Höfundar:
Gunnlaugur Jónasson, Kristin Briem, Þórarinn Sveinsson
Introduction: The aim of this study was to identify if any sex dependent differences existed in neuromuscular pre-activation of m.gluteus medius (GM), isometric hip strength, or duration of stance (DoS) in 10-12 year old athletes performing a cutting maneuver.
Methods: 56 football and handball players (35 female) underwent electromyography (EMG) recordings of GM during the performance of a cutting maneuver. Isometric strength (MVIC) of hip abductors and external rotators was measured using a handheld dynamometer and force plate data was used to identify DoS. The EMG signal, 50msprior to initial contact (IC) normalized to that obtained during the hip abductor MVIC. In addition to descriptive statistics, mixed model analysis was used, with Alpha set at 0.05.
Results: EMG: Boys showed significantly greater pre-activation of m.gluteus medius than girls (p=0.022). Muscle strength had no significant effect on activity. Hip strength: When normalized to weight, boys were significantly stronger in external rotation than girls (p=0.038), with no significant difference in abduction. DoS: No significant difference was found between the sexes. Strength had a significant association with DoS and when adjusted for abduction strength boys had significantly shorter DoS than girls (p=0.006).
Conclusion: Results indicate that a sex dependent difference in neuromuscular activity and performance of a cutting maneuver exists in children before or in their early stages of puberty. Further research is needed to elucidate whether greater pre-activation of hip abductors during cutting maneuvers is of value in terms of injury prevention.