timing how long it takes for your kettle to boil 1 cup (250ml) of water. looking at the power of your kettle (Watts, often found on the base of the kettle) joules = wattage x time (in seconds)
Rock climbing can help build and tone your legs and glutes. Indoor rock climbing is a sport that when properly executed, recruits every major muscle group in the body. Rock climbing is a full body workout that tones and strengthens the arms, shoulders and core muscles. You can also effectively strengthen and tone your legs and buttocks with regular indoor rock climbing sessions.
When you perform leg extensions, you contract the quad to bring your knees up against the weighted resistance. While many other exercises such as squats, lunges or deadlifts also provide a heavy workout for the quads, they do not isolate the muscle like a leg extension does. Any exercise that requires you to contract your quadriceps against resistance can accomplish the same effect as a leg extension machine.