Table 3.
Cadence thresholds (steps/min) for relatively-defined intensity indicators of moderate and vigorous intensity based on regression and ROC curve analyses
| Regression | ROC | ||
|---|---|---|---|
| Moderate Intensity | |||
| ≥ 64% HR max | Threshold (steps/min) | 105.9 (38.0-135.7) | 104.3 (97.1-110.7) |
| Se | 60.5 | 65.6 | |
| Sp | 78.0 | 75.8 | |
| PPV | 60.2 | 59.8 | |
| NPV | 78.2 | 80.1 | |
| Accuracy | 71.8 | 72.2 | |
| AUC | – | 76.7 (72.5–80.9) | |
| ≥ 40% HRR | Threshold (steps/min) | 107.1 (38.0-129.8) | 103.3 (100.8-110.7) |
| Se | 66.3 | 77.5 | |
| Sp | 83.5 | 75.6 | |
| PPV | 64.0 | 58.5 | |
| NPV | 84.8 | 88.3 | |
| Accuracy | 78.2 | 76.2 | |
| AUC | – | 83.1 (79.3–86.9) | |
| ≥ 12 RPE | Threshold (steps/min) | 112.8 (46.6-148.4) | 102.0 (95.8-104.1) |
| Se | 40.1 | 71.0 | |
| Sp | 88.3 | 74.9 | |
| PPV | 67.5 | 63.1 | |
| NPV | 71.0 | 81.1 | |
| Accuracy | 70.2 | 73.5 | |
| AUC | – | 78.2 (74.3–82.0) | |
| Vigorous Intensity | |||
| ≥ 77% HR max | Threshold (steps/min) | 126.1 (79.0-148.4) | 116.0 (97.1-128.6) |
| Se | 36.0 | 60.0 | |
| Sp | 96.0 | 85.9 | |
| PPV | 30.0 | 16.9 | |
| NPV | 96.9 | 97.8 | |
| Accuracy | 93.3 | 84.7 | |
| AUC | – | 76.1 (65.4–86.8) | |
| ≥ 60% HRR | Threshold (steps/min) | 126.4 (103.6-148.4) | 109.7 (109.7-119.1) |
| Se | 46.2 | 92.3 | |
| Sp | 96.9 | 76.0 | |
| PPV | 42.9 | 16.0 | |
| NPV | 97.3 | 99.5 | |
| Accuracy | 94.5 | 76.7 | |
| AUC | – | 88.4 (80.7–96.1) | |
| ≥ 14 RPE | Threshold (steps/min) | 132.1 (94.9-148.4) | 106.7 (98.1-116.8) |
| Se | 15.8 | 84.2 | |
| Sp | 99.2 | 70.3 | |
| PPV | 60.0 | 17.4 | |
| NPV | 94.1 | 98.4 | |
| Accuracy | 93.5 | 71.3 | |
| AUC | – | 84.4 (78.4–90.3) | |
The thresholds are represented as means (95% Prediction Intervals) for segmented regression and means (99% Confidence Intervals) for Receiver Operating Characteristic (ROC) curve. Classification accuracy analyses to calculate Sensitivity (Se), Specificity (Sp), Positive Predictive Value (PPV), Negative Predictive Value (NPV) and Accuracy were performed independently on these two optimal thresholds derived from segmented regression and ROC curve analysis, therefore yielding two values for each classification accuracy metric. AUC = area under the curve. HR maximum [HRmax] = 220 - age. Heart rate reserve [HRR] = HRmax - HRresting. RPE = Rate of Perceived Exertion