The Relationship Between Stride Frequency And Speed During Gait At Different Body Weight Support Levels

The relationship between stride frequency (SF) and speed during gait is well researched. However, there is a gap in the research examining the relationship between these parameters when walking and running at matched speeds with different levels of body weight support (BWS). PURPOSE: To compare the relationship of SF and speed when walking and running at the same speed at different levels of BWS. METHODS: Subjects (n = 10, 4 females, 6 males: 42.2 ± 17.6 yrs; 73.5 ± 13.5 kg; 1.70 ± 0.11 m; body fat 19.7 ± 9.6%) completed a familiarization period using various BWS levels using a lower body positive pressure (LBPP) treadmill (Boost Treadmills, OH). An accelerometer (Cometa, Italy) was secured on the surface of the left leg. Prior to data collection, the subject’s walk to run gait transition speed (GTS) was determined (BWS 0%: 1.72 ± 0.28 m·s-1; BWS 20%: 1.72 ± 0.31 m·s-1; BWS 50%: 1.58 ± 0.36 m·s-1). Five test speeds were then determined based upon GTS (GTS, GTS ± 0.09 and ± 0.18 m·s-1). Subjects then completed walking and running at each test speed at 0%, 20%, and 50% BWS. SF was determined using accelerometer data (2000 Hz). Specifically, the resultant acceleration was calculated and then six consecutive peaks were identified with each peak representing the start/end of a stride. SF was calculated as 5 strides divided by the time to complete the 5 strides. A 2 (gait type: walk, run) x 3 (BWS: 0%, 20%, and 50%) x 5 (speed: GTS, GTS ± 0.09, and ± 0.18 m·s-1) repeated measures ANOVA was used with SF as the dependent variable (α = 0.05). RESULTS: SF increased with speed for each BWS level for walking but not running regardless of BWS (<0.05). SF was lower for walking vs. running at each speed and BWS combination (p < 0.05) except for the fastest speed at 50% BWS (p > 0.05). CONCLUSION: The movement strategy during gait at matched speeds was different for walking vs. running, regardless of BWS. At faster speeds and higher BWS levels, SF converged for walking and running. During walking, subjects increased speed by increasing SF for all BWS levels. However, during running at matched speeds, SF did not change across speeds, meaning that stride length increased.