Finally! The six-pack you’ve always dreamed of is only a plank (or two!) away. But there’s just one catch: While the act of planking is pretty straightforward, how long you should actually hold one is probably a bit less clear. Thankfully, the experts have you covered.

To reap the most rewards, holding three planks for up to 60 seconds each is ideal.

But if you’re new to planking, don’t risk injuring yourself in the name of a slimmer waistline. ‘It’s OK to start with shorter sets and work up to 60 seconds. Forcing yourself to hold a plank for an excessive amount of time can put a lot of strain on your lower back. As fatigue sets in, the lower back may start to arch. This is where you put yourself at risk for injury.

If one minute is too challenging, try holding a plank for 10 seconds, relaxing for five to 10 seconds, then re-engaging for 10 seconds. Repeat each set three to six times.

And don’t worry about losing out on any gains in the meantime; planking for shorter periods of time can still amount to a solid workout. You receive very similar strengthening benefits because you are engaging your muscles for the same amount of total time as if you just held the plank for 30 to 60 seconds without stopping.

On the flip side, holding a plank for one minute might be a breeze for you. If that’s the case try increasing the difficulty by contracting your abs, as well as squeezing your glutes and quads.

Form should always come before figure, of course. Although planking can strengthen your entire body, you should only do it for as long as you can hold the correct position, experts say. Keeping perfect form is the goal—only do it as long as you can keep your form.