More than 900,000 teens logged nearly 5.5 million workouts at Planet Fitness this summer?; Lululemon planning expansion of self-care line; Carrie Underwood writing fitness book; Swim goggles that display heart rate data in the pool?; How long your workouts should be to lose belly fat; What to look for when you sign fitness club contract; Tech that actually makes treadmill workouts…fun? Sorta? Kinda?