Muscle coordination and function during cutting movements

Purpose: The objectives of this study were to: 1) establish a database of k inematic and EMG data during cutting movements, 2) describe normal muscle f unction and coordination of 12 lower extremity muscles during cutting movem ents susceptible to ankle sprains, and 3) identify potential muscle coordin ation deficiencies that may lead to ankle sprain injuries. Methods: Kinemat ic, EMG, and GRF data were collected from 10 recreationally active male sub jects during bath a side-shuffle and v-cut movement. Results: The data show ed that muscles functioned similarly during both movements. The primary fun ction of the hip and knee extensors was to decelerate the center-of-mass du ring landing and to provide propulsion during toe-off. The hip add/abductor s functioned primarily to stabilize the hip rather than provide mechanical power. The ankle plantar flexors functioned to provide propulsion during to e-off, and the gastrocnemius had an additional burst of activity to plantar flex the foot before touchdown during the side-shuffle to help absorb the i mpact. The tibialis anterior functioned differently during each movement: t o dorsiflex and supinate the foot after toe-off in preparation for the next step cycle during the side-shuffle and to dorsiflex the foot before impact to provide the heel-down landing and ankle stability in the stance phase d uring the v-cut. Conclusions: The muscles crossing the ankle joint, especia lly the tibialis anterior and peroneus longus, may play an important role t o prevent ankle sprain injuries. Both muscles provided stability about the subtalar joint by preventing excessive joint rotations. Future theoretical studies with forward dynamic simulations incorporating individual muscle ac tuators are needed to quantify the segment accelerations induced by active muscles which may prevent or lead to ankle sprain injuries.