The effects of treadmill type on heart rate and pain threshold velocity in individuals with lower-extremity musculoskeletal pain.

Abstract

This study utilized a quasi-experimental design in which subjects served as their own controls. To determine whether heart rate, pain threshold velocity, and pain perception varied in patients running on a soft-belt treadmill versus a standard hard-belt treadmill. According to promotional literature, the relatively new Orbiter soft-belt tread produces a greater increase in heart rate at a given velocity as well as a higher velocity tolerance while walking or running. The manufacturer also asserts that decreased forces transmitted through the lower extremity should decrease pain levels while exercising on the soft-belt treadmill. Twenty-seven subjects walked or ran on each of 2 treadmills at incrementally increasing velocities until they experienced either the onset of pain or an increase in pain from baseline levels. Locomotion continued for 2 minutes after that, during which time heart rate and pain level on a visual analog scale (VAS) were recorded. Two univariate paired t tests and a Wilcoxon's signed rank test revealed a greater heart rate and pain threshold velocity when using the soft-belt treadmill with no statistical difference in the pain reported between the 2 treadmills. Our study revealed a 10% higher heart rate and a 14.5% higher pain threshold velocity with the soft-belt treadmill compared to a hard-belt treadmill. These differences are considered clinically meaningful.