.

Ankle kinematics

The ankle was found to be significantly (t (11) = 4.51, p<0.05) more plantarflexed at footstrike in the barefoot conditions in comparison to shod. Furthermore, the relative range of motion was found to be significantly (t (11) = 4.08, p<0.05) greater when running barefoot in comparison to shod (Figure 1).

Muscle kinematics

For the lateral Gastrocnemius muscle running barefoot was associated with significantly (t (11) = 2.81, p<0.05) larger muscles strain in comparison to shod running (Figure 2a; Table 1). In addition when running barefoot the lateral Gastrocnemius exhibited a significantly (t (11) = 2.37, p<0.05) greater lengthening velocity than during shod running (Figure 2a; Table 1). Finally barefoot running was associated with a significantly (t (11) = 2.81, p<0.05) greater strain experienced per mile (Table 1).

For the medial Gastrocnemius muscle running barefoot was associated with significantly (t (11) = 2.79, p<0.05) larger muscle strain in comparison to shod running (Figure 2b; Table 1). In addition when running barefoot the medial Gastrocnemius exhibited a significantly (t (11) = 2.39, p<0.05) greater lengthening velocity than during shod running (Figure 3b; Table 1). Finally barefoot running was associated with a significantly (t (11) = 2.83, p<0.05) greater strain experienced per mile (Table 1).

For the Soleus muscle running barefoot was associated with significantly (t (11) = 3.79, p<0.05) larger muscle strain in comparison to shod running (Figure 2c; Table 1). In addition when running barefoot the Soleus exhibited a significantly (t (11) = 2.69, p<0.05) greater lengthening velocity than during shod running (Figure 3c; Table 1). Finally barefoot running was associated with a significantly (t (11) = 3.93, p<0.05) greater strain experienced per mile (Table 1).

Fig1

Figure 1 Sagittal ankle kinematics as a function of barefoot and shod conditions (black = barefoot and grey = shod) (DF = dorsiflexion).

Fig2

Figure 2 Tirceps Surae muscle kinematics as a function of barefoot and shod conditions (black = barefoot and grey = shod) (a. = lateral Gastrocnemius, b. = medial Gastrocnemius, c. = Soleus).

Fig3

Figure 3 Tirceps Surae muscle velocities as a function of barefoot and shod conditions (black = barefoot and grey = shod) (a. = lateral Gastrocnemius, b. = medial Gastrocnemius, c. = Soleus).

Tab1

Table 1 Triceps Surae muscle kinematics (Means, SD’s & 95% CI’s) as a function of barefoot and shod conditions.

Discussion

The aim of the current investigation was to quantify the effects of barefoot and shod running on Triceps Surae muscle kinematics. To the authors knowledge this represents the first comparative analysis of Triceps Surae mechanics when running in different footwear.

The first key observation from the current paper is that ankle was shown to be significantly plantarflexed at footstrike in the barefoot condition in comparison to running shod. This indicates that runners modified their footstrike pattern and adopted a non-rearfoot strike when running barefoot. This finding concurs with the observations of Squadrone & Gallozzi, [9], Lieberman et al, [5] and Sinclair et al, [7, 8] who each showed a more plantarflexed ankle position when wearing running barefoot. It proposed that this finding relates to the absence of shoe cushioning when running barefoot. Runners adopt a non-rearfoot strike pattern in order to compensate for the lack of a shoe midsole and attenuate the loads experienced by the musculoskeletal system [5]. The first key finding from the current work is that strain magnitude and velocity in each of the three muscles associated with the Triceps-Surae was significantly larger in the barefoot condition in comparison to shod. This observation supports our original hypothesis and may have clinical significance. Muscle strains occur as a function of excessive muscle lengthening during periods of eccentric muscle lengthening [23]. The findings from the current investigation therefore support the proposition of Altman & Davis, [15] in that running barefoot appears to place runners at increased risk from Triceps-Surae strain injuries.

It is proposed that these observations relate to the change in footstrike pattern and increased range of motion mediated by running without shoes. The Triceps-Surae muscles insert distally into the Achilles tendon insertion and proximally at the posterior aspects of the tibia/ femur. Therefore the increased plantar flexion at footstrike observed when running barefoot means that the muscles are in a shortened position compared shod running. This in conjunction with the increased dorsiflexion range of motion at the ankle means that the Triceps-Surae must lengthen to a greater extent given the anterior translation of the proximal muscle insertion points. This finding therefore suggests that whilst the non-rearfoot strike pattern associated with barefoot running may reduce the load experienced by the patellofemoral joint [10, 11] and also vertical rate of loading [5,9] it may be at the expense of increased Triceps-Surae strain.

The findings in relation to muscle strains from the current investigation can be further contextualized taking into account the increased number of steps required to complete one mile when running barefoot. This led to further increases in the amount of muscle strain experienced per mile, over and above those reported per footfall when participants ran barefoot. Therefore, whilst the amount of strain experienced per footfall is relatively small when contrasted against muscle strains shown in other sports [24], because running represents a cyclical activity which involves multiple footfalls the cumulative strain is high. This observation further supports the notion that running barefoot may enhance the likelihood of experiencing a chronic muscle strain injury at the Triceps-Surae.

In conclusion, although differences in the effects of barefoot running have been examined extensively, the current knowledge regarding the differences in Triceps-Surae kinematics between barefoot and shod running is limited. The present investigation therefore adds to the current knowledge by providing a comprehensive evaluation of Triceps-Surae muscle kinematic parameters when running in barefoot and shod conditions. On the basis muscle strain parameters were significantly greater when running barefoot; the findings from the current investigation indicate that barefoot running may place runners at increases risk from chronic Triceps-Surae muscle strain injuries in comparison to running shod.

