Talking about your chin in boxing is not actually referring to your chin, but your neck muscles. When your opponent takes a jab at your face, you are said to have a good or strong chin if you can handle the punch without going down for the count. Being knocked out by such a blow is described as having no chin, also called a glass jar. Strengthening your neck muscles helps you get a stronger chin so you can hold your own in the ring.
Perform isometric exercises to improve your neck strength. Isometrics use your body's weight to counter a force without actually moving your body. Place the palm of your hand on your forehead. Apply pressure to your head with your hand. Push against your hand with your head and neck without moving your head forward. Repeat the exercise on each side of your head to improve your lateral neck strength as well.
Hold a tennis ball under your chin. Using your neck muscles to keep the ball in place helps you get a stronger chin for boxing. Complete punching bag drills while the ball is tucked away under your chin to challenge yourself even more.
Perform modified bridges that are designed to strengthen boxers' chins. Instead of balancing on your arms, a boxer's bridge uses your head as well as your lower body. Lie down on your back with your knees bent and your feet flat on the floor. Raise your trunk off the ground. Keeping the back of your head on the ground, let your weight fall onto your head. Use your arms for support if needed as you get into the bridge position, then fold your arms over your chest. Work your way up to 10 repetitions.
Use free weights to get a stronger chin. String a weight onto the chain portion of a neck strap. Start with just a few pounds to avoid injury if you have never worked with a neck strap. Drape the padded section of the neck strap over the top of your head so the weight hangs down around your waist. Squat down with your knees bent, head down and back straight. Lift your head up, using your neck muscles. Hold for a count of three and bring your neck back down. Perform a set of 10 repetitions.