EFFECT OF EXPOSURE TO CONTACT SPORT PARTICIPATION ON CERVICAL SPINE SENSORIMOTOR FUNCTION

Abstract

Head and neck injuries are common in contact sports. Proper function of the cervical spine sensorimotor system is important in limiting these injuries. Repetitive stress incurred during contact sport participation may negatively affect this system and increase injury risk. Currently, there is a paucity of research examining contact sport exposure and cervical spine sensorimotor function. The purpose of this study was to examine the effect of contact sport participation on cervical sensorimotor function. The independent variables were group (rugby, non-contact), sex (male, female), and time (pre-season, post-season). The primary dependent variable was neck position sense error as measured by total neck reposition (TNRE) error and maximum neck reposition error (MaxNRE). Secondary dependent variables included neck disability index, signs and symptom (S/S) number, symptom severity, concussion history, cervical range of motion, and isometric neck strength. This prospective observational study included forty-nine participants (15 male rugby, 11 female rugby, 11 non-contact male control, 12 non-contact female control) from Temple University campus recreation club sport teams. Athletes participated in two testing sessions, one prior to the season (i.e., pre-season) and one following the season. Data were analyzed using descriptive and inferential statistics. Independent-sample t-tests with Bonferroni corrections were used to assess statistically significant differences in dependent variables at pre-season between groups (Aim 1) and sex (Aim 2). Independent-samples t-tests with Bonferroni correction were also used to explore statistically significant differences in dependent variables change scores from pre-season to post-season between groups (Aim 1). Pearson correlations (r > .60) were used to assess potential covariates but none were identified. Pearson correlations were also used to evaluate the relationship between pre-season maximum and total neck reposition sense error and the following dependent variables: years of contact sport participation, concussion S/S number and severity score, global cervical range of motion and global cervical isometric strength (Aim 3). For Aim 1, between group differences were identified for global cervical isometric strength, t (1, 45) = 2.98, p = .005, and total joint reposition error t (1, 45) = 2.78, p = .008, only. There were no significant change score differences between groups across time. For Aim 2, sex differences were identified in years of contact sport exposure (p = .004), height (p < .001) and global isometric strength (p <.001), only. For Aim 3, preseason concussion S/S number and severity scores were significantly correlated (p < .05) with total joint reposition error (r = .352) and maximum joint reposition error (r = .476). The present study findings indicate a difference in cervical spine sensorimotor function between collegiate club rugby athletes and controls. Specifically, rugby athletes exhibited significantly greater neck reposition sense error than controls. Additionally, concussion S/S scores were related to reposition sense error. Differences in position sense error were not identified between males and females, however females did exhibit less neck strength mirroring previous reports. These findings suggest that exposure to contact sport-related impacts may lead to changes in cervical spine sensorimotor function. These changes are important as they could represent an increased risk of injury and can be modified proactively. A comprehensive cervical spine pre-season examination including concussion S/S and position sense assessments could identify individuals needing preventative intervention. Future research should explore the risk associated with these proprioceptive deficits and the benefits of proactive therapeutic intervention designed to mitigate sensorimotor deficits in contact sport athletes.