Reactive Postural Responses After Mild Traumatic Brain Injury and Their Association With Musculoskeletal Injury Risk in Collegiate Athletes: A Study Protocol

Abstract

Background: Deficits in neuromuscular control are widely reported after mild traumatic brain injury (mTBI). These deficits are speculated to contribute to the increased rate of musculoskeletal injuries after mTBI. However, a concrete mechanistic connection between post-mTBI deficits and musculoskeletal injuries has yet to be established. While impairments in some domains of balance control have been linked to musculoskeletal injuries, reactive balance control has received little attention in the mTBI literature, despite the inherent demand of balance recovery in athletics. Our central hypothesis is that the high rate of musculoskeletal injuries after mTBI is in part due to impaired reactive balance control necessary for balance recovery. The purpose of this study is to (1) characterize reactive postural responses to recover balance in athletes with recent mTBI compared to healthy control subjects, (2) determine the extent to which reactive postural responses remain impaired in athletes with recent mTBI who have been cleared to return to play, and (3) determine the relationship between reactive postural responses and acute lower extremity musculoskeletal injuries in a general sample of healthy collegiate athletes. Methods: This two-phase study will take place at the University of Utah in coordination with the University of Utah Athletics Department. Phase 1 will evaluate student-athletes who have sustained mTBI and teammate-matched controls who meet all the inclusion criteria. The participants will be assessed at multiple time points along the return-to-play progress of the athlete with mTBI. The primary outcome will be measures of reactive postural response derived from wearable sensors during the Push and Release (P&R) test. In phase 2, student-athletes will undergo a baseline assessment of postural responses. Acute lower extremity musculoskeletal injuries for each participant will be prospectively tracked for 1 year from the date of first team activity. The primary outcomes will be the measures of reactive postural responses and the time from first team activity to lower extremity injury. Discussion: Results from this study will further our understanding of changes in balance control, across all domains, after mTBI and identify the extent to which postural responses can be used to assess injury risk in collegiate athletes.

Reactive Postural Responses Predict Risk For Acute Musculoskeletal Injury In Collegiate Athletes

“…Exclusion based on medical history was determined by the study team. The instrumented, modified Push and Release test (I-mP&R) was administered as described in Morris et al 18 prior to, or at the beginning, of each athlete's competitive season. IMUs were placed on the participants' feet, right shank, lumbar spine, and sternum.…”

“…22 The primary measure, as described in the published protocol paper, was median time-to-stability. 18 Secondary measures included: maximum step latency and median step length. 22 Acute, lower extremity MSK injuries were tracked from the date of the first organized team Overuse injuries and preexisting conditions were excluded.…”

“…18,19 The purpose of this study was to examine if reactive postural responses (i.e., the neuromechanical responses to a loss of stability) are associated with the risk for acute lower extremity MSK injuries in collegiate athletes. 18 Reactive postural responses occur when there is a sudden change in posture or support surface, are shaped by the pre-perturbation neuromotor state (i.e. central set), and result from interaction between spinal circuits, the brainstem, and the cerebral cortex.…”

“…Clinical assessments that probe neuromechanical responses, including the identification of a sensory stimuli; integration of multiple senses; and short-, medium-, and long-latency responses to achieve fast, yet precise motion are promising, but under-utilized, avenues for identifying athletes at risk for future acute MSK injury particularly under dual-task conditions. 18,19 The purpose of this study was to examine if reactive postural responses (i.e., the neuromechanical responses to a loss of stability) are associated with the risk for acute lower extremity MSK injuries in collegiate athletes. 18 Reactive postural responses occur when there is a sudden change in posture or support surface, are shaped by the pre-perturbation neuromotor state (i.e.…”

Research Letter: Reactive balance responses after mild traumatic brain injury (mTBI): a scoping review

“…While too recent to be included within the review, these additional results support the need for further study of reactive balance; perturbations eliciting reactive postural responses were more sensitive than standard clinical tests such as the Berg Balance Scale, Dynamic Gait Index, and High-Level Mobility Assessment Tool to detecting lingering balance deficits post-mTBI [74]. Although reactive postural responses have been used in balance impaired populations to successfully predict fall risk [67-71], the area remains understudied after mTBI and should be included in future study protocols [75]. This review highlights the infancy of the current evidence, and provides a valuable new direction for balance assessments after mTBI.…”