By Will Duru, BSc (Hons) Sport and Exercise Science
I’ve coached people for over 10 years now, and there’s one thing I keep coming back to: training should be hard, but it should also make sense. This 3-day split is one of my favourites. It mixes strength work with short bursts of high-effort cardio. We call this HIIT, which stands for High-Intensity Interval Training. It means you push hard for a short time, then rest, then push again.
I built this plan to run for 6 weeks. It’s advanced, so you’ll need some training experience under your belt already. But don’t worry, every exercise here is simple. No fancy moves. Just hard work done right.
Why HIIT Works So Well
HIIT is popular for a good reason. It works your heart and lungs hard in a short space of time. You don’t need an hour on a treadmill. You need 20 to 30 minutes of real effort.
When you train this way, your body keeps burning extra calories even after you’ve stopped. This is sometimes called the “afterburn effect.” Your body has to work to recover, and that recovery costs energy. So you’re still burning fuel hours after you’ve left the gym.
HIIT also builds your fitness fast. Your heart gets stronger. Your body gets better at clearing out lactic acid, which is the stuff that makes your muscles burn during hard sets. Over time, you’ll notice you can push harder for longer without gassing out.
Why HIIT Plus Weight Training Is a Strong Combo for Fat Loss
Here’s where it gets interesting. HIIT on its own is good. But when you combine it with weight training, you get the best of both worlds.
Weight training builds muscle. Muscle is active tissue. It burns energy all day long, even when you’re sitting on the sofa watching TV. The more muscle you carry, the more your body burns at rest. This is called your resting metabolic rate.
HIIT, on the other hand, burns a lot of energy in a short space of time and trains your heart and lungs to work harder.
Put the two together, and you get a plan that builds shape and strength while also stripping away body fat. You’re not just losing weight on the scale. You’re changing what your body is made of. Less fat, more muscle. That’s what we call body recomposition, and it’s a much better goal than just “getting smaller.”
This is backed by research too. A study by Burrup and colleagues found that for each day per week women did strength training, body fat was 1.3 percentage points lower and fat-free mass was 656 grams higher. That tells us something important: lifting weights regularly changes your body shape for the better. It’s not just about the scale. It’s about what your body is made of.
Cardio plays a role too. Research published in the journal Sports Medicine shows that combining resistance training with aerobic exercise, like HIIT, can lead to better improvements in body composition than doing either one alone, particularly when it comes to reducing fat mass while protecting muscle (Schoenfeld, Grgic & Krieger, 2021). This is exactly why I’ve built this plan to use both styles of training together.
Building This on the 12REPS App
You can build this entire plan inside the 12REPS app. Just go to “build your routine” and select each exercise from this workout. Add your sets, reps, and weight for each one. When it’s time to rest, use the stopwatch built into the app to time your rest periods exactly. This keeps you honest and keeps your sessions consistent week to week.
The best part is you can build this routine with whatever equipment you have. Got dumbbells at home? Use them. Training in a full gym with kettlebells, an airbike, and machines? Even better. Just swap in what you have access to and keep the structure the same.
