Affiliations: [a] Medical Clinic, Department of Rehabilitative and
Preventive Sports Medicine, University of Freiburg, Germany | [b] Laboratory of Physiology, University of St. Etienne,
France
Note: [] Address for correspondence: Heiner Baur, University Hospital,
Medical Clinic, Department of Rehabilitative and Preventive Sports Medicine,
Hugstetter Strasse 55, D-79106 Freiburg, Germany. Tel.: +49 761 270 7493; Fax:
+49 761 270 7470; E-mail: baur@msm1.ukl.uni-freiburg.de
Abstract: Differences in lower extremity movement characteristics are stated
as a reason for overuse injuries. The causal assignment of biomechanical
quantities to the onset of complaints is still subject of debate in gait
analysis. The purpose of this study was therefore to compare biomechanical gait
characteristics by means of plantar pressure distribution (PPD), EMG and ground
reaction forces (GRF) in healthy runners and in runners with chronic Achilles
tendon complaints (AT). Fourteen healthy runners and 8 runners with AT were
examined at 12 km/h. Surface EMG, in-shoe PPD and GRFs were evaluated on a
treadmill mounted on force transducers. Subjects ran barefoot and with a
reference shoe in random order. EMG time and amplitude quantities,
characteristics of the path of the center of pressure (CoP), vertical and a-p
forces and impulses were extracted. In AT no differences in CoP-characteristics
between barefoot and reference shoe were observed, compared to corresponding
significant differences in the control group. Compared to the AT group, the
control subjects had a higher activity EMG-amplitudes in the extensor loop
during weight acceptance phase, a higher braking impulse and a lower pushing
impulse. It is thus concluded that healthy runners differ from AT patients in
terms of movement characteristics especially in running.
Keywords: barefoot and shod running, electromyography, gait analysis, ground reaction forces, overuse injury, plantar pressure distribution
