Transfrom your body with the Stella Body Plan: cardio exercises Strike the ground heel first; roll over the ball of your foot, then push off with the toes. Relax the shoulders with arms loose at the sides. Work on using your arms, swinging them backwards and forwards while taking shorter strides to increase your speed. Watch your posture - focus your eyes straight ahead and try not to lean forward. What is your start level? Complete beginners 100 steps per minute can be hard work if you're new to exercise. Do the best you can at working up to this pace over four weeks. Incorporate low-intensity intervals where indicated. Quite new to exercise Aim for a pace of 100-115 steps per minute, which is equal to 3mph-3.3mph. Intermediate Aim for 125-135 steps per minute, about 3.5mph-4mph. Incorporate the high-intensity intervals where indicated. Regular exercisers Aim for 136-141 steps per minute, 4.1mph-4.5mph. Incorporate high-intensity intervals where indicated. Power-walk programme Choose your starting level, then aim to maintain the pace for as much of the given time as you can. As you become fitter, aim to increase your mileage in the same amount of time by increasing your pace. Start slowly, then speed up, and towards the end cool down by decreasing speed slowly. Steady pace walking/moving The goal for this session is simply to think about walking and moving in the day. Become more active by taking the stairs, walking part of or the whole way to work or the shops, or by going dancing. If you have a pedometer measure your steps and try to improve each week. The more you move, the more you burn. Interval programme (see video above) This is a fun fat-burning session that also improves fitness, speed and endurance. It consists of four one-minute skipping intervals. Between each interval you will power walk for four minutes. To decrease the intensity you can replace the side steps with a walking side squat. Visit telegraph.co.uk/stellabodyplan to watch the sequence. The skipping interval 1 min skip, knees up high, swinging the arms 30 secs side step facing right; 30 secs side step facing left 1 min of two single skips then a double skip (lifting the same knee twice) on one side, two single skips then a double skip on the other side 1 min skipping backwards How to perform the interval session Warm up with 4 mins of power walking, gently increasing your pace Walk for 4 mins at speed at your chosen level Interval (see above) Repeat 4 mins power walk building your paces back up, and then slowing down towards the end of the session. As you progress over the weeks you will repeat more skipping intervals in each session. Top tips Always think about the area you are working. You need to connect to each move and really feel it. Always think about engaging your lower abdominals throughout every exercise. You don't need to do endless crunches to work your tummy - rather, just engage your core. Quality over quantity. Keep the movements precise and don't worry if you can't get to the suggested repetitions just yet; you will achieve nothing by rushing the move or compromising the technique. As with any diet and fitness regimen, if you are unsure if it's for you, consult your GP. Typical weight loss should be between 1lb and 2lb per week but, more importantly, Howells says, you should begin to see a real difference in your shape: "Longer, leaner, strong but feminine."