Pop quiz, hotshot: what’s the best bit of training kit that everyone has in their house? No: it’s not cans of soup, which only work for curls if you’ve got the arm strength of an inactive toddler. It’s not even bottles of water, though they’re a better bet, or crates of booze – they’re handy for squatting, but at some point you’ll end up drinking them. Nope: to add variety (and function) to your home workout, your best bet’s a towel.