In-and-out waves legitimately tax your upper body and core to a greater degree than your lower body. This is because you’re swinging your arms in-and-out laterally throughout the exercise, requiring exceptional back, shoulder, chest, and core engagement to control the rope while maintaining power and speed.
• Stand with feet hip-distance apart, your knees and hips slightly bent, your core engaged, and your shoulders rolled back. Hold one end of the rope in each hand, the center of the rope secured.
• With your elbows slightly bent, swing both arms out laterally from your midline, then forcefully swing them back to center. Continue this in-and-out motion, causing the rope to snake in front of you, each side repeatedly touching, then separating in the middle.
• Continue this swinging motion as fast as you can, performing the exercise for 15 to 30 seconds, depending on your ability. Rest and repeat, completing between four to six sets, resting 15 to 30 seconds between attempts.