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Table 3 Cadence thresholds (steps/min) for moderate and vigorous relative intensity based on 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)

 

Group 1: Ages 21–30

Group 2: Ages 31–40

Group 3: Ages 41–50

Group 4: Ages 51–60

Regression

ROC

Regression

ROC

Regression

ROC

Regression

ROC

Moderate Intensity

  ≥ 64% HRmax

  Threshold (steps/min)

127.5 (110.4–144.7)

115.5 (114–122.5)

126 (107.2–144.9)

113.5 (110.5–120.5)

122.7 (101.5–143.9)

112.9 (108.7–117.2)

116.1 (65.1–135.9)

104.8 (100.8–112.5)

  Se

60

100

57.8

91.1

57.7

88.5

52.2

85.5

  Sp

95.2

78.4

93.6

79.5

92.5

80.3

89.1

68.8

  PPV

64.9

40.8

60.5

43.2

61.2

47.9

60

46.1

  NPV

94.1

100

92.9

98.1

91.4

97.1

85.7

93.8

  Accuracy

90.6

81.2

88.3

81.2

86.6

81.7

80.3

72.8

  AUC

–

94.4 (91.8–97)

–

92.2 (88.8–95.7)

–

88.5 (84–93.1)

–

82.9 (77.5–88.2)

  ≥ 40% HRR

  Threshold (steps/min)

123.8 (112.2–135.5)

118.5 (114–121.5)

121.3 (108.2–134.5)

114.5 (109.5–119.5)

119.6 (102.9–136.4)

112.9 (110.7–116.1)

113.8 (99.7–128)

106 (100.9–113)

  Se

79.6

91.8

72.5

94.1

71.7

90

72.6

91.9

  Sp

94.2

90.8

91.1

81.8

90.7

82.9

89.5

78.5

  PPV

72.2

65.2

61.7

50.5

65.2

56.3

65.2

53.8

  NPV

96.1

98.3

94.4

98.6

92.9

97.1

92.3

97.3

  Accuracy

91.9

90.9

88

83.8

86.9

84.3

85.9

81.4

  AUC

–

96.7 (94.9–98.5)

–

93.9 (91.3–96.6)

–

90.6 (86.7–94.6)

–

91.6 (88.4–94.9)

  ≥ 12 RPE

  Threshold (steps/min)

126.5 (109.7–143.3)

114.5 (109.5–118.5)

120.2 (93.5–147)

113.5 (103.5–115.5)

117.7 (89.6–145.9)

104.6 (102.6–112.1)

113.3 (85.8–140.9)

103.6 (96.5–111.4)

  Se

51.6

93.8

58.8

75.3

56.7

91.8

56.7

78.4

  Sp

96.7

80.8

93.3

86.2

91.4

77

91.7

81.3

  PPV

80.5

56.1

76.9

67.4

75.3

65

77.5

67.9

  NPV

88.4

98

85.7

90.2

82

95.3

80.8

88.2

  Accuracy

87.4

83.5

83.8

83.2

80.4

81.7

80.0

80.3

  AUC

–

93.7 (91–96.4)

–

87.8 (83.6–91.9)

–

89.2 (85.6–92.8)

–

86.8 (82.7–91)

Vigorous Intensity

  ≥ 77% HRmax

  Threshold (steps/min)

144.1 (126.9–148)

127.5 (127.5–133.5)

142.6 (123.8–156)

121.5 (121.5–128.5)

143.6 (122.5–157.4)

123.2 (116.3–129.7)

132.8 (113.1–151.8)

113 (110.2–124.6)

  Se

22.2

100

15.4

100

17.6

100

28.6

100

  Sp

99.7

90.7

98.6

84.1

99.3

78.2

98.2

72.8

  PPV

66.7

24.3

33.3

21.7

60

21.3

44.4

15.7

  NPV

97.7

100

96.4

100

95.3

100

96.4

100

  Accuracy

97.4

90.9

95.1

84.8

94.8

79.4

94.8

74.1

  AUC

–

96.4 (93.7–99.2)

–

94.4 (91.4–97.4)

–

94.3 (90.7–97.8)

–

92.2 (87.3–97.1)

  ≥ 60% HRR

  Threshold (steps/min)

140.3 (128.6–148)

127.5 (127.5–133.5)

140.2 (127–153.6)

121.5 (121.5–126.5)

139.3 (122.5–156.2)

117.2 (116.3–128.1)

131.6 (117.6–145.9)

113 (110.2–126.2)

  Se

30

100

12.5

100

38.1

100

35.7

100

  Sp

99.3

91

98.6

85

98.6

79.3

97.8

72.8

  PPV

60

27

33.3

26.7

66.7

26.3

45.5

15.7

  NPV

97.7

100

95.4

100

95.6

100

96.8

100

  Accuracy

97.1

91.3

94.2

85.8

94.4

80.7

94.8

74.1

  AUC

–

96.9 (94.6–99.2)

–

94.3 (91.6–97.1)

–

94.6 (91.5–97.8)

–

92.6 (87.7–97.4)

  ≥ 14 RPE

  Threshold (steps/min)

143.9 (127.2–148.0)

124.5 (114.5–130.5)

139.6 (112.9–156.0)

121.5 (104.5–129.5)

138.7 (110.6–157.4)

120.9 (120.5–122.1)

135.2 (107.8–151.8)

122.2 (110.2–126.0)

  Se

12.5

87.5

21.1

84.2

19.0

90.5

23.8

81.0

  Sp

99.7

88.4

99.3

84.8

97.2

85.6

99.3

92.9

  PPV

66.7

29.2

66.7

26.7

33.3

31.7

71.4

47.2

  NPV

95.4

99.2

95.0

98.8

94.2

99.2

94.3

98.4

  Accuracy

95.1

88.3

91.8

84.8

91.8

85.9

93.8

92.1

  AUC

–

94.2 (90.2–98.3)

–

90.0 (83.7–96.3)

–

88.2 (80.7–95.8)

–

92.7 (87.9–97.5)

  1. The thresholds are represented as means (95% Prediction Intervals) for segmented regression and means (99% Confidence Intervals) for ROC Receiver Operating Characteristic. Classification accuracy analyses to calculate Se Sensitivity, Sp Specificity, PPV Positive Predictive Value, NGV Negative Predictive Value and Accuracy were performed independently on these two optimal thresholds derived from segmented regression and ROC 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