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Eur J Appl Physiol (2015) 115:691701 DOI 10.1007/s00421-014-3056-x
ORIGINAL ARTICLE
Coordination of intrinsic and extrinsic foot muscles during walking
Karl E. Zelik Valentina La Scaleia Yuri P. Ivanenko Francesco Lacquaniti
Communicated by Fausto Baldissera.
K. E. Zelik Y. P. Ivanenko F. Lacquaniti
Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy
Y. P. Ivanenkoe-mail: [email protected]
F. Lacquanitie-mail: [email protected]
K. E. Zelik (*)
Department of Mechanical Engineering, Vanderbilt University, 2400 Highland Avenue, Nashville, TN 37212, USAe-mail: [email protected]; [email protected]
K. E. Zelik
Department of Physical Medicine and Rehabilitation, Vanderbilt University, 2201 Childrens Way, Nashville, TN 37212, USA
V. La Scaleia F. Lacquaniti
Department of Systems Medicine, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italye-mail: [email protected]
F. Lacquaniti
Centre of Space Bio-medicine, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
Received: 26 June 2014 / Accepted: 15 November 2014 / Published online: 25 November 2014 Springer-Verlag Berlin Heidelberg 2014
Methods We analyzed surface electromyographic (EMG) recordings of intrinsic and extrinsic foot muscles for healthy individuals during level treadmill walking, and also during sideways and tiptoe gaits. We computed stride-averaged EMG envelopes and used the timing of peak muscle activity to assess synchronous vs. sequential coordination.Results We found that peak MTP exor activity occurred signicantly before peak MTP extensor activity during walking (P < 0.001). The period around stance-to-swing transition could be roughly characterized by sequential peak muscle activity from the ankle plantarexors, MTP exors, MTP extensors, and then ankle dorsiexors. We found that foot muscles that activated synchronously during forward walking tended to dissociate during other locomotor tasks. For instance, extensor hallucis brevis and extensor digitorum brevis muscle activation peaks decoupled during sideways gait.
Conclusions The sequential peak activity of MTP exors followed by MTP extensors suggests that their biomechanical contributions may be largely separable from each other and from other extrinsic foot muscles during walking.Meanwhile, the task-specic coordination of the foot muscles during other modes of locomotion indicates a high-level of specicity in their function and control.
Keywords Foot Ankle Metatarsophalangeal exion and extension EMG Walking Muscle coordination
Abbreviations
EDB Extensor digitorum brevis EHB Extensor hallucis brevis EHL
Extensor hallucis longusEMG Electromyographic, electromyogram FDB
Flexor digitorum brevis FDHL
Flexor digitorum longus and exor hallucis longus
Abstract