Age-related differences in the neck strength of adolescent rugby players: A cross-sectional cohort study of Scottish schoolchildren

Abstract

Objectives: To evaluate the neck strength of school-aged rugby players, and to define the relationship with proxy physical measures with a view to predicting neck strength.

Methods: Cross-sectional cohort study involving 382 rugby playing schoolchildren at three Scottish schools (all male, aged between 12 and 18 years). Outcome measures included maximal isometric neck extension, weight, height, grip strength, cervical range of movement and neck circumference.

Results: Mean neck extension strength increased with age (p = 0.001), although a wide inter-age range variation was evident, with the result that some of the oldest children presented with the same neck strength as the mean of the youngest group. Grip strength explained the most variation in neck strength (R(2) = 0.53), while cervical range of movement and neck girth demonstrated no relationship. Multivariable analysis demonstrated the independent effects of age, weight and grip strength, and the resultant model explained 62.1% of the variance in neck strength. This model predicted actual neck strength well for the majority of players, although there was a tendency towards overestimation at the lowest range and underestimation at the highest.

Conclusion: A wide variation was evident in neck strength across the range of the schoolchild-playing population, with a surprisingly large number of senior players demonstrating the same mean strength as the 12-year-old mean value. This may suggest that current training regimes address limb strength but not neck strength, which may be significant for future neck injury prevention strategies. Age, weight and grip strength can predict around two thirds of the variation in neck strength, however specific assessment is required if precise data is sought.

Keywords: Adolescent; Injury prevention; Neck; Physical assessment; Rugby; Strength.

Conflict of interest statement

ICMJE Conflict of Interest:None declared

Figures

Fig. 1

Box plot showing neck extension strength by age group. The boxes represent the median value and interquartile range, and the whiskers represent the range of data.

Figs. 2a - 2b

Plots showing bivariate correlations of neck extension strength versus a) grip strength and b) neck circumference.

Figs. 2a - 2b

Plots showing bivariate correlations of neck extension strength versus a) grip strength and b) neck circumference.

Fig. 3

Bivariate correlation of predicted versus actual neck extension strength based on multiple linear regression model R2 = 0.621.

Fig. 4

Bland-Altman plot showing agreement between predictive model and actual neck extension strength (error bars represent the 95% confidence intervals (1.96×sd)).