The Best HIIT Workout for Muscle Building

• Metabolic stress. HIIT workouts create metabolic stress on the muscles. This stress can stimulate the release of anabolic hormones including those responsible for growth, helping to support muscle gain and repair.

• Fast-twitch muscle fibre activation. HIIT workouts often involve explosive movements, like plyometric exercises, that recruit fast-twitch muscle fibres. In addition to improving speed and power, fast-twitch muscle fibres have a higher potential for muscle growth than slow-twitch fibres.

• Increased calorie burn. HIIT workouts typically burn a significant amount of calories during and after the session thanks to the high intensity nature and metabolic demands. This can be helpful both for those who want to lose fat to enhance their muscle definition, or those who want to maintain their weight while building muscle, as it creates a calorie deficit which allows for more food and nutrients to be eaten, which can fuel muscle growth.

1. Burpees

   Burpees are a firm favourite with fitness fans, as this full-body compound movement engages your chest, shoulders, arms, core, glutes, and legs. The explosive jump at the end of each repetition also helps to build power and strength while encouraging muscle growth.

   Start in a standing position, then squat down and place your hands on the ground in front of you. Kick your feet back into a push-up position, perform a classic push-up, and then quickly jump your feet back into the squat position. Jump energetically into the air, raising your arms overhead. Repeat.

2. Renegade rows

   Renegade rows combine two strength building exercises, planks and dumbbell rows, for a challenging exercise that works the upper body and core, fatigues the muscles, and builds endurance.

   Adopt a high plank position while gripping a dumbbell in each hand, shoulder-width apart. Engage the core and drive the left dumbbell firmly into the floor, then pull your right elbow back and up to row the right dumbbell up to your ribs. Lower the dumbbell back to the floor and repeat on the other side.

3. Squat to overhead press

   The squat to overhead press combines squats with a dumbbell shoulder press, working multiple large muscle groups to build mass and burn calories.  In addition to building full body strength, squat to overhead presses improve power, balance, and coordination.

   Stand with feet between hip and shoulder-width apart, holding a dumbbell in each hand by your shoulders. Lower your hips down and back into a squat position, then drive through your heels back up to standing. As you stand, push the dumbbells up above your head by extending the arms straight. Lower the dumbbells back to shoulder height and repeat.

4. Kettlebell swings

   Kettlebell swings are a full-body exercise that engages multiple muscle groups, including the glutes, hamstrings, core, shoulders, and back. It's a dynamic, high-energy and challenging movement that helps to build power and strength while keeping your heart rate high.

   Stand with your back straight and feet shoulder-width apart. Lower into a half-squat and pick up the kettlebell with both hands so your palms are facing your body.

   Keep your core tight and a slight bend in your knees as you straighten your legs, push from your heels and thrust your hips forward as you swing the kettlebell upwards to chest height. As you guide the kettlebell down between your legs, return to the half-squat position. That's one rep.

5. Push ups

   Push-ups primarily target the chest muscles (pectoralis major and minor), shoulders (deltoids), and triceps. They also engage your core, back, and lower body muscles to stabilise your body during the movement. Push-ups are a classic compound exercise that can help build upper body strength and promote muscle growth.

   Start in a high plank position. Slowly bend your elbows and lower your chest towards the floor whilst keeping your body in a straight line. When your elbows are fully bent, press them into the floor to push yourself back to starting position. Make sure your abs are engaged and your spine is in a neutral position throughout the movement.

6. Jumping lunges

   Jumping lunges are an energetic lower-body exercise that targets the quadriceps, hamstrings, glutes, and calves. The jumping action adds intensity and engages your fast-twitch muscle fibres, contributing to muscle development. As a unilateral exercise, lunges help improve balance, stability, and overall lower body strength.

   Starting in a lunge position with one leg forward, jump with as much power as you can, switching your legs mid-air and landing with your other leg forward. Continue alternating the lunge jumps for the duration of the exercise.