Posterior Pelvic Tilt During the Squat: A Biomechanical Perspective and Possible Solution with Short-Term Exercise Intervention

Background: Posterior pelvic tilt during the squat, commonly referred to as “butt wink” can potentially increase the risk of spine injury when squatting this way. The main goal of this study is to objectively assess the immediate effect of a short-term exercise intervention on the total pelvis range of motion in the sagittal plane (mainly posterior pelvic tilt). Methods: This study has a quasi-experimental design with the participants divided into experimental and control groups based on pre-existing condition—occurrence of PTT during bodyweight squat. A total of 42 participants (21 females and 21 males) were divided into an experimental group (n = 23) and a control group (n = 19). The division was made according to the incidence of posterior pelvic tilt during the bodyweight squat. Qualisys, three-dimensional kinematic motion analysis with Functional Assessment module, was used to analyze pelvis kinematics. Both groups underwent a twenty-minute exercise intervention aimed at strengthening trunk stabilizing muscles, improving squat technique and body awareness in space. Data from the three-dimensional kinematic motion analysis were statistically processed using Restricted Maximum Likelihood analysis (REML) of linear mixed models and repeated measures analysis of variance (rANOVA); Results: There was no statistically significant difference in the range of motion of posterior pelvic tilt before and after the exercise intervention (p = 0.89 and p = 0.42). Only the individual repetitions of the squat were statistically significantly different from each other (p < 0.001) and no statistically significant relationship between posterior pelvic tilt and initial pelvic position was found (p = 0.13). Conclusions: The short exercise intervention did not acutely alter pelvic kinematics (the range of motion of posterior pelvic tilt). Future research should focus on longer exercise interventions (4–8 weeks) with progressive loading and looking for possible associations between different variables of squat execution and the incidence of posterior pelvic tilt.