It’s no question that skiing and snowboarding are great workouts, and these ski runs are sure to test even the most physically fit slopegoers.

Here’s a list of notably long runs around Colorado that travel from the top to the bottom of the mountain. Some of these are sure to leave you heaving for breath with burning legs.

1. Schoolmarm (Keystone)

Keystone’s Schoolmarm is a great beginner cruiser of 3.5 miles. The trail runs from the summit of Mt. Dercum all the way to both River Run and Mountain House Base Areas. The run consists of a variety of terrain, including rolling hills, challenging pitches, cat walks and kid’s adventure zones.

2. Riva Ridge (Vail)

As Vail’s longest single-run ski trail, this run is a classic, with its mix of intermediate and expert sections. The run is accessible from the Mountain Express Lift and the top of Chair 4. The trail starts out easy as a blue groomed trail but then turns into the aptly named Tourist Trap, a tight mogul section. According to Vail Resorts, the run drops 3,000 feet from 11,250 feet and will lead you right to the base of Gondola One (with your legs probably burning).

3. Centennial (Beaver Creek)

Beaver Creek’s 2.5-mile World Championship downhill course starts at the top of Cinch Express at 11,440 feet and runs along the mountain. The run ends right in the village.

4. 4 O’Clock (Breckenridge)

Access the full 4 O’Clock run via Colorado Super Chair to 6-Chair to Imperial Superchair on Peak 8. At 3.5 miles in length, this is Breckenridge’s longest run. It ranges in difficulty throughout the run. At the top it starts as a black diamond before turning to blue in the middle and then ending up as a green as it approaches the base of the mountain. Those hitting this one will also have to ski down the Imperial Bowl to find its upper reaches and will also have the option to take the lower portion of the run all the way into the gondola lot near the downtown Main Street.

5. Galloping Goose (Telluride)

This run is 4.6 miles of corduroy. Galloping Goose leads all the way down the mountain from the top of the Prospect Express lift. The run will drop you off right at the base of the mountain near Big Billie’s Restaurant.

6. Why Not (Steamboat)

Starting at the top of Steamboat’s Central Mountain, this run takes you to the bottom of the Thunderhead Express lift.

7. Green Cabin (Aspen Snowmass)

This run at Snowmass will take you from the top of the High Alpine lift to the base of the mountain. It’s a blue run, so it’s not too challenging.