Exposure to impacts across a competitive rugby season impairs balance and neuromuscular function in female rugby athletes

Abstract

ObjectivesWe used objective assessment tools to detect subtle neurological deficits that accompany repetitive and mild head impacts in contact sport across a season.MethodsFemale participants (n=13, 21±1.8 years old; 167.6±6.7 cm; 72.8±6.1 kg) completed assessments pre and post the varsity rugby season. A commercial balance board was used to assess static balance and response to dynamic postural challenge. Spinal cord excitability via the soleus H-reflex was assessed in both legs. Video analysis was used to identify head impact exposures.ResultsA total of 172 potential concussive events were verified across 11 athletes (15.6±11; 95% CI: 6.5 to 19.8). Balance performance was worse at post-season for total centre of pressure which increased by 26% in the double stance on a stable surface (t(12)=-2.33; p=0.03; d=0.6) and by 140% in the tandem stance on a foam surface (t(12)=-3.43; p<0.01; d=0.9). Despite that, dynamic postural performance was improved after the season (p<0.01). Spinal cord excitability in rugby athletes did not change across the season but deviated from normative values at baseline.ConclusionQuantitative measures revealed that exposure to impacts across a competitive rugby season impair balance in two specific stances in female rugby athletes. Tandem-leg stance on an unstable surface and double-leg stance on firm surface are useful assessment conditions when performed over a low-cost balance board, even without clinically diagnosed concussion.

Effects of chronic exposure to head impacts on the balance function of combat sports athletes

“…Although only one variable in the present study showed statistical significance, a few particularities must be considered. The BESS protocol is widely performed by clinicians, 15 recommended by specialists, 1 and it can provide useful information on the effects of subconcussions even in such a fundamental posture for humans (ie, double‐leg stance) when integrated with a portable and low‐cost balance board 19 . Moreover, our static protocol was composed by a single‐task, whereas other studies detected similar outcomes only when performing double‐task protocols, 37,38 which is believed to exacerbate stability deficits 39 .…”

“…Participants were instructed to shift their weight on the BB so that the CoP meets the target on the screen as quickly and accurately as possible. Following the familiarization set, participants completed five trials 19,33 . The averaged time to reach target (tTarget), time to return to center from target (tCenter), and their computed sum (tTotal) were obtained and analyzed 19,33 …”

“…Following the familiarization set, participants completed five trials 19,33 . The averaged time to reach target (tTarget), time to return to center from target (tCenter), and their computed sum (tTotal) were obtained and analyzed 19,33 …”

“…This can also be seen in dynamic postural control, where athletes diagnosed with a concussion within the last two years presented deficits compared to a control group 18 . The evidence for effects of repetitive subconcussive head impacts on balance function after a competitive season of contact modalities is variable with findings supporting presence 19 and absence 20 of alterations.…”

Five Weeks of Yuishinkai Karate Training Improves Balance and Neuromuscular Function in Older Adults

“…A commercially available balance board (Wii Balance Board, Nintendo, Kyoto, Japan) was used with customized software (LabVIEW 2011 National Instruments, Austin, TX, USA), and data were sampled at 100 Hz. The validity (r = 0.99) and reliability (ICC = 0.88) of balance board has been con rmed [35] and used in several previous studies to assess postural control [33,36,37].…”