Preliminary data of a 3D single-limb-squat assessment of laterality in exercise-proficient physiotherapists

Single-Limb-Squat (SLS) is a common functional test and exercise in conditions such as ACL rupture, and degenerative knee or hip pathologies [1,2]. Lower limb valgus has been assessed two-dimensionally in numerous studies [3]. Although SLS is a multidimensional and neuromuscularly highly demanding task [4], only a few studies assessed its kinematics and kinetics three-dimensionally [2]. Previous pertinent studies differed in terms of sample size [5,6], non-consideration of the role of gender [7], or the role of health status and exercise proficiency [5] on the SLS execution quality. Does the dominant side differ from the non-dominant one regarding hip and knee frontal moments (fM) as well as frontal Range of Motion (fRoM) in performing SLS by a healthy exercise-proficient sample? Eighteen (9 female / 9 male) healthy physiotherapists aged 19 to 62 (mean 34, sd 9.6) years performed five SLS with the right and left leg each. Data were captured using an optoelectronic movement analysis system with the modified Cleveland Clinical Markerset and a three-axis force plate. Processed trials were time-normalized for the down-phase and up-phase. Hip and knee fM, as well as fRoM were tested for difference between the dominant and non-dominant leg using one-dimensional parametric statistical mapping (1dSPM) [8]; paired t-tests with alpha set at 0.05. The 1dSPM analyses did result in statistically significant differences between the dominant and non-dominant leg in any of the parameters for the lower limb (indicated by the solid white bars at the graphs’ bottoms in Fig. 1). The null hypothesis was thus not rejected by the sample, although the trajectories show a clear deviation in the knee fM. Download : Download high-res image (432KB)Download : Download full-size image This study is the first to provide three-dimensional reference data of SLS performed by a healthy exercise proficient sample. Laterality seems to be relevant for knee fM, when defining feedback thresholds. Parameters characterizing the quality of exercise execution related to the control of dynamic leg alignment show smaller values compared to prior studies [7,9]. Gender differences are subject to the analysis of the complete dataset. As a limitation, squatting velocity and depth was monitored only verbally, which however did not affect the homogeneity of relevant biomechanical outcomes. Based on well-executed exercises, the physiological range of kinematic and kinetic parameters’ cut-offs shall be established, by opposing the data of the exercise proficient sample to that of less experienced exercisers.