Relationship of the Frontal Knee Alignment Measured by the HKA-Angle with the Relative Activation of the Quadriceps Muscles

Abstract

Purpose: The purpose of this study was to compare Hip-Knee-Ankle(HKA) angle and muscle activation ratio between vastus medialis(VM), rectus femoris(RF), and vastus lateralis (VL), and by this, to examine their relationship. It is aimed to explore how the activation ratio among the muscles involved in patellofemoral kinetics would vary in relation with the frontal alignment of the lower extremity.Subjects and Methods: 26 healthy subjects were recruited for the study. The HKA angles were measured with radiograph. The VM, RF, VL muscle activation level were measured by surface electromyography while each participant performed 4 different types of movement (isometric knee extension, squat, ambulation, step-up) and VM/RF, VM/VL, RF/VL ratios were calculated.Pearson correlation was used to estimate the relationship between the HKA angle and the muscle ratio.Results: There was significant moderate correlation between HKA angle and VM: RF on the left side during ambulation (p<0.05). Moderate correlations were also observed during step-up and squat with less significance (p<0.1). Conclusion:The frontal alignment of the knee measured by the HKA angle was conditionally associated with muscle activation ratio between VM and RF (VM:RF); On the left, during ambulation, step-up, and squat, the more valgus knee tended to correlate with the more VM muscle activation ratio, which is expected to induce more stabilizing effect to the patella and its tracking. It suggests that the frontal alignement measured by the HKA-angle can affect PF kinetics. It also indicates a possibility that increase in valgus alignment of the knee, by the HKA measurement, may not act unfavorably to generate PFP.

Does the relative muscle activation of the vastus medialis, rectus femoris, and vastus lateralis, during the various activities, change in relation to the quadriceps angle?

“…Controversial results and studies on whether larger quadriceps angle is more generative of PFP exist probably and partly for this reason 15 , 16 , 17 ) . Kim et al 18 ) reported in their study where they investigated the correlation between the hip-knee-ankle (HKA) angle and activation the muscles composing quadriceps that, the greater the HKA angle, the more medial muscle’s activation ratio increased in ambulation, which is similar to the findings of this study.…”

The Effect of Motorized vs Non-Motorized Treadmills on Exercise Economy during Acute Sub-maximal Bouts in Collegiate Cross-Country Female Athletes

“…When exercising on a NMT or MT, different gait patterns occur even at the same given speed, creating different tasks in movement (S. M. C. Lee et al, 2008), while changes of speed and gait have been shown to effect muscle activation (Cappellini, Ivanenko, Poppele, & Lacquaniti, 2006). Recent studies have found correlations between a greater hip-knee-ankle (HKA) angle and an increase in medial muscle activation (Kim, Bae, Lee, & Lee, 2016;N. Lee, 2018), however in our study there was a significant difference only in the VL during the walking condition.…”