Context:
Neuromuscular training (NMT) facilitates the acquisition of new movement patterns that reduce ACL injury risk; however, the neural mechanisms underlying these changes are unknown.
Objective:
Determine the relationship between brain activation and biomechanical changes following NMT with biofeedback.
Study Design:
Controlled Laboratory Study
Setting:
Research laboratory
Participants:
Final analyses included twenty high school female soccer athletes (15.7±0.95 years; 1.68±0.05 m; 59.91±5.62 kg).
Main Outcome Measures:
Ten participants completed 6 weeks of NMT augmented with real-time biofeedback (aNMT) to reduce knee injury risk movements, and 10 participants completed no training. aNMT was implemented with visual biofeedback that responded in real-time to injury-risk biomechanical variables. A drop vertical jump with 3D motion capture was used to assess injury risk neuromuscular changes before and after the six-week intervention. Pre to post brain activation changes were measured using functional magnetic resonance imaging (fMRI) during unilateral knee and multi-joint motor tasks.
Results:
Following aNMT, sensory (precuneus), visual-spatial (lingual gyrus), and motor planning (pre-motor) brain activity increased for knee specific movement and sensorimotor cortex activity for multi-joint movement decreased. Knee abduction moment during landing also decreased (4.66±5.45 Nm; p=0.02; g=0.82) in the aNMT group with no change in the control group (p>0.05). The training-induced increased brain activity for isolated knee movement was associated with decreases in knee abduction moment (r=.67, p=.036) and sensorimotor cortex activity for multi-joint movement (r=.87, p=.001). No significant change in brain activity was observed in the control group (p>0.05).
Conclusions:
The relationship between neural changes observed across tasks and reduced knee abduction suggests that aNMT facilitates recruitment of sensory integration centers to support reduced injury risk mechanics and improve sensorimotor neural efficiency for multi-joint control. Further research is warranted to determine if this training related multimodal neuroplasticity enhances neuromuscular control during more complex sport-specific activities.