⏵ Course guide · Tennessee ultra
Mamba 100 Course Guide
The Mamba 100 is Memphis’s flat, fast looped ultra on the Wolf River trails, and it runs the whole menu from 25K up to a full 100 miler. This is the opposite of a mountain race. Almost no climbing, smooth runnable singletrack, the same 14.35-mile loop over and over, and a long night out there. That makes it a real PR and Western States qualifier hunting ground, as long as you respect the loop grind and the dark. I’ll walk you through the course first, then give you a pacing and fueling plan for a fast, flat hundred, with free calculators along the way to dial in your own numbers.
The course: where the Mamba 100 is won and lost
Everything here is built on one 14.35-mile loop of mostly smooth singletrack along the Wolf River, repeated as many times as your distance calls for. The 100 miler is seven loops, the 50K is two, the 25K is one, and the 100K stacks loops on a starter section. About a mile of it is road, half of each loop hugs the river, and there is a bridge crossing near the middle where they punch your bib to count the lap. It is flat, it is fast, and it is honest. There is no climb to hide behind and no terrain to blame, so the race comes down to pacing, fueling, your feet, and your head.
The loop: fast and smooth, but the same thing seven times
The Wolf River loop is the kind of trail you can actually run almost all of, which is rare for a hundred. That is the gift and the trap. Because nothing forces you to walk, it is easy to run too much of the early loops at a pace that feels effortless, and then the repetition catches up with you. Flat ground means your legs repeat the exact same stride for hours with no change in muscle pattern, and that monotony quietly wears you down even though no single section is hard.
Treat the loop as your unit of pacing and fueling, not the mile. Settle into a relaxed, repeatable rhythm you could honestly hold for all seven laps, walk a little on purpose before you have to, and let the loops tick by. The runners who blow up here are almost always the ones who treated the early laps like a road race.
The night: about half the hundred is run in the dark
The 100 miler starts Friday at 7:00 AM, so for most runners the back half of the race happens in the dark, and a finisher reported roughly twelve hours of headlamp time. The 100K actually starts in the evening at 7:00 PM, so it is a night race from the gun. Darkness is where a flat, easy course gets interesting: your pace drops, your focus drifts, and the low points hit hardest somewhere in the small hours.
Bring a bright headlamp and a backup, and practice running at night before race day so it feels normal. The good news is the loop course means you pass through the start/finish every 14 miles, so you are never far from light, aid, your drop bag, and your crew. Use that. Break the night into one loop at a time.
Footing, leaves, and the river
Do not let flat fool you into switching your brain off. This is a November race in West Tennessee, and fallen leaves can hide roots and rocks on the singletrack, especially on the river side of the loop. Organizers have cleared leaf cover for safety in past years, but tired feet plus hidden roots late at night is still the most likely way to trip in an otherwise gentle race. Pick your feet up, particularly on the second half of each loop and once it gets dark.
Half of every loop runs right along the Wolf River, which is genuinely scenic and helps the miles pass. The bridge crossing near the middle of the loop is your lap checkpoint, where they punch your bib, so you always know exactly how many loops you have left. That countdown is a useful mental tool late in the day.
Aid, crew, and drop bags every loop
The loop format is a huge logistical advantage. You get aid roughly every 4 to 5 miles, with a Bridge aid station out on the loop (around 4.5 and 9.5 miles in) and the big Start/Finish aid station every time you complete a lap. Finishers describe the aid as very well stocked, with real food like sandwiches, quesadillas, and pickles, not just gels.
Because you return to the start/finish every 14.35 miles, you can stage a drop bag there and your crew can see you every loop. That is gold on a hundred. Pre-plan exactly what you grab each lap (calories, fresh bottle, headlamp, dry socks, a layer for the night) so your stops are quick and deliberate instead of long and aimless. On a loop course, time lost lingering at the tent adds up fast.
Pacing strategy for a flat, fast looped hundred
With no climbs to slow you and a roomy 34-hour cutoff, the Mamba 100 is a discipline race. The whole game is holding back early so you can still run late, because on flat ground there is nothing to hide a blowup.
Pace by effort, and bank patience instead of time
On a course this flat it is tempting to lock onto a pace and chase it, but the smarter move is to run by easy effort and let the pace be whatever it is. Your early loops should feel almost too easy. The classic Mamba mistake is running the first two or three laps a chunk faster than goal because the trail is smooth and the legs are fresh, then grinding to a walk in the dark. Keep a grade-adjusted pace target as a sanity check so you can see when you are pushing harder than your real fitness supports, even on the flats.
Walk the few small rises and a few steps out of every aid station on purpose, from the very first loop. That tiny bit of restraint early is what keeps the wheels on at loop five and six.
Build a realistic finish and a buckle plan
A flat hundred is one of the few ultras where a goal time is actually meaningful, because the terrain is not constantly changing your pace. That makes it a great PR and buckle target (there are sub-20 and sub-24 hour buckles), but only if your goal is honest. Do not just multiply a 50-mile pace and hope. Use a finish-time prediction that accounts for the full distance and the fade that every hundred brings, then work backward into a per-loop schedule with real margin against the 34-hour cutoff.
Knowing your target split for each of the seven loops turns a daunting 100 miles into seven manageable chunks, and it tells you immediately when you are ahead, on track, or slipping, while there is still time to adjust.
⏵ Free tools to pace this course
- Grade-adjusted pace calculator to turn your fitness into an honest, repeatable effort target you can hold on the flats for all seven loops.
- Race-time calculator for a realistic finish prediction and per-loop splits, so you can plan against the 34-hour cutoff and the buckle times.
- Race-equivalent calculator to turn a recent race result into a Mamba goal you can actually hold over 100 flat miles.
Fueling strategy for a long, flat day and night
A flat hundred can keep you moving steadily for a very long time, which is great for fueling because you can actually eat, and dangerous because a small per-hour deficit compounds over 20-plus hours. Get the carbs in early and keep them coming.
Carbs: steady, trained, and never skipped
For a hundred that can run past 24 hours, aim for somewhere around 60 to 90 grams of carbohydrate per hour, leaning higher early when your gut is fresh and easing off only if your stomach genuinely rebels. The mild November temps actually help your appetite compared to a hot summer race, so use that early window to bank calories. Because you are running steadily the whole time with no big climbs to force a reset, it is easy to forget to eat, so put it on a schedule (a set amount every loop, or every 30 minutes) and stick to it.
Rehearse your exact race-day carb number on long training runs so 70 to 90 grams an hour feels routine, not like an experiment at mile 60. A trained gut is the difference between running the night and shuffling it.
Sodium, fluid, and the cold-night problem
Even in cool weather you are sweating steadily for a long time, so keep sodium coming, generally in the 300 to 600 milligrams per liter of fluid range, and more if you are a heavy or salty sweater. The cool November air is a quiet trap here: you sweat less obviously, so it is easy to under-drink and let dehydration sneak up on you over many hours. Sip consistently rather than waiting until you feel thirsty.
Once it gets dark and the temperature drops toward the 40s, hot food and warm drink at the start/finish do double duty, calories plus a morale and core-temperature boost. Weigh yourself before and after a long run to learn your real sweat rate, then build your plan around your own number instead of a generic one.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a long flat night with the free ultra fueling calculator. Browse the rest of the free running tools at the tools hub.
This guide is independent and for planning only. The course details, dates, start times, 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.