References

  1. Schnohr P, O’Keefe JH, Marott JL, Lange P, Jensen GB. Dose of jogging and long-term mortality: the Copenhagen City Heart Study. Journal of the American College of Cardiology 2015; 65: 411-419. (PubMed)
  2. Taunton JE, Clement DB, McNicol K. Plantar fasciitis in runners. Canadian Journal of Applied Sport Sciences 1982; 7: 41-44. (PubMed)
  3. van Gent R, Siem DD, van Middelkoop M, van Os TA, Bierma-Zeinstra SS, Koes, BB. Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. British Journal of Sports Medicine 2007: 41: 469-480. (PubMed)
  4. Shorten, MA. Running shoe design: protection and performance. pp 159-169 in Marathon Medicine (Ed. D. Tunstall Pedoe). 2000; London, Royal Society of Medicine.
  5. Lieberman DE, Venkadesan M, Werbel WA, Daoud AI, D’Andrea S, Davis IS, et al. Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature; 2010; 463: 531-535. (Link)
  6. Warburton, M. Barefoot running. Sportscience 2000; 5; 1-4.
  7. Sinclair J, Greenhalgh A, Brooks D, Edmundson CJ, Hobbs SJ. The influence of barefoot and barefoot-inspired footwear on the kinetics and kinematics of running in comparison to conventional running shoes. Footwear Science 2013: 5, 45-53.
  8. Sinclair, J, Hobbs, SJ, Currigan, G, Taylor PJ. A comparison of several barefoot inspired footwear models in relation to barefoot and conventional running footwear. Comparative Exercise Physiology 2013; 9: 13-21.
  9. Squadrone R, Gallozzi C. Biomechanical and physiological comparison of barefoot and two shod conditions in experienced barefoot runners. Journal of Sports Medicine & Physical Fitness 2009; 49: 6-13. (PubMed)
  10. Bonacci J, Vicenzino B, Spratford W, Collins P. Take your shoes off to reduce patellofemoral joint stress during running. British Journal of Sports Medicine, (In press). (Link)
  11. Sinclair J. Effects of barefoot and barefoot inspired footwear on knee and ankle loading during running. Clinical Biomechanics 2014; 29: 395-399. (PubMed)
  12. Sinclair J, Atkins, S, Taylor PJ. The Effects of Barefoot and Shod Running on Limb and Joint Stiffness Characteristics in Recreational Runners. Journal of Motor Behavior 2015 (In press). (PubMed)
  13. Sinclair J, Atkins S, Richards J, Vincent H. Modelling of Muscle Force Distributions During Barefoot and Shod Running. Journal of Human Kinetics 2015 (In press).
  14. Sinclair, J. (2015). Barefoot and shod running: their effects on foot muscle kinetics. FAOJ 2015; 8: 2. (Link)
  15. Altman AR, Davis IS. Prospective comparison of running injuries between shod and barefoot runners. British Journal of Sports Medicine, 2015 (In press). (Link)
  16. Sinclair J, Hobbs SJ, Taylor PJ, Currigan G, Greenhalgh A. The Influence of Different Force and Pressure Measuring Transducers on Lower Extremity Kinematics Measured During Running. Journal of Applied Biomechanics 2014 30: 166–172. (PubMed)
  17. Sinclair J, Edmundson CJ, Brooks D, Hobbs SJ. Evaluation of kinematic methods of identifying gait Events during running. International Journal of Sport Science & Engineering 2011; 5: 188-192. (Link)
  18. Delp SL, Anderson FC, Arnold AS, Loan P, Habib A, John CT, Thelen DG. OpenSim: open-source software to create and analyze dynamic simulations of movement. IEEE Transactions on Biomedical Engineering 2007; 54: 1940-1950. (PubMed)
  19. Zajac FE. Muscle and tendon: properties, models, scaling, and application to biomechanics and motor control. Critical Reviews in Biomedical Engineering. 1989; 17: 359–411.
  20. Delp SL, Loan JP, Hoy MG, Zajac FE, Topp EL, Rosen JM. An interactive graphics-based model of the lower extremity to study orthopaedic surgical procedures. IEEE Transactions on Biomedical Engineering 1990; 37: 757–767. (PubMed)
  21. Almonroeder, T, Willson, JD, Kernozek, TW. The effect of foot strike pattern on Achilles tendon load during running. Annals of Biomedical Engineering 2013; 41: 1758-1766. (PubMed)
  22. Sinclair J, Richards J, Shore H. Effects of minimalist and maximalist footwear on Achilles tendon load in recreational runners. Comparative Exercise Physiology 2015 (In press).
  23. Mueller-Wohlfahrt HW, Haensel L, Mithoefer K, Ekstrand J, English B, McNally S, Ueblacker P. Terminology and classification of muscle injuries in sport: a consensus statement. British Journal of Sports Medicine 2012; 47: 342-350. (PubMed)
  24. Sinclair J. Side to side differences in hamstring kinematics during maximal instep kicking in male soccer players. Movement & Sport Sciences 2015 (In press).

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Barefoot and shod running: their effects on foot muscle kinetics

Posted on June 30, 2015 | Comments Off on Barefoot and shod running: their effects on foot muscle kinetics

by Jonathan Sinclairpdflrg

The Foot and Ankle Online Journal 8 (2): 2

Running shoe technology has advanced significantly in the last 50 years, although the overall injury rate has yet to decrease. Barefoot (BF) running has become increasing more popular in the last 10 years. The current investigation aimed to explore differences in the forces produced by the foot muscles during BF and shod (SH) running. Fifteen male participants ran at 4.0 m.s-1 (± 5%). Kinematics were measured using an eight-camera motion analysis system alongside ground reaction forces. Peak and average stance phase forces from the flexor digitorum longus (FDL), flexor hallucis longus (FHL), peroneus longus (PL), extensor digitorum longus (EDL) and extensor hallucis longus (EHL) muscles were obtained using OpenSim v3.2. Peak and average forces of the FDL, FHL and PL muscles were significantly larger when running BF, whereas peak and average forces of the FHL and EHL muscles were significantly larger when running SH. This study supports the conjecture that the plantar muscles are required to work harder when running BF in relation to SH, indicating that BF training may serve to strengthen the foot musculature.

Keywords barefoot, medial longitudinal arch, running, muscle force

ISSN 1941-6806
doi: 10.3827/faoj.2015.0802.0002

Address correspondence to:Jonathan Sinclair
Division of Sport, Exercise and Nutritional Sciences
Centre for Applied Sport and Exercise Sciences,
School of Sport Tourism and Outdoors,
University of Central Lancashire, UK
e-mail: jksinclair@uclan.ac.uk

Running training is known to be physiologically beneficial, serving to enhance the cardiovascular system and reduce morbidity [1]. Recreational running is therefore becoming increasingly popular, with over 50,000,000 participants in the US alone [2]. The vast increase in the running population has created a large market leading to a corresponding increase in running equipment sales [2]. Running footwear technology has expanded significantly in recent years as researchers and manufacturers seek to control the incidence of chronic injuries through reductions in impact loading and skeletal mal-alignment [3]. However, despite the advances in footwear technology, chronic injuries related to running are equally as prevalent as always with up to 75% of recreational runners becoming injured each year [4].

For many thousands of years human beings have performed their running activities barefoot (BF) and only in the last 50 years has the modern running shoe as we know it been considered an essential piece of equipment [5]. There is currently a trend in footwear biomechanics and also the running community towards the adaptation of barefoot running [6]. This trend has garnered a significant amount of attention from both the media and biomechanical researchers, based on the supposition that the absence of footwear can mediate a reduction in running injuries [7].

The mechanical characteristics of modern running footwear enhance overall comfort [8], but may also potentially reduce the demands placed on the foot musculature [9]. Although conventional running shoes are designed with specific features designed to reduce kinetic and kinematic mechanisms linked to the etiology of injury, these features may however interfere with normal foot function [10] and reduce the extent of the work output of the foot muscles [9]. During the loading phase of stance, the medial longitudinal arch serves to deflect inferiorly, recruiting the muscles that support the arch allowing elastic energy to be stored and then subsequently released in the push off phase [11]. Under recruitment of the foot musculature as a function of habitual footwear utilization has been linked to weakness of the muscles of the foot [9].

