How You Know It's Time to Lift Heavier Weights

POPSUGAR Photography | Blake Smith
POPSUGAR Photography | Blake Smith

Cardio helps burn fat, but your body's real reshaping happens during a strength-training workout. If you're committed to seeing a radical transformation in your physique, you can't be afraid to lift weights. But if you're new to strength training, choosing the perfect size for your body's needs can be confusing. Celebrity trainer and Lift to Get Lean author Holly Perkins has an easy-to-follow tip to determine what size weight you should be lifting for every exercise: the 12th rep should not feel like the first.

According to Holly, if every rep feels the same, you're not pushing your muscles to their ultimate transformative potential — it's time to go heavier. I know your next question: how heavy is too heavy? Holly makes it simple: during the last two reps, you should "lose about 20 percent of perfect technique." This is not an excuse for the last two moves to be sloppy and all over the place — technique is Holly's number one priority — but your muscles should be seriously worn out by the end of your set. Doing five more reps should not sound like a good time. Oppositely, if your form is off during the majority of a set, Holly recommends going lighter in order to prevent injury.

It's important to note that you need to perform this test for every exercise in your workout; you might be lifting 10-pound dumbbells during a set of dead lifts and 15-pounders on your bicep curls. If you're a home-workout-lover, this means investing in additional sets of weights, while gym-goers need to experiment to find the pair that's just right for every move. If you've never lifted before but you're ready to start, this beginner strength-training workout was designed by our fitness host Anna Renderer just for you!