Specificity of isokinetic assessment in noncontact knee injury prevention screening: A novel assessment procedure with relationships between variables in amateur adult agility-sport athletes

Objectives To present a new knee isokinetic assessment procedure linked to noncontact knee injury mechanisms and examine correlations between variables relevant to noncontact knee injury prevention screening (peak torque [PT, Nm], time-to-peak torque [TTPT, ms], angle-of-peak torque [APT, °], mean PT [MPT, Nm]). Design Cross-sectional. Setting Sports medicine laboratory. Participants Thirty-four agility-sport athletes (male/female n=18/16, age 24.1±3.5yr, height 171.8±9.6cm, mass 70.6±12 kg). Main outcome measures Pearson's/Spearman's correlation (r/rs), coefficient of determination (r2/rs2). Results Most correlations were statistically non-significant or statistically-significant with only weak-to-moderate coefficients. For both knee extension and flexion, PT and MPT were significantly and strongly correlated (r=0.99, r2=0.98, p=0.001). Graphical analyses revealed two datapoint clusters for knee flexion TTPT and APT. One cluster indicated some participants could generate knee flexor PT rapidly (<150ms) at low knee flexion angles (<45°) and the other cluster indicated that other participants could not (>200ms, >50°). Conclusions In this study, most isokinetic variables represented distinct knee neuromuscular characteristics. For both knee extension and flexion, only PT or MPT need be used to represent isokinetic maximal strength. Knee flexion TTPT and APT may have utility in noncontact knee injury prevention screening with amateur adult agility-sport athletes.