A Comparison of 3D Methods for Identifying the Stance Phase in Treadmill Running for Both Rearfoot and Forefoot Runners

We compared six 3D methods, OptoGait, and Myotest Run for the determination of contact time for runners with different foot strike patterns. Twenty male participants were divided into two groups: the heel group, who attack the ground with the heel (n = 12), and the toe group, who attack the ground with the middle/front of the foot (n = 8). They performed trials at speeds of 8 km/h then 16 km/h. To detect foot strike, the use of peak velocity of 3D markers located on the heel, the fifth metatarsal, and the great toe provided the best results for both groups. To detect the toe off, the minimum vertical position of a 3D marker placed in line with the great toe gave the most satisfactory results for both groups. In this way, the values of contact time measured with the 3D methods are consistent. Values measured with OptoGait appear consistent too, while those of the Myotest Run underestimate the contact time for both speeds. 3D analysis provides interesting opportunities for calculation of contact time for both rearfoot and forefoot runners, using specific peak velocities to determine foot strike and marker displacement to determine toe off.