Investigation of the Pattern and Activity of Quadriceps and Hamstring Muscles in Drop from Different Heights in Collegiate Male Athletes

Lack of balance in pattern and activity of quadriceps and hamstring muscles increases the risk of Anterior Cruciate Ligament injury (ACL). The purpose of the present study was to investigate the changes in pattern and activity of vastus medialis and semitendinosusmuscles in landing from different heights and to understand if these changes will increase the risk of ACL injury or not.
Following a semi-experimental method, in the present study, 16 athletes (from volleyball, handball, and basketball sports), 23/1±1/2 years, 178±4/5 cm height, and 64/8±2/4 kg weights, did jump-landing from 20, 40, and 70 cm heights. The results of activity in feed forward and feedback phases and pattern were investigated using ME6000. To compare pattern and activity of each muscle in the three heights use, one way repeated measures ANOVA and to compare pattern and activity between vastus medialis and semitendinosus, independent T test were run in SPSS (version 20) (p≤0/05).
Feed forward activity (p=0/001) and onset time (p=0/014) of vastus medialis in 70-cm height were found to be significantly more than those of 20- and 40-cm heights, but in activity and onset time of semitendinosus,no significant difference was observed (p>0/05). The results of independent T showed that feed forward and feedback activity of semitendinosusis significantly fewer than those of vastus medialis (p Increase in landing height can increase the quadriceps to hamstring activity ratio and onset time of vastus medialis. These negative changes in pattern and activity of muscles increase the shear forces on ACL and the risk of injury.