Currently the notion that traditional running shoes promote weakness of the foot muscles is purely circumstantial; largely do the challenges associated with quantifying foot muscle forces. However, specific software has been developed that allows the kinetics of some foot muscles to be estimated during dynamic situations, using motion capture based data [12]. The aim of the current investigation was to examine the differences in the forces produced by the foot muscles during BF and shod (SH) running. A study of this nature may provide data with important clinical implications regarding the development of the foot musculature.

 Methods

Participants

Fifteen male recreational runners, completing at least 35 km per week, volunteered to take part in this study. All were free from musculoskeletal pathology at the time of data collection and provided written informed consent. The mean characteristics of the participants were; age 23.46 ± 2.54 years, height 175.54 ± 5.84 cm and body mass 72.16 ± 6.65 kg. The procedure utilized for this investigation was approved by the University of Central Lancashire, School of Sport Tourism and Outdoors, ethical committee in agreement with the principles outlined in the declaration of Helsinki.

Procedure

Participants ran at a velocity of 4.0 m.s-1 ±5%, striking an embedded force platform (Kistler, Kistler Instruments Ltd., Alton, Hampshire) with their right (dominant) foot [13]. The velocity of running was monitored using infrared timing gates (Newtest, Oy Koulukatu, Finland). The stance phase was defined as the duration over which 20 N or greater of vertical force was applied to the force platform. All runners completed five successful trials in each condition. Kinematics and ground reaction forces data were synchronously collected using an analogue to digital interface board. Kinematic information was obtained at a frequency of 250 Hz using an eight camera optoelectric system (Qualisys Medical AB, Goteburg, Sweden).

To define the anatomical frames of the thorax, pelvis, thighs, shanks and feet retroreflective markers were placed at the C7, T12 and xiphoid process landmarks and also positioned bilaterally onto the acromion process, iliac crest, anterior superior iliac spine, posterior super iliac spine, medial and lateral malleoli, medial and lateral femoral epicondyles and greater trochanter. Carbon-fiber tracking clusters comprising of four non-linear retroreflective markers were positioned onto the thigh and shank segments. Static calibration trials were obtained with the participant in the anatomical position allowing the positions of the anatomical markers to be referenced in relation to the tracking clusters/markers.

 Data processing

Marker data were digitized using Qualisys Track Manager in order to identify anatomical and tracking markers then exported as C3D format files to Visual 3D (C-Motion, Germantown, MD, USA). Ground reaction force and kinematic data were smoothed using cut-off frequencies of 25 and 12 Hz with a low-pass Butterworth 4th order zero lag filter.

The stance phase was exported from Visual 3D to OpenSim software (Simtk.org, Stanford USA), which was utilized to quantify muscle forces during BF and SH running. Simulations of muscle forces were undertaken using the generic gait2392 model within OpenSim v3.2. This model corresponds to the eight segments that were exported from Visual 3D and features 19 total degrees of freedom and 92 muscle-tendon actuators. The muscle intrinsic properties were modelled using the Hill recommendations based on the links between force-velocity-length [14]. These muscle properties were scaled for each individual based on the recommendations of Delp et al., [15]. Following this residual reduction algorithm (RRA) was employed within OpenSim; this utilized the inverse kinematics and ground reaction forces that were exported from Visual 3D. The RRA calculates the joint torques required to re-create the dynamic motion. The RRA calculations produced route mean squared errors <2°, which correspond with the recommendations for good quality data.  Following the RRA, the computed muscle control (CMC) procedure was then employed to estimate a set of muscle force patterns allowing the model to replicate the required kinematics [16]. The CMC procedure works by estimating the required muscle forces to produce the net joint torques.

Following the CMC procedure, average and peak forces during the stance phase were calculated for the flexor digitorum longus (FDL), flexor hallucis longus (FHL), peroneus longus (PL), extensor digitorum longus (EDL) and extensor hallucis longus (EHL) muscles on the right side.

Experimental footwear

The shod condition during this study consisted of New Balance 1226 running trainers. The shoes were the same for all runners; they differed in size only (sizes 8-10 in men’s shoe UK sizes).

Statistical Analysis

Descriptive statistics (means and standard deviations) were obtained for each footwear condition. Shapiro-Wilk tests were used to screen the data for normality. Footwear mediated differences in foot muscle kinetics were examined using paired samples t-tests. To control type I error, statistical significance was accepted at the p<0.01 level based on the number of comparisons being made. Effect sizes for all significant findings were calculated using partial Eta2 (pη2). All statistical actions were conducted using SPSS v22.0 (SPSS Inc., Chicago, USA).

Results

Figure 1 displays foot muscle force distributions as a function of different footwear. The results indicate that the outcome muscle kinetics were significantly influenced by BF and SH running conditions.

  fig1

Figure 1 Foot muscle kinetics as a function of footwear. * denotes significant difference.  (black = barefoot and grey = shod) (a. = peak muscle forces and b. = average muscle forces).

Peak forces of the FDL (t (14) = 2.74, pη2 = 0.59), FHL (t (14) = 2.36, pη2 = 0.53), and PL (t (14) = 2.80, pη2 = 0.60) muscles were significantly larger in the BF condition in relation to running SH. Conversely peak forces at the EDL (t (14) = 4.73, pη2 = 0.78) and EHL (t (14) = 3.41, pη2 = 0.67) muscles were significantly larger when running SH in comparison to BF (Figure 1a).

Average forces of the FDL (t (14) = 5.62, pη2 = 0.82), FHL (t (14) = 3.91, pη2 = 0.72), and PL (t (14) = 2.49, pη2 = 0.55) muscles were significantly larger in the BF condition in relation to running SH. Conversely peak forces at the EDL (t (14) = 5.21, pη2 = 0.81) and EHL (t (14) = 3.45, pη2 = 0.68) muscles were significantly larger when running SH in comparison to BF (Figure 1b).

Discussion

The current investigation aimed to determine the differences in the forces produced by the foot muscles during BF and SH running. To the authors knowledge this represents the first comparative investigation of the foot muscle forces measured when running BF in relation to SH.

The first key finding from the current investigation was that both average and peak forces of the FDL, FHL and PL muscles were found to be significantly larger when running BF in relation to SH. Secondly it was also demonstrated that average and peak forces of the FHL and EHL muscles were significantly larger when running SH. It is proposed that these observations relates to the differences in sagittal plane ankle kinematics typically observed as a function of running BF [5, 7]. When running BF the ankle exhibits considerably more plantarflexion in comparison to running SH [5, 7]. Changing from a rear to a mid/fore foot strike pattern has been associated with increased foot muscle recruitment and thus greater mechanical work performed by the foot musculature [10]. The findings in relation to the current investigation support this notion, the FDL, FHL and PL muscles are all active plantar flexors whereas the FHL and EHL muscles serve to dorsiflex the foot segment; therefore these observations appear to make intuitive sense.

