Comparisons Of Patellofemoral Joint Loading Variable And Kinematics Across Split Squat Variations

Patellofemoral pain (PFP) is common in active females. Increased patellofemoral (PF) force may increase symptoms. Understanding PF loading in split squat (SS) variations may guide exercise progression. PURPOSE: Examine differences in PF joint related loading variables and kinematics during SS variations. METHODS: 27 college-aged, recreationally active females were measured using three-dimensional kinematic data (180 Hz) from a 16-camera motion analysis system and kinetic (1800 Hz) data from a force platform. In a random order, the following were performed: a SS with both feet on the floor (baseline), a SS with the posterior foot elevated on a 41 cm box (standard bench height), and a SS with the posterior foot elevated on a 61 cm box. Stance width for each variation was 75% of leg length. All completed seven repetitions per variation at a set rate of 60 bpm using a metronome. Inverse dynamics and static optimization using a 16-segment musculoskeletal model determined muscle forces and kinematics. These data were used to calculate PF force. A repeated measures ANOVA was used to determine differences among the 3 variations (α = 0.05). Post-hoc comparisons were performed using the Bonferroni technique. RESULTS: Differences in PF joint loading was shown among SS variations (p < 0.05). Use of the 61 cm box decreased PF force 20% compared to baseline. Quadriceps force decreased from baseline by 12% for the 41 cm box, 21% for the 61 cm box. Compared to the 41 cm box, quadriceps force using a 61 cm box decreased 10%. Ankle range of motion (ROM) decreased 35% and 39% from baseline for the 41 cm box and 61 cm box, respectively. CONCLUSION: SS from a 61 cm box decreased PF force. This may decrease PF joint loading during strengthening exercises for those with PFP. The SS increased knee extensor muscle force compared to the other two variations (41 cm box and 61 cm box). Supported by: UW La Crosse Graduate Studies