Preliminary Analysis of a Randomized Parallel Trial: A 10-Week Training Program Comparing Traditional and Single-Foot Elevated Full Squats in ACL Injured Persons

• Author / Creator

  Jean, Liane MY

• Quadriceps atrophy and weakness is a common sequela following ACL injury. Restoring quadriceps function, defined as coordination, size and strength, is imperative for individuals to return to activity to the same level prior to injury. Current rehabilitation programs are unable to fully restore quadriceps function. Therefore, the purpose of this study was to investigate differences in quadriceps strength, kinetics and function during multi-joint tasks between traditional and single-foot elevated squats after a 10-week training program emphasizing full depth squats. A randomized parallel trials research design was employed. ACL injured persons, prior to surgery were randomly assigned to a traditional (n=10) or single-foot elevated (n=10) group. The traditional group performed plate squats with both feet on the ground, the single-foot elevated group performed plate squats with the non-involved limb placed on a 5 cm platform. Maximal isometric knee extensor strength was measure between 15°-75° of knee flexion. Motion analysis was used to measure ankle, knee and hip extensor work during sit-to-stands, vertical jumping and landing. ANOVA and cohen’s d effect sizes were used to compare between the involved and non-involved limb and from pre- to post-intervention. Maximal isometric knee extensor strength increased at all knee flexion angles. Further, knee extensor asymmetry between 30°-75° knee flexion was eliminated post- intervention. Knee extensor work increased in the involved limb post-intervention in the traditional (d=0.25) and single foot elevated group (d=0.38). However, the non-involved limb also had an increase in knee extensor work in the traditional (d=0.36) but not the single-foot elevated group (d=-0.02). Resulting in larger knee extensor work asymmetry performed in the traditional squat group (d=0.85) post intervention, but reduced asymmetry in the single-foot elevated group (d=0.67). Concluding, full depth squats was successful at increasing knee extensor strength in both groups. Single-foot elevated squats provided a motor learning effect that transferred to sit-to-stands.

• Subjects / Keywords

  • Quadriceps
  • Knee Extensor Strength
  • Training Intervention
  • ACL
  • Squat

• Graduation date

  Fall 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3C53F61P

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.