There is a common misconception that doing endless crunches and leg extensions will result in fat loss around the abdominal region and an incredible six-pack. Sadly it doesn’t quite work like that! There is far more to core strength training than spending an hour at the gym on a mat doing the typical exercises that most people associate with core work. Recently core training has become synonymous with abdominal training and the media play on this to attract people into buying the latest magazine etc with articles and programmes that will promise to transform a flabby tummy into an impressive six-pack by doing a few simple exercises. 
The functional role of the core is described by Elphinstone and Pook (1998) as “the ability of your trunk to support the effort and forces from your arms and legs, so that muscles and joints can perform in their safest, strongest and most effective positions.” Therefore crunches and leg extensions will help to improve core strength to a certain extent but there are other exercises that will strengthen your core far more effectively which I always ensure that I incorporate into my programmes with my personal training clients.
Your core is a collection of muscles that stabilise and move your spine. The inner core is made up of the transversus abdominis, internal obliques, lumbar multifidus, diaphragm and pelvic floor muscles. When these muscles contract they create a non-compressible cylinder where the spine is stabilised and this allows your legs and arms to function optimally. The outer core muscles include the rectus abdominis, external obliques, erector spinae, latissimus dorsi, the gluteals and abductors. The core protects and stabilises your spine by creating a rigidity that prevents excessive movement in any one direction. This is why I always remind my personal training clients to engage their core muscles when doing an exercise whether it be squats, lunges, or overhead lifts as it helps to prevent injury and increases core activation and strength.
Exercises that you do standing will work your core the most. Anything where you are seated or lying down will take the pressure off your core muscles. Whilst personal training, a lot of people have told me that they only use the fixed path resistance machines in the gym and steer away from free weights. This is any easy pattern to get into as usually people are told how to use these machines first during gym inductions. These machines do have their benefits, they’re good for beginners and do provide you with a good workout however they don’t engage your core muscles anywhere near as much as using free weights. This doesn’t mean that you have to start lifting ridiculous weights, bodyweight exercises are also very effective and will increase core strength.
Exercises like squats, lunges, deadlifts and one leg squats will work your legs but will also hugely increase your core strength. Upper body exercises such as overhead press, clean and press, front raises and bentover rows are great for working your core as your muscles are having to work really hard to stabilise your body and keep good technique. Planks, side planks, crunches, Russian twists and leg extensions are all still good things to include in your exercise training programme but most resistance exercises will train your core anyway so try not to focus too heavily on just the typical ‘ab exercises’.
