Neuromuscular Training Alters Preparatory Lower Extremity Muscle Activation and Movement in Subjects with Ankle Instability

Chronic ankle instability (CAI) may, in part, be due to poor positioning of lower extremity segments during movement. Altered preparatory muscle activation from sensorimotor deficits could perpetuate this problem. PURPOSE: to determine if a 6-week neuromuscular training program can alter preparatory lower extremity muscle activation and frontal plane movement in CAI subjects. METHODS: 15 CAI subjects in a rehab group (23±2 yrs, 178±8 cm, 76±9 kg, 83±7% FAAM ADL, 56±10% FAAM Sports, 3.6±1.1 MAII, 4.7±2.0 ankle sprains) completed a series of 10 ankle and hip strength and proprioceptive exercises (theraband, wobble board, ankle disk, etc.) 3 times/week for 6 weeks under supervision. 14 CAI subjects participated in a control group (22±2 yrs, 177±9 cm, 75±12 kg, 81±9% FAAM ADL, 56±12% FAAM Sports, 3.4±1.2 MAII, 5.9±3.3 sprains). Subjects performed 10 jumps consisting of a max vertical jump plus a side cut. Functional analyses (α=.05) were used to detect a group x treatment interaction over time. If 95% CI did not cross the zero, significant differences existed. RESULTS: Figure 1. The rehab intervention resulted in up to (i) 23% more gluteus medius activation from 75 ms pre-contact to initial-contact, while no changes were detected in other variables (frontal ankle angle, frontal hip angle, and peroneus longus activation). CONCLUSIONS: Strength and neuromuscular control exercises enhanced GM activation prior to a demanding, athletic movement. While no corresponding preparatory movement differences were detected, the motion effect might be evident during or after foot contact. More data are needed to determine if the observed training effect could play a role in reducing injury.Figure