Influence of Ramp Position on Joint Biomechanics During Elliptical Trainer Exercise

The elliptical trainer, developed to simulate running while minimizing joint loads, elicits a unique lower extremity biomechanical response. The purpose of this study was to examine the angular kinematics, peak net joint moments, and peak joint powers at the hip, knee and ankle joints while exercising at three different ramp settings on the elliptical trainer exercise machine (Precor EFX).

Twenty-six healthy individuals with no history of lower extremity injury and with previous experience exercising on an elliptical trainer volunteered for this study. Motion was captured with two cameras as subjects performed exercise at three ramp conditions. The pedal resistance was kept constant at the lowest setting. The pedals of the elliptical were fitted with three orthogonal load cells. Video and force data were synchronized and used to perform a 2D inverse dynamics analysis.

As the ramp inclination increased, subjects demonstrated greater amounts of ankle dorsiflexion, knee flexion, hip flexion and lesser degrees of plantar flexion and hip extension (p <.000). Mean peak moments at the ankle joint were not significantly different across the ramp settings, but peak knee extensor and hip flexor moments increased while knee flexor and hip extensor at the hip decreased (p <.000). As the ramp inclination increased, peak positive power at both the knee and hip significantly decreased and negative power decreased at the knee joint (p <.000), though the effect size for these changes was small.

The hip and knee joints were observed as the primary sources of power during exercise on the elliptical trainer at the lowest resistance setting.