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Sean O’Brien 50K Training Run

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Rock outcrops of the Sespe Formation along the Mesa Peak Mtwy segment of the Backbone Trail in the Santa Monica Mountains.

I looked at the mileage on my Garmin watch — 11.93 miles. I was at Kanan Dume Road and debating whether to make Kanan my turnaround point. My run had started at Malibu Canyon Rd. & Piuma Rd., where I’d picked up the Sean O’Brien Trail Runs course at around mile 2. After crossing Malibu Creek, the 100K, 50M, 50K and Marathon courses all follow the Backbone Trail westbound from Malibu Canyon.

The ground had been spotted with raindrops as I started the nearly 3 mile, 1500′ climb out of Malibu canyon. Subtropical moisture was streaming in from the southwest and there was a broad swath of clouds over Southern California. There were scattered showers, but most of the rain was evaporating before it reached the ground. The last time it had rained was more than a month ago, and the smell of rain was intoxicating.

Mesa Peak Mtwy segment of the Backbone Trail.
A short downhill on Mesa Peak Mtwy before the next climb.. Click for larger image.

Two weeks ago I’d done this climb as part of a “reverse” Bulldog loop. It hadn’t become any less steep. Most of the climb is on a fire road and some of it is runnable — just how runnable depends on your VO2max, determination and inclination. It was a relief to reach the top and start running downhill, even if another climb loomed just ahead.

Rock gateway on the Backbone Trail east of Corral Canyon Rd.
Rock gateway on the Backbone Trail. Click for larger image.

Once to the top of this next climb, it is about a mile and a half to Corral Canyon. There are a couple of short ups and downs along the way and the rock formations become increasingly dramatic. Just east of Corral Canyon the Backbone Trail winds through a wonderland of rocks and pinnacles, climbing a steep sandstone ramp and passing through a rock gateway.

A tranquil spot along the Backbone Trail in Upper Solstice Canyon.
A tranquil spot along the Backbone Trail in Upper Solstice Canyon.

From Corral Canyon the Backbone Trail drops into Upper Solstice Canyon. Today, the 16 crossings of the small creek in the canyon were all dry. Someone had provided log seats under a sprawling oak at “heart” meadow. I had to stop for a moment just to enjoy its tranquility. On a run here in January several years ago, the area was covered in ladybugs.

Gate on Newton Mtwy on Castro Peak.
Gate on Newton Mtwy on Castro Peak. (Not on the Backbone Trail.)

The high point of the 50K course follows the climb out of Upper Solstice Canyon and is near the saddle at Newton Mtwy. Back in the day the Bulldog 50K used to climb up and over the shoulder of Castro Peak from the top of Bulldog; then descend to this saddle and continue to Corral Canyon on the Upper Solstice Canyon Trail. This 2004 Los Angeles times article describes why the road is now gated and private.

Hummingbird Sage along the Backbone Trail
Hummingbird Sage along the Backbone Trail

The day was a little warmer than expected and the shaded sections of trail in Newton Canyon were refreshingly cool. The dried out stalks of last year’s hummingbird sage were common along the trail and given the lack of rain, I was very surprised to find a plant that was blooming.

The Sean O’Brien Marathon turns around at Kanan Dume Road, which is what I should have done. That would have resulted in a pleasant 24 mile training run with a bit over 5000′ of gain. Instead I decided to continue west on the Backbone Trail and “just run down to the bridge” to see if there was any water in Zuma Creek. There wasn’t. The bridge also would have been a perfectly good turnaround point that would have netted a 26 mile run.

But it was one of those rare, long run kind of days where the mind and legs are in sync and the miles almost didn’t matter. I reasoned that the Sean O’Brien 50K turnaround was “only” another mile and a half away, so why not continue. That way I’d have an even better idea of what to expect on race day.

Runners descending Mesa Peak Mtwy into Malibu Canyon.
Descending Mesa Peak Mtwy into Malibu Canyon.

I did continue, and with the exception of running low on water, everything went well. At Latigo Canyon several runners had just returned to their cars and I was able to fill up my Camelbak(R). Thanks Lou! And thanks to the other runners at the trailhead for their offers of gels, beer and salt!

I’ve run that section of the Backbone Trail several times, but never as an out and back. I now understand why the times for the Sean O’ Brien 50K are a little longer than the typical 50K. For one thing the course is about 1.5 mile longer than a 50K. For another, it has a TON of elevation gain. Using the elevation profile from my fenix 3 and a 1/3 arc-sec DEM from the USGS, the hand-calculated elevation gain worked out to be around 6000′. Tack on another 500′ of gain to account for the Tapia Spur Trail and the total gain for the Sean O’Brien 50K works out to a stout 6500′, give or take.