Reciprocal versus non-reciprocal assessment of knee flexors and 1 extensors in concentric actions using the CON-TREX multi-joint 2 isokinetic dynamometer: A reliability study

Knee flexor and extensor muscular assessment via isokinetic dynamometry is common practice and established in the research literature. However, reporting assessment methodology regarding reciprocal and non-reciprocal movements is often vague or absent. Such methodological issues are crucial for accurate assessments. Therefore, knee extensor and flexor peak moment using either reciprocal movement or non-reciprocal modalities was assessed. Fifteen participants performed 3 blocks of 5 concentric muscle actions at three angular velocities [1: non-reciprocal (maximal active flexion followed by passive extension); B2: reciprocal (maximal active extension followed by maximal active flexion); B3 non-reciprocal (maximal active extension followed by passive flexion)]. ANOVA revealed statistically significant within-subject modality effects for peak knee extensor moment and flexor velocity and modality differences (P<0.05). Reciprocal and non-reciprocal assessments give significantly different results, with non-reciprocal giving higher peak moments. Reporting which modality is used is crucial to allow for greater clarity for the reader and practitioner.