The effect of neck strength and anthropometric properties of academy football players on the linear and rotational accelerations experienced during heading
Introduction and purpose: Research on heading a football ball has gained interest in recent years due to the proposed association with long-term brain health and rule changes at a governing body level. Currently, evidence exploring linear and rotational accelerations is largely limited to standardised and lab-based headers and use of a hand-held dynamometer to assess neck strength, thus potentially lack ecological and concurrent validity. Therefore, this study examined the association between anthropometric properties and neck strength with linear and rotational accelerations during typical football activity. Materials and Methods: Eleven football players from a single category one academy underwent an anthropometric assessment (stature, body mass, neck length, neck circumference, and estimated head mass) and had isometric neck strength (allometrically scaled forward, lateral flexion, and extension force) determined using a fixed dynamometer. Linear and rotational accelerations were measured using instrumented mouthguards. To assess the associations, two separate linear mixed models were constructed. Results: A total of 259 ‘player observations’ were included. A small negative association was observed between neck length, head-neck segment mass and side flexion strength with linear acceleration. A positive association was observed between neck circumference, head mass, and strength in forward flexion and extension. Neck length, neck circumference and side flexion strength were negatively associated with rotational accelerations whilst head mass, head-neck segment mass, and strength in forward flexion and extension was positively associated. The magnitude of the association and effect on the estimate for a one standard deviation change is presented in Figure 1 and 2. Conclusion: The findings in this study highlight an association between anthropometric and neck strength properties with linear and rotational accelerations experienced by players during typical football activity. These findings could have important implications when managing young athlete returning to heading activity as they progress and when developing individualised neck strengthening programmes
