Even if you feel like you’re in good shape, tackling hills on foot is tough. Most people assume going uphill is more difficult than going down; however, both sides of the hill have their pros and cons. Inclines can be a great way to burn calories. For each degree of incline, you can expect to burn 10% more calories than if you were on a flat surface, says Blake Dircksen, DPT, certified strength and conditioning specialist and physical therapist at Bespoke Treatments in New York City. “As you walk or run up a hill your body recruits more muscle fibers, which requires more energy and calorie expenditure,” explains Dircksen. But going downhill can also be beneficial. “Going uphill, you’re powering through gravity, while going downhill you’re controlling your momentum and utilizing more passive energy.”

Here, a look at the muscle groups targeted by each type of terrain, the benefits and three tips for getting started.

When going uphill, the major muscle groups being utilized are all in the posterior chain, including the calves, hamstrings and glutes, says Dircksen.

The benefits:

“Uphill movement is a great way to develop power and speed as it places you more on the forefoot and necessitates higher power development from those posterior chain muscles,” says Dircksen.

Downhill walking puts a greater force on the front side of the body — particularly the quads and lateral hip stabilizers, notes Dircksen.

The benefits:

Instead of letting gravity win, picking up the speed and letting your form go out the window, downhill walking is the perfect opportunity to focus on crisp form and control, says Dirksen. Plus, a study showed downhill walking helps remove blood sugar and improve glucose tolerance.

It’s important to vary your walking and running routes. Including both uphill and downhill training can help balance and strengthen the body.

Here, three important things to keep in mind when getting started with hill training:

1. AVOID DOING TOO MUCH TOO SOON

The last thing you want is an overuse injury. Just like when it comes to adding more weight to your traditional lifting routine, hill work is something you should add gradually and only once you feel like your form is on point, says Dircksen.

2. STAY ON LEVEL GROUND IF YOU’RE INJURED

Since going downhill puts a greater amount of force on the lower body than going uphill, it’s important to make sure you’re not powering through an injury and potentially putting yourself at risk for additional damage. “If you’re battling an injury, ask a physical therapist about hills and any strategies to mitigate overload,” says Dircksen.

3. DON’T FORGET RECOVERY

Hill training should be spread out. “Make sure to take adequate recovery days between hill workout days and during the training session, keep form and body position in control,” advises Dircksen.