Neck Muscle Strength Training in the Risk Management of Concussion in Contact Sports: Critical Appraisal of Application to Practice

Abstract

Neck Muscle Strength Training in the Risk Management of Concussion in Contact Sports: Critical Appraisal of Application to Practice Background: Neck strength training has been advocated as a player-specific modifiable factor in the risk management for concussion in contact sports. A scoping review of the literature was undertaken to address two specific aims. The first was to identify and critically appraise the level and quality of evidence relating neck strength and resistance training to concussion incidence and risk in contact sports. The second was to compare and contrast the effectiveness of resistance neck strengthening programs and to evaluate effects of increased strength in attenuating the postimpact kinematics of the head, a proxy measure of concussion risk. Methods: Structured search of five electronic databases (Ovid MEDLINE, CINAHL, PubMED, EMBASE, and AMED), combining MeSH and generic search terms relating neck strength to concussion biomechanics, risk and incidence. Level of research evidence (Oxford Centre of Evidence-based Medicine) and methodological quality were determined (PEDro and Newcastle-Ottawa Scales). Results: Total isometric neck strength predicted concussion incidence in one prospective study (level 1b). The effect size of strength on concussion incidence was small (Cohen’s d, 0.29). Peak isometric strength did not predict the odds of sustaining a moderate or severe head impact in contact sports (level 1b, 2b, and 4). Short-latency anticipatory strength exerts an attenuating effect on post-impact kinematics of the head (level 1b, 2b) and can be facilitated by selective parameters of isotonic strength training. Methodological quality of the research evidence ranged from 6/10 to 8/10 for controlled trials and 6/9 to 9/9 for case-series and cohort studies. Conclusion: Short-latency strength, developed prior to impact, is a key modifying variable of the post-impact kinematics of the head. By facilitating short-latency neck strength, muscle strength training is a potential target to favorably influence concussion risk, but further study is required to determine the translation of neck/head kinematics to concussion risk. Standardized methods for assessment of multi-directional short-latency, and peak neck, strength need to be adopted and combined with prospective studies.