Biomechanical study of plantar pressures during walking in male soccer players with increased vs. normal hip alpha angles.
BACKGROUND
Femoroacetabular impingement (FAI) is accompanied by increased hip alpha angles, in particular in athletes with high impact sports.


OBJECTIVE
The aim of our study was to investigate the dynamic function of the foot during walking in male soccer players with increased versus normal alpha angles.


METHODS
Plantar pressures of 20 injury-free male soccer players were recorded during barefoot walking at 1.6 m/s. Ten subjects had bilaterally increased (>55°) (IA) and ten subjects normal (<50°) hip alpha angles (NA). Both standing and kicking leg were analyzed.


RESULTS
Compared to NA, IA showed lower force-time-integrals (-23%; p< 0.01), pressure-time-integrals (-29%; p< 0.001) and relative loads (p< 0.05) under the heel. In IA contact area of the hallux is about 13% (p< 0.05) reduced. In IA relative loads are increased under the lateral midfoot (p< 0.05) and the second toe (p< 0.05). Higher loading of the lateral midfoot is also reflected in the increased force-time integral (+33%; p< 0.001). No differences between legs and no interactions, indicating a specifity in kicking or standing leg, are found.


CONCLUSIONS
Compared to NA, soccer players with IA show a forward shifting of the center of pressure which indicates a compensatory mechanism of the foot during walking.
Biomechanics Laboratory, Department of Sport and Movement Sciences, University of Duisburg-Essen, Essen, Germany.
Marco
M
Hagen
Biomechanics Laboratory, Department of Sport and Movement Sciences, University of Duisburg-Essen, Essen, Germany.
Christoph
C
Abraham
Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich, Munich, Germany.
Andreas
A
Ficklscherer
Department of Orthopaedic Surgery, Ruhr-University Bochum, St. Josef-Hospital, Bochum, Germany.
Matthias
M
Lahner
D000328:Adult; D056352:Athletes; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D004576:Electromyography / Q000379:methods; D057925:Femoracetabular Impingement / Q000503:physiopathology; D005528:Foot / Q000502:physiology*; D006621:Hip Joint / Q000503:physiopathology*; D006801:Humans; D008297:Male; D011312:Pressure; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values; D012916:Soccer / Q000502:physiology; D013314:Stress, Mechanical; D016138:Walking / Q000502:physiology*
Increased hip alpha angle; kicking leg; plantar pressures; soccer players; standing leg; walking