Further to this, running BF has been linked to increases in medial longitudinal arch deflection during the loading phase of running [17]. Contraction of the FDL, FHL and PL muscles with their distal insertions at the metatarsal/ phalanx serve to stabilize the deflection of the arch when under tension [18]. This windlass mechanism is much less pronounced during SH running [7] as the thus the extent of muscle force required to support the arch is reduced. Furthermore the current study supports the observations of Miller et al., [10] who demonstrated increases in foot muscle cross-sectional area following a 12 week training program using minimal footwear. Although their muscles were distinct from those in this study this nonetheless provides further experimental evidence to support the notion that BF running may serve to strengthen the plantar foot musculature.

Weakness in the foot musculature may have clinical significance with regards to the etiology of running injuries. Firstly weakness in the plantar foot musculature as a function of habitual footwear utilization may lead to a lowering of the medial longitudinal arch, as the supporting structures are no longer able to produce sufficient tension to maintain arch stiffness [10]. A lowering of the arch would firstly reduce the potential for elastic energy storage [11] but may also promote higher levels of foot eversion that have been associated with lower arch structures [19]. Increases in foot eversion and accompanying tibial internal rotation have been linked to the etiology of a number of chronic pathologies [20]. Weakness of the plantar musculature may also lead to an increased risk from plantar fasciitis. As plantar muscle strength diminishes their ability to maintain normal foot and arch structure during running is diminished, thus the load that must be borne by the plantar fascia is enhanced [21].

A limitation to the current musculature is that an all-male sample was used. Although gender differences in foot muscle mechanics have yet to be investigated, Sinclair et al., [22] demonstrated that foot kinematics and plantar fascia kinetics differed as a function of gender. This therefore indicates that foot muscle function may differ between genders. It is recommended that this investigation be repeated using a female sample to improve generalizability. A further drawback from this investigation is that OpenSim does not model all of the muscles associated with foot function. Muscles purely intrinsic to the foot such as the flexor digitorum brevis, abductor digiti minimi and abductor hallucis therefore cannot be quantified. Future developments in inverse muscle modelling to include these muscles are required before additional information regarding their recruitment as a function of BF running can be examined.

In conclusion, although previous analyses have comparatively examined the mechanics of BF and SH running the current knowledge concerning the differences in foot muscle forces between the two modalities is limited. The current investigation addresses this by providing a comparison of foot muscles forces when running BF and SH. The current study shows that that peak and average forces from FDL, FHL and PL were significantly larger in the BF condition whereas EDL and EHL were significantly larger when running SH. Firstly these observations provide further insight into the mechanical alterations that runners make when running BF. In addition, this study supports the conjecture that the plantar muscles are required to work harder when running BF in relation to SH, indicating that BF training may serve to strengthen the foot musculature.

References

  1. Lee DC, Pate RR, Lavie CJ, Sui X, Church TS, Blair SN. Leisure-time running reduces all-cause and cardiovascular mortality risk. Journal of the American College of Cardiology 2014; 64: 472-481. Link
  2. Hryvniak D, Dicharry J, Wilder R. Barefoot running survey: Evidence from the field. Journal of Sport and Health Science 2014; 3: 131-136. Link
  3. Aguinaldo A, Mahar A. Impact loading in running shoes with cushioning column systems. Journal of Applied Biomechanics 2003; 19: 353-360.
  4. van Gent R, Siem DD, van Middelkoop M, van Os TA, Bierma-Zeinstra SS, Koes, BB. Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. British Journal of Sports Medicine 2007: 41: 469-480. Pubmed
  5. Lieberman DE, Davis IS, Nigg BM. The past, present, and future of research on running barefoot and in minimal shoes. Journal of Sport and Health Science 2014: 3, 65-66. Link
  6. Sinclair J, Greenhalgh A, Brooks D, Edmundson CJ, Hobbs SJ. The influence of barefoot and barefoot-inspired footwear on the kinetics and kinematics of running in comparison to conventional running shoes. Footwear Science 2013: 5, 45-53.
  7. Lieberman DE, Venkadesan M, Werbel WA, Daoud AI, D’Andrea S, Davis IS, et al. Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature; 2010; 463: 531-535. Link
  8. Wegener C, Burns J, Penkala S. Effect of Neutral-Cushioned Running Shoes on Plantar Pressure Loading and Comfort in Athletes With Cavus Feet A Crossover Randomized Controlled Trial. The American Journal of Sports Medicine 2008: 36, 2139-2146. Pubmed
  9. Nigg B. Biomechanical considerations on barefoot movement and barefoot shoe concepts. Footwear Science 2009; 1: 73-9. Link
  10. Miller EE, Whitcome KK, Lieberman DE, Norton HL, Dyer RE. The effect of minimal shoes on arch structure and intrinsic foot muscle strength. Journal of Sport and Health Science 2014; 3: 74-85. Link
  11. Fukano M, Fukubayashi T. Motion characteristics of the medial and lateral longitudinal arch during landing. European Journal of Applied Physiology 2009; 105: 387-392. Pubmed
  12. Delp SL, Anderson FC, Arnold AS, Loan P, Habib A, John CT, Thelen DG. OpenSim: open-source software to create and analyze dynamic simulations of movement. IEEE Transactions on Biomedical Engineering 2007; 54: 1940-1950. Pubmed
  13. Sinclair J, Hobbs SJ, Taylor PJ, Currigan G, Greenhalgh A. The Influence of Different Force and Pressure Measuring Transducers on Lower Extremity Kinematics Measured During Running. Journal of Applied Biomechanics 2014 30: 166–172. Pubmed
  14. Zajac FE. Muscle and tendon: properties, models, scaling, and application to biomechanics and motor control. Critical Reviews in Biomedical Engineering. 1989; 17: 359–411,.
  15. Delp SL, Loan JP, Hoy MG, Zajac FE, Topp EL, Rosen JM. An interactive graphics-based model of the lower extremity to study orthopaedic surgical procedures. IEEE Transactions on Biomedical Engineering 1990; 37: 757–767. Pubmed
  16. Thelen DG, Anderson FC, Delp SL. Generating dynamic simulations of movement using computed muscle control. Journal of Biomechanics 2003; 36: 321–328. Pubmed
  17. D’Aout K, Pataky TC, De Clercq D, Aerts P. The effects of habitual footwear use: foot shape and function in native barefoot walkers. Footwear Science 2009; 1: 81-94. Link
  18. Thordarson DB, Schmotzer H, Chon J, Peters J. Dynamic support of the human longitudinal arch: a biomechanical evaluation. Clinical Orthopaedics and Related Research 1995; 316: 165-172. Pubmed
  19. Lee SY, Hertel J. Arch height and maximum rearfoot eversion during jogging in 2 static neutral positions. Journal of Athletic Training 2012; 47: 83-90. Pubmed
  20. Van Mechelen, W. Running injuries: a review of the epidemiological literature. Sports Medicine 2012; 14: 320–335. Pubmed
  21. Pohl MB, Hamill J, Davis IS. Biomechanical and anatomical factors associated with a history of plantar fasciitis in female runners. Clinical Journal of Sports Medicine 2009; 19: 372-376. Pubmed
  22. Sinclair J, Chockalingam N, Vincent H. Gender differences in multi-segment foot kinematics and plantar fascia strain during running. Foot and Ankle Online Journal 2014; 7: 2-10. Link

