Ideas to improve endurance (exercise)

[CaptainF]

Can swimming be used to increase endurance?

So far I've got biking and jogging and both are not good in this bloody weather. Are there other sports for endurance that can be practiced in winter?

Indoor sports FTW!

This includes:

Tennis, Table Tennis, Badminton, Volleyball, Basketball, Wrestling, Boxing, and of course swimming.

 

[Gelion]

Thanks, that broadened my horizon