Dobbin, NicholasHunwicks, RichardJones, BenTill, KevinHighton, JamieTwist, Craig2017-06-212017-06-212018-02-31Dobbin, N., Hunwicks, R., Jones, B., Till, K., Highton, J., & Twist, C. (2018). Criterion and construct validity of an isometric mid-thigh pull dynamometer for assessing whole body strength in professional rugby league players. International Journal of Sports Physiology and Performance, 13(2), 235-239. https://doi.org/10.1123/ijspp.2017-01661555-026510.1123/ijspp.2017-0166http://hdl.handle.net/10034/620540Purpose: The purpose of this study was to examine the criterion and construct validity of an isometric mid-thigh pull dynamometer to assess whole body strength in professional rugby league players. Methods: Fifty-six male rugby league players, (33 senior and 23 youth professional players) performed four isometric mid-thigh pull efforts (i.e. two on the dynamometer and two on the force platform) in a randomised and counterbalanced order. Results: Isometric peak force was underestimated (P<0.05) using the dynamometer compared to the force platform (95% LoA: -213.5 ± 342.6 N). Linear regression showed that peak force derived from the dynamometer explained 85% (adjusted R2 = 0.85, SEE = 173 N) of the variance in the dependent variable, with the following prediction equation derived: predicted peak force = [1.046 * dynamometer peak force] + 117.594. Cross-validation revealed a non-significant bias (P>0.05) between the predicted and peak force from the force platform, and an adjusted R2 (79.6%), that represented shrinkage of 0.4% relative to the cross-validation model (80%). Peak force was greater for the senior compared to youth professionals using the dynamometer (2261.2 ± 222 cf. 1725.1 ± 298.0 N, respectively; P<0.05). Conclusion: The isometric mid-thigh pull assessed using a dynamometer underestimates criterion peak force but is capable of distinguishing muscle function characteristics between professional rugby league players of different standards.enPeak forceMeasurement errorCriterion and construct validity of an isometric mid-thigh pull dynamometer for assessing whole body strength in professional rugby league playersArticle1555-0273International Journal of Sports Physiology and Performance