Award Date

5-1-2021

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Kinesiology and Nutrition Sciences

First Committee Member

Julia Freedman Silvernail

Second Committee Member

Kai-Yu Ho

Third Committee Member

Brian Schilling

Fourth Committee Member

Xan Goodman

Number of Pages

98

Abstract

The anterior cruciate ligament (ACL) is commonly injured, especially in individuals under the age of 25. ACL reconstruction (ACLR) is the most common treatment after ACL injury, followed by physical therapy. However, successful surgery and completion of rehabilitation, individuals still demonstrate quadriceps weakness and asymmetries during locomotion. To improve these deficits, an intervention that improves quadriceps strength and lower extremity biomechanics during locomotion is required. First, we aimed to complete a systematic review of the literature to determine the efficacy of resistance training in improving outcomes after ACLR. Second, we aimed to identify if a history of resistance training positively influences limb symmetry in individuals with ACLR during locomotion. We hypothesized that due to the strength adaptations of resistance training, individuals with ACLR who resistance train will move more symmetrically than those who do not. Lastly, we aimed to evaluate the relationship between lower extremity LBM and limb symmetry in individuals with ACLR during locomotion. We hypothesized that lower extremity lean body mass (LBM) would be positively associated with limb symmetry.

From our systematic review, we can conclude that resistance training should be used by clinicians in rehabilitation after ACL reconstruction due to the improvements in muscle size and strength. Secondly, we found that during walking, the resistance trained group demonstrated greater LSI for knee range of motion (d=1.20), peak knee flexion angle (d=1.05), and peak knee extensor moment (d=1.51). We found similar results during running, as the resistance trained group demonstrated greater LSI for knee range of motion (d=1.13), peak knee flexion angle (d=1.32), and peak knee extensor moment (d=1.17). During the sit to stand task, the resistance trained group demonstrated greater LSI for peak vertical GRF (d=1.12) and peak knee extensor moment (d=0.71). Lastly, lower extremity LBM was positively associated with knee range of motion LSI (F1,21= 6.16, p=0.022) during walking. For running, lower extremity LBM was positively associated with knee range of motion LSI (F1,21= 4.726, p=0.042), peak knee flexion angle LSI (F1,21= 9.200, p=0.007) and knee extensor moment LSI (F1,21= 8.124, p=0.020). For the sit to stand task, lower extremity LBM was positively associated peak knee extensor moment LSI (F1,21= 6.673, p=0.018).

Our results demonstrate that resistance training is effective in improving muscle strength after surgery. Additionally, individuals who have had ACLR who resistance train after surgery move more symmetrically than those who do not during functional tasks. An adaptation of resistance training is increased lower extremity LBM, which is positively associated with limb symmetry index during locomotion. Therefore, individuals should resistance train after ACLR to increase the odds of moving symmetrically, which has implications for knee osteoarthritis. Furthermore, clinicians should incorporate resistance training and interventions to improve lower extremity LBM after ACLR. Future aims should prospectively investigate the effects of resistance training after ACLR.

Keywords

ACL; ACL reconstruction; anterior cruciate ligament; gait; resistance training

Disciplines

Biomechanics

File Format

pdf

File Size

1182 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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