Table 4. Between-day reliability for PF and RFD across age categories.
Category
Variable
Mean ±
SD
ICC (95%
CI)
ICC Interpretation
CV (%)
(95% CI)
SEM (95%
CI)
All
PF
1898.93
± 748.81
0.95 (0.92-0.97)
Excellent
7.6 (6.6-8.6)
39.01 (35.11-42.91)
RFD50
3349.71
± 2411.45
0.48 (0.32-0.64)
Poor
39.3 (33.4-45.2)
1282.64
(1154.37-1410.90)
RFD100
3555.87
± 2271.47
0.73 (0.62-0.83)
Moderate
27.8 (23.6-32.0)
614.53
(553.08-675.99)
RFD150
3513.91
± 2025.33
0.79 (0.71-0.87)
Good
22.9 (19.5-26.4)
416.52
(374.87-458.17)
RFD200
3501.99
± 1786.05
0.81 (0.75-0.89)
Good
19.6 (16.3-22.8)
338.10
(304.29-371.92)
RFD250
3289.96
± 1531.18
0.87 (0.82-0.93)
Good
14.7 (12.4-17.1)
205.23
(184.71-225.75)
U12
PF
1036.19
± 184.02
0.77 (0.61-0.93)
Good
7.5 (5.4-9.6)
41.24 (37.11-45.36)
RFD50
1812.85
± 792.50
0.35 (0.04-0.71)
Poor
33.6 (21.3-45.8)
520.12
(468.10-572.13)
RFD100
1822.43
± 738.51
0.35 (0.02-0.69)
Poor
26.3 (16.2-36.3)
450.89
(405.80-495.98)
RFD150
1823.32
± 708.99
0.46 (0.12-0.76)
Poor
23.9 (16.9-30.9)
362.69
(326.42-398.96)
RFD200
1875.15
± 608.47
0.59 (0.31-0.85)
Moderate
19.3 (14.4-24.3)
246.15
(221.53-270.76)
RFD250
1747.53
± 521.38
0.58 (0.35-0.86)
Moderate
16.6 (12.7-20.4)
205.75
(185.17-226.32)
U15
PF
1946.07
± 494.25
0.85 (0.78-0.94)
Good
8.2 (6.6-9.8)
71.88 (64.70-79.07)
RFD50
3469.93
± 2297.85
0.08 (0.00-0.38)
Poor
49.2 (40.0-58.4)
2182.95
(1964.66-2401.25)
RFD100
3543.24
± 1647.33
0.33 (0.10-0.61)
Poor
32.7 (26.5-38.8)
1131.70
(1018.53-1244.87)
RFD150
3424.35
± 1427.75
0.47 (0.28-0.74)
Poor
25.6 (19.9-31.3)
760.71
(684.64-836.78)
RFD200
3417.90
± 1284.60
0.45 (0.30-0.75)
Poor
23.7 (18.0-29.4)
703.89
(633.50-774.28)
RFD250
3263.41
± 1028.98
0.60 (0.47-0.83)
Moderate
16.1 (12.0-20.3)
405.29
(364.76-445.82)
U18
PF
2738.00
± 435.94
0.79 (0.55-0.91)
Good
6.7 (4.9-8.5)
91.86 (82.67-101.05)
RFD50
4778.79
± 2816.51
0.70 (0.43-0.88)
Moderate
28.4 (21.5-35.4)
822.23
(740.00-904.45)
RFD100
5435.97
± 2813.88
0.79 (0.56-0.92)
Good
21.3 (14.7-28.0)
571.56
(514.40-628.71)
RFD150
5487.32
± 2190.50
0.79 (0.56-0.91)
Good
17.7 (11.8-23.7)
458.38
(412.55-504.22)
RFD200
5397.21
± 1609.62
0.79 (0.55-0.91)
Good
13.0 (8.7-17.2)
338.72
(304.84-372.59)
RFD250
4990.62
± 1208.25
0.75 (0.50-0.90)
Good
10.7 (7.3-14.1)
293.14
(263.82-322.45)
PF = peak force; RFD = rate of force development; SD = standard deviation; ICC = intraclass correlation coefficient; CI = confidence interval; CV = coefficient of variation; SEM = standard error of measurement.