With gloomy autumn nights drawing in, it's tempting to give up the gym or early morning jog and curl up in bed instead. Now nutritionist and exercise expert Yinka Thomas, has created a fun and easy-to-follow workout using a mini-trampoline. And the best news is you don't even have to leave your lounge. Spending 20 minutes on a rebounder a day will help you tone and firm your body in just six weeks. 'The reason it's so effective is because your body feels an increased gravitational (G) force at the bottom of the bounce,' Yinka said. 'This can be equivalent to two or three times your bodyweight, and every cell in your body responds to this perceived 'stress' by strengthening.'