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A comparison of center of pressure variables recorded during running in barefoot, minimalist footwear, and traditional running shoes in the female population

Posted on September 30, 2014 | Comments Off on A comparison of center of pressure variables recorded during running in barefoot, minimalist footwear, and traditional running shoes in the female population

by Andrew Greenhalgh1PhD, Jenny Hampson2Bsc, Peter Thain2 PhD, and Jonathan Sinclair3PhDpdflrg

The Foot and Ankle Online Journal 7 (3): 6

In recent years, barefoot running and running in minimalist footwear as opposed to running in traditional running shoes has increased in popularity. The influence of such footwear choices on center of pressure (COP) displacements and velocity variables linked to injuries is yet to be understood. The aim of this study was to investigate differences between COP variables, linked to injuries measured in barefoot running, a minimalist running shoe, and with traditional running shoes and conditions during running in a healthy female population. Seventeen healthy female participants were examined. Participants performed five footfalls in each footwear condition while running at 12km/h±10% over a pressure plate while COP variables were recorded at 500Hz. The results suggest that minimalist running shoe COP characteristics were similar to those of barefoot runners, with various significant differences reported in both groups compared to runners with the traditional running shoe.

Keywords: footwear, barefoot, running, COP, center of pressure, plantar pressure

ISSN 1941-6806
doi: 10.3827/faoj.2014.0703.0006

Address correspondence to: Andrew Greenhalgh PhD
Email: a.greenhalgh@mdx.ac.uk

1 London Sport Institute, Middlesex University, Hendon, UK
2 School of Life & Medical Sciences, University of Hertfordshire, Hatfield, UK
3 Division of Sport Exercise and Nutritional Sciences, University of Central Lancashire, Preston, UK

Following the introduction of running specific footwear, in recent years barefoot (BF) running as opposed to running in traditional running shoes (TRS) with elevated cushioned heels has increased in popularity among participants and coaches [1]. When running barefoot on roads or pathways the plantar region of the foot may be exposed to cuts and general discomfort from debris and uneven surfaces, therefore running in minimalist footwear that may allow for the change in running kinetics and kinematics observed in barefoot running compared to shod while protecting the plantar region of the feet from injury and discomfort appears to be desirable.

This has led to a rise in the popularity of barefoot inspired footwear amongst running populations and subsequent research [2]. Running barefoot does not appear to restrict athletes from competing at an elite level, with competitors winning Olympic medals in such conditions. In terms of energy cost to the runner, running barefoot appears to reducing angular inertia of the lower extremities. Research suggests minimalist shoes may also decrease oxygen consumption during running [3,4]. However, recent research suggests there is no reduction of metabolic cost when running barefoot compared to lightweight running shoes [5].

Some research suggests that wearing traditional running shoes may restrict freedom of movement and flexibility that can be achieved in comparison to barefoot running [6]. Furthermore, running barefoot compared to shod has been identified as causing adaptation in running mechanics, resulting in a more midfoot footfall in contrast to a favored heel striking movement strategy while running in traditional running shoes [2,7]. Research also suggests that such adaptations occur instantaneously with only minor changes in the lower extremity kinematics  observed in the reported knee angle after two weeks of training in minimalist footwear [8].  Such adaptations observed in barefoot running have been proposed as a mechanism by which the potentially detrimental loading imposed upon the musculoskeletal system during running may be attenuated [9–11]. Conflicting research has however reported such increases in loading of the musculoskeletal system in barefoot running compared to shod, in participants who habitually wore shoes [12,13]. Furthermore, foot injuries including stress fractures most prominently in the metatarsals have been reported in minimalist shoe runners [14]. Currently there appears to be a lack of evidence confirming the influence of barefoot running on movement strategy and injury rates [15,16].

Research identifying the influence of footwear conditions should initially focus on areas of greatest injury risk within the musculoskeletal system which research suggests is ankle ligament damage [17]. The ankle joint is unique in that the vast majority of injuries sustained across different populations are of one type;  ligament sprains [17–21]. It is worth noting that such injury rates in females [22] are higher than those of males [23].

The reason for the higher occurrence of ankle sprains while running can only be hypothesized.  Research has suggested that during running the ankle is often placed in a compromised supinated position when the athlete’s center of gravity (COG) is positioned over the lateral border of the weight bearing limb [24,25]. It has been identified that the functionally unstable ankle may be the result of proprioceptive neuromuscular deficits arising from structural damage following an injury [26–29].

Various kinetic and kinematic variables have been investigated to compare differences between barefoot and shod conditions.  However there is a paucity of research investigating the differences in center of pressure (COP) variables between the conditions [16]. Plantar COP velocities and displacements measured during running have been identified as indicators of exercise induced lower leg injuries [30,31]. As such, identifying characteristics of the COP have been identified as suitable reference points for studying the dynamics of the rearfoot and foot function [31,32] and to identify differences in footwear conditions [33]. Studies analyzing the gait of those individuals with functional unstable ankles have identified a tendency for a laterally situated COP on initial foot contact with a greater pressure concentration at the lateral aspect of the heel [26,30].  If the COP is focused to the lateral side of the calcaneus during heel strike, it is possible that the additional force required to place the individual into a compromised position may be minimal [30]. As a result, by examining the location of the COP upon initial contact it may be possible to identify running conditions that could potentially reduce the likelihood of sustaining a lateral ankle sprain by avoiding the COP displacements seen in the unstable ankles.

A commercially available design of minimalist design footwear (huaraches (HU)) have been developed (Figure 1) with minimum cushioning (4mm tread) and string uppers designed to minimally restrict natural foot movement. By comparing COP variables in participants running barefoot and wearing the HU footwear it may be possible to see the different foot mechanics in each. Therefore the aim of this study was to investigate the differences between COP variables, many of which are linked to ankle ligament injuries, measured in barefoot, huaraches and traditional foot wear runners (Figure 1). The differences in kinetics and kinematics measured between genders [19,34–37] demonstrates a need for studies investigating kinetics of locomotion to consider each gender separately and as such this research will focus on conditions during running in a healthy female population.

Methods

Selection and Description of Participants

Seventeen healthy female participants were examined (aged 21.2±2.3 years, height 165.4±5.6 cm, body mass 66.9±9.5 kg, foot size 6.8±1.0 UK). All participants were free from musculoskeletal pathology and provided written informed consent in accordance with the declaration of Helsinki.

