Classification of moderate-intensity overground walking speed in 21- to 85-year-old adults

Free-living ambulatory physical activity and cognitive function in multiple sclerosis: the significance of step rate vs. step volume

BACKGROUND

Physical activity (PA) represents a promising behavioral approach for managing cognitive dysfunction in multiple sclerosis (MS). However, there is a lack of information on the pattern of free-living PA intensity (e.g., step rate) and its unique association with cognition. Such information is essential for informing clinical trials in MS.

OBJECTIVE

We examined associations among PA volume and intensity with cognitive function in persons with MS, and intensity was derived from steps-based metrics (peak 30-min cadence [Peak-30CAD], and time spent in incremental cadence bands).

METHODS

We included data from 147 persons with MS who underwent assessments of cognitive function (via Brief International Cognitive Assessment in MS) and wore an ActiGraph GT3X + accelerometer for 7 days. We performed bivariate and partial correlations and regression analyses examining associations among PA metrics and cognitive outcomes.

RESULTS

Higher Peak-30CAD was significantly associated with better performance in cognitive processing speed and verbal learning and memory (rs = 0.19-0.38), and the associations remained significant when controlling for daily steps, age, sex, and years of education (p < 0.05). By comparison, daily steps was only correlated with cognitive processing speed (rs = 0.26), and the association was non-significant when controlling for Peak-30CAD and covariates. There were stronger correlations among time spent in higher intensity cadence bands with cognitive performance (rs = 0.18-0.38).

CONCLUSION

Our results highlight the important role of PA intensity for cognition in MS, and may inform future development of focal PA interventions that focusing on step rate patterns for improving cognition in persons with MS.

Determination of moderate walking intensity using step rate and VO2 reserve in healthy men

OBJECTIVE

This study investigated step rates (SR) during overground walking to estimate the relative aerobic capacity that corresponds to a moderate intensity.

METHODS

The present study utilized a repeated measure, within-subjects design incorporating a counterbalanced order. A total of twenty-three healthy men walked on a 119-meter oval track with artificial turf at self-selected pace (FP), 100, 120, and 140 steps/min for 6 min each while oxygen uptake (VO2), speed (in km/h), distance (in m), and steps (in steps/min) were measured.

RESULTS

During FP, participants walked an average cadence of 117 ± 9.3 steps/minclose to 120 steps/min, which corresponds to 4.7 metabolic equivalents (METs). The estimated VO2 reserve was 30.5% of VO2 reserve at the FP and was close to the 120 steps/min of 33.3%. At the 100 and 140 steps/min, the VO2 reserve were 24.1% and 45.2%, respectively. The regression analysis revealed that an SR of 88.2 elicited 3METs and 17.1% of VO2reserve. Additionally, an SR of 129 elicited 5.9METs and 40% of VO2 reserve.

CONCLUSIONS

This study demonstrated that a moderate walking intensity for young, healthy men corresponded to 128.9 steps per minute. A range of 120 ~ 140 steps/min for walking could be recommended as a general guideline for moderate-intensity exercise. However, concerning providing public guidelines, caution should be taken regarding determining the moderate walking intensity due to the individual's fitness level.

Free-Living Peak Cadence in Multiple Sclerosis: A New Measure of Real-World Walking?

BACKGROUND

Physical function and walking performance have become important outcomes in clinical trials and rehabilitation involving persons with multiple sclerosis (MS). However, assessments conducted in controlled settings may not reflect real-world capacity and movement in a natural environment. Peak cadence via accelerometry might represent a novel measure of walking intensity and prolonged natural effort under free-living conditions.

OBJECTIVE

We compared peak 30-minute cadence, peak 1-minute cadence, and time spent in incremental cadence bands between persons with MS and healthy controls, and examined the associations between peak cadence and laboratory-assessed physical function and walking performance.

METHODS

Participants (147 MS and 54 healthy controls) completed questionnaires on disability status and self-reported physical activity, underwent the Short Physical Performance Battery, Timed 25-Foot Walk, Timed Up and Go, and 6-Minute Walk, and wore an accelerometer for 7 days. We performed independent samples t-tests and Spearman bivariate and partial correlations adjusting for daily steps.

RESULTS

The MS sample demonstrated lower physical function and walking performance scores, daily steps, and peak cadence (P < .001), and spent less time in purposeful steps and slow-to-brisk walking (40-119 steps/minutes), but accumulated more incidental movement (1-19 steps/minutes) than healthy controls. The associations between peak cadence and performance outcomes were strong in MS (|rs| = 0.59-0.68) and remained significant after controlling for daily steps (|prs| = 0.22-0.44), P-values < .01. Peak cadence was inversely correlated with age and disability, regardless of daily steps (P < .01).

CONCLUSIONS

Our findings provide preliminary evidence for the potential use of peak cadence with step-based metrics for comprehensively evaluating free-living walking performance in MS.