I do 100 sit-​ups every morn­ing but they don’t seem to be doing any­thing for my stom­ach defin­i­tion. Should I be vary­ing the sit-​up a little more?

If you really are per­form­ing 100 per­fect sit-​ups every day, there are two pos­sible reas­ons for your lack of notice­able improve­ment. First, our bod­ies quickly adapt to spe­cific tasks, and once the muscles have strengthened suf­fi­ciently to cope, they will not carry on improv­ing unless you set them a tougher chal­lenge. So your daily régime may be “main­ten­ance only” by now.

Alternatively your genetic make-​up may be thwart­ing your “six-​pack” ambi­tions. However strong your stom­ach muscles, if you are car­ry­ing any appre­ciable fat around your trunk, those muscles will be hid­den from view. You simply can­not sculpt a more defined pro­file through overly­ing fat, even a rel­at­ively thin layer of it.

However, it is more likely you are not get­ting your sit-​ups quite right. The abdom­inal sit-​up is without doubt one of the most abused of gym exer­cises — very easy to get wrong, and com­pletely inef­fect­ive without the right tech­nique.

I sug­gest you go back to basics, start­ing with this simple “abdom­inal crunch” tech­nique. When you do it cor­rectly, you should feel the effects very clearly in the centre of your abs, and it is hard work com­plet­ing 15 crunches, let alone 100 (as a rule you don’t need to do more than 30 repe­ti­tions of any muscle exer­cise).

I am assum­ing you have no back prob­lems. If you do, take advice from a trainer or physio­ther­ap­ist before prac­tising sit-​ups.

• Lie on your back, knees bent and feet firmly flat on the ground in line with your hips
• Do a little pel­vic tilt (draw front hip bones slightly up to your eye­brows), and suck down your tummy but­ton to keep your low back and but­tocks on the ground dur­ing the move­ment
• Rest your fin­gers at the top of your bent legs
• Keeping your head and neck still, tighten your cent­ral abs and slide hands towards your knees
• Your head and upper back should lift dir­ectly upwards (keep look­ing at the ceil­ing), as though being pulled up by a piece of string in your stom­ach
• Do not round your shoulders or dip your chin to your chest
• Hold the pos­i­tion briefly at the top point (which may be only 10 to 20 degrees off the floor), before lower­ing back down slowly and under con­trol.

When you can man­age 20 crunches with per­fect con­trol, you need to move on to a harder chal­lenge. Here are some options:

• Hold each crunch at the top point for 5 seconds before lower­ing down again slowly
• Place your feet against a wall, mak­ing a 90 degree bend at the knee, to do the exer­cise
• Keeping your low back and bum firmly on the ground, increase your move­ment to a “sit-​up” (about 30 degrees), tak­ing your fin­ger­tips bey­ond your knees.

For a fuller ver­sion of the ab curl, click here. For great torso defin­i­tion you should also be doing work on your diag­onal “twist­ing” muscles (obliques) and your lower ab muscle (trans­verse).