Table 3.

Associations between significant characteristics after bi-variate analysis and race time for the master half-marathoners, master marathoners and 100-km master ultra-marathoners using multiple linear regression analysis after removing the age variable

Group		β	SE	P Value
Half-marathoners(n=103)	Skeletal muscle mass	-0.3	0.3	0.3
	Percentage of body fat	0.9	0.3	0.0003
	Weekly running hours	0.6	0.8	0.4
	Weekly running kilometres	-0.3	0.08	0.002
	Speed in running training	-4.3	0.8	< 0.0001
Marathoners(n=91)	Skeletal muscle mass	0.9	0.7	0.2
	Percentage of body fat	2.2	0.6	0.0008
	Weekly running hours	0.8	1.3	0.5
	Weekly running kilometres	-0.2	0.1	0.2
	Speed in running training	-11.9	1.7	< 0.0001
100-km ultra-marathoners(n=155)	Skeletal muscle mass	-0.7	2.1	0.8
	Percentage of body fat	10.5	2.0	< 0.0001
	Weekly running hours	0.05	2.0	0.9
	Weekly running kilometres	-1.6	0.4	< 0.0001
	Speed in running training	-3.0	4.2	0.5

β = regression coefficient; SE = standard error of the regression coefficient. The coefficient of determination (r ²) of the model was 0.48 for master half-marathoners, 0.45 for master marathoners, and 0.36 for master ultra-marathoners, respectively