Date of Completion


Embargo Period



Dr. Douglas J. Casa, Dr. Craig R. Denegar, Dr. Thomas H. Trojian

Field of Study



Master of Science

Open Access

Open Access



A Comparison of Single Leg Squat and Side Step Cut Kinematics in Healthy and ACL Reconstructed Populations

Jarrett JE Sorge, University of Connecticut

STUDY DESIGN: Case Control Study

OBJECTIVE: To compare single leg squat (SLS) kinematics to side step cut (SSC) kinematics and vertical ground reaction force in individuals with a history of ACL reconstruction and healthy controls.

BACKGROUND: There are currently no objective criteria to progress athletes into cutting activities during rehabilitation. The single leg squat possesses similar three-planar neuromuscular control as a cutting task. Assessing movement dysfunction during the single leg squat could limit injury risk during cutting activities.

METHODS: 44 individuals active in cutting, jumping, or landing activities participated in this study. 22 athletes had a history of ACL reconstruction (14 male, 8 female) Age, years; Height, ; Mass, kg). 22 healthy athletes (14 male, 8 female) with no history of ACL reconstruction or any other lower extremity surgery (Age years; height: ; massserved as a matched control group based on sex, height, mass, age, and activity level. Kinematic data was collected during both tasks; participants completed five single leg squats and two side step cutting tasks on each leg. The means across were determined and correlated between tasks. Independent sample t-tests were used to determine any significance between groups.

RESULTS: Individuals with a history of ACL reconstruction squatted and cut with significantly less sagittal plane motion compared to healthy controls. Healthy controls also cut with more trunk rotation towards the direction of travel and higher VGRF compared to individuals with a history of ACLR. Numerous correlations were seen between tasks.

CONCLUSION: Sagittal, frontal, and transverse plane motion during the SLS were predictive of motion during the SSC. Lack of frontal and transverse plane trunk, hip, and knee control during the SLS resulted in positions of increased lateral trunk flexion, hip adduction, and medial knee displacement during a cutting task. The SLS can be used as a clinical predictor of SSC in athletes during injury prevention or return to play rehabilitation.

Key Words: single leg squat, cutting, side step cut, anterior cruciate ligament, injury prevention

Major Advisor

Dr. Lindsay J. DiStefano