Random Riddle: A Family Sport

Three brothers share a family sport:
A non-stop marathon
The oldest one is fat and short
And trudges slowly on
The middle brother’s tall and slim
And keeps a steady pace
The youngest runs just like the wind,
Speeding through the race
“He’s young in years, we let him run,”
The other brothers say
“’Cause though he’s surely number one,
He’s second, in a way.”
 
Random Riddle: A Family Sport