Table 4. Quantile regression models for physical performance measures according to self-rated health (good vs. poor), stratified by age categories (poor SRH is the reference category) (N = 571).

	Model 1	Model 2	Model 3	Model 4
	b (95% CI)
	Middle-aged group (40–59 years-old)
Handgrip strength (kgf)	2.28 [1.16–3.41]	1.65 [0.43–2.88]	2.22 [0.87–3.56]	1.75 [0.47–3.02]
p Value	0.001	0.013	0.004	0.004
One legged balance-eyes open (s)(§)	3.64 [1.34–5.94]	1.37 [−0.14 to 2.88]	2.02 [0.64–3.40]	0.81 [−0.94 to 2.57]
p Value	0.001	0.033	0.006	0.290
One legged balance-eyes closed (s)(§)	1.40 [−0.20 to 3.00]	1.64 [0.35–2.93]	1.73 [0.58–2.89]	1.31 [0.00–2.61]
p Value	0.037	0.027	0.015	0.030
Chair Stands (s)(§)	−0.39 [−0.83 to 0.06]	−0.52 [−0.96 to −0.09]	−0.56 [−0.99 to −0.13]	−0.56 [−0.94 to −0.18]
p Value	0.008	0.010	0.064	0.009
	Older adults’ group (60–80 years-old)
Handgrip strength (kgf)	0.75 [−1.41 to 2.91]	−0.35 [−2.30 to 1.61]	0.60 [−1.18 to 2.37]	−0.13 [−2.02 to 1.76]
p Value	0.449	0.831	0.801	0.654
One legged balance-eyes open (s)(§)	−0.47 [−7.47 to 6.53]	−1.31 [−6.90 to 4.29]	−1.22 [−5.67 to 3.22]	−1.41 [−4.71 to 1.89]
p Value	0.896	0.929	0.495	0.581
One legged balance-eyes closed (s)(§)	1.06 [−0.02 to 2.15]	0.99 [0.25–1.73]	0.41 [−0.61 to 1.43]	0.54 [−0.34 to 1.41]
p Value	0.070	0.228	0.481	0.756
Chair stands (s)(§)	−1.17 [−2.35 to 0.00]	−0.67 [−1.91 to 0.56]	−0.62 [−1.31 to 0.08]	−0.72 [−1.75 to 0.31]
p Value	0.009	0.131	0.024	0.172

Notes:

^§2 missing values.

SRH, Self-rated health.

Model 1, Unadjusted; Model 2, Adjusted for age, education and family income; Model 3, Adjusted for age, education, family income, parity, age first birth and menopausal status; Model 4, Adjusted for age, education, family income, parity, age first birth, menopausal status, body mass index, physical activity and chronic conditions.

Higher values indicate better performance for grip strength and the balance tests, and worse performance for chair stands.