Hip joint forces Hip joint forces of 40 to 60 year old normal and total hip replacement subjects during walking and stair, ramp and camber negotiation

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Step accumulation per minute epoch is not the same as cadence for free-living adults

Purpose: The term cadence has been used interchangeably to describe both the rate of stepping and the number of steps in a minute epoch. This is only strictly true if walking is continuous within that epoch. This study directly compared these two outcomes in minute epochs of data from free-living adults to assess the scale of any difference between them.Methods: A convenience sample of healthy adults wore an activPAL activity monitor for seven days. The event record output of the activPAL, providing the start time and duration of each stride to the nearest 0.1s, was used to calculate step accumulation (number of steps), duration of walking and cadence (number of steps/ duration of walking) for each minute of measurement.Results: Data from 117 individuals (78 female, mean age 46±16 years, mean BMI 24.9±3.7 kg·m) were analysed. Twenty-one percent of minutes (n=310/day) contained walking. The distribution (most minutes less than 40 steps/min) and mean (34±9 steps/min) of step accumulation, was very different from that of cadence (most minutes between 60-100 steps/min, mean 76±6 steps/min). Only 12% of minutes with stepping were walked continuously, while 69% of minutes with stepping contained less than 30s of walking. This is key to the difference between step accumulation and cadence, and means that cadence cannot be reconstructed from step accumulation without also knowing the duration that was walked.Conclusion: Step accumulation, the number of steps in a fixed period of time, and cadence, the rate of stepping whilst walking, are not interchangeable outcome measures. It is vitally important that unambiguous terminology is used to describe the rate of stepping so that the outcomes of studies can be correctly interpreted