A Novel Noninvasive Method for Measuring Fatigability of the Quadriceps Muscle in Noncooperating Healthy Subjects
Table 1
Descriptive and reliability data.
Variable
Test visit
Retest visit
Difference
ICC3.1 (95% CI)
SEM (95% CI)
MDC95%
Motor threshold (mA)
Vastus medialis
16.32 ± 4.53
17.68 ± 4.45
1.36 ± 1.85
0.92 (0.72–0.98)
1.29 (−1.24–3.82)
3.57
Vastus lateralis
18.86 ± 2.96
19.86 ± 1.63
1.00 ± 1.41
0.64 (0.11–0.89)
1.02 (−0.98–3.03)
2.84
Tetanic contractions
Peak torque (Nm)
27.03 ± 14.76
29.28 ± 17.09
2.25 ± 3.90
0.97 (0.89–0.99)
2.70 (−2.59–7.99)
7.48
Fatigue Index
Interval 1 (contract. 1–15)
0.57 ± 0.11
0.59 ± 0.11
0.02 ± 0.06
0.84 (0.51–0.95)
0.04 (−0.04–0.12)
0.12
Interval 2 (contract. 16–30)
0.69 ± 0.08
0.70 ± 0.09
0.01 ± 0.09
0.51 (0.09–0.84)
0.06 (−0.06–0.18)
0.17
Interval 3 (contract. 1–30)
0.33 ± 0.08
0.35 ± 0.10
0.02 ± 0.05
0.82 (0.46–0.95)
0.04 (−0.04–0.11)
0.10
Interval 4 (contract. 1–40)
0.30 ± 0.09
0.31 ± 0.10
0.01 ± 0.07
0.71 (0.22–0.91)
0.05 (−0.05–0.15)
0.14
Slope of regression line (Nm/s)
Interval 1
−0.86 ± 0.20
−0.82 ± 0.23
0.04 ± 0.14
0.77 (0.36–0.93)
0.10 (−0.10–0.30)
0.28
Interval 2
−0.25 ± 0.08
−0.23 ± 0.07
0.02 ± 0.08
0.52 (−0.08–0.84)
0.05 (−0.05–0.16)
0.15
Interval 3
−0.20 ± 0.12
−0.20 ± 0.12
0.00 ± 0.02
0.99 (0.96–1.00)
0.01 (−0.01–0.04)
0.03
Interval 4
−0.19 ± 0.11
−0.14 ± 0.09
0.05 ± 0.05
0.85 (0.54–0.96)
0.04 (−0.04–0.11)
0.11
Twitch contractions
Initial twitch series
Peak torque (Nm)
2.63 ± 1.32
2.95 ± 1.33
0.32 ± 1.12
0.64 (0.11–0.89)
0.78 (−0.75–2.30)
2.16
Rise time (Nm/s)
40.60 ± 17.94
35.52 ± 15.49
−5.08 ± 9.45
0.84 (0.51–0.96)
6.61 (−6.34–19.55)
18.31
Final twitch series
Peak torque (Nm)
1.23 ± 0.65
1.33 ± 0.60
0.10 ± 0.33
0.87 (0.58–0.96)
0.23 (−0.22–0.67)
0.62
Rise time (Nm/s)
20.82 ± 11.50
17.78 ± 8.92
−3.04 ± 10.65
NS
Data are expressed as means ± standard deviations.
ICC3.1: intraclass correlation coefficients; CI: confidence interval; SEM: standard error of measurement; MDC95%: minimal detectable change; mA: milliamperes; Nm: newton meters; NS: not significant.
