Overcoming Chronic GI Distress: Pacing & Fuelling in Tandem
For many ultra runners, the biggest threat to reaching the finish line isn't muscle fatigue, it's stomach shutdown. Going into the Great Ocean Trail Ultra, Mark's primary goal was to overcome the frequent GI issues that had plagued his previous ultras, allowing him to finish strong and under manageable effort.
Before working together, his biggest concern was an inability to fuel leading directly to a DNF. By pairing custom sector timings with exact hourly fuelling, Data to Dirt provided a clear framework that aligned his output with his fuelling capacity from the start line to the finish.
Data to Dirt in action: Mark's finisher buckle from the 2026 Great Ocean Trail Ultra 100k.
From Pre-Race Stress to Predicted Certainty
Standard pacing tools often fail ultra runners because they treat pacing and nutrition as separate problems. On technical ultra courses, pushing even slightly too hard on early runnable stints elevates the body's work rate where the gut stops absorbing carbohydrates, causing severe GI distress and potentially a total shutdown.
"The fuelling targets were revelatory, and gave me confidence that I could meet the timings throughout the race."
Translating course telemetry and Mark's individual physiology into a personalised strategy transformed his race. Having timing targets adjusted for gradient and technicality, combined with exact fuelling and hydration targets, replaced pre-race anxiety with firm goals and predicted certainty.
Executing Under the Pump: Trusting Conservative Early Splits
When looking at his strategy sheet before the race, Mark initially thought the early sector splits seemed too conservative. However, by trusting the plan and holding back on Leg 1, he protected his engine for the second half of the race.
When adverse weather struck towards the end of the 100k course and severe fatigue set in, trusting the strategy sheet gave him the motivation to keep on track. Furthermore, having sector splits mapped out beforehand eliminated cognitive strain, allowing him to simply run without worrying about doing mental maths between aid stations.
"Whilst I initially thought that the early timing splits were too conservative, by more or less sticking to them I finished the race without GI distress, as well as hitting my race goal time."
When disruptions hit the course, he adapted smoothly using RPE. Data to Dirt gave him the benchmark he needed to stay in control and execute under tough conditions.
A Revelatory Strategy: 99.6% Time Split Accuracy
Crossing the finish line brought immense relief; not only had Mark completed the 100k uninjured and free of GI distress, but he also executed with near-perfect timing accuracy.
Predicted Finish Time: 15:56:29
Actual Finish Time: 16:00:03
Across a 16 hour race, Data to Dirt predicted his finish time within 3 and a half minutes.
The Data to Dirt Edge
Coastal routes are notorious for elevation errors. Like many undulating coastal courses, the Great Ocean Trail Ultra suffers from classic GPX smoothing. The official route file lists the course at 2660m of vertical gain, when in reality the true gain is over 3200m (a 20% undercount). Basing your pacing with a 20% elevation error means potentially missing cut-offs, under-fuelling, or blowing up hours before the finish.
Using Data to Dirt, we extracted 3212m of vertical gain from the route file, matching the 3221m actually recorded during the race. That level of accuracy is the difference between a strategy which can be executed with complete confidence, and a race ending error.
Race Day Is Approaching, Do You Have a Strategy?
Great race-day execution begins long before you reach the start line, there is no cramming for an ultra. Data to Dirt takes training data gathered during your build phase and combines it with high-resolution telemetry extracted from your race GPX file. By mapping your unique performance metrics across micro-sector gradients alongside target fuelling and hydration, the system delivers realistic, terrain-adjusted pacing, accurate checkpoint time splits, and exact hourly nutrition targets. We remove the guesswork so you can execute with total confidence.
Whether you are chasing a podium finish or fighting cut-offs, get a custom Data to Dirt race strategy. The first step? Book a discovery call to talk through your race and goals.
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