THE EFFECT OF AN ANTI-GRAVITY TREADMILL ON RUNNING CADENCE

BACKGROUND: Running cadence, or step rate, is often measured in running gait analysis and manipulated in gait retraining. A lower body positive pressure treadmill, or anti-gravity treadmill, allows users to walk/run in a reduced gravity environment. PURPOSE: The primary purpose of this study was to determine how natural running cadence is affected by running on an anti-gravity treadmill compared to a standard treadmill in a healthy, active population. The secondary purpose was to determine if natural and increased cadence is affected by amount of body weight support. STUDY DESIGN: Cross-sectional study (convenience sample). METHODS: M320) at their pre-determined, self-selected, comfortable treadmill speed. Cadence was recorded at nine randomized bodyweight conditions, ranging from 100% of body weight to 20% of body weight, in 10% increments. An additional nine participants were recruited to try to replicate their natural, standard treadmill cadence, as well as increase it by 5% and 10%, while on an anti-gravity treadmill with the same randomized body weight conditions. RESULTS: Thirty participants, 19 females and 11 males, mean age 27.3 years (range, 22-45), completed Part 1 of the study protocol, while nine additional participants (2 females and 7 males) with a mean age of 29.6 years old (range, 25-40 years) completed Part 2 of the protocol. There was a significant effect of natural running cadence on the anti-gravity treadmill at reduced body weight percentages (p<.01). Post-hoc t-tests revealed that every 10% bodyweight interval was significantly lower than the previous 10% interval (p<.01) on the anti-gravity treadmill, with cadence decreases ranging from 1.5%-3.5% between intervals. Seven of the nine (77.8%) participants in Part 2 were able to replicate and increase their cadence at all body weight levels on the anti-gravity treadmill. CONCLUSIONS: Decreasing bodyweight level on an anti-gravity treadmill yields a significant and linear decrease in running cadence when performed at a self-selected, moderate intensity pace. Further, the vast majority of participants were able to successfully replicate and increase cadence at all levels of bodyweight percentage.