Human Walking Kinematic Data for Speed Transitions

Data and code associated with the submitted paper "A Kinematic Model to Predict a Continuous Range of Human-like Walking Speed Transitions" by Greggory F. Murray and Anne E. Martin.

This submission contains the experimental kinematic data for the speed transitions and the code needed to analyze and model the transitions.

The experiment received Institutional Review Board approval from the Pennsylvania State University (study number STUDY00011094), and all subjects provided informed consent. In these experiments, 21 healthy subjects aged 18 to 62 years old (median (range), 10 male, 11 female, height 169 (159–184) cm, mass 68.9 (46.5–90.7) kg, BMI less than 30) walked on a split-belt instrumented treadmill (Bertec, Columbus, OH). Subjects walked in both a constant speed regime and a speed change regime. The constant speed regime consisted of one minute trials at one of 5 leg length and mass normalized walking speeds. For the speed change regime, subjects walked at a starting speed for 14 steps, facing an eye-level visual display with a step counter and a shaded bar chart indicating current speed. After 14 steps, an outlined bar was added to the chart indicating the upcoming treadmill speed. After an anticipatory region of 3 steps, the treadmill accelerated to the new speed. To reach the new speed before the next heel contact, the treadmill accelerated both belts at 2 m/s2 during the single support period of the transition step. These transitions were carried out randomly and sequentially until all 20 unique combinations of speed change had been recorded. Each subject completed 10 of these 20-transition serial speed change trials. During the trials, ground reaction forces (GRF) were measured at 1000 Hz using the force plates embedded in the treadmill. Kinematics were recorded at 100 Hz using a motion capture system (Vicon, Oxford, UK) with the Plug-in gait lower-body marker set. During post-processing, trials with significant gaps in the recorded marker trajectories were omitted. The kinematic data were separated into steps using a GRF threshold of 4.9 N, then resampled to 100 points per step.