Development of a Regression Model for the Treadmill Ground Reaction Force Components

Abstract

Treadmills allow for collecting multiple steps in a small area, and continuous testing for a long period of time with multiple speeds. These factors prove to be useful for biomechanics research laboratories that are usually equipped with floor embedded platforms. Acquiring instrumented treadmills with a built in force plate(s) – may not be financially feasible for many general purpose biomechanics laboratories; additionally instrumented treadmills only measures the vertical component of ground reaction force. The purpose of this study was to examine the components of Ground Reaction Force (GRF) in treadmill walking which were measured by placing a treadmill over floor-mounted force plates and to develop a set of regression equations to be used in associating treadmill’s GRF components with GRF components obtained during overground walking. The GRF measured during the treadmill walk was compared to GRF measured in overground walking. A total of twelve male subjects participated in this study. The analysis of the data did not reveal statistical differences in the anterior-posterior component of the GRF (APGRFP1 and APGRFP2) and in the early-stance and mid-stance peaks of the vertical GRF (VGRFP1 and VGRFP2) between treadmill and overground walking. Statistical differences between treadmill and overground walking were found during latestance for vertical ground reaction force (VGRFP3) and medial lateral ground reaction force (MLGRFP2) (p<0.05). During push-offoccurring in late-stance-vertical ground reaction force peaks (VGRFP3) were less in treadmill walking than in overground walking by 5-6% (p<0.05). The Medial-lateral ground reaction forces peaks (MLGRFP2) were also less in treadmill walking than in overground walking by 1-2% (p<0.05). In addition, five regression equations were developed for treadmill’s GRF.