Build full-body muscle in just 20 minutes with this four-move dumbbell workout

If you want to build lean muscle, you might imagine you'd need to spend hours at the gym to see results. But if you're tight on time, you can develop muscle all over in just 20 minutes with this four-move routine and a set of dumbbells.

When working out at home, it's worth investing in a set of the best adjustable dumbbells. These customizable weights combine several dumbbells in one and are a great way to increase the load using the progressive overload technique gradually.

But if you prefer working out at the gym, you may be wondering what dumbbell weights should you use. The aim is to find a load that'll challenge your muscles but won't affect your form. Then you're ready to take on personal trainer Rhiannon Bailey's routine.

There are just four dumbbell moves, and you'll exercise for 40 seconds, take a 20-second rest, then move on to the next exercise. You can repeat the round five times for a 20-minute muscle-building, fat-burning workout.

To get the most from your training and avoid injury (especially when working with weights) it's crucial to focus on your form. Whether you're new to strength workouts or could use a refresher, you can follow Bailey's demonstrations to practice your technique.

Watch Rhiannon Bailey's four-move dumbbell workout

This exercise style is known as high-intensity resistance training (HIRT), where the aim is to work out intensely in short bursts with minimal rest. You'll work your muscles hard in a short period, but there are other benefits.

Exercising at a high intensity raises your heart rate, increasing the energy you burn compared to an equivalent steady-paced routine. And sustaining this elevated heart rate by only taking short rests also boosts your metabolism, the energy you burn at rest.

If this sounds a lot like high-intensity interval training (HIIT), that's because it is, but with a focus on strength training moves rather than cardio-based exercise. This is why people also often reach for a HIIT workout for fat loss.

It's one of the reasons why Bailey's routine is so effective, even though it only takes 20 minutes. But just as important is the choice of moves. The routine is based on compound exercises, which work multiple muscles simultaneously.

And, if you have one of the best kettlebells to hand, you can learn how to do kettlebell swings for a similarly effective workout. This compound exercise works your whole body, strengthens your core, and boosts your metabolism.