The best indicator of the efficiency of exercise is?

Can doing Pilates cause further injury to a knee that cracks when straightened? How many calories can you burn walking four blocks? What is the short term effects of exercise on the respiratory system? How is physical fitness a relative concept? Do squats without weights stunt growth? How old was the endurance ship? What are the muscles that are used when biking? Are there muscles of the body that do not need stretching? How long should you exercise for fast weight loss? Is using True Mass to gain muscle safe? Why do you want to throw up when you drink water while you exercise? How can I prevent or alleviate constipation after running long distances? Which muscles are primarily engaged when performing handstand push-ups? During which one of the following exercise intensity levels would you still be able to sing? What are some good exercise activities that you can do daily? How can I effectively perform the lat single arm pull down exercise to target my back muscles? The exercise phase where lactic acid is being produced? Where can you find a free assembly manual or instructions for Weider Pro 9400 Home Gym? How long does it take to walk 2556.8 yards at a speed of 4 mph? How many pounds is 106.4 kilos?