The effects of a standard elliptical vs. a modified elliptical with a converging footpath on lower limb kinematics and muscle activity

Abstract

Elliptical trainers that increase the inter-pedal distance may have potential benefits for knee osteoarthritis by decreasing the amount of knee varus. Modifying elliptical trainers with a converging footpath and reduced inter-pedal distance may be beneficial for reducing anterior knee pathology risk by decreasing knee valgus angles. Twenty-one college students participated in a single testing session. Participants exercised on two different elliptical trainers, one modified with a converging footpath and reduced inter-pedal width, and a standard elliptical trainer. Participants exercised for 2 min at three ramps incline at 120 strides per minute and constant work rate. Three-dimensional kinematics and electromyography of the dominant lower limb were recorded. Multiple 2 × 3 (Elliptical x Incline) ANOVAs with Bonferroni corrections were used to compare the two elliptical trainers at each incline for kinematics and muscle activity. The modified elliptical trainer displayed significantly decreased peak knee valgus (p = 0.031, ${\eta }_p^2=0.234$ ), peak knee flexion (p = 0.006, ${\eta }_p^2=0.246$ ), and interactions for peak knee flexion (p = 0.001, ${\eta }_p^2=0.250$ ) and vastus lateralis (p < 0.01, ${\eta }_p^2=0.380$ ) muscle activity compared to the standard elliptical trainer. The decreased peak knee valgus and flexion angles could be beneficial for reducing long-term injury risk for anterior knee pathologies.

Keywords: Elliptical; converging footpath; electromyography; gait; hip; kinematics; knee.