Fig1

Figure 1 HU footwear (above) and TRS (below).

Technical Information

Participants were given time to practice running in the minimalist footwear until they felt comfortable, no prior training was undertaken [8]. Participants performed five footfalls in each footwear condition at a controlled speed of 12km/h±10% over a Footscan pressure plate (RsScan International, 1m x 0.4m, 8192 sensors) (Figure 1) collecting COP data at 250Hz positioned in the center of a 28.5m runway. Participants practiced running along the runway and adjusted their starting position to achieve a natural footstrike on the pressure mat to minimize any influence of targeting [38]. They were also instructed to look at a point on the far wall and not slow down until passing the second timing gate.

Various times (Initial Metatarsal contact (IMC), initial forefoot flat contact (IFFC, first instant all the metatarsals heads are in ground contact) and heel off (HO)) during foot to ground contact were identified (Fig.2), anterior-posterior and medial-lateral displacement and velocity data were calculated at these time points [30,39]. COP displacement and velocity values were normalized to a percentage of foot width and length as appropriate and using the same methods as in previous research [30,39]. This method of collecting COP progression data in direct foot contact and under the shoe has been confirmed as reasonable [40,41].

Statistics

Descriptive statistics including means and standard deviations were calculated for each COP variable in each condition. One way repeated measures ANOVAs were used to determine the differences between footwear conditions with significance accepted at the p<0.05 level. The Shapiro-Wilk statistic for each condition confirmed that the data were normally distributed and where the sphericity assumption was not met, correctional adjustment was made using Greenhouse-Geisser. Effect sizes were calculated using an Eta2 (η2). Post-hoc analyses were conducted using a Bonferroni correction to control type I error (Table 1). All statistical procedures were conducted using SPSS 19.0 (SPSS Inc., Chicago, IL, USA).

Results

The COP data collected was observed for each trial and various key points in time during the stance phase were identified (Figure 2)

Fig2

Figure 2 Typical BF plantar pressure.

The means were calculated for the COP timing (Table 1), COP medial-lateral (Table 2) and COP anterior-posterior (Table 3) variables.

Time variables

Analysis of the timing variables reported between the footwear conditions is displayed in Table 1 and indicated a significant main effect for the timing of IMC (F(1.41, 22.55)= 57.29, p<0.0005,  η2=0.782) and IFFC (F(2, 32)= 43.69, p<0.001,  η2=0.732) no significant effect was reported for HO (F(1.30, 20.87)= 2.56, p=0.118,  η2=0.138). Post hoc analysis revealed significant differences (p<0.001) between the TRS and both the BF and HU conditions for timing of IMC, This was also the case for the IFFC event timing which additionally reported a significant difference (p=0.04) between the BF and HU conditions.

Tab1

Table 1 Means and standard deviations of center of pressure variables timing variables. †=Significantly different (p<0.05) from BF, ¥=significantly different (p<0.05) from HU, *=significantly different (p<0.05) from TRS.

Medial Lateral COP Variables

Analysis of the movement of the COP in the Medial Lateral plane of the foot between footwear conditions are displayed in Table 2 and report that a significant main effects for the position of the COP in terms of medial lateral position (X-comp) were identified at IMC X-comp (F(1.454, 23.268= 5.87, p=0.014,  η2=0.269), IFFC X-comp (F(2, 32)= 18.9, p<0.001,  η2=0.542) and HO X-comp (F(2, 32)= 15.6, p<0.001,  η2=0.494).) No significant main effect was identified for IFCX-comp (F (2, 32) = 3.161, p=0.056, η2=0.165). Post hoc analysis revealed a significant difference for IMC X-comp (p=0.025), IFFC X-comp (p=0.001) and HO X-comp (P=0.003) between BF and TRS conditions, and a significant difference between IFFC X-comp (p<0.001) and HO X-comp (p<0.001) between HU and TRS conditions.

Significant main effects for the position of the medial lateral velocity of the COP in terms of position (VEL-X) were identified for HO VEL-X (F (2, 32) = 32.6, p<0.001, η2=0.671). Post hoc analysis revealed a significant difference for HO VEL-X between BF and TRS (p<0.001) and HU and TRS (p<0.001).  No significant main effect was identified for IMC VEL-X (F (1.46, 23.31= 1.314, p=0.279, η2=0.076) or IFFC VEL-X (F (1.33, 21.24) = 2.073, p=0.161, η2=0.115).

Tab2

Table 2 Means and standard deviations of center of medial-lateral pressure variables. †=Significantly different (P<0.05) from BF, ¥=significantly different (p<0.05) from HU, *=significantly different (p<0.05) from TRS, FW%=Percentage of foot width.

Anterior Posterior COP Variables

Analysis of the movement of the COP in the Anterior Posterior plane of the foot between footwear conditions are displayed in Table 2 and report that a significant main effects for the position of the COP in terms of anterior posterior position (Y-comp) were identified at IFCY-comp (F (2, 32) = 5.04, p<0.013, η2=0.239) and HO Y-comp (F (1.09, 17.39) = 30.71, p<0.001, η2=0.657). No significant main effect was identified for IMC Y-comp (F (1.42, 22.66) = 3.28, p=0.07,  η2=0.170) or IFFC Y-comp (F(1.22, 19.58)= 0.88, p=0.38,  η2=0.052). Post hoc analysis revealed a significant difference for HO Y-comp (p<0.001) and IFC Y-comp (p=0.025) between BF and TRS, a significant difference was also identified for HO Y-comp between HU and TRS conditions (p<0.001).

Significant main effects for the position of the anterior posterior velocity of the COP in terms of position (VEL-Y) were identified for IMC VEL-Y (F(1.41, 22.58)= 13.60, p<0.0005 η2=0.460)  and HO VEL-Y (F(1.17, 18.77)= 13.26, p=0.001,  η2=0.453) No significant main effect was identified for IFFC VEL-Y (F(1.21, 19.33)= 1.710, p=0.209,  η2=0.097). Post hoc analysis revealed a significant difference between BF and TRS for IMC VEL-Y (p=0.005) and HO VEL-Y (p=0.001), significant differences were also identified between HU and TRS for IMC VEL-Y (p=0.002) and HO VEL-Y (P=0.011).

Tab3

Table 3 Means and standard deviations of anterior-posterior center of pressure variables.†=significantly different (p<0.05) from BF, ¥=significantly different (p<0.05) from HU, *=significantly different (p<0.05) from TRS,  FL%=Percentage of foot length.

Discussion

The purpose of the current investigation was to compare the COP variables of a healthy female population running in BF, HU and TRS conditions. The first aim was to identify if there existed any differences between the shod and BF conditions, in order to identify whether running in such footwear produced similar kinetics to those found in BF running. The second aim was to determine if there were any significant differences between footwear in the COP variables implicated in the etiology of injury [30].

