Article Text
Abstract
Background One of many risk factors for ACL injury may involve neuromuscular activation patterns of muscles in the lower extremities. These have been studied for some muscles in pre- and post-pubescent female and male athletes. Although m.gluteus medius (GM) activity may be important during dynamic activities, its activation patterns have not been extensively studied.
Objective To identify gender differences in neuromuscular activation of GM in young athletes.
Design Cross-sectional controlled laboratory trial.
Setting Measurements took place in the Research Centre of Movement Science at the University of Iceland.
Participants 11–12 years old football and handball players were recruited from local sports clubs, 9 boys and 36 girls.
Risk factor assessment Surface electrodes were used to collect EMG activity from GM during two dynamic tasks (drop-jumps (DJ) and cutting maneuvers (CM)), before and after a fatigue protocol.
Main outcome measurements Timing of peak muscle activation and activation levels at initial contact (IC), normalized to peak activation, were analyzed pre- and post-fatigue between genders for each task.
Results Girls demonstrated greater activation at IC than boys (P=.02) and peak activation occurred earlier in girls than boys (P<.01) during the DJ. Moreover, GM activation levels at IC were overall significantly greater after a fatigue protocol than before (P<.01) and peaked earlier (P<.01). During CM the only significant finding was a main effect of fatigue for activation levels at IC (P<.01).
Conclusions Gender differences in activation patterns of GM were identified during DJ in young athletes. This may, in part, reflect different kinematic strategies during this dynamic task or gender biased training. As girls go into puberty earlier than boys, this may have influenced movement patterns of some of the female participants. Further investigation into GM activation in relation to lower extremity kinematics within the context of injury prevention is warranted.