⏵ Course guide · San Antonio club institution
The SARR Prickly Pear runs mostly flat single-track through McAllister Park, rocks, roots, dry creek beds, and plenty of prickly pear cactus, with a 50K, 15K, and 5K sharing the same loop. Now in its 24th year, this is a San Antonio RoadRunners club institution. I will walk you through the loop structure and cutoffs first, then give you a pacing and fueling plan, plus free tools to dial in your own numbers.
These facts come from the official RunSignUp race page. Check the current year details, cutoffs, and aid stations before you commit. Race logistics change year to year.
All distances start and finish at Optimist Pavilion #3 in McAllister Park, running the Blue Loop, Mud Creek Loop, and Mosquito Lake trails. The 50K covers three 10.34 mile loops, the 15K one 9.36 mile loop, and the 5K a separate 3.38 mile course.
The official course description calls this a mostly flat and fast single-track course, but that does not mean easy footing: expect dirt, rocks, tree roots, and dry creek beds throughout, plus plenty of prickly pear cactus lining the trail. Stay attentive even on the flatter stretches.
There are three water stations on the 50K/15K loop and one on the 5K, all cupless, stocked exclusively with Crazy Water and Gatorade, no food. Bring your own collapsible cup or hydration device, and plan to carry any solid food or gels you want, since the aid stations here are hydration-only.
Despite the club's community-event feel, this is a no-dogs, no-strollers race for safety reasons on the trail sections. If you typically train with either, plan for a solo trail day here.
The 50K's real constraint is not the 4:00 PM finish cutoff: it is the requirement to start your third and final loop before 12:45 PM.
To start loop three by 12:45 PM from a 6:00 AM start, your first two loops (20.68 miles) need to average under roughly 6 hours 45 minutes combined. Use a race-time calculator to check your projected pace against this specific gate rather than only the 4:00 PM overall finish.
Since all three loops on the 50K cover the same terrain, a grade-adjusted pace target for the rooty, rocky sections gives you an honest number for what you can repeat three times rather than just once. Even splits protect your buffer for the 12:45 PM cutoff far better than a fast first loop followed by a fade.
⏵ Free tools to pace this course
Early March in San Antonio can still run warm, and since aid stations here are hydration-only, your own carried calories carry more of the load than at a typical ultra.
Aim for roughly 60 to 90 grams of carbohydrate per hour on the 50K. Since the water stations stock only Crazy Water and Gatorade with no solid food, bring your own gels, chews, or real food and plan your pack or vest capacity around carrying a full race's worth of calories rather than topping off at aid.
Sodium in the 300 to 700 mg per liter range covers most runners, leaning toward the higher end if early March runs warm in San Antonio. The Gatorade on course provides some baseline electrolytes, but bring your own concentrate or tabs if you know you need more than a sports drink alone provides.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and an early-March San Antonio day with the free ultra fueling calculator. Browse the rest of the free running tools at the tools hub.
⏵ Train for it with Summit Line
Get a race-day plan built around YOUR fitness, this exact three-loop McAllister Park course profile, and your projected splits. Summit Line reads your real training, builds a plan for a food-light aid course, and rehearses your fueling so race day is something you execute, not guess at.
The official race description calls the McAllister Park course "mostly flat and fast single-track trails," running the Blue Loop, Mud Creek Loop, and Mosquito Lake trails through rocks, tree roots, dry creek beds, and plenty of prickly pear cactus. This is one of the more approachable Texas 50Ks by terrain: the challenge is more about the cumulative three-loop distance and the cactus-lined footing than climbing or technical difficulty.
No elevation gain figure is published on the official race page, which describes the course as "mostly flat" single-track. Treat this as a low-vert Texas 50K rather than a climbing-focused course, and focus your training on sustained trail running rather than hill work specific to this race.
This is a cupless race: bring your own hydration device or a collapsible cup to fill at the three water stations, which are stocked exclusively with Crazy Water and Gatorade and no other food. Since this is a low-food-aid course, plan to carry your own calories rather than relying on aid station snacks. Aim for roughly 60 to 90 grams of carbohydrate per hour on the 50K, and sodium in the 300 to 700 mg per liter range for early-March San Antonio conditions. Build your own numbers with the free ultra fueling calculator before race day.
The overall course cutoff is 4:00 PM, 10 hours after the 50K's 6:00 AM start. The harder constraint for 50K runners is that you must start your third and final loop before 12:45 PM, so your first two loops (20.68 miles) need to average under roughly 6 hours 45 minutes to keep that option open.
No. The official race page states plainly that dogs and strollers are not allowed on the course for the trail races, for safety reasons. Plan accordingly if you typically run with either.
A mostly flat, three-loop course with a 600-runner field and a well-established 24-year history from a nonprofit running club gives a first-time 50K runner real structure and community support. The main things to respect are the cupless, food-light aid stations (bring your own calories) and the 12:45 PM deadline to start your final loop.
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<a href="https://runsummitline.com/guides/sarr-prickly-pear">The SARR Prickly Pear course guide</a><iframe src="https://runsummitline.com/embed/race/sarr-prickly-pear" style="width:100%;max-width:420px;height:180px;border:0;" loading="lazy" title="SARR Prickly Pear course guide by Summit Line"></iframe>This guide is independent and for planning only. The course details, dates, cutoffs, and aid stations come from public sources and can change year to year, so confirm the current specifics with the official race before you register or run. The fueling and pacing advice is general and not medical advice.
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