The significant differences in the IMC and IFFC time parameters (p<0.05) in the TRS compared to the BF and HU conditions, suggest a more plantarflexed foot placement (in BF and HU) at ground contact. This has been reported previously in analyses comparing BF to shod [2,12] and minimalist footwear compared to shod [3] conditions and suggests HU rather than TRS would be the favored footwear to reduce the incidence of injury in runners [10–12]. During running there is often uneven terrain, and as the calcaneus lands, it lends itself to movement in the coronal plane by the very nature of its shape. Furthermore, it has been identified that patients with ankle instability have a longer duration of contact from the initial heel contact to the forefoot landing [42]. Therefore, a quicker loading of the forefoot as observed in the BF and HU conditions, may offer greater support to potentially limit hazardous injury.

During locomotion, as the foot makes contact with the ground, the line of the resulting reaction force is determined by the position of the foot in relation to the athletes COG [24]. Previous research reported that when an increased angle of supination upon touchdown was present, an apparent increase in the number of ankle sprains ensued [43]. With the TRS condition in the current study exhibiting a trend towards a more laterally displaced COP, this may infer that the initial contact of the foot was made whilst being held in slight supination, and therefore similar those suffering from ankle instability which may increase susceptibility to injury.

Previous research identified that an ankle sprain group exhibited a higher loading under the medial border of the foot, and this was identified as an indicator or susceptibility to ankle sprain [30]. The significant difference between the shod and both the BF and HU condition for the IFFC X-comp variable indicated a more medially loaded foot. This may also be a predisposing factor for an inversion ankle sprain.

It appears that the HU shoe minimizes the changes in COP characteristics seen in TRS compared to BF running with only one variable (IFFC time) reporting a significant (p<0.05) difference between HU and BF. Furthermore, this particular minimalist design (HU) may more closely simulate BF running compared to some other footwear designed to simulate BF running [2]. These results suggest that proposed health benefits associated with BF running  [10] may be prevalent in HU footwear conditions.

Conclusions

The data collected in this study provides evidence that the HU design of footwear may be a suitable alternative to running BF for females, by offering protection to the plantar surface of the foot whilst adjusting the running strategy identified through COP variables in a similar way to BF running when compared to running in TRS. From a rehabilitation point of view, it may advantageous to initiate a return to running using minimalist footwear as this appears to have the potential to reduce excessive COP characteristics linked to ankle inversion injury compared to shoes. However potential injury risk reduction benefits of BF running are yet to be conclusively substantiated and any change in habitual running style through footwear choice should be approached with caution.

Future research

This study focused on a population of healthy females. Previous research has demonstrated differences between genders biomechanically and regarding injury rates [19,44] and as such the results cannot be generalized to a male sample. Therefore there is clear need to perform a similar examination using a male population. Previous research has suggested that the thickness of cushioning in running shoes may not have a significant effect on loading characteristics [7] during foot to ground impact. The HU design of shoe is commercially available in different sole thickness. Testing for similar effects of sole thickness that are observed in the HU design of shoe warrant further investigation to identify a move towards the possibility for an optimum design in the general population.

