Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to gain muscle without weights [title] Work out a routine that rotates among strength-training exercises. [step] When you're not using weights, your body becomes the " weight " that you use to build muscle. For instance, a pushup, where you're pushing your body off the floor, uses your body's weight to build muscle.

Ending1: You'll also use this weight for resistance workouts. [substeps] Try starting with light weights and working your way up. Ending2: While you can build muscle while taking ab and pelvic strength classes, you can also work on weight training that targets other lean muscle groups. [substeps] For example, if you want to kick butt, try dancing, yoga, and tai chi. Ending3: [substeps] However, not all athletic people will develop muscle from a diet or exercise program. This isn't a good indication of whether or not muscle building will be successful. Ending4: However, you can't just stick with 1 exercise. You need to rotate through exercises to build up muscle across your body.

Answer format: ending1/ending2/ending3/ending4