Research Impact: In this paper we document the relationship between maximal strength level and the reliability of an isometric squat test in two isometric squat positions (120° and 90° knee angle) using a heterogeneous sample of male subjects with varying degrees of maximal strength, as indicated by their training history and peak isometric force output values. Despite extensive use of the isometric squat in the literature, no previous investigations have examined the influence that maximal strength level may have on the reliability of peak force measurement in the isometric squat. Documenting the reliability of the measure across a board range of maximal strength levels may be of relevance to researchers and practitioners who deal with subjects or athletes across this spectrum of maximal strength (i.e. ranging from untrained to highly strength trained individuals). We observed no relationship between maximal strength level and the reliability of peak force measurement in the isometric squat at either a 120° (r = 0.052, p = 0.327) or 90° (r = 0.014, p = 0.613) knee angle. Therefore, the data indicate that this is an appropriate strength test to use regardless of the maximal strength level of an individual.
In addition to reporting the reliability of previously investigated isometric squat positions (i.e. 120° and 90° knee angle respectively), we also investigated the reliability of a ‘deep’ isometric squat position (i.e. a 65° knee angle). We observed acceptable levels of reliability in this position, comparable with the previously established isometric squat positions. As such, we deem this information to be noteworthy, of potential relevance to the field and future research investigations in which maximal strength is a variable of interest.
Lynch A, Davies R, Jakeman P, Locke T, Allardyce M, Carson B. The Influence of Maximal Strength and Knee Angle on the Reliability of Peak Force in the Isometric Squat. 2021; 9(10):140 https://doi.org/10.3390/sports9100140