Neuromuscular function after sports consussion: implications for injury risk and rehabilitation [abstract] Abstract uri icon
  • PURPOSE: To summarize published research and our pilot data demonstrating impairments in neuromuscular function after sports concussion and to relate these impairments to subsequent musculoskeletal injury risk. DESCRIPTION: Concussion is a common injury in sports. After concussion, athletes experience a variety of symptoms (headache, nausea, dizziness, etc) and functional impairments (altered cognition, balance, vision, etc). Sports concussion return-to-play guidelines typically require symptom resolution at rest and with activity as well as restoration of preinjury function. Even if return-to-play criteria are met, subclinical impairments in neuromuscular function may persist. Increased intracortical inhibition, reduced intracortical excitability, and decreased metabolic activity of the motor cortex have been reported past the fulfillment of return-to-play criteria. Recent evidence indicates that these changes in the motor cortex affect neuromuscular function. Our pilot data show decreased voluntary activation of the quadriceps in athletes with concussion (n = 4) compared to matched controls at the time of return to play (70.2% versus 91.7%, respectively) and at 30 days of follow-up (76.9% versus 88.5%, respectively). Additionally, our work and that of others has shown decreased muscle strength after concussion. In our pilot study, collegiate football players with an in-season concussion (n = 16) demonstrated decreased normalized knee flexor torque (3.0 ± 8.9 body weight) postseason compared to preseason, which was a greater amount of change than in matched controls. Changes in neuromuscular function may then alter movement patterns. Several researchers have reported altered gait postconcussion, especially if a cognitive task is performed simultaneously. Using a single-leg forward drop land, we found that collegiate football players with an inseason concussion (n = 13) demonstrated increased hip stiffness and decreased knee and leg stiffness postseason when compared to matched controls. Extrapolating from research in other populations (eg, athletes with anterior cruciate ligament injury), alterations in motor cortex activity, neuromuscular function, and movement patterns could increase subsequent injury risk. In concordance, recent studies have demonstrated a greater risk of musculoskeletal injury postconcussion, including our study in concussed collegiate athletes showing 3.39 times higher odds of sustaining a lower extremity injury within a 90-day period after return to play compared to matched controls. SUMMARY OF USE: Unresolved neuromuscular impairments can exist after sports concussion, even if return to play criteria are met, increasing the risk for subsequent musculoskeletal injury. Sports concussion rehabilitation might be improved by including clinical tests and interventions that address these neuromuscular impairments. IMPORTANCE TO MEMBERS: Sports physical therapists need to consider a wider range of functional domains during rehabilitation in order to adequately prepare concussed athletes for return to play.

  • publication date
  • 2017
  • Research
  • Brain
  • Injuries
  • Physical Therapy
  • Rehabilitation
  • Sports
  • Additional Document Info
  • 47
  • issue
  • 1