Most people find it difficult to stick to an exercise regime after work. The lack of interest in your exercise routine is probably a result of lack of motivation.
Here are some tips:
Goal-setting
Set both short-term goals as stepping-stones that eventually lead to long-term goals.
Constant Feedback
Acknowledge your progress.
Vary your workout
Be innovative and creative. Alternate weight training in the gym with aerobics classes, cycling or swimming.
Develop group relationship
Get a few friends together to play a racket game, jogging session or aerobics class.
Managing Intensity
It is important that exercise is maintained at appropriate intensity.