tedium

Tedium occurs in sports when you are doing nothing, such as standing around. Tedium avoidance is when you are trying to keep on going, or not get bored

Tedium: a state of being bored during anything, such as sports, art, school, etc.

Reading a good book will relieve the tedium of the lengthy flight to Africa.

Tedium avoidance is what you need to do to avoid boredom because if you get bored in training you can get demotivated which will decrease your fitness level. Make sure you vary you activities to avoid tedium in sport