Going to the gym is intimidating enough. But not knowing how much weight to use for an exercise can make you feel even more uncomfortable. If you grab a weight that’s too light, you’ll waste your time. If you grab a weight that’s too heavy, you risk injury.
In a 12-week study published in the Journal of Applied Physiology, researchers found that subjects gained the most strength when using a weight that corresponded to 70 percent of their 1-repetition maximum – meaning 70 percent of the heaviest weight they could lift in the exercise.
Here’s how to figure out what that ideal weight should be…
In most cases, if you’re lifting 70 percent of the heaviest weight you could lift, you can do about 10 to 12 repetitions. So you want to use a weight that allows you to do no fewer than 10 reps and no more than 12 reps per set. For example, if you can do seated rows with 50 pounds for 20 reps, you should try using 70 pounds for 10 reps instead.
Unfortunately, the only way to identify an ideal weight is by trial and error. Start conservatively with an easy weight. Do six repetitions. If that feels too easy, increase the weight by 10 percent and try again. Do this until you find a weight that is a challenge for 10-12 reps. It should take you about three minutes to find the right weight for each exercise in your program.[Ed. Note: Building muscle and burning fat doesn’t have to take hours of work. Fitness expert Craig Ballantyne has put together a Turbulence Training program that can help you get fit in three 45-minute workouts a week.]