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The Ultimate 3-Day Advanced HIIT Workout for Maximum Fat Burn and Muscle Growth

By Will Duru, BSc (Hons) Sport and Exercise Science

As a personal trainer with over a decade of experience in strength training and recovery, I’ve seen countless fitness trends come and go. But one training method has consistently delivered incredible results for my clients: High-Intensity Interval Training (HIIT). When combined with strategic strength training, HIIT becomes a powerful tool for torching fat, building lean muscle, and achieving peak physical condition. My name is Will Duru, and I’m here to guide you through a 6-week advanced HIIT program designed to get you in the best shape of your life.

This isn’t your average workout plan. This is a scientifically-backed, 3-day split that will push your limits and redefine what you thought was possible. We’ll combine explosive HIIT circuits with targeted strength training to create a powerful stimulus for fat burning and muscle building. This program is designed for individuals who are ready to elevate their fitness to the next level and achieve a lean, powerful physique.

Personal Training (Tower Bridge/London Bridge)

Why HIIT is a Game-Changer for Fat Loss

HIIT is a training method that involves short bursts of intense, all-out effort followed by brief recovery periods. This approach has been scientifically proven to be incredibly effective for fat loss, and for several key reasons:

  1. The Afterburn Effect (EPOC): One of the biggest advantages of HIIT is its ability to boost your metabolism for hours after your workout is over. This phenomenon, known as Excess Post-exercise Oxygen Consumption (EPOC), means your body continues to burn calories at an elevated rate long after you’ve left the gym. In fact, studies have shown that HIIT can burn 25-30% more calories than other forms of exercise [1]
 
  1. Time Efficiency: Let’s be honest, we’re all busy. HIIT workouts are incredibly time-efficient, allowing you to achieve a full-body workout and significant cardiovascular benefits in a fraction of the time required for traditional cardio. This makes it a sustainable option for those with demanding schedules.
  1. Hormonal Response: Intense exercise, such as HIIT, triggers a powerful hormonal response, including the release of growth hormone and adrenaline. These hormones play a crucial role in fat mobilisation, helping your body tap into stubborn fat stores for energy.
The Ultimate 3-Day Advanced HIIT Workout for Maximum Fat Burn and Muscle Growth

The Power of Combining HIIT and Strength Training

While HIIT is a fantastic tool for fat loss, combining it with strength training is where the real magic happens. This powerful duo creates a synergistic effect that accelerates your results and builds a well-rounded, athletic physique.

Strength training builds and maintains lean muscle mass, which is metabolically active tissue. The more muscle you have, the more calories your body burns at rest. When you combine this with the intense calorie-burning effects of HIIT, you create a powerful fat-loss machine. As one study found, participants who engaged in high-intensity resistance training exercises experienced more significant strength improvements and greater fat loss compared to those doing medium-intensity workouts [2].

This program is designed to give you the best of both worlds. We’ll use HIIT circuits to elevate your heart rate and torch calories, followed by targeted strength training exercises to build muscle and sculpt your physique. This approach ensures you’re not just losing weight, but building a strong, lean, and powerful body.

Strength Training Is Key to Your Health

Your Digital Personal Trainer: The 12Reps App

To get the most out of this advanced program, I highly recommend using the 12Reps app. This powerful workout tracker app and strength training app will be your digital personal trainer, guiding you through every exercise with video demonstrations, tracking your progress, and timing your rest periods to the second.

The app’s “Build Your Routine” feature allows you to create this entire program, plan your workouts, and monitor your progress over the 6 weeks. You can track your weights, reps, and rounds, ensuring you’re consistently pushing your limits and making progress. Download the 12Reps app and start your 7-day free trial today, it’s an investment in your health and longevity.

The 6-Week Advanced HIIT Workout Program

This program is designed as a 3-day split, targeting different muscle groups and energy systems on each day. Remember to start each workout with a 1k run to warm up your body and prepare for the intensity to come.

Understanding the Science Behind This Program

The beauty of this advanced HIIT program lies in its strategic design. Each workout is carefully crafted to maximise both fat burning and muscle building through specific training principles:

Progressive Overload: Throughout the 6 weeks, you’ll gradually increase the intensity, weight, or volume to ensure continuous adaptation and improvement. This principle is fundamental to both strength training and cardiovascular fitness.

Metabolic Stress: The short rest periods and high-intensity nature of these workouts create significant metabolic stress, which triggers muscle growth and fat loss. Your body will be forced to adapt by becoming more efficient at burning fat and building lean muscle.

