1. Grab a towel or t-shirt, hold it in both hands, and stand in either squat position or upright with feet hip-width apart.

2. Hold the towel overhead with your arms extended, and pull on both sides of the t-shirt or towel as hard as you can, as if you were trying to rip it.

3. As you continue to try to rip the towel or t-shirt, slowly bring your elbows out and back behind your body, squeezing your shoulder blades together.

4. When your hands get as close to your chest as possible, slowly return to the starting position and repeat until the set is complete.

1. Start by standing or sitting with your arms relaxed at your sides, palms facing inwards towards your body.

2. Flex your biceps as hard as you possibly can, and bring your fists up to your shoulders, keeping your elbow close to your body.

3. Squeeze even more at the top of the movement, and then lower your fists back down to the start position, maintaining flexion throughout.

4. Repeat for the desired number of reps.

1. Start in high plank position, keeping your core engaged.

2. Jump your feet toward your hands, creating a squat position.

3. Jump from this position, arms in the air.

4. Land softly and return to plank position.

5. Repeat for desired number of reps.

6. To make the exercise harder, add a push-up when in the plank position or a jump squat when standing up.

7. To modify, step your legs toward your hands and stand up, removing the jumps.