Sharon Dixon

University of Exeter

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Victoria Stiles

University of Exeter

Matt Carré

University of Sheffield

Michael Nunns

University of Exeter

James Clarke

Merck & Co., Inc., Rahway, NJ, USA (United States)

Hannah Rice

Norwegian School of Sport Sciences

Carol House

Royal Hospital Haslar

Adrian Allsopp

Royal Hospital Haslar

Iain James

Game & Wildlife Conservation Trust

Loïc Damm

IMT Mines Alès

Joanne L. Fallowfield

Royal Hospital Haslar

Cooperative Institutions

University of Exeter

Loughborough University

Technical University of Munich

Biomechanics Institute of Valencia

University of Sheffield

Otto-von-Guericke University Magdeburg

RMIT University

Universitat Politècnica de València

University of Southampton

University of Calgary

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Corrigendum to ‘A Systematic review of the discriminating biomechanical parameters during the single leg Squat’ [Physical Therapy in Sport 36 (2019) 78–91]

Physical Therapy in Sport (2019)

Martin Warner David A. Wilson Lee Herrington Sharon Dixon Conor Power

Squat

10.1016/j.ptsp.2019.02.008

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Citations (1)

A Comparison of the effects of exergaming versus standard exercise on balance in health sedentary adults

Gill Barry Alasdair MacSween John Dixon Paul van-Schaik Sharon Dixon

Background: Exergaming is the use of computer gaming technology and virtual reality environments for exercise is an option to encourage people to exercise. Exergaming has been used clinically with positive results [1-5]. As exergaming is still a novel approach, there is a shortage of good quality evidence of its effects on balance, an outcome of functional importance. The aim of this study was to investigate the effects on balance of a two-week exergaming programme compared to a standard exercise programme. Methods: Ethical clearance was granted by Teesside University (TU) School of Health and Social Care Research Governance and Ethics Committee. We tested claims that exergaming is useful for improving balance in an experimental design with a convenience sample of healthy sedentary adult participants randomised to one of two groups taking part in a two week programme of either exergaming (n=17) or standard exercise (n=16). Balance was measured with a Kistler™ force platform as the range and standard deviation of the centre of pressure (CoP) excursions in the anterior-posterior and medio-lateral directions, and the CoP velocity during both unipedal and bipedal standing. Results: Analysis of covariance (ANCOVAs) comparing the post-intervention differences between the groups, with baseline values comprising the covariate where used. An alpha level of 0.05 was used throughout and 95% confidence intervals of the differences between the groups’ post-intervention scores were calculated. Results showed statistically significant differences in the range (p < 0.05) and standard deviation (p < 0.01) of the anterior-posterior CoP excursion in unipedal standing between the exercise groups after intervention, with lower values in the exergaming group, indicating better postural stability. Conclusion: The results show that exercising in an exergaming environment can be more beneficial for balance training than doing the same exercise without that environment.

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Neuromechanical adaptations of foot function to changes in surface stiffness during hopping

Journal of Applied Physiology (2021)

Jonathon Birch Luke A. Kelly Andrew G. Cresswell Sharon Dixon Dominic J. Farris

Humans choose work-minimizing movement strategies when interacting with compliant surfaces. Our ankles are credited with stiffening our lower limbs and maintaining the excursion of our body's center of mass on a range of surface stiffnesses. We may also be able to stiffen our feet through an active contribution from our plantar intrinsic muscles (PIMs) on such surfaces. However, traditional modeling of the ankle joint has masked this contribution. We compared foot and ankle mechanics and muscle activation on low, medium, and high stiffness surfaces during bilateral hopping using a traditional and anatomical ankle model. The traditional ankle model overestimated work and underestimated stiffness compared with the anatomical model. Hopping on a low stiffness surface resulted in less longitudinal arch compression with respect to the high stiffness surface. However, because midfoot torque was also reduced, midfoot stiffness remained unchanged. We observed lower activation of the PIMs, soleus, and tibialis anterior on the low and medium stiffness conditions, which paralleled the pattern we saw in the work performed by the foot and ankle. Rather than performing unnecessary work, participants altered their landing posture to harness the energy stored by the sprung surface in the low and medium conditions. These findings highlight our preference to minimize mechanical work when transitioning to compliant surfaces and highlight the importance of considering the foot as an active, multiarticular, part of the human leg.NEW & NOTEWORTHY When seeking to understand how humans adapt their movement to changes in substrate, the role of the human foot has been neglected. Using multi-segment foot modeling, we highlight the importance of adaptable foot mechanics in adjusting to surfaces of different compliance. We also show, via electromyography, that the adaptations are under active muscular control.

Foot (prosody)

Biomechanics

Motor Control

Movement control

10.1152/japplphysiol.00401.2020

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Citations (9)

Surface effects on ground reaction forces and lower extremity kinematics in running

Medicine & Science in Sports & Exercise (2000)

Sharon Dixon Andrew C. Collop Mark E. Batt

Although running surface stiffness has been associated with overuse injuries, all evidence to support this suggestion has been circumstantial. In the present study, the biomechanical response of heel-toe runners to changes in running surface has been investigated.Six heel-toe runners performed shod running trials over three surfaces: a conventional asphalt surface, a new rubber-modified asphalt surface, and an acrylic sports surface. The surfaces were categorised according to impact absorbing ability using standard impact test procedures (BS 7044).The rubber-modified asphalt was found to exhibit the greatest amount of mechanical impact absorption, and the conventional asphalt the least. The comparison of peak impact force values across surfaces for the group of subjects demonstrated no significant differences in magnitude of force. However, a significant reduction in loading rate of peak impact force was detected for the rubber-modified surface compared with conventional asphalt (P < 0.1). Although analysis of group data revealed no significant differences in kinematic variables when running on the different surfaces, a varied response to surface manipulation among runners was demonstrated, with marked differences in initial joint angles, peak joint angles, and peak joint angular velocities being observed.For some subjects, the maintenance of similar peak impact forces for different running surfaces was explained by observed kinematic adjustments. For example, when running on the surface providing the least impact absorption, an increased initial knee flexion was observed for some subjects, suggesting an increased lower extremity compliance. However, for some subjects, sagittal plane kinematic data were not sufficient for the explanation of peak impact force results. It appears that the mechanism of adaptation varies among runners, highlighting the requirement of individual subject analyses.