Movement Variety: By incorporating different movement patterns—from explosive power movements like dumbbell snatches to grinding strength exercises like leg presses—we ensure your body never adapts completely, thereby maintaining consistent progress.

Nutrition and Recovery for Maximum Results

While this workout app will guide you through every exercise, remember that your results depend on more than just training. Proper nutrition and recovery are crucial components of any successful transformation.

Hydration: HIIT workouts are incredibly demanding on your cardiovascular system. Ensure you’re drinking plenty of water before, during, and after your workouts. Dehydration can significantly impact performance and recovery.

Post-Workout Nutrition: Within 30 minutes of completing your workout, consume a combination of protein and carbohydrates to support muscle recovery and replenish energy stores. This is when your body is most receptive to nutrients.

Sleep Quality: Your body repairs and grows stronger during sleep. Aim for 7-9 hours of quality sleep each night to maximise the benefits of your training and support longevity.

Tracking Your Progress with the 12Reps App

The 12Reps app isn’t just a workout tracker app—it’s your complete fitness companion. Here’s how to maximise its potential for this program:

Custom Workout Creation: Use the “Build Your Routine” feature to input each day’s workout exactly as outlined. The app will guide you through proper form with video demonstrations and ensure you’re hitting the right intensity.

Rest Period Timing: The precise 45-second and 1-minute rest periods are essential for the effectiveness of this program. The app’s built-in timer takes the guesswork out of rest periods, ensuring you maintain the right intensity throughout your workout.

Progress Tracking: Document your weights, reps, and your feelings after each workout. This data becomes invaluable for adjusting the program and seeing your progress over the 6 weeks.

Heart Rate Monitoring: If you have a heart rate monitor, the app can help you stay in the optimal training zones for maximum fat burning and cardiovascular benefits.

Day 1: Full Body Power

Exercise

Reps

Rounds

Rest

Dumbbell Snatch

16 (8 per side)

4

45 seconds

Dumbbell Reverse Lunges

16 (8 per side)

4

45 seconds

Bodyweight Press/Knee Press

10

4

45 seconds

Session 1: Strength Focus

Exercise

Sets

Reps

Weight

Leg Press

5

15

50-100kg

Leg Curl

4

12

Moderate

Leg Extension

4

20

Light

Dumbbell Glute Bridge

4

15

30kg

Dumbbell RDL

4

12

Moderate

Session 2: HIIT Circuit

Exercise

Reps

Rounds

Rest

Airbike

10 calories

4

45 seconds

Plank Twisting

30

4

45 seconds

Kettlebell Gorilla Row

16 (8 per hand)

4

45 seconds

Day 3: Upper Body & Core

Session 1: Strength Focus

Exercise

Sets

Reps

Weight

Lat Pulldown

4

12

Moderate

Machine Chest Press

4

12

Moderate

Machine Assisted Pull-ups

4

8-10

As needed

Session 2: HIIT Circuit

Exercise

Reps

Rounds

Rest

Rowing

200 meters

4

45 seconds

Dumbbell Goblet Squats

10

4

45 seconds

Chest to Floor Burpees/Knee Press-ups

10

4

45 seconds

Finisher

Exercise

Reps

Rounds

Rest

Sledge Push

20 meters

4

1 minute

Kettlebell Farmer’s Carry

20 meters

4

1 minute

200-meter Run

1

4

1 minute

Your Transformation Awaits

This 6-week advanced HIIT program is designed to be challenging, but the results will be worth it. By combining the power of HIIT with strategic strength training, you’ll unlock a new level of fitness, burn stubborn fat, and build a lean, powerful physique.

Remember to listen to your body, focus on proper form, and use the 12Reps app to track your progress. Your strongest, most confident self is within reach. Download the app, start your 7-day free trial, and let’s get to work.

strength training app

References

[1] Healthline. (2025). 7 Benefits of High Intensity Interval Training (HIIT). https://www.healthline.com/nutrition/benefits-of-hiit

[2] ISSA. (2024). HIIT and Strength Training – Should You Do Both?. https://www.issaonline.com/blog/post/hiit-and-strength-training-should-you-do-both

Will Duru

Level 4 Qualified Personal Training Coach Sports & Exercise Science BSc (Hons)

Disclaimer: The ideas in this blog post are not medical advice. They shouldn’t be used for diagnosing, treating, or preventing any health problems. Always check with your doctor before changing your diet, sleep habits, daily activities, or exercise. WILL POWER FITNESS isn’t responsible for any injuries or harm from the suggestions, opinions, or tips in this article.

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