Validity and Reliability of the Newly Developed Surface Electromyography Device for Measuring Muscle Activity during Voluntary Isometric Contraction
Table 1
Reliability comparison of the Biodex System 3 PRO and BTS-FREEEMG, PSL-EMG-Tr1.
Device
Variable
Trial 1
Trial 2
ICC
Difference of means (95% CI)
value
(a) Biceps brachii muscle
MVIC
Biodex (N·m)
Week 1
36.65 ± 14.56
35.98 ± 13.78
0.985
0.68 (−0.9, 2.3)
0.387
Week 2
38.60 ± 14.53
38.59 ± 14.27
0.986
0.01 (−1.6, 1.6)
0.990
BTS-FREEEMG (μV)
Week 1
460.50 ± 257.49
395.52 ± 216.69
0.930
64.98 (14.4, 115.5)
0.014
Week 2
470.34 ± 243.38
413.91 ± 208.48
0.848
56.43 (−18.7, 131.5)
0.132
PSL-EMG-Tr1 (μV)
Week 1
398.07 ± 231.36
435.05 ± 281.16
0.937
−36.98 (−96.3, 22.3)
0.207
Week 2
392.39 ± 227.36
435.65 ± 268.89
0.875
−43.26 (−120.4, 33.9)
0.255
80% MVIC
Biodex (N·m)
Week 1
29.11 ± 11.65
28.52 ± 10.66
0.992
0.60 (−0.3, 1.5)
0.197
Week 2
31.10 ± 11.18
30.95 ± 11.52
0.986
0.15 (−1.1, 1.4)
0.807
BTS-FREEEMG (μV)
Week 1
364.27 ± 220.15
333.32±183.99
0.934
30.95 (−15.2, 77.1)
0.177
Week 2
387.76 ± 220.15
356.38 ± 192.92
0.859
31.08 (−37.13, 99.3)
0.352
PSL-EMG-Tr1 (μV)
Week 1
304.71 ± 198.40
354.03 ± 218.37
0.872
−49.32 (−115.1, 16.4)
0.132
Week 2
324.07 ± 185.61
368.97 ± 233.94
0.916
−44.90 (−97.6, 7.8)
0.090
40% MVIC
Biodex (N·m)
Week 1
14.41±5.74
14.55 ± 5.09
0.986
−0.14 (−0.8, 0.5)
0.645
Week 2
15.48 ± 5.72
15.75 ± 6.00
0.994
−0.28 (−0.7, 0.2)
0.199
BTS-FREEEMG (μV)
Week 1
118.42 ± 81.22
101.81 ± 75.70
0.920
16.61 (−2.5, 35.7)
0.084
Week 2
121.36 ± 75.72
115.91 ± 69.50
0.906
5.45 (−14.8, 25.7)
0.579
PSL-EMG-Tr1 (μV)
Week 1
96.69 ± 67.98
94.32 ± 57.30
0.922
2.36 (−14.2, 19.0)
0.768
Week 2
94.98 ± 53.06
116.68 ± 72.75
0.832
−21.81 (−43.1, −0.5)
0.045
(b) Rectus femoris muscle
MVIC
Biodex (N·m)
Week 1
147.80 ± 40.50
154.08 ± 36.38
0.948
−6.28 (−13.9, 1.4)
0.103
Week 2
159.18 ± 46.04
160.05 ± 45.95
0.981
−0.88 (−6.8, 5.1)
0.762
BTS-FREEEMG (μV)
Week 1
147.82 ± 65.95
144.25 ± 59.11
0.945
3.58 (−10.0, 17.2)
0.588
Week 2
175.99 ± 59.53
156.78 ± 59.53
0.864
19.21 (−2.7, 41.1)
0.082
PSL-EMG-Tr1 (μV)
Week 1
123.96±49.66
124.87 ± 55.45
0.899
−0.91 (−16.1, 14.3)
0.901
Week 2
129.90 ± 52.05
138.30 ± 56.79
0.907
−8.40 (−23.2, 6.4)
0.249
80% MVIC
Biodex (N·m)
Week 1
115.58 ± 31.82
121.67 ± 30.34
0.964
−6.09 (−10.9, −1.3)
0.015
Week 2
127.06 ± 35.52
126.45 ± 35.75
0.977
0.61 (−4.5, 5.7)
0.805
BTS-FREEEMG (μV)
Week 1
118.59 ± 80.28
115.13 ± 51.59
0.910
3.47 (−15.0, 21.9)
0.699
Week 2
136.71 ± 67.52
123.54 ± 48.67
0.898
13.21 (−2.9, 29.3)
0.103
PSL-EMG-Tr1 (μV)
Week 1
95.46 ± 57.58
101.13 ± 49.94
0.922
−5.66 (−19.3, 8.0)
0.396
Week 2
100.46 ± 41.52
109.22 ± 45.45
0.943
−8.76 (−17.6, 0.1)
0.051
40% MVIC
Biodex (N·m)
Week 1
57.70 ± 15.90
61.50 ± 15.37
0.956
−3.80 (−6.3, −1.3)
0.005
Week 2
63.59 ± 18.34
63.81 ± 17.74
0.979
−0.23 (−2.7, 2.2)
0.851
BTS-FREEEMG (μV)
Week 1
43.45 ± 17.65
44.53 ± 16.57
0.931
−1.08 (−5.2, 3.0)
0.590
Week 2
50.89 ± 23.43
48.05 ± 21.21
0.883
2.84 (−4.0, 9.6)
0.393
PSL-EMG-Tr1 (μV)
Week 1
36.15 ± 14.45
39.43 ± 18.16
0.814
−3.28 (−9.3, 2.8)
0.271
Week 2
38.44 ± 15.68
41.24 ± 18.17
0.957
−2.80 (−5.8, 0.2)
0.070
Values are number or mean ± SD. MVIC, maximum voluntary isometric contraction; ICC, intraclass correlation coefficients; paired t-test, ; CI, confidence interval.