References

  1. Nigg B, Enders H. Barefoot running – some critical considerations. Footwear Sci . Taylor & Francis; 2013 Feb 26;35(1):1–7. – Link
  2. Sinclair J, Greenhalgh A, Brooks D, Edmundson CJ, Hobbs SJ. The influence of barefoot and barefoot-inspired footwear on the kinetics and kinematics of running in comparison to conventional running shoes. Footwear Sci . Taylor & Francis; 2013;5:45–53. – Link
  3. Squadrone R, Gallozzi C. Biomechanical and physiological comparison of barefoot and two shod conditions in experienced barefoot runners. J Sports Med Phys Fitness . 2009/02/04 ed. 2009;49(1):6–13. – Pubmed citation
  4. Perl DP, Daoud AI, Lieberman DE. Effects of Footwear and Strike Type on Running Economy. Med Sci Sport Exerc . 2012;44(7). – Link
  5. Franz JR, Wierzbinski CM, Kram R. Metabolic cost of running barefoot versus shod: is lighter better? Med Sci Sports Exerc . 2012;44:1519–25. – Pubmed citation
  6. Morio C, Lake MJ, Gueguen N, Rao G, Baly L. The influence of footwear on foot motion during walking and running. J Biomech . 2009/08/01 ed. 2009;42(13):2081–8. – Pubmed citation
  7. Hamill J, Russell EM, Gruber AH, Miller R. Impact characteristics in shod and barefoot running. Footwear Sci . Taylor & Francis; 2011 Feb 13;3(1):33–40. – Link
  8. Willson JD, Bjorhus JS, Williams DSB, Butler RJ, Porcari JP, Kernozek TW. Short-Term Changes in Running Mechanics and Foot Strike Pattern After Introduction to Minimalistic Footwear. PM&R . 2013 [cited 2013 Dec 20]; – Link
  9. Daoud AI, Geissler GJ, Wang F, Saretsky J, Daoud YA, Lieberman DE. Foot strike and injury rates in endurance runners: a retrospective study. Med Sci Sport Exerc . 2012/01/06 ed. 2012;44(7):1325–34. – Pubmed citation
  10. Lieberman DE, Venkadesan M, Werbel WA, Daoud AI, D’Andrea S, Davis IS, et al. Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature . 2010/01/30 ed. 2010;463(7280):531–5. – Pubmed citation
  11. Robbins SE, Hanna AM. Running-related injury prevention through barefoot adaptations. Med Sci Sports Exerc . 1987/04/01 ed. 1987;19(2):148–56. – Pubmed citation
  12. De Wit B, De Clercq D, Aerts P. Biomechanical analysis of the stance phase during barefoot and shod running. J Biomech . 2000;33(3):269–78. – Link
  13. Giuliani J, Masini B, Alitz C, Owens BD. Barefoot-simulating footwear associated with metatarsal stress injury in 2 runners. Orthopedics . 2011/07/02 ed. 2011;34(7):e320–e323. – Pubmed citation
  14. Salzler MJ, Bluman EM, Noonan S, Chiodo CP, de Asla RJ. Injuries Observed in Minimalist Runners. Foot Ankle Int . 2012 Apr 1;33 (4 ):262–6. – Link
  15. Jenkins DW, Cauthon DJ. Barefoot running claims and controversies: a review of the literature. J Am Podiatr Med Assoc . 2011/05/31 ed. 2011;101(3):231–46. – Pubmed citation
  16. Rixe JA, Gallo RA, Silvis ML. The barefoot debate: can minimalist shoes reduce running-related injuries? Curr Sports Med Rep . 2012/05/15 ed. 2012;11(3):160–5. – Pubmed citation
  17. Nelson AJ, Collins CL, Yard EE, Fields SK, Comstock RD. Ankle Injuries Among United States High School Sports Athletes, 2005–2006. J Athl Train. 2007;42:381–7.
  18. Bahr R, Bahr IA. Incidence of acute volleyball injuries: a prospective cohort study of injury mechanisms and risk factors. Scand J Med Sci Sports. 1997;7:166–71.
  19. Beynnon BD, Renström PA, Alosa DM, Baumhauer JF, Vacek PM. Ankle ligament injury risk factors: a prospective study of college athletes. J Orthop Res . 2001;19(2):213–20. – Link
  20. Fong DT, Hong Y, Chan LK, Yung PS, Chan KM. A systematic review on ankle injury and ankle sprain in sports. Sport Med . 2006/12/28 ed. 2007;37(1):73–94. – Pubmed citation
  21. Hawkins RD, Hulse MA, Wilkinson C, Hodson A, Gibson M. The association football medical research programme: an audit of injuries in professional football. Br J Sports Med. 2001;35:43–7.
  22. Willems TM, Witvrouw E, Delbaere K, Philippaerts R, De Bourdeaudhuij I, De Clercq D. Intrinsic risk factors for inversion ankle sprains in females–a prospective study. Scand J Med Sci Sport . 2005/09/27 ed. 2005;15(5):336–45. – Pubmed citation
  23. Willems TM, Witvrouw E, Delbaere K, Mahieu N, De Bourdeaudhuij I, De Clercq D. Intrinsic risk factors for inversion ankle sprains in male subjects: a prospective study. Am J Sports Med . 2005/02/18 ed. 2005;33(3):415–23. – Pubmed citation
  24. Tropp H. Commentary: Functional Ankle Instability Revisited. J Athl Train . 2003/08/26 ed. 2002;37(4):512–5. – Pubmed citation
  25. Wilkerson GB, Pinerola JJ, Caturano RW. Invertor vs. evertor peak torque and power deficiencies associated with lateral ankle ligament injury. J Orthop Sports Phys Ther . 1997/08/01 ed. 1997;26(2):78–86. – Pubmed citation
  26. Becker H, Rosenbaum D, Claes L, Gerngro H. Measurement of plantar pressure distribution during gait for diagnosis of functional lateral ankle instability. Clin Biomech . 1997/04/01 ed. 1997;12(3):S19. – Pubmed citation
  27. Hertel J. Functional Anatomy, Pathomechanics, and Pathophysiology of Lateral Ankle Instability. J Athl Train . 2003/08/26 ed. 2002;37(4):364–75. – Pubmed citation
  28. Konradsen L. Factors Contributing to Chronic Ankle Instability: Kinesthesia and Joint Position Sense. J Athl Train . 2003/08/26 ed. 2002;37(4):381–5. – Pubmed citation
  29. Lentell G, Baas B, Lopez D, McGuire L, Sarrels M, Snyder P. The contributions of proprioceptive deficits, muscle function, and anatomic laxity to functional instability of the ankle. J Orthop Sports Phys Ther . 1995/04/01 ed. 1995;21(4):206–15. – Pubmed citation
  30. Willems T, Witvrouw E, Delbaere K, De Cock A, De Clercq D. Relationship between gait biomechanics and inversion sprains: a prospective study of risk factors. Gait Posture . 2005/05/12 ed. 2005;21(4):379–87. – Pubmed citation
  31. Willems TM, De Clercq D, Delbaere K, Vanderstraeten G, De Cock A, Witvrouw E. A prospective study of gait related risk factors for exercise-related lower leg pain. Gait Posture . 2005/11/29 ed. 2006;23(1):91–8. – Pubmed citation
  32. Dixon SJ. Application of center-of-pressure data to indicate rearfoot inversion-eversion in shod running. J Am Pod Med Assoc . 2006/07/27 ed. 2006;96(4):305–12. – Pubmed citation
  33. Nigg BM, Stergiou P, Cole G, Stefanyshyn D, Mundermann A, Humble N. Effect of shoe inserts on kinematics, center of pressure, and leg joint moments during running. Med Sci Sport Exerc . 2003/02/06 ed. 2003;35(2):314–9. – Pubmed citation
  34. Chumanov ES, Wall-Scheffler C, Heiderscheit BC. Gender differences in walking and running on level and inclined surfaces. Clin Biomech . 2008/09/09 ed. 2008;23(10):1260–8. – Pubmed citation
  35. Chung MJ, Wang MJ. Gender and walking speed effects on plantar pressure distribution for adults aged 20-60 years. Ergonomics . 2011/08/20 ed. 2011; – Pubmed citation
  36. Eskofier BM, Kraus M, Worobets JT, Stefanyshyn DJ, Nigg BM. Pattern classification of kinematic and kinetic running data to distinguish gender, shod/barefoot and injury groups with feature ranking. Comput Methods Biomech Biomed Engin . 2011/02/05 ed. 2011;15(5):467–74. – Pubmed citation
  37. Ferber R, Davis IM, Williams  3rd DS. Gender differences in lower extremity mechanics during running. Clin Biomech (Bristol, Avon) . 2003/04/12 ed. 2003;18(4):350–7. – Pubmed citation
  38. Sinclair J, Hobbs SJ, Taylor PJ, Currigan G, Greenhalgh A. The Influence of Different Force and Pressure Measuring Transducers on Lower Extremity Kinematics Measured During Running. J Appl Biomech . Division of Sport Exercise and Nutritional Sciences, University of Central Lancashire, Lancashire, UK.; 2013 Jul; – Link
  39. De Cock A, Vanrenterghem J, Willems T, Witvrouw E, De Clercq D. The trajectory of the centre of pressure during barefoot running as a potential measure for foot function. Gait Posture . 2008;27(4):669–75. – Link
  40. Chesnin KJ, Selby-Silverstein L, Besser MP. Comparison of an in-shoe pressure measurement device to a force plate: concurrent validity of center of pressure measurements. Gait Posture . 2000/09/22 ed. 2000;12(2):128–33. – Link
  41. Lake M, Wilssens JP, Lens T, Mark R, Digby C. Barefoot, shod, plate and insole pressure measurement comparisons during 4-4.5m/s running in relationships to lower limb movements. 23 International Symposium on Biomechanics in Sports. 2005. p. 761–4.
  42. Nyska M, Shabat S, Simkin A, Neeb M, Matan Y, Mann G. Dynamic force distribution during level walking under the feet of patients with chronic ankle instability. Br J Sports Med . 2003/12/11 ed. 2003;37(6):495–7. – Pubmed citation
  43. Wright IC, Neptune RR, van den Bogert AJ, Nigg BM. The influence of foot positioning on ankle sprains. J Biomech . 2000;33(5):513–9. – Link
  44. Sinclair J, Greenhalgh A, Edmundson CJ, Brooks D, Hobbs SJ. Gender Differences in the Kinetics and Kinematics of Distance Running: Implications for Footwear Design. Int J Sport Sci Eng. 2012;6(2):118–28.

 

 

 

 

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