Heavy lifting in off season and pre season.
Very briefly here is an example of exercice to do in order to reinforce endurance athletes
Week Number Exercise Sets Reps
1-3 Back Squat 3-4 8-10
4-6 Trap Bar Dead Lift 4-6 4-6
7-9 Front Squat 4-6 4-6
10-12 Hang Clean 3-4 6-8