Trail Running Fartlek Training

I went out this morning for some winter trail running. My goal for the current program was 4.2 miles. I figured I’d be able to crank that out even with some uphill walking in less than an hour depending on snow conditions. I started at a local pool parking lot, like usual. I had done some ice climbing the day before which required a mile approach with over 500′ of elevation gain hiking up a steep gully of rock and ice. I wasn’t sure how that would affect my trail running, so I was ready to just jog lightly if needed.

Spiked Trail Running Shoes
Spiked Trail Running Shoes: Hoka One One Mafate WP with screws

The first part of the road was slick ice over the surface. I was glad to be wearing my spiked trail running shoes [article]. They stuck to the ice and I didn’t feel at risk of falling at all. I ran to the gate, and through. The road surface was pretty icy for the first half mile, with long strips of ice-impregnated dirt showing through. My shoes stuck well. I was glad to be wearing them.

Trail Running in Keystone Colorado
Trail running up Keystone Gulch Road behind Keystone Ski Resort in Colorado

I actually felt really good. I did intervals up the road, choosing somewhat random targets. I ran to a fence post, or a stick along the shoulder, or a mottled shadow. Since you’re not at a track, trail running intervals don’t need to be structured as exact distances or times. This type of random-ish unstructured interval is called “Fartlek”.

Trail Running Fartlek

Fartlek, which means “speed play” in Swedish, is a training method that blends continuous training with interval training. The variable intensity and continuous nature of the exercise places stress on both the aerobic and anaerobic systems. It differs from traditional interval training in that it is unstructured; intensity and/or speed varies, as the athlete wishes. Most fartlek sessions last a minimum of 45 minutes and can vary from aerobic walking to anaerobic sprinting. Fartlek training is generally associated with running, but can include almost any kind of exercise. From Wiki

I ran out 2.1 miles, my half-way point and rested for a minute and took some pictures. I started down, and felt like I was flying. I did a somewhat long trail running interval, and walked down till my heart rate was below 130, then took off flying again. Usually in winter trail running I slog along and just enjoy the scenery. I again set my distance target to various appealing looking sticks or trees or shadows or rocks. It was a struggle to get there sometimes, but it’s great mental discipline.

Trail Running at Keystone Gulch Road
Trail running turnaround point at 2.1 miles surrounded by snowcat tracks

I continued my trail running intervals to my “targets” and walking till my heart rate descended below 130 till I got to the gate. There were a couple guys skinning-up their skis, and someone walking a big dog. I walked past them so I wouldn’t scare them. My heart rate got below 120 for a couple minutes. I took off again on the ice-covered road to the parking area. I felt great. Since I set my new goal to do the Uber Rock 50k trail run in Vail this coming September I’ve adjusted my training program into something like “40 weeks to an ultra”. Trail running 30 miles up and down the mountains between Vail and Minturn will require that I be in the best of shape for it. I learned that in Aspen Backcountry Marathon in 2011. I survived. That about sums it up.

trail running stats on a gps hrm watch
Stats from my Polar RS800cx

Above is the result of my winter trail running fartlek session, via my Polar RS800CX GPS G5 Heart Rate Monitor. Oddly the intervals are mostly fairly regular. I didn’t do that intentionally. According to the Google Earth elevation profile I did 560′ up and down. I take into account stats from both Polar and Google. One is based on atmospheric pressure, the other on waypoint interpretation.

The temperature was about 15 degrees F, but in the sun it felt warm and in the shade cool. For winter trail running you have to dress for both the fast and slow portions of your run. You should feel a little bit warm while fast, and a little cool while slow. I had dressed for a slow trail running session, so I was really warm during the speed intervals. It was a bit too cool to unzip during them though. If you choose to go trail running in the winter, please be careful, dress appropriately to your own metabolism and running goals, and consider wearing spiked shoes or some detachable traction device.

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