Two- and 3-Dimensional Knee Valgus Are Reduced After an Exercise Intervention in Young Adults With Demonstrable Valgus During Squatting

Abstract

Context: Two-dimensional (or medial knee displacement [MKD]) and 3-dimensional (3D) knee valgus are theorized to contribute to anterior cruciate ligament injuries. However, whether these displacements can be improved in the doublelegged squat (DLS) after an exercise intervention is unclear.Objective: To determine if MKD and 3D knee valgus are improved in a DLS after an exercise intervention.Design: Randomized controlled clinical trial. Setting: Research laboratory. Patients or Other Participants: A total of 32 participants were enrolled in this study and were randomly assigned to the control (n ¼ 16) or intervention (n ¼ 16) group. During a DLS, all participants demonstrated knee valgus that was corrected with a heel lift.Intervention(s): The intervention group completed 10 sessions of directed exercise that focused on hip and ankle strength and flexibility over a 2-to 3-week period.Main Outcome Measure(s): We assessed MKD and 3D knee valgus during the DLS using an electromagnetic tracking system. Hip strength and ankle-dorsiflexion range of motion were measured. Change scores were calculated for MKD and 3D valgus at 0%, 10%, 20%, 30%, 40%, and 50% phases, and group (2 levels)-by phase (6 levels) repeated-measures analyses of variance were conducted. Independent t tests were used to compare change scores in other variables (a , .05).Results: The MKD decreased from 20% to 50% of the DLS (P ¼ .02) and 3D knee valgus improved from 30% to 50% of the squat phase (P ¼ .001). Ankle-dorsiflexion range of motion (knee extended) increased in the intervention group (P ¼ .009). No other significant findings were observed (P . .05).Conclusions: The intervention reduced MKD and 3D knee valgus during a DLS. The intervention also increased ankle range of motion. Our inclusion criteria might have limited our ability to observe changes in hip strength.Key Words: movement analysis, screening, anterior cruciate ligament, dynamic knee valgus, dorsiflexion Key PointsA systemic corrective exercise program decreased 2-and 3-dimensional knee valgus and increased ankledorsiflexion flexibility during a double-legged squat. Hip-extension and -abduction strength increased after the exercise program, but the findings were not statistically significant.

Differences and correlations in knee and hip mechanics during single-leg landing, single-leg squat, double-leg landing, and double-leg squat tasks

“…Previous investigators have utilized landings and squats to assess lower extremity biomechanics associated with ACL loading and injury risks (Ali et al, 2013;Bell et al, 2013;Hewett et al, 2005;Lyle et al, 2014;Nguyen et al, 2011;Padua, 2012;Padua et al, 2012;Stensrud et al, 2011). In the current study, the differences and correlations for five biomechanical variables were identified during a single-leg landing, a single-leg squat, a double-leg landing, and a double-leg squat.…”

“…Therefore, it is valuable to evaluate lower extremity biomechanics during single-leg landings. In addition, double-leg squats (Bell, Oates, Clark, & Padua, 2013;Padua, Bell, & Clark, 2012) and single-leg squats (Nguyen, Shultz, Schmitz, Luecht, & Perrin, 2011;Stensrud, Myklebust, 2 M.R. Donohue et al Kristianslund, Bahr, & Krosshaug, 2011) have been used to assess lower extremity biomechanics.…”

A resistance band increased internal hip abduction moments and gluteus medius activation during pre-landing and early-landing

“…Collecting bilateral data would demonstrate whether stance width changed between conditions. We examined gluteus medius activation as a factor related to knee abduction without including other factors such as ankle muscles and ankle motion (Bell et al, 2013;Padua et al, 2012aPadua et al, , 2012b. Only one resistance band and one band placement were evaluated.…”

Getting Back To Exercise Without Pain: The Knee

“…it might be an equally important factor that weak buttocks are usually coupled with the presence of a stiff ankle and lack of dorsiflexion, where the foot's upward movement to the shin in weight-bearing exercises is limited (30). This subsequently forces the foot to pronate in order to gain range while in the squatting position (2,3). These impacting factors will be revisited in my next article of the series about the ankle complex.…”