We all hit slumps, when we either don't want to exercise or working out just doesn't feel as good as it used to. When you hit the wall, using your imagination can help motivate you to get up and get moving.
Imagining your workout, be it running or rowing, activates the same part of your brain as actually doing the activity. Jumping into your workout is considerably less difficult when you harness this visualization. Picture yourself barreling up the hills then skipping down the other side, and your motivation will soon follow. Mentally reviewing the technique of your sport can help work out the kinks that are causing your discomfort or hurting your performance. Use your brain and get moving.