DeekFit Gym app for Windows Phone 7
The app is a fully-featured gym suite, it lets you create routines and schedules, add/track your workouts, view your progress, track your body weight, calculate one-rep max, BMR, BMI, kg/lb, etc. The paid version also syncs with deekfit.com, where you can view your workouts and weight history, or use it as a cloud backup feature.