EFFECTS OF ANTERIOR-POSTERIOR LOAD PLACEMENTS IMPOSED BY A TRANSFORMER BAR ON SQUAT BIOMECHANICS

Examining the effect of anterior-posterior load placements imposed by a transformer bar could provide additional options for squatting exercises. The purpose of this study was to quantify trunk and pelvis angles and low back and lower extremity joint moments among the regular back and front squats and four squats with a transformer bar. Twelve males and 12 females performed six different squatting variations with a load of 70% of their one-repetition maximum of the regular front squat: back and front squats with a regular bar, back and front squats with a transformer bar, and squats with more anterior or posterior loads with a transformer bar. Joint angles and moments were extracted at the thigh angle of 70° in the ascending phases, corresponding to a posture close to a parallel squat. Trunk flexion angles were the highest for the transformer bar back squat and transformer bar posterior load squat. The greatest pelvis flexion angles were observed for the regular back squat, transformer bar back squat, and transformer bar posterior load squat. Low back joint moments were the highest for the transformer bar anterior load squat. Hip joint moments were significantly lower for the regular bar front squat compared to the other squat conditions. More posterior load placements resulted in decreased low back moments, increased trunk and pelvis flexion angles, and similar hip and knee moments compared to more anterior load placements. Changing the load placement does not affect low back and lower extremity loading as expected because the trunk and pelvis angles could be adjusted according to load placements. An anterior load placement may result in greater low back moments while a posterior load placement has greater trunk and pelvis flexion, which should be taken into consideration for people with low back impairments