How we can change our body shape with exercise

This article is part of our package looking at the benefits of exercise. Have a look at our interactive body map on the risks of inactivity.

For most of us, heading into a gym can lead to confusion about what exercises to do. If you want to change the shape of your body, can selecting certain exercises really work?

Once we reach adulthood, our bone structure and proportions are largely fixed. Essentially, the length of your collar bones versus the size of your pelvis, and the length of your body compared to the length of your legs are big factors in determining proportions and aesthetic beauty.

However, we can use exercise to enhance our body shape and appearance, as well as increase muscle and bone strength.

Fat and muscle

We cannot physiologically change fat to muscle. For example, although doing lots of repetitions squeezing your knees together on a hip adductor machine creates a feeling of using this muscle group, it will not burn the fat deposits off the targeted area. What will occur is that with training, the muscles become stronger and larger, which may be contrary to what many women may be trying to achieve in attempting to sculpt leaner-looking legs.

Another example is trying to burn off excessive abdominal fat, which increases the risk of chronic diseases such as diabetes and heart disease. No amount of crunches will burn off abdominal fat directly.

Increased physical activity in general, exercise and good nutrition are key to losing fat. Although there’s no way to induce spot reduction in fat that is stored under the skin, moderate to high-intensity cardiovascular training is very effective in reducing fat. This includes running, skipping, cycling and boxing.

We’ve all heard women say: “I don’t want to lift weights because I don’t want to look muscly.” But it’s really not that easy to put on significant muscle mass. Many bodybuilders will attest to the amount of work and overfeeding required to promote muscle growth. So the idea that weight training will make women bulky is a fallacy.

Training specific muscles

If you train specific muscles, these will increase in mass. So targeting specific muscle groups, as body builders do, can shape your body.

If you only do repetitive cardio exercise in the gym on equipment such as treadmills, a cross trainer or an exercise bike, only the large muscle groups you use to move will get stronger and increase in size.

So running on a treadmill may make your bottom (gluteus maximus), hamstrings, quadriceps (front thighs) and calf muscles bigger; and using a cross trainer will work the same leg muscles, as well as target the muscles in the chest, back and shoulders that push and pull.

Whereas attending a bootcamp-style class, or doing compound exercises (like squats or dead lifts that work lots of different muscles) where the types of exercises are more varied will stimulate a larger number of muscle groups.

To look more athletic, train the shoulders (deltoid muscles) so they broaden compared to the pelvis. This creates a more V-shaped body.

Examples of weight-training exercises that work the deltoid muscles include shoulder presses (lifting weights from shoulder to above the head) and seated dumb-bell flies (lifting weights from the midline of one’s body in an arc to shoulder height).

In order to have longer-looking, shapely legs, over-emphasise training the hamstring and bottom (gluteus maximus) muscles, and de-emphasise training the quads and adductor groups (front of thigh).

This will give less width and more depth to the thighs. Examples of exercises that shape the thighs include hamstring curls (bringing the heels to the bottom by bending the knees) and stiff-legged barbell dead lifts (bending at the hip to lower weights down the front of the legs).

In order to have more fullness in the chest, inclined chest presses (pushing weights from the chest level) and pec flies (moving in an arc at chest level) will emphasise the upper chest muscles.

These are often neglected because they’re not as naturally strong as the chest muscles lower down near the sternum which are used in common weight-training exercises like bench pressing.

Training back and abdominal muscles that form the corset around the torso is important in providing a stable base from which our bodies move, and supports the natural curves of the spine, improving our posture and body shape.

A simple, effective exercise is lying rotations. Lie face up and bend the hips and knees to 90 degrees and keep the knees together. With arms outstretched to 90 degrees and on the floor, slowly allow the knees to rotate towards one of the outstretched hands, then stop just before reaching the hand and repeat on the other side.

Form is key

What is important is training with good form. Our bodies are wired to avoid discomfort, so it’s easy to use larger muscle groups or momentum to lift weights. This can be counter-productive as the muscle groups being used may not be the targeted ones in any particular exercise.

An example of this is using the back muscles in creating momentum from repeated backward bends in performing dumb-bell or barbell bicep curls. A much more targeted way of performing this exercise is to maintain the natural curves of the spine by supporting the back, either on a bench or against a wall.

Stretching matters

Stretching will prevent any unwanted loss of range of motion in joints due to muscle tightness. Exercises such as yoga and pilates, as well as general stretching, are great at keeping us supple and lithe.

Yoga, pilates and even martial arts nurture the practice of movement patterns through each joint’s range of motion. If efficiency of movement is a pleasure to the eye, then there is much to be said about developing grace in order to enhance aesthetic beauty.

Julie Netto does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.