So far our 12-week new body plan will have helped you to gain bulk. This means you can forget about trying to bench press the weight of a cow. It's  now time to strip away fat and increase muscle density to form a lean, powerful body. But don't panic - we're not going to force you through epic, fat-burning marathons. In the final four-week part of the programme you'll do short, sharp, efficient workouts.

One new thing you'll have to get used to is cutting down the rests you take between exercises. In this fat-burning phase, you need to keep your heart rate high rather than taking time to recover fully. But because these workouts use higher reps and explosive movements, you'll need to select less weight than you used in part two of this programme. If you overload your bars you could be looking at a progress-punishing muscle tear.

The other new tactic in these workouts is plyometrics. Simply put, a plyometric exercise is one that extends a muscle across its entire range of motion before explosively contracting it against resistance. The effect of doing such an exercise is to increase the power available to your muscles, and because the training burns calories you'll lose body fat too.

One word of caution: this training method carries a higher risk of injury than usual. So if you've picked up any niggles so far, seek advice from a fitness professional before starting the final phase. You'll soon see the results of your 12-week effort. Oh, and get ready for some serious muscle envy from your fellow gym users - we'd appreciate it if you'd blame it on us.

How to do this workout
Do workouts A, B and C once a week each, leaving at least one day's rest between each. Choose a lighter weight than normal and concentrate on maintaining good form, but perform the lifting part of the exercise faster than normal. Drink some carbohydrate or eat a banana 30 minutes before each workout to fuel your effort.

Warm up by doing five minutes on a cardio machine then light sets of press-ups and bodyweight squats to raise your heart rate and get your muscles working. Leave one minute's rest between sets and two minutes between exercises, except in workout C when you should have only one minute's rest between moves.