Sex Differences in Anthropometrics and Heading Kinematics Among Division I Soccer Athletes

Abstract

Background:Soccer players head the ball repetitively throughout their careers; this is also a potential mechanism for a concussion. Although not all soccer headers result in a concussion, these subconcussive impacts may impart acceleration, deceleration, and rotational forces on the brain, leaving structural and functional deficits. Stronger neck musculature may reduce head-neck segment kinematics.Hypothesis:The relationship between anthropometrics and soccer heading kinematics will not differ between sexes. The relationship between anthropometrics and soccer heading kinematics will not differ between ball speeds.Study Design:Pilot, cross-sectional design.Level of Evidence:Level 3.Methods:Division I soccer athletes (5 male, 8 female) were assessed for head-neck anthropometric and neck strength measurements in 6 directions (ie, flexion, extension, right and left lateral flexions and rotations). Participants headed the ball 10 times (25 or 40 mph) while wearing an accelerometer secured to their head. Kinematic measurements (ie, linear acceleration and rotational velocity) were recorded at 2 ball speeds.Results:Sex differences were observed in neck girth (t = 5.09, P < 0.001), flexor and left lateral flexor strength (t = 3.006, P = 0.012 and t = 4.182, P = 0.002, respectively), and rotational velocity at both speeds (t = −2.628, P = 0.024 and t = −2.227, P = 0.048). Neck girth had negative correlations with both linear acceleration (r = −0.599, P = 0.031) and rotational velocity at both speeds (r = −0.551, P = 0.012 and r = −0.652, P = 0.016). Also, stronger muscle groups had lower linear accelerations at both speeds (P < 0.05).Conclusion:There was a significant relationship between anthropometrics and soccer heading kinematics for sex and ball speeds.Clinical Relevance:Neck girth and neck strength are factors that may limit head impact kinematics.

Concussion-Prevention Strategies Used in National Collegiate Athletic Association Divisions I and II Women's Soccer

“…Previous researchers 13,20 observed that neck strength was not associated with concussion rates in contact sports. However, authors 15,16,[21][22][23] have offered emerging evidence supporting the use of cervical strengthening in female soccer players for preventing concussion. Sex-based differences in neck strength may contribute to the elevated concussion rates in female soccer players, given that those with weaker overall neck strength appeared to be at a higher risk of concussion.…”

“…Sex-based differences in neck strength may contribute to the elevated concussion rates in female soccer players, given that those with weaker overall neck strength appeared to be at a higher risk of concussion. 16 Greater neck strength and anticipatory cervical muscle activation has been associated with a reduction in the head's kinematic response to external force, 21,22 which may aid in concussion prevention. Females displayed greater head-neck segment peak angular acceleration and displacement than their male counterparts, even though they exhibited earlier muscle activation than males.…”

“…23 In adolescent female soccer athletes, neck strength and header acceleration were significantly negatively correlated: those with weaker necks endured greater impacts during heading. 15 In addition, Bretzin et al 21 determined that soccer players with greater neck strength had decreased linear head accelerations. Although further investigations are necessary to fully evaluate the influence of neck strength on concussion rates, based on our findings, implementation of neck-strengthening protocols in women's soccer seem to be an emerging practice.…”

Sex Differences in Common Sports Injuries

“…Higher incidence in females [77][78][79][80][81][82][83][84][85][86][87][88][89] Female risk factors include reduced neck girth and strength relative to head size compared to males [88][89][90][91][92][93][94] Females report more symptoms postinjury and have higher rates of postconcussive syndrome [110,111] RED-S ¼ relative energy deficiency in sport; BMI ¼ body mass index; BMD ¼ bone mineral density; BSI ¼ bone stress injury; ACL ¼ anterior cruciate ligament.…”

“…Several different factors have previously been cited to contribute to this sex and gender disparity in concussion incidence. In particular, females tend to have a reduced amount of neck girth and strength relative to head size and head-neck length compared to males [88][89][90][91][92][93][94]. This may reduce the overall stability and stiffness of the head-neck segment such that it is less able to absorb externally applied forces.…”