Runtastic knows that you'll be sitting on your ass for hours during Google I/O, watching the conference and gorging on all the news, so it decided to release a new app to... taunt you? Or motivate you to get back in shape once I/O is over? Whatever the purpose, Leg Workout Trainer is now available on the Play Store.

Leg Workout Trainer joins the previously released Butt Trainer in bringing a series of muscle-focused (or group of muscles-focused) exercises to your phone in video form, with step-by-step instructions and photos. It has predefined workouts (7-minute, Pilates, and more) and three levels of difficulty, but also allows you to customize the training to target a specific problem area in your lower body.

The app is free to try, with some features available only with an IAP. It's optimized for phones and tablets, and runs the usual gamut of features from Runtastic (social sharing, MyFitnessPal integration, voice instructions, etc).