43% The increase in electromyographic (EMG) activity measured in the leg and core muscles of subjects doing free weight squats over using a Smith machine, according to Canadian research
Real-world strength
If you’ve ever tried to drag a heavy bag through a packed airport or lug a TV up to a second-floor flat, you know the real-life requirements of functional strength. And you can only train for it with dumbbells, barbells and kettlebells. “You might be able to build size that makes you look the part with resistance machines, but you won’t have the strength in your tendons, ligaments and stabilising muscles for the real world,” says PT Alex Gildea (gildeafitness.com).
Fix your weaknesses
Body symmetry is important for more than just aesthetic reasons. “An imbalanced body can be especially vulnerable to injury when one side compensates for the other,” says Gildea. It can be hard to target individual limbs or muscles using machines alone but also when using barbells for overhead lifts and bench presses, so swap in dumbbell variations. “You might find you lift less at first but once you’ve exposed and addressed weaknesses you’ll be able to lift bigger in the long run.”
Six-pack perks
Dumbbells come in matching pairs but that doesn’t mean you have to use them together. “Doing unilateral – one-sided – lifts with free weights activates your anti-rotational core muscles to target your abs muscles, which usually get an easy ride with machines,” says Gildea. Try single-arm dumbbell chest presses and suitcase carries (like farmer’s walks but on just one side) to strengthen your core and forge more robust foundations for your lifts.