Table 1 Characterisitics of the participants for eqation development and cross-validation

Age (years)

77.5 ± 4.1

76.9 ± 4.4

76.5 ± 4.4

76.9 ± 3.7

Height (cm)

166 ± 5.0

153 ± 4.5^*

168 ± 4.5

153 ± 5.0^*

Weight (kg)

65.0 ± 7.5

55.3 ± 6.5^*

67.2 ± 7.0

55.8 ± 5.5^*

BMI (kg/m²)

23.5 ± 2.4

23.6 ± 2.5

23.7 ± 2.4

23.8 ± 2.1

FFM (kg)

49.8 ± 4.3

37.2 ± 3.4^*

51.6 ± 4.2^†

37.8 ± 3.5^*

FM (kg)

15.2 ± 5.8

18.1 ± 4.7^*

15.6 ± 4.3

17.9 ± 3.5^*

PBF (%)

22.9 ± 6.9

32.4 ± 5.4^*

22.8 ± 5.0

32.0 ± 4.3^*

ALM (kg)

20.4 ± 2.2

14.3 ± 1.6^*

21.3 ± 2.1

14.4 ± 1.4^*

Xc_@5 kHz

13.6 ± 4.1

12.5 ± 3.4

13.8 ± 3.3

14.0 ± 3.2^†

Xc_@50 kHz

38.0 ± 6.6

37.8 ± 5.7

37.4 ± 4.5

39.8 ± 5.4

Xc_@250 kHz

28.6 ± 3.8

30.5 ± 3.4^*

27.7 ± 2.5

31.6 ± 3.3^*

R_@5 kHz

563 ± 57

656 ± 66^*

553 ± 49

657 ± 46^*

R_@50 kHz

502 ± 50

595 ± 60^*

493 ± 46

594 ± 42^*

R_@250 kHz

453 ± 45

543 ± 55^*

445 ± 42

539 ± 38^*

ZI_@1 kHz

48.6 ± 6.0

35.4 ± 4.1^*

50.4 ± 5.4

35.0 ± 3.9^*

ZI_@5 kHz

49.6 ± 6.1

36.1 ± 4.1^*

51.5 ± 5.5

35.8 ± 3.9^*

ZI_@50 kHz

55.4 ± 6.6

39.7 ± 4.6^*

57.8 ± 6.3

39.6 ± 4.3^*

RI_@50 kHz

55.4 ± 6.8

39.5 ± 4.6^*

57.7 ± 6.4

40.0 ± 4.4^*

ZI_@250 kHz

61.4 ± 7.2

43.6 ± 5.1^*

64.0 ± 7.0

43.6 ± 4.7^*

RI_@250 kHz

61.3 ± 7.5

43.4 ± 5.1^*

63.9 ± 7.1

43.8 ± 4.8^*

ZI_@500 kHz

63.5 ± 7.5

45.0 ± 5.2^*

66.2 ± 7.2

45.0 ± 4.8^*

ZI_@1 MHz

65.4 ± 7.7

46.3 ± 5.4^*

68.1 ± 7.4

46.3 ± 5.0^*

ZI_@2 MHz

67.3 ± 7.9

47.6 ± 5.6^*

70.1 ± 7.7

47.7 ± 5.1^*

ZI_@3 MHz

68.7 ± 8.1

48.6 ± 5.7^*

71.6 ± 7.9

48.7 ± 5.2^*