Table 2 Intra-rater intraclass correlations for muscle architecture in the three muscles and the two age groups

Young

 Rater 1

  Rest

0.77 (0.24–0.93)

0.70 (0.26–0.90)

0.98 (0.96–0.99)

0.79 (0.19–0.95)

0.56 (0.22–0.82)

0.98 (0.95–0.99)

0.86 (0.45–0.96)

0.93 (0.81–0.98)

0.96 (0.90–0.99)

  Contraction

0.82 (0.30–0.95)

0.94 (0.73–0.98)

0.99 (0.98–1.00)

0.82 (0.40–0.95)

0.72 (0.43–0.90)

0.99 (0.97–1.00)

0.88 (0.42–0.97)

0.83 (0.50–0.95)

0.98 (0.94–0.99)

 Rater 2

  Rest

0.71 (0.43–0.90)

0.80 (0.57–0.93)

0.97 (0.93–0.99)

0.72 (0.44–0.90)

0.74 (0.47–0.91)

0.96 (0.91–0.99)

0.62 (0.26–0.87)

0.82 (0.59–0.94)

0.93 (0.82–0.98)

  Contraction

0.81 (0.57–0.94)

0.95 (0.87–0.98)

0.99 (0.97–1.00)

0.94 (0.84–0.98)

0.84 (0.64–0.94)

0.96 (0.89–0.99)

0.79 (0.54–0.93)

0.85 (0.67–0.95)

0.80 (0.57–0.93)

 Rater 3

  Rest

0.91 (0.78–0.97)

0.78 (0.54–0.92)

0.99 (0.98–1.00)

0.83 (0.62–0.94)

0.79 (0.56–0.93)

0.99 (0.97–1.00)

0.70 (0.39–0.9)

0.81 (0.57–0.94)

0.98 (0.95–0.99)

  Contraction

0.70 (0.39–0.90)

0.88 (0.71–0.96)

0.99 (0.98–1.00)

0.85 (0.66–0.95)

0.84 (0.64–0.95)

1.00 (0.99–1.00)

0.89 (0.74–0.96)

0.97 (0.92–0.99)

0.75 (0.49v0.91)

 Mean

  Rest

0.80

0.76

0.98

0.78

0.70

0.98

0.73

0.85

0.96

  Contraction

0.78

0.92

0.99

0.87

0.80

0.98

0.85

0.88

0.84

Old

 Rater 1

  Rest

0.83 (0.61–0.94)

0.98 (0.96–1.00)

0.98 (0.94–0.99)

0.82 (0.61–0.94)

0.85 (0.66–0.95)

0.96 (0.9–0.99)

0.86 (0.69–0.95)

0.84 (0.64–0.95)

0.97 (0.92–0.99)

  Contraction

0.95 (0.88–0.98)

0.99 (0.98–1.00)

0.98 (0.96–1.00)

0.96 (0.91–0.99)

0.92 (0.79–0.97)

0.97 (0.92–0.99)

0.51 (0.17–0.8)

0.90 (0.77–0.97)

0.92 (0.81–0.97)

 Rater 2

  Rest

0.69 (0.40–0.89)

0.88 (0.72–0.96)

0.95 (0.87–0.98)

0.89 (0.75–0.96)

0.80 (0.57–0.93)

0.94 (0.86–0.98)

0.57 (0.22–0.83)

0.81 (0.58–0.93)

0.94 (0.84–0.98)

  Contraction

0.91 (0.78–0.97)

0.85 (0.65–0.95)

0.98 (0.95–0.99)

0.90 (0.75–0.97)

0.85 (0.66–0.95)

0.97 (0.93–0.99)

0.62 (0.30–0.86)

0.76 (0.50–0.92)

0.87 (0.70–0.96)

 Rater 3

  Rest

0.82 (0.60–0.94)

0.98 (0.95–0.99)

0.99 (0.96–1.00)

0.90 (0.77–0.97)

0.54 (0.19–0.82)

0.93 (0.83–0.98)

0.63 (0.31–0.86)

0.81 (0.55–0.94)

0.98 (0.94–0.99)

  Contraction

0.88 (0.72–0.96)

0.95 (0.88–0.98)

0.99 (0.98–1.00)

0.67 (0.37–0.88)

0.82 (0.61–0.94)

0.92 (0.81–0.98)

0.64 (0.32–0.87)

0.87 (0.71–0.96)

0.90 (0.77–0.97)

 Mean

  Rest

0.78

0.95

0.97

0.87

0.73

0.94

0.69

0.82

0.96

  Contraction

0.91

0.93

0.98

0.84

0.86

0.95

0.59

0.84

0.90