Reliability of variables collected during single leg squat

Functional performance tests, such as the single leg squat and single leg landing test, are commonly used to evaluate lower extremity biomechanics. To establish the within- and between-day reliability of these tasks, this study included fifteen subjects who  performed various trials in one session and at another session one week later. Although between-day reliability was lower than within-day reliability, all collected variables showed good consistency.

Recently, there has been a shift from clinical diagnostic testing maneuvers towards a more common use of functional performance tests like the single leg squat and single leg landing maneuvers. These movements are thought to reflect the demands of athletic performance better. However, knowledge of the key variables and their variability over trials is essential to distinguish between random error and real difference.

Fifteen subjects performed both maneuvers: there were two sessions on one day with an hour in between and another session one week later. Data was collected using a 3-D motion analysis system and a force platform; the variables that were determined included hip flexion and adduction moments, knee flexion and adduction moments, peak joint angles of the lower limb in the frontal, sagittal and transverse plane and ground reaction force.

The combined averages of within-day ICC values (single leg squat = 0.87; single leg landing = 0.90) were higher than the between-day ICC values (single leg squat = 0.81; single leg landing = 0.78). However, all of these values are indicative of good to excellent consistency.

> From: Alenezi et al., J Electromyogr Kinesiol 24 (2015) 718-721. All rights reserved to Elsevier Ltd. Click here for the Pubmed summary.