Knee Extensor Strength in Anterior Cruciate Ligament-Deficient Individuals Following Normal and Modified Squats: A Randomized Controlled Trial

• Liane M.Y. Jean ^[1] ; Douglas P. Gross ^[1] ; Loren Z. F. Chiu
  1. [1] University of Alberta

     University of Alberta

     Canadá

     
• Localización: Journal of strength and conditioning research: the research journal of the NSCA, ISSN 1064-8011, Vol. 36, Nº. 1, 2022, págs. 47-54
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Training with barbell squats, which load the quadriceps, increases knee extensor strength. Anterior cruciate ligament (ACL) injury results in a quadriceps avoidance substitution strategy, which may impair the efficacy of barbell squat training. Modified squats to promote quadriceps loading have been proposed to facilitate restoring knee extensor strength and function. This research compared resistance training using traditional squats (TRAD) versus traditional plus modified squats (EXP) in ACL-deficient individuals. Thirty-seven ACL-deficient individuals were randomly assigned to TRAD or EXP. Knee extensor function was assessed using maximum isometric strength testing and 3D motion analysis of sit-to-stand. Effect sizes for minimum meaningful improvement were established (d = 0.28-0.47). There were no significant differences between TRAD and EXP for knee extensor strength before, in response to, or after the training interventions (p > 0.05). Involved limb knee extensor strength increased at 15[degrees] (95% CI [0.09, 0.27] N[middle dot]m[middle dot]kgBM-1, d = 0.60), 30[degrees] (95% CI [0.25, 0.48] N[middle dot]m[middle dot]kgBM-1, d = 0.82), 45[degrees] (95% CI [0.32, 0.58] N[middle dot]m[middle dot]kgBM-1, d = 0.78), and 75[degrees] (95% CI [0.18, 0.46] N[middle dot]m[middle dot]kgBM-1, d = 0.54) knee flexion. Involved limb knee extensor net joint moment work in sit-to-stand (95% CI [0.034, 0.135] J[middle dot]kgBM-1, d = 0.48) increased in both groups. Squat training was effective for increasing involved limb isometric knee extensor strength and knee extensor work performed in the sit-to-stand. Modified squats do not seem to provide additional benefit.