Workout 1 – Day 1
Warm-up: 1km run
Exercise | Sets/Rounds | Reps/Distance | Weight | Rest |
Dumbbell snatch | 4 rounds | 16 (8 each hand) | Light–moderate dumbbell | 45 sec between rounds |
Dumbbell reverse lunges | 4 rounds | 16 (8 each leg) | Light–moderate dumbbell | 45 sec between rounds |
Bodyweight press-up / knee press-up | 4 rounds | 10 | Bodyweight | 45 sec between rounds |
Exercise | Sets/Rounds | Reps/Distance | Weight | Rest |
Airbike | 4 rounds | 10 calories | N/A | 45 sec between rounds |
Bodyweight squats | 4 rounds | 20 | Bodyweight | 45 sec between rounds |
Dumbbell shoulder press | 4 rounds | 10 | Light–moderate dumbbell | 45 sec between rounds |
Finisher
Exercise | Sets/Rounds | Reps/Distance | Weight | Rest |
Sit-ups | 4 sets | 12 | Bodyweight | As needed |
Plank twist side to side | 4 sets | 10 each side | Bodyweight | As needed |
Flutter kicks | 4 sets | 20 | Bodyweight | As needed |
Workout 2 – Day 2
Warm-up: 1km run
Exercise | Sets/Rounds | Reps/Distance | Weight | Rest |
Leg press | 5 sets | 15 | 50–100kg | 60 sec |
Leg curl | 4 sets | 12 | Moderate | 60 sec |
Leg extension | 4 sets | 20 | Light–moderate | 60 sec |
Dumbbell glute bridge | — | 15 | 30kg | 60 sec |
Dumbbell RDL | 4 sets | 12 | Moderate | 60 sec |
Exercise | Sets/Rounds | Reps/Distance | Weight | Rest |
Airbike | 4 rounds | 10 calories | N/A | 45 sec between rounds |
Plank twist | 4 rounds | 30 | Bodyweight | 45 sec between rounds |
Kettlebell gorilla row | 4 rounds | 16 (8 each hand) | Light–moderate kettlebell | 45 sec between rounds |
Exercise | Sets/Rounds | Reps/Distance | Weight | Rest |
Kettlebell swings | 4 rounds | 12 | Light–moderate kettlebell | 45 sec between rounds |
Kettlebell farmer’s carry | 4 rounds | 20 metres | Moderate–heavy kettlebell | 45 sec between rounds |
Side plank | 4 rounds | 20 sec each side | Bodyweight | 45 sec between rounds |
Workout 3 – Day 3
Warm-up: 1km run
Exercise | Sets/Rounds | Reps/Distance | Weight | Rest |
Lat pulldown | 4 sets | 12 | Moderate | 60 sec |
Machine chest press | 4 sets | 12 | Moderate | 60 sec |
Machine assisted pull-ups | 4 sets | 8–10 | Assisted to suit | 60 sec |
Exercise | Sets/Rounds | Reps/Distance | Weight | Rest |
Rowing machine | 4 rounds | 200 metres | N/A | 45 sec between rounds |
Dumbbell goblet squats | 4 rounds | 10 | Light–moderate dumbbell | 45 sec between rounds |
Chest-to-floor burpees or knee press-ups | 4 rounds | 10 | Bodyweight | 45 sec between rounds |
Exercise | Sets/Rounds | Reps/Distance | Weight | Rest |
Sledge push | 4 rounds | 20 metres | Loaded sledge | 60 sec between rounds |
Kettlebell farmer’s carry | 4 rounds | 20 metres | Moderate–heavy kettlebell | 60 sec between rounds |
200-metre run | 4 rounds | 200 metres | N/A | 60 sec between rounds |
A Final Word From Me
Most women don’t need more cardio to change their shape. They need more muscle. Cardio can support heart health and fitness, but if your goal is lifted glutes, firmer legs, stronger arms, and a more defined body, strength training needs to lead the plan. This is where many curvy women get stuck: they try to shrink their body instead of building it. The better goal is body recomposition, which means losing body fat while building lean muscle.
The research backs this up. Burrup and colleagues found that for each day per week women did strength training, body fat was 1.3 percentage points lower and fat-free mass was 656g higher. That matters because muscle gives your body shape. It helps create curves with structure, not just weight loss on the scale. So the aim is not to become smaller at any cost. The aim is to build the areas you want to shape, especially your glutes, legs, back, shoulders, and arms, while reducing body fat over time.
Stick to this plan for the full 6 weeks. Be consistent. Don’t skip the warm-up, don’t rush your rest periods, and track every session on the 12REPS app so you can see your progress build week by week. That’s how real change happens.
References
- Burrup, R., et al. (2018). Strength training frequency and body composition in women. PubMed. Available at: https://pubmed.ncbi.nlm.nih.gov/28181774/
- Schoenfeld, B.J., Grgic, J. & Krieger, J. (2021). Concurrent resistance and aerobic training and body composition outcomes. Sports Medicine. Available at: https://pubmed.ncbi.nlm.nih.gov/?term=concurrent+training+resistance+aerobic+body+composition
