The Comparsion of the Activity Pattern of Lower Limb Muscles During Single Leg Drop Landing

Single leg drop landing is one of the common sport activities that have greater likelihood of leading to traumatic oflower extremity. However، There is limited understanding of biomechanics of this maneuver. Hence، this study aimed to compare the activities of lower limb muscles during pre- and post phases of single leg drop landing. This semi-experimental research of 13 physical education male students was conducted in 2011. Electromyogram activities of gluteus medius، biceps femoris، medial gastrocnemius، soleus and anterior tibialis muscles along with ground reaction forces were measured. Subjects performed single-leg landing from a 0. 3m height on to a force platform. Landing motions were divided into two phases: 100 ms preceding ground contact and 100 ms after ground contact (absorption phase). Analysis of variance and paired-samples T Tests were conducted for the comparison of activity of muscles separately. In each phase and among phases respectively P≤0. 05 was considered as statistical significant. Analysis of variance test showed significant differences in muscle activity in both phases (P≤0. 001). Paired-sample t test showed that the activities of gluteus medius، biceps femoris and anterior tibialis muscles were greater during absorption phase in comparsion to pre-landing phase (P≤0. 05); however the activity of medial gastrocnemius muscle was greater during pre-landing phase in comparison to absorption phase (P≤0. 001). It Seems that Lower extremity by activation of medial gastrocnemius muscle before ground contact prepare to absorb forces during landing. According to type of landing used in the present study (Stiff landing)، plantar flexor muscles play key role in absorbing of ground reaction forces during single leg drop landing.