Ground reaction force

Biomechanics

Impact

Force platform

10.1097/00005768-200011000-00016

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Citations (238)

Current Issues in Biomechanics

British Journal of Sports Medicine (1994)

Sharon Dixon

However, this is an excellent text which I would thoroughly recommend, especially in this cheaper paperback format, for the dedicated coach, the informed swimmer and all who are scientifically involved with swimming.

Biomechanics

10.1136/bjsm.28.2.138

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Citations (47)

Impact absorption of tennis shoe-surface combinations

Sports Engineering (2003)

Sharon Dixon Victoria Stiles

Cushioning

Drop test

Impact

10.1007/bf02844155

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Citations (32)

Understanding the traction of tennis surfaces

Procedia Engineering (2011)

James Clarke Matt Carré Andrea Richardson Zhijun Yang Loïc Damm

The traction provided by a footwear-surface interaction can have an impact on player safety, performance and overall enjoyment of sport.Mechanical test methods used for the testing and categorisation of safe playing surfaces do not tend to simulate loads occurring during participation on the surface, and thus are unlikely to predict human response to the surface.For example, the pendulum system routinely employed by the International Tennis Federation (I.T.F.) utilises a standard rubber 'foot', rather than a shoe sole, and does not apply forces comparable to those in real play.There is a requirement for an improved scientific understanding of the tribological interactions at the shoe surface interface and the effects footwear and surface parameters have on the traction mechanism developed.The relationship between normal force and the coefficient of traction for the forefoot of a tennis shoe in contact with different tennis surfaces was examined using a bespoke traction rig.The effects of surface roughness were also examined.A power relationship was found between normal force and traction.As normal force increased differences in surface traction were found.The normal force, stiffness, and roughness of the surfaces affected the adhesive and hysteresis friction mechanisms that contribute to the overall traction force.

10.1016/j.proeng.2011.05.105

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Citations (8)

The influence of surface characteristics on the tribological interactions at the shoe-surface interface in tennis

Procedia Engineering (2012)

James Clarke Matt Carré Loïc Damm Sharon Dixon

During dynamic tennis specific movements, such as accelerating and side stepping, the traction provided by a shoe-surface combination plays an important role in the injury risk and performance of the player. Acrylic hard court tennis surfaces have been reported to have increased injury occurrence due to an increased traction coefficient. There is a requirement for an improved scientific understanding of the tribological interactions at the shoe surface interface and the effects footwear and surface parameters have on the friction mechanism developed. Often mechanical test methods used for the testing and categorisation of playing surfaces do not tend to simulate loads occurring during participation on the surface, and thus are unlikely to predict human response to the surface. A new traction testing device, discussed in this paper, has been developed to mechanically measure the traction force between the shoe and the surface under appropriate loading conditions. Acrylic Harcourt tennis surfaces generally have a rough surface topography, due to a sand and acrylic paint mixed top coating, and have a deformable under layer to provide impact attenuation. Surface micro-roughness has been found to influence the friction mechanisms presents during viscoelastic contacts, as found in footwear-surface interactions. This paper aims to further understand the influence of micro-roughness on tennis surfaces. The micro-roughness and traction of a controlled set of acrylic hard court tennis surfaces have been measured. The influence of roughness on tennis surfaces traction is discussed.

Interface (matter)

10.1016/j.proeng.2012.04.148

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Citations (7)

Boot-insole effects on comfort and plantar loading at the heel and fifth metatarsal during running and turning in soccer

Journal of Sports Sciences (2015)

Michael Nunns Sharon Dixon James Clarke Matt Carré

Plantar loading may influence comfort, performance and injury risk in soccer boots. This study investigated the effect of cleat configuration and insole cushioning levels on perception of comfort and in-shoe plantar pressures at the heel and fifth metatarsal head region. Nine soccer academy players (age 15.7 ± 1.6 years; height 1.80 ± 0.40 m; body mass 71.9 ± 6.1 kg) took part in the study. Two boot models (8 and 6 cleats) and two insoles (Poron and Poron/gel) provided four footwear combinations assessed using pressure insoles during running and 180° turning. Mechanical and comfort perception tests differentiated boot and insole conditions. During biomechanical testing, the Poron insole generally provided lower peak pressures than the Poron/gel insole, particularly during the braking step of the turn. The boot model did not independently influence peak pressures at the fifth metatarsal, and had minimal influence on heel loads. Specific boot-insole combinations performed differently (P < 0.05). The 8-cleat boot and the Poron insole performed best biomechanically and perceptually, but the combined condition did not. Inclusion of kinematic data and improved control of the turning technique are recommended to strengthen future research. The mechanical, perception and biomechanical results highlight the need for a multi-faceted approach in the assessment of footwear.

Cushioning

Plantar pressure

First metatarsal

Biomechanics

10.1080/02640414.2015.1069378

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Citations (17)

Biomechanical responses to changes in friction on a clay court surface

Journal of science and medicine in sport (2016)

Chelsea Starbuck Victoria Stiles Daniel P. Ura Matt Carré Sharon Dixon

10.1016/j.jsams.2016.08.019

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Citations (8)