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Table 3 Intra- and inter-rater agreement according to Bland and Altman plots and limits of agreement

From: Psychometric properties of a standardized protocol of muscle strength assessment by hand-held dynamometry in healthy adults: a reliability study

Muscle Groups

T value (Sig.)

Mean difference Nm (%)

Mean difference 95% CI in Nm

SD

Limits of agreement in Nm (95% CI)

Lower

Upper

Lower

Upper

Intra-rater agreement (S1-S3)

Shoulder ABD

-0.2 (0.86)

-0.5 (0.6)

-6.1

5.1

14.7

-29.4 (-30.2; -28.5)

28.4 (27.5; 28.4)

Shoulder IR

-0.03 (0.98)

-0.01 (0.04)

-1.1

1.0

2.8

-5.5 (-5.5; -5.4)

5.4 (5.4; 5.5)

Shoulder ER

-0.9(0.40)

-0.4 (1.4)

-1.3

0.5

2.3

-4.9 (-5.6; -4.3)

4.2 (3.6; 4.8)

Shoulder flexors

-3.4 (0.002)

-3.9 (5.5)

-6.2

-1.5

6.3

-16.2 (-22.9; -9.5)

8.4 (1.7; 15.2)

Elbow flexors

-0.1 (0.90)

-0.1 (0.2)

-1.6

1.4

4.0

-7.9 (-8.1; -7.8)

7.8 (7.6; 7.9)

Elbow extensors

2,1 (0.044)

0.9 (2.7)

0.0

1.8

2.3

-3.7 (-5.2; -2.1)

5.4 (3.9; 7.0)

Wrist flexors

-1.7 (0.09)

-0.6 (5.6)

-1.3

0.1

1.8

-4.1 (-5.1; -3.1)

3.0 (2.0; 4.0)

Wrist extensors

-0.8 (0.43)

-0.2 (2.2)

-0.6

0.3

1.1

-2.4 (-2.7; -2.1)

2.1 (1.8; 2.4)

Hip ABD

-0.8 (0.42)

-2.4 (1.9)

-8.4

3.6

15.7

-33.2 (-37.3; -29)

28.3 (24.2; 32.5)

Hip IR

-2.4 (0.03)

-3.3 (4.4)

-6.1

-0.4

7.4

-17.8 (-23.4; -12.1)

11.3 (5.6; 16.9)

Hip ER

-0.9 (0.36)

-1.2 (2.1)

-3.7

1.4

6.7

-14.4 (-16.4; -12.3)

12.0 (10.0; 14.0)

Hip flexors

-1.8 (0.09)

-7.4 (5.5)

-15.9

1.2

22.4

-51.3 (-64.1; -38.6)

36.6 (23.8; 49.4)

Hip extensors

-0.7 (0.48)

-3.7 (1.7)

-14.3

6.8

27.8

-58.2 (-64.6; -51.7)

50.7 (44.3; 57.2)

Knee flexors

0.8 (0.43)

1.9 (2.1)

-3.0

6.9

13.0

-23.6 (-26.9; -20.2)

27.4 (24.1; 30.8)

Knee extensors

0.5 (0.64)

1.2 (0.8)

-3.9

6.2

13.5

-25.2 (-27.2; -23.2)

27.5 (25.5; 29.5)

Ankle DF

-0.7 (0.52)

-0.2 (1.0)

-1.0

0.5

2.0

-4.1 (-4.5; -3.7)

3.6 (3.2; 3.6)

Ankle evertors

-2.1 (0.046)

-0.9 (4.3)

-1.7

0.0

2.3

-5.4 (-6.9; -3.9)

3.6 (2.1; 5.2)

Muscle groups

Inter-rater agreement (S1-S2)

Shoulder ABD

-0.2 (0.86)

0.5 (0.6)

-5.4

6.4

15.4

-29.7 (-30.6; -28.9)

30.7 (29.7; 31.6)

Shoulder IR

-0.6 (0.57)

-0.4 (1.2)

-1.9

1.1

3.9

-8.0 (-8.7; -7.3)

7.2 (6.4; 7.9)

Shoulder ER

-0.8 (0.46)

-0.4 (1.4)

-1.3

0.6

2.6

-5.5 (-6.1; -4.8)

4.7 (4.1; 5.4)

Shoulder flexors

-4.4(< 0.001)

-7.3 (10.2)

-10.7

-3.9

9.0

-24.9 (-37.6; -12.3)

10.4 (-2.3; 23.0)

Elbow flexors

-1.9 (0.07)

-1.3 (2.4)

-2.7

0.1

3.7

-8.6 (-10.8; -6.4)

6.0 (3.8; 8.3)

Elbow extensors

0.8 (0.46)

0.4 (1.1)

-0.6

1.3

2.6

-4.7 (-5.3; -4.1)

5.4 (4.8; 6.0)

Wrist flexors

2.6 (0.01)

0.9 (8.6)

0.2

1.5

1.8

-2.6 (-4.0; -1.1)

4.3 (2.8;5.7)

Wrist extensors

0.1 (0.93)

0.02 (0.3)

-0.5

0.6

1.5

-3.0 (-3.0; -2.9)

3.0 (3.0; 3.0)

Hip ABD

0.4 (0.68)

1.0 (0.8)

-3.9

5.9

13.2

-24.8 (-26.6; -23.0)

26.8 (25.1;28.6)

Hip IR

4.4 (< 0.001)

8.5 (12.6)

4.5

12.4

10.2

-11.4 (-26.1; 3.3)

28.4 (13.7; 43.1)

Hip ER

2.3 (0.03)

3.7 (7.1)

0.5

6.9

8.3

-12.6 (-18.9; -6.2)

19.9 (13.6;26.3)

Hip flexors

2.6 (0.02)

7.0 (5.5)

1.5

12.5

14.2

-20.8 (-32.9; -8.7)

34.8 (22.7; 46.8)

Hip extensors

-2.8 (0.005)

-17.8 (8.0)

-31.1

-4.6

35.5

-87.3 (-118.2;56.4)

51.7 (20.8; 82.6)

Knee flexors

3.0 (0.005)

8.2 (9.2)

2.7

13.8

14.3

-19.8 (-34.0; -5.6)

36.2 (22.0; 50.5)

Knee extensors

1.8 (0.09)

7.4 (5.0)

-1.1

15.9

22.8

-37.3 (-50.0; -24.5)

52.0 (39.2; 64.8)

Ankle DF

-0.2 (0.85)

-0.1 (0.4)

-1.2

1.0

2.8

-5.7 (-5.8; -5.5)

5.5 (5.3;5.6)

Ankle evertors

2.7 (0.01)

1.3 (6.6)

0.3

2.2

2.6

-3.7 (-5.9; -1.5)

6.3 (4.1;8.5)

  1. T-values and corresponding p-values (Sig.) obtained using one-sample t-tests, the mean difference, the standard deviation (SD) and the limits of agreement (LOA) of the difference between the mean values obtained at Session 1 (S1) and Session 3 (S3) (intra-rater), and Session 1 (S1) and Session 2 (S2) (inter-rater) in Newton-meters (Nm). The mean difference of each muscle group is also expressed in percentage of the mean torque values of the two measurement time-points in parentheses. The results in bold are significant, meaning there is a significant systematic bias between the two measurement time-points
  2. ABD Abductors, IR/ER Internal and External rotators, DF Dorsiflexors