Electromyographic changes in the gluteus medius during stair ascent and descent in subjects with anterior knee pain

Abstract

Ascending and descending stairs is a provocative activity for anterior knee pain (AKP) patients. The gluteus medius (GM) acts on the lower extremity in the frontal plane and can affect forces at the knee. Determining activation patterns of the GM in patients with AKP can help identify efficacy of training the GM in this population. This study examined electromyographic (EMG) firing patterns in lower extremity muscles in subjects with AKP while ascending and descending stairs. Subjects in the AKP group ( n=16) demonstrated general AKP for at least 2 months compared to the control group ( n=12); neither group had any history of knee trauma. Subjects were instrumented with EMG electrodes on the vastus medialis oblique (VMO), vastus lateralis (VL), and GM. Retroreflective markers were placed on lower extremities to determine knee flexion angle, and frontal plane pelvis orientation at toe contact. Subjects then performed a series of five stair (height=18 cm) ascent and descent trials. Repeated measures analyses of variance were performed on EMG and kinematic variables, between the two groups and between the symptomatic and asymptomatic sides. In the AKP group the GM demonstrated delayed onset and shorter durations for stair ascent and shorter duration during descent. There were no significant differences between sides in the AKP group. Consistent with previous studies, subjects in the AKP group demonstrated no difference in the VMO onsets relative to VL onsets compared to the control group. Changes in neuromuscular activity patterns may be a result of a compensations strategy due to AKP. Training of GM and other hip muscles is warranted during rehabilitation of AKP patients.

Comparison of the VMO/VL EMG Ratio and Onset Timing of VMO Relative to VL in Subjects with and without Patellofemoral Pain Syndrome

“…However, it has been noted by Powers et al 20) that there is no significant onset timing difference between VMO and VL when walking on a flat surface, ascending/descending stairs, or walking up or down a slope. In contrast to the present study, Brindle et al 21) showed that the onset timing difference between the VMO and VL in PFPS patients was −17.50 ms during ascent,similar to normal individuals(−13.70 ms).…”

Influence of Step Height on Quadriceps Onset Timing and Activation During Stair Ascent in Individuals With Patellofemoral Pain Syndrome

“…Further, relative onset timing and activation ratios (magnitude and duration) were not significantly different across step heights, with no correlation observed between knee flexion angle at foot-step contact and any of these muscle activity variables. Step Our findings are consistent with previous studies that have demonstrated no difference in onset timing 7,17,24,28 and activation magnitude ratio 5,28,29,34 of the VMO and VL between individuals with and without PFPS. This study is the first to systematically test VMO and VL relative onset timing and activation magnitude ratios across various step heights and knee flexion angles.…”

“…That is, the control subjects displayed similar activation duration of the VMO and VL during the stepping task, while the subjects with PFPS showed an early cessation of the VL. As both groups performed the task at a constant cadence (96 steps per minute), the change in VL activation duration can not be attributed to different stepping speeds as suggested by Brindle et al 7 Further, the similarity in activation onset times between the 2 groups indicates that the reduction in VL activation time occurred toward the end of the stepping task, with a corresponding knee flexion angle of less than 20°. As this phase of stepping corresponds to a small knee extension moment, 27 the significance of this early VL cessation to functional performance may be questioned.…”

Functional relevance of the small muscles crossing the ankle joint – the bottom-up approach

“…One theory suggests that increased muscular strength around the hip and the core should help to reduce lower extremity joint movement and external joint moments at the lower extremities during running, and thus, reduce the frequency of running injuries (Hott, Liavaag, Juel, & Brox, 2015;Palmer, Hebron, & Williams, 2015;Powers, 2010). This approach could be called a top-down approach (Barton, Lack, Malliaras, & Morrissey, 2012, Brindle, Mattacola, & McCrory, 2003Brumitt, 2009;Grelsamer & McConnell, 1998;Fredericson & Moore, 2005;Hollman, Kolbeck, Hitchcick, Koverman, & Krause, 2005;Hollman et al, 2006;Powers, 2010;). However, related experimental studies have shown no general support for the concept that strengthening the hip muscles affects the running mechanics such as range of motion and external moments during dynamic tasks (Herman et al, 2008;Willy & Davis, 2011;Palmer et al, 2015) suggesting that the top-down approach does not produce a change in the mechanics of the knee and ankle joint.…”