The problem: Flared elbows, sagging hips.
Many people press their elbows out to the side (more than 45 degrees relative to their torsos) as they lower themselves to the floor. That’s hard on your shoulders. They also allow their hips to droop, which is hard on the lower back.
How to fix it:
• Assume a plank position — this time with your arms straight and your hands in line with (but slightly wider than) your shoulders. Clench your glutes and brace your core to keep your body straight from head to heels.
• Keeping your head in line with your spine (look down, not forward) and elbows tucked, lower your body until your chest is within a few inches of the floor. When you do the move properly, your head, elbows, and upper body form an arrow shape (as opposed to a “T”) when viewed from above.
• Pause, and then push yourself back up to the starting position as quickly as possible.
If you find the classic push-up too tough, perform the move with your hands on a sturdy, elevated surface (box, bench, etc.), and gradually move closer to the floor as you become stronger. That’s a better option than knee push-ups, which don’t condition the right movement pattern or activate all of the right muscles to build the strength you’ll need to perform the standard push-up with good form.