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Table 4 Heuristic cadence thresholds (steps/min) for relatively-defined moderate and vigorous intensity based on segmented regression and ROC curve analyses

From: Cadence (steps/min) and relative intensity in 21 to 60-year-olds: the CADENCE-adults study

     Age Groups (years)   
Intensity Level Intensity Indicator Measure Group 1
(2130)
Group 2
(3140)
Group 3
(4150)
Group 4
(5160)
Moderate Intensity ≥ 64%HRmax Threshold (steps/min) 120 120 115 110
Se 87.5 80.0 82.7 66.7
Sp 86.2 87.1 81.1 79.6
PPV 48.6 51.4 47.2 50.5
NPV 97.9 96.2 95.8 88.4
Accuracy 86.4 96.2 95.8 88.4
≥ 40%HRR Threshold (steps/min) 120 120 115 110
Se 91.8 82.4 85.0 83.9
Sp 89.6 89.1 83.7 82.9
PPV 62.5 60.0 56.0 57.1
NPV 98.3 96.2 95.8 95.0
Accuracy 90.0 88.0 84.0 83.1
≥ 12 RPE Threshold (steps/min) 120 120 115 110
Se 76.7 61.2 68.0 67.0
Sp 90.6 92.0 88.0 86.5
PPV 68.1 74.3 72.5 71.4
NPV 93.7 86.2 85.6 83.9
Accuracy 87.7 83.5 81.7 80.0
Vigorous Intensity ≥ 77%HRmax Threshold (steps/min) 135 130 125 120
Se 55.6 69.2 82.3 78.6
Sp 97.0 93.9 90.0 87.3
PPV 35.7 33.3 32.6 23.9
NPV 98.6 98.6 98.9 98.8
Accuracy 95.8 92.9 89.5 86.9
≥ 60%HRR Threshold (steps/min) 135 130 125 120
Se 60.0 62.5 76.2 78.6
Sp 97.3 94.2 90.5 87.3
PPV 42.9 37.0 89.5 23.9
NPV 98.6 97.9 37.1 98.8
Accuracy 96.1 92.6 89.5 86.9
≥ 14 RPE Threshold (steps/min) 135 130 125 120
Se 50.0 63.2 61.9 81.0
Sp 98.0 94.8 89.5 89.2
PPV 95.5 92.9 87.6 88.6
NPV 57.1 44.4 30.2 37.0
Accuracy 97.3 97.5 97.0 98.4
  1. Trade-offs in terms of Se Sensitivity, Sp Specificity, PPV Positive Predictive Value, NPV Negative Predictive Value, and overall accuracy between the thresholds derived from the segmented regression and the ROC Receiver Operating Characteristic analyses were considered. The finally selected heuristic thresholds purposely reflected a favored tolerance for false negative versus false positive classifications