Quadriceps muscle and squatting deficits after passing return-to-sport testing following anterior cruciate ligament reconstruction

Presenter Information

Vanessa DernerFollow

Advisor Information

Christopher Burcal, Elizabeth Wellsandt

Presentation Type

Poster

Start Date

26-3-2021 12:00 AM

End Date

26-3-2021 12:00 AM

Abstract

Quadriceps muscle and squatting deficits after passing return-to-sport testing following anterior cruciate ligament reconstruction

Vanessa Derner, Austin Post, Mike Wellsandt, Matthew Tao, Elizabeth Wellsandt, Christopher Burcal

Background: Restoration of muscle strength and elimination of biomechanical movement asymmetries are important prior to athletes returning to sports after anterior cruciate ligament reconstruction (ACLR) to reduce rates of reinjury.

Objective: To determine if athletes who pass clinically-based return-to-sport testing after ACLR still demonstrate asymmetry in laboratory-based measures of quadriceps rate of torque development (RTD), isokinetic hamstring strength, and external hip flexion moment to knee flexion moment ratio (hip-to-knee ratio) during bilateral squatting.

Methods: To be eligible, athletes first passed clinically-based return-to-sport testing (>90% limb-symmetry index for quadriceps strength, single-leg hops testing, and self-reported knee function). Within two weeks of passing clinically-based return-to-sport testing, participants completed lab testing including isometric and isokinetic strength testing on an electromechanical dynamometer and 3-dimensional biomechanical analysis of bilateral bodyweight squats.

Results: Ten participants were included (70% female; mean 183 years old; mean 123 months post-ACLR). Participants demonstrated a smaller quadriceps RTD in the involved compared to the uninvolved limb (217.1 N*m/kg*s vs 248.3 N*m/kg*s; p=0.020). A trend towards significance was present for a greater hip-to-knee ratio in the involved versus uninvolved limb (1.43 vs 1.12; p=0.071). The inter-limb difference for isokinetic hamstring strength was not significant (85.7 N*m vs 82.2 N*m; p=0.165).

Conclusions: After passing clinic-based return-to-sport testing, asymmetries still exist in the involved limb for quadriceps RTD and hip to knee ratio, but not in isokinetic hamstring strength. These deficits may be risk factors for future knee injuries and should serve as targets for correction during the return-to-sport phase of rehabilitation.

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Mar 26th, 12:00 AM Mar 26th, 12:00 AM

Quadriceps muscle and squatting deficits after passing return-to-sport testing following anterior cruciate ligament reconstruction

Quadriceps muscle and squatting deficits after passing return-to-sport testing following anterior cruciate ligament reconstruction

Vanessa Derner, Austin Post, Mike Wellsandt, Matthew Tao, Elizabeth Wellsandt, Christopher Burcal

Background: Restoration of muscle strength and elimination of biomechanical movement asymmetries are important prior to athletes returning to sports after anterior cruciate ligament reconstruction (ACLR) to reduce rates of reinjury.

Objective: To determine if athletes who pass clinically-based return-to-sport testing after ACLR still demonstrate asymmetry in laboratory-based measures of quadriceps rate of torque development (RTD), isokinetic hamstring strength, and external hip flexion moment to knee flexion moment ratio (hip-to-knee ratio) during bilateral squatting.

Methods: To be eligible, athletes first passed clinically-based return-to-sport testing (>90% limb-symmetry index for quadriceps strength, single-leg hops testing, and self-reported knee function). Within two weeks of passing clinically-based return-to-sport testing, participants completed lab testing including isometric and isokinetic strength testing on an electromechanical dynamometer and 3-dimensional biomechanical analysis of bilateral bodyweight squats.

Results: Ten participants were included (70% female; mean 183 years old; mean 123 months post-ACLR). Participants demonstrated a smaller quadriceps RTD in the involved compared to the uninvolved limb (217.1 N*m/kg*s vs 248.3 N*m/kg*s; p=0.020). A trend towards significance was present for a greater hip-to-knee ratio in the involved versus uninvolved limb (1.43 vs 1.12; p=0.071). The inter-limb difference for isokinetic hamstring strength was not significant (85.7 N*m vs 82.2 N*m; p=0.165).

Conclusions: After passing clinic-based return-to-sport testing, asymmetries still exist in the involved limb for quadriceps RTD and hip to knee ratio, but not in isokinetic hamstring strength. These deficits may be risk factors for future knee injuries and should serve as targets for correction during the return-to-sport phase of rehabilitation.