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Table 2 Reliability indices of grip strength test

From: Test-retest reliability and measurement errors of grip strength test in patients with traumatic injuries in the upper extremity: a cross-sectional study

Grip strength n The first test The second test Difference Paired t ICCa (95% CI) SEMb MDC95c
mean ± SD (kg) mean ± SD (kg) mean ± SD (kg) mean (95% CI) (kg) P-value
First trial (healthy) 109 35.4 ± 10.7 35.4 ± 10.4 0.1 ± 3.8 0.1 (−0.7, 0.8) 0.880 0.936 (0.908, 0.956) 2.7 7.4
Mean2d (healthy) 109 34.6 ± 10.2 34.8 ± 10.1 0.2 ± 3.3 0.2 (−0.4, 0.8) 0.503 0.949 (0.926, 0.965) 2.3 6.4
Mean3e (healthy) 109 34.1 ± 9.9 34.3 ± 9.9 0.2 ± 3.0 0.2 (−0.4, 0.7) 0.601 0.956 (0.936, 0.970) 2.1 5.8
First trial (injured) 109 15.0 ± 11.5 15.8 ± 11.6 0.7 ± 3.8 0.7 (0.0, 1.4) 0.052 0.945 (0.920, 0.962) 2.7 7.4
Mean2 (injured) 109 15.1 ± 11.2 15.4 ± 11.4 0.4 ± 2.8 0.4 (−0.1, 0.9) 0.140 0.970 (0.956, 0.979) 2.0 5.4
Mean3 (injured) 109 15.1 ± 11.2 15.4 ± 11.3 0.4 ± 2.5 0.4 (−0.1, 0.8) 0.143 0.974 (0.963, 0.982) 1.8 5.0
Mean3 (injured, ≤ 20 kg) 76 8.9 ± 5.7 9.3 ± 6.1 0.4 ± 2.5 0.4 (−0.2, 1.0) 0.145 0.908 (0.859, 0.941) 1.8 4.9
Mean3 (injured, > 20 kg) 33 29.3 ± 6.6 29.5 ± 6.9 0.2 ± 2.6 0.2 (−0.7, 1.1) 0.659 0.928 (0.859, 0.964) 1.8 5.1
  1. aIntraclass correlation coefficient
  2. bStandard error measurement
  3. cMinimal detectable change with 95% certainty
  4. dMean of the first two trials
  5. eMean of the three trials