Comparison of kinematic parameters, muscle activity and movement timing between "good" and "poor" performers of a single-leg squat

INTRODUCTION

Visual scales offer a cost-effective alternative to complex biomechanical analysis for single-leg squat (SLS) performance. There is a lack of consensus on the relationship between visual rating and kinematic measurements in physical therapy assessments. The study aimed to compare kinematic parameters, muscle activity and timing between good and poor performers of SLS, selected based on visual evaluation of movement.

METHODS

Forty asymptomatic male volunteers were classified based on a visual assessment of their SLS movements. For participants rated as good performers (n = 19) and poor performers (n = 8), electromyographic activity, kinematic parameters and movement timing were compared.

RESULTS

SLS execution was significantly different in groups in terms of the hip frontal plane and spine transversal plane of movement and the timing of the hip and knee motion. There were no statistically significant differences between groups in multifidus muscle activity during SLS, frontal plane movement of the knee and squat depth.

CONCLUSIONS

The findings of this study indicate that coordination and timing of movements should be carefully considered during SLS examinations to obtain a comprehensive evaluation for planning exercise rehabilitation.

Athletes with a clinical rating of good and poor lumbopelvic stability have different kinematic variables during single leg squat and dip test

OBJECTIVES

To examine the kinematics of athletes with good and poor lumbopelvic stability (LPS) based on clinical rating criteria of single leg squat (SLS) and dip test (DT) The aim was to establish if good and poor LPS categorization is supported by differences in kinematic variables.

METHODS

Sixty-two recreational athletes had their LPS categorized using clinical rating criteria for SLS and DT as good, poor or neither good nor poor. Kinematic measures were examined in those with good (N = 8) or poor (N = 14) LPS and results compared to the rating criteria.

RESULTS

Multiple clinical rating criteria for good and poor LPS groups were distinguished by kinematic measures. Smoothness of motion for both SLS and DT distinguished good and poor LPS. Minimal (good) or discernible movement (poor) out of the starting plane was confirmed with kinematic measures. For SLS these movements were: weight-bearing hip adduction, non-weightbearing hip abduction, pelvic rotation, and trunk sideflexion, and for DT: weightbearing hip adduction, non-weightbearing hip abduction and pelvic obliquity. Additionally, hip dissociation (SLS) distinguished good and poor LPS.

CONCLUSION

Athletes with good and poor LPS have different kinematic measures in single leg squat and dip test. Multiple clinical rating criteria of LPS that distinguish good and poor stability were confirmed by kinematic measures.