Data collection and analysis

Sagittal trunk excursion (Fig. 3) was determined as the difference in the sagittal trunk flexion angle from the start to the end of the mini-squat (end angle minus start angle).⁵⁸ A single examiner performed the 2D analysis after data collection using Surgimap software. The built-in angle tool was used to determine joint angle values for each participant. The angle tool permits the measurement of a generic angle between the two segments. The angle (in degrees) created between the set of two lines is displayed on the image. On the selected image, the examiner drew lines from which he could measure the trunk angles. The measured angle is graphically represented on the image by an arc. Good intra-rater reliability for measuring the sagittal trunk angle was established in the standing and mini-squat positions (ICC = 0.89 and 0.86, respectively).

Measurement of trunk excursion.

For active lumbar repositioning, the absolute error values for the 30^∘ target position were recorded for the three trials performed by each participant. The mean deviation for each participant was calculated.⁵⁹