I'm very thin and taking steroids due to autoimmune disease. My arms are like sticks, with prominent veins. Doctors say they won't improve even when I'm off the steroids.

We need to address two issues: size, and the strength of your arm muscles, to safeguard against osteoporosis. Regarding size, some individuals are slow responders - that is, their bodies respond less than others to training programmes, and this may be a factor to consider.

I have two suggestions aimed at the arm muscles. Targeting the short head of the biceps, rather than the long head of the front arm, can create a more pronounced shape; and targeting the shoulder deltoid group of muscles can create better shape throughout your upper torso, so improving overall appearance.

For women training for aesthetic purposes, I do not normally prescribe bicep curls as they create a shorter, bulkier shape, but in your case I feel they're perfect. Use a heavier weight, with fewer reps. For the shoulders, try these arm raises to create long, lean definition through the front of the arm, as well as shaping shoulders. Stand with good posture, hold a 1-3kg weight in each hand, palms away from thighs. Slowly lift in front of you to eye line on four counts, keeping elbows in line with wrists. When level with eyes, turn palms down, taking arms out to side on four counts, then slowly lower to your thighs on eight counts. Reverse the sequence at the same pace, performing a total of 12-16 reps. Start with lighter weights: the long levers of your arms can make them seem very heavy.

· Joanna Hall is a fitness expert (joannahall.com). Send your exercise questions to Weekend, 119 Farringdon Road, London EC1R 3ER (weekend@theguardian.com).