Try these basic exercises :

- Squat

Standing with the feet about hip width apart, sit back in the heels and then stand back up. Ten-12 reps. Progressions include the one-legged squat.

- Lunge

Forward lunge bending both legs. Alternate sides, doing 10-12 per side. Progressions include jumping lunges.

- Push-up

Against a wall or inclined against a bench in a position that ensures a straight back and hips that stay up. Ten-12 reps. Progressions include traditional push-ups.

- Pull-up

Starting at an incline, hold a strap looped around a bar and pull the body which should be rigid up. 10-12 reps. Progressions include full-body pull-ups.