Comparison of habitual stepping cadence analysis methods: Relationship with step counts.

BACKGROUND: Different approaches have been implemented to calculate stepping cadence (steps/min) that vary in the time demominator used. Given the differences in how stepping intensity are calculated, it is unclear if they are more so associated with total step counts. RESEARCH OBJECTIVE: This study compared three methods of calculating stepping cadence and determined their relationship with total step counts. METHODS: 132 participants (74♀; 35 ± 20 years; body mass index: 24.9 ± 4.0 kg•m-2) wore an activPAL monitor 24-hr/day for up to 8-d (total: 869-d). The total steps/day, time spent stepping (0.1 s resolution; to calculate bout stepping rate), time spent stepping in 60 s epochs (step accumulation), and awake time (awake cadence) were determined. Each cadence method (in steps/min) were compared via Spearman's rank correlation. The relationships versus total step count were determined, and the strength of these relationships compared between cadence measures (95% confidence interval of correlation differences). RESULTS: Bout stepping rate (85 ± 14 steps/min) was larger than step accumulation (34 ± 12 steps/min) and awake cadence (10 ± 5 steps/min, both: P < 0.001). Step accumulation was positively strongly related to bout stepping rate (ρ = 0.813; P < 0.001) whereas awake cadence was weakly related to bout stepping rate (ρ = 0.496; P < 0.001). Step accumulation (ρ = 0.634; P < 0.001) and awake cadence (ρ = 0.964; P < 0.001) were more related to step counts than bout stepping rate (ρ = 0.497; P < 0.001; 95% confidence intervals of correlation differences: step accumulation=0.10-0.17, awake cadence: 0.42-0.52). SIGNIFICANCE: Without a precise measure of time spent stepping, stepping cadence is lower using the step accumulation and awake cadence methods. Step accumulation and awake cadence are more related to total step counts than bout stepping rate. Bout stepping rate outcomes reflect continuous stepping rate, does not rely on a preset epoch, and may have less overlap with step counts, which may have implications for determining the unique contributions of step count versus stepping cadence on health outcomes.

Assessment of Free-Living Cadence Using ActiGraph Accelerometers Between Individuals With and Without Anterior Cruciate Ligament Reconstruction.

CONTEXT: Anterior cruciate ligament reconstruction (ACLR) and gait speed are risk factors for developing knee osteoarthritis (OA). Measuring minute-level cadence during free-living activities may aid in identifying individuals at elevated risk of developing slow habitual gait speed and, in the long term, OA. OBJECTIVE: To assess differences in peak 1-minute cadence and weekly time in different cadence intensities between individuals with and without ACLR. DESIGN: Cross-sectional study. SETTING: Short-term, free-living conditions. PATIENTS OR OTHER PARTICIPANTS: A total of 57 participants with ACLR (34 women, 23 men; age = 20.9 ± 3.2 years, time since surgery = 28.7 ± 17.7 months) and 42 healthy control participants (22 women, 20 men; age = 20.7 ± 1.7 years). MAIN OUTCOME MEASURE(S): Each participant wore a physical activity monitor for 7 days. Data were collected at 30 Hz, processed in 60-second epochs, and included in the analyses if the activity monitor was worn for at least 10 hours per day over 4 days. Mean daily steps, peak 1-minute cadence, and weekly minutes spent at 60 to 79 (slow walking), 80 to 99 (medium walking), 100 to 119 (brisk walking), ≥100 (moderate- to vigorous-intensity ambulation), and ≥130 (vigorous-intensity ambulation) steps per minute were calculated. One-way analyses of covariance were conducted to determine differences between groups, controlling for height and activity-monitor wear time. RESULTS: Those with ACLR took fewer daily steps (8422 ± 2663 versus 10 033 ± 3046 steps; P = .005) and spent fewer weekly minutes in moderate- to vigorous-intensity cadence (175.8 ± 116.5 minutes versus 218.5 ± 137.1 minutes; P = .048) than participants without ACLR. We observed no differences in minutes spent at slow (ACLR = 77.4 ± 40.5 minutes versus control = 83.9 ± 34.3 minutes; P = .88), medium (ACLR = 71.6 ± 40.2 minutes versus control = 82.9 ± 46.8 minutes; P = .56), brisk (ACLR = 115.3 ± 70.3 minutes versus control = 138.3 ± 73.3 minutes; P = .18), or vigorous-intensity (ACLR = 24.3 ± 36.5 minutes versus control = 38.1 ± 60.9 minutes; P = .10) cadences per week. CONCLUSIONS: Participants with ACLR walked approximately 40 fewer minutes per week in moderate- to vigorous-intensity cadence than participants without ACLR. Increasing the time spent at cadence ≥100 steps per minute and overall volume of physical activity may be useful as interventional targets to help reduce the risk of early development of OA after ACLR.