Today is exclusively a chest day, and I’ll be including some new challenges for this muscle group. Chest is the favorite body part for many people to train, and you’ll often notice that everyone is fighting for chest equipment on Mondays at most gyms. Well, that’s not the case with my 12-Week Lean Muscle Program—I have placed it third in the week, just at the point when you’re potentially feeling fairly exhausted from the work from the previous two days. I hope this workout will help revitalize you.

We begin today’s workout with bear crawls, which uses many muscle groups including the chest. You’ll get on your hands and feet with your butt in the air, and you’ll take 10 steps forward and 10 back for each set. Notice how Kai and Danielle perform this warm-up move in the video.

Then we’ll transition to unilateral medicine ball pushups. These work just like a regular pushup except that you place one hand on a medicine ball while you perform a pushup. This requires one side to stabilize more while the pectorals on the other side work more intensely. After performing 1 rep, roll the ball to the side and perform another rep. Continue alternating sides with the medicine ball until you reach failure. Perform these from your knees if you are not able to do them from your toes. You can burn out with regular pushups, then rest 2 minutes between sets.

The next move is staggered pushups. For this move you’ll place one hand high and the other low—and you’ll work from your knees. Then you’ll explode up so that your hands leave the ground, allowing you to shift positions. Catch your bodyweight at the top of the pushup, and then lower, emphasizing the stretch in your pectorals from these differing angles. Bring your knees in closer to your hands if this move is challenging from your toes.

After these plyometric moves, we’ll shift to more traditional weight-training moves. First up is decline dumbbell flyes, which targets the lower portion of the chest. Perform as many reps as you can and then switch to decline dumbbell presses.

Don’t forget to perform your 2 sets of cardio today, including HIIT for 10 minutes in the first session and 15 minutes in the second session as described in the chart.

Workout

GETHIN’S GO-TO:

Plyometric moves such as staggered pushups, where you explode out of the bottom of a movement, place increased neural demands on your body. You’re forced to stabilize and perform more explosive action with your target muscles. Over time, this improves the function and strength of the muscle group, allowing for enhanced growth.

WHAT SUPP?

KASEIN provides benefits on both non- and weight-training days. While you’re following my 12-Week Lean Muscle Program, you’ll take in a serving of KASEIN each night before bed to support anabolism (positive nitrogen balance important for maintaining muscle) while you sleep. KASEIN is a slow-digesting form of protein that prevents muscle breakdown (catabolism) while you sleep and are not consuming protein. KASEIN can also be taken between meals when you want a slow, sustained release of amino acids. I carry KASEIN with me everywhere I go in case I am not able to get in protein from a meal. DOSE AND TIMING: Mix 1 scoop of KASEIN with about 8 ounces of water and consume each night before you go to sleep. Follow similar dosing info for other times of day when you need a slow, sustained release of amino acids. I personally prefer to mix it in a bowl with just a little water so that it is thick, with the great taste of a good-for-you pudding.