Table 4.

Coefficients and standard errors from a multivariable regression model: ln (distance in km) = UM × Age + UM × Age² + UM × Sex + Calendar year + Calendar year + with a random intercept for each finisher

	Coefficient	Standard error	p value
Intercept	17.6	0.31	<0.001
Ultra-marathon (UM)
UM-12	0.47	0.004	<0.001
UM-24	0.99	0.004	<0.001
UM-48	1.41	0.006	<0.001
UM-72	1.68	0.018	<0.001
UM-124	2.30	0.008	<0.001
UM-240	2.80	0.016	<0.001
Age
Linear	−0.0037	0.00013	<0.001
Squared	−0.00015	0.00001	<0.001
Sex (male)	0.0872	0.0034	<0.001
Calendar year of race	−0.0068	0.0002	<0.001
Experience	0.0055	0.0002	<0.001
Interaction UM and Age, linear
(UM-12) × Age	0.00074	0.00016	<0.001
(UM-24) × Age	0.00261	0.00015	<0.001
(UM-48) × Age	0.00423	0.00026	<0.001
(UM-72) × Age	0.00231	0.00077	0.003
(UM-144) × Age	0.00306	0.00031	<0.001
(UM-240) × Age	0.00268	0.00072	<0.001
Interaction UM and Age, squared
(UM-12) × Age2	−0.000076	0.000011	<0.001
(UM-24) × Age2	−0.000081	0.000011	<0.001
(UM-48) × Age2	−0.000133	0.000018	<0.001
(UM-72) × Age2	−0.000147	0.000043	<0.001
(UM-144) × Age2	−0.000131	0.000021	<0.001
(UM-240) × Age2	−0.000234	0.000055	<0.001
Interaction UM and Sex
(UM-12) × Sex (male)	−0.0007	0.0040	0.870
(UM-24) × Sex (male)	−0.0484	0.0039	<0.001
(UM-48) × Sex (male)	−0.0611	0.0066	<0.001
(UM-72) × Sex (male)	−0.0478	0.0201	0.017
(UM-144) × Sex (male)	−0.0569	0.0082	<0.001
(UM-240) × Sex (male)	−0.0832	0.0172	<0.001