The question: My trainer tells me I need to ditch traditional crunches and instead do functional core work. What exactly does that mean? Is he just trying to sell me training? Can't I just do my crunches?
The answer: You can, but since we all have limited time to train, I wouldn't make them your priority.
Crunches primarily work the superficial rectus abdominis (a.k.a. "the six pack"). I know, so far they sound great. Who doesn't want toned abs? The problem is that if you are just doing crunches, you are ignoring the rest of your core.
Functional exercises work your abs in addition to the other muscles that form your core (like your back), integrating your trunk into the rest of your body and preparing you for real life.
Another strike against crunches is that they curl you forward into that terrible hunched posture that sitting promotes.
Lastly, too many crunches – especially if done with added weight or bad form – are not great for the lower back.
If you decide to ignore my advice, say you need to strengthen your abs for sports or because of an injury, just ensure they are not your entire abdominal routine. Make it balanced by including functional core exercises like planks, wood chops and squats, and back exercises like back extensions.
Back extensions: Place your stomach on a stability ball, chest rounded over the ball and knees on floor. Use your bum and lower back to lift your chest up to hip height 10 times.
The main takeaway: Crunches are out of style at the moment. Although I agree with this general trend, most exercises aren't simply good or bad. Unless you have osteoporosis, a few crunches won't kill you – they just aren't the best use of your time.
Trainer's tip: If your goal is more defined abs, remember that no amount of any core work will magically create definition unless you reduce your overall body fat. Try getting more sleep, hydrating, strength-training and, most importantly, paying attention to your diet!