Hills: The Workout That Does Double Duty

If you've got six weeks before a 5K and limited time to train, hills might be the single best workout you can add. A recent study found that runners who did one hill session a week for six weeks improved their 5K time by about 2 percent — not from getting fitter aerobically, but from running more efficiently and building leg strength. Think of it as a two-for-one: you get the benefits of a speed workout and a strength session packed into one hard effort on an incline.

Why does this work? Running uphill forces your legs to produce more force per stride, which builds strength in the same muscles you'd target in the gym — quads, glutes, calves. At the same time, the repeated high-effort bursts train your neuromuscular system to recruit muscle fibers more efficiently, which is a big part of what "running economy" actually means. You're not necessarily getting a bigger aerobic engine; you're getting better at using the engine you've got.

The practical upside is that hills can replace, not add to, your existing hard days. Instead of stacking a track workout and a gym session into your week, one well-structured hill session can cover both bases — which matters if you're short on time or prone to overdoing it.

For most intermediate runners, that means starting with short, steep hills — 8 to 15 seconds at a hard effort, with a full walk back down between reps, for 6 to 10 reps. As your legs adapt, you can shift toward medium hills of 60 to 90 seconds at something like 5K effort. The key is judging the climb by how hard it feels, not by pace — steep grades will always slow your watch down, but your effort should stay consistent.