Wayne has decided that he wants to start strength training. he discovers that he really likes lifting weights, so he is intrinsically motivated to accomplish this goal, theory bests captures wayne's situation.

Incentive  

Explanation:  

Incentive theory divides motivation is heavily influences by two things : extrinsic motivation and intrinsic motivation

Extrinsic motivation says that people do something because of external factors, like doing exercise to have good looks so they can get praises from other people

Intrinsic motivation is a form of motivation that come from within. Like doing something because they genuinely enjoy it or having personal drive to be a better version than themselves. (this is what happened to wayne)