Abstract
The barbell squat is a popular exercise for building strength in the lower extremities. Some lifters show a characteristic posterior tilt of the pelvis in the bottom part of the movement, which is feared to increase risk of lumbar spine injury. Limitation in hip flexion is assumed to be involved, but no direct cause has been found through biomechanical research. Properties of both soft and bone tissue can be part of the mechanism, the latter being the object here. The aim of this study is to show correlation between posterior pelvic tilt in squats and measurements on CT-scans of healthy men. Previously healthy men were visually observed doing barbell back squats, and categorized in three groups depending on their amount of posterior pelvic tilt. Subjects with the most and least pronounced pelvic tilt went through a 3D motion analysis quantifying this more precisely There was no correlation between the posterior pelvic tilt measured in the 3D motion analysis and the measurements done on the CT-images. All variables were tested for correlation using linear regression producing R2 values in the range from <0.001 to 0.032, which indicates lack of correlation. No correlation between posterior pelvic tilt in squats and measurements on CT-scans of healthy men was observed. The consistent lack of correlation makes it unlikely that the shape of bone structure in close to the hip joint is important in creating posterior pelvic tilt in squats.