Table 2 Age, BMI, grip strength and lower limb muscle strength and muscle mass in subjects with and without knee pain

Overall

 N

1708

444

1721

431

 Age, years

70.8 ± 12.5

74.8 ± 10.4*

1.04

1.03–1.035

<0.0001

70.8 ± 12.5

74.7 ± 10.4*

1.04

1.03–1.05

<0.0001

 BMI, kg/m²

22.5 ± 3.3

23.7 ± 3.7*

1.13

1.10–1.17

<0.0001

22.4 ± 3.3

23.8 ± 3.5*

1.14

1.11–1.18

<0.0001

 Grip strength, kgf

28.7 ± 9.7

25.5 ± 8.5*

0.98

0.96–0.9996

0.0448

26.9 ± 9.5

23.8 ± 8.5*

0.99

0.97–1.01

0.3464

 Quadriceps muscle strength,kgf (5kgf increase)

29.1 ± 11.2

23.9 ± 10.3*

0.83

0.78–0.88

<0.0001

27.9 ± 11.2

22.8 ± 10.2*

0.84

0.79–0.89

<0.0001

Weight bearing index, kgf/kg (0.1 kgf/kg increase)

0.54 ± 0.20

0.44 ± 0.18*

0.81

0.76–0.86

<0.0001

0.52 ± 0.19

0.42 ± 0.19*

0.83

0.77–0.88

<0.0001

 Lower limb muscle mass/height²,kg/m² (0.1kg/m² increase)

2.59 ± 0.43

2.58 ± 0.43

0.97

0.92–1.02

0.2421

2.56 ± 0.43

2.56 ± 0.42

0.98

0.94–1.03

0.4326

Men

 N

586

104

594

96

 Age, years

71.9 ± 12.5

76.1 ± 11.0*

1.04

1.02–1.07

<0.0001

72.0 ± 12.3

76.1 ± 11.7*

1.04

1.02–1.07

<0.0001

 BMI, kg/m²

22.9 ± 3.2

23.9 ± 3.8*

1.13

1.06–1.21

0.0002

22.9 ± 3.2

23.9 ± 4.0*

1.13

1.06–1.21

0.0003

 Grip strength, kgf

37.5 ± 9.5

35.1 ± 9.0*

0.98

0.95–1.01

0.3070

35.5 ± 9.0

33.3 ± 9.7*

0.99

0.96–1.02

0.5031

 Quadriceps muscle strength,kgf (5kgf increase)

32.9 ± 12.5

26.4 ± 12.0*

0.80

0.72–0.89

<0.0001

31.4 ± 12.6

25.4 ± 11.4*

0.82

0.91–1.23

0.0001

Weight bearing index, kgf/kg (0.1 kgf/kg increase)

0.54 ± 0.20

0.42 ± 0.19*

0.75

0.65–0.85

<0.0001

0.52 ± 0.20

0.41 ± 0.18*

0.78

0.68–0.89

0.0002

 Lower limb muscle mass/height², kg/m² (0.1kg/m² increase)

2.95 ± 0.44

3.03 ± 0.47

1.01

0.92–1.10

0.8897

2.90 ± 0.44

2.97 ± 0.50

0.98

0.89–1.08

0.7281

Women

 N

1122

340

1127

335

 Age, years

70.2 ± 12.5

74.4 ± 10.2*

1.03

1.02–1.05

<0.0001

70.2 ± 12.6

74.3 ± 10.0*

1.03

1.02–1.05

<0.0001

 BMI, kg/m²

22.2 ± 3.3

23.7 ± 3.6*

1.13

1.09–1.18

<0.0001

22.2 ± 3.4

23.8 ± 3.4*

1.15

1.11–1.19

<0.0001

 Grip strength, kgf

24.1 ± 5.8

22.5 ± 5.8*

0.98

0.95–1.004

0.1014

22.3 ± 6.0

21.1 ± 5.7*

0.99

0.97–1.02

0.6256

 Quadriceps muscle strength, kgf (5kgf increase)

27.2 ± 9.9

23.2 ± 9.5*

0.84

0.78–0.91

<0.0001

26.1 ± 9.8

22.1 ± 9.7*

0.85

0.79–0.91

<0.0001

Weight bearing index, kgf/kg (0.1 kgf/kg increase)

0.55 ± 0.20

0.45 ± 0.18*

0.83

0.77–0.90

<0.0001

0.52 ± 0.19

0.43 ± 0.19*

0.84

0.78–0.91

<0.0001

 Lower limb muscle mass/height²,kg/m² (0.1kg/m² increase)

2.41 ± 0.27

2.45 ± 0.32*

0.95

0.89–1.02

0.1421

2.38 ± 0.29

2.44 ± 0.31*

0.99

0.93–1.04

0.6166