Why faster training is wrecking your endurance performance.
There is a massive misconception dominating the endurance world right now. It is this unspoken rule in our training feeds that if you aren't completely cooked after a workout, you didn't do it right. Far too often do we tie performance directly to sheer volume, suffering and junk miles.
But as legendary coach Rick Niles famously noted: “It is not a matter of how much you train, but of how you train.”
The vast majority of triathletes and cyclists I see fall into that exact trap. They train too hard, too often, getting sucked into a "faster is better" mentality, turning deliberate, aerobic base-building sessions into ego-driven tempo efforts. This is extenuated by limited training hours. Athletes with fewer hours to train think that all sessions must be all-out or they’re not going to get better. Let me tell you why that’s wrong.
When your easy sessions are pushed too hard and your hard sessions lack true intentionality, you land squarely in the intensity black hole. The results are completely predictable: chronic fatigue, frustrating performance plateaus and elevated injury risks that can derail your entire season.
To unlock your true potential, you have to look under the hood of your own physiology as well as understanding why intensity regulation is so important.
“It is not a matter of how much you train, but of how you train.” - Rick Niles
The anatomy of effort: What is actually happening inside your muscles?
To train smart, we categorise intensity based on blood lactate accumulation, heart rate thresholds and your primary metabolic fuel sources. Understanding this changes how you execute every single session.
Low intensity (Zones 1 – 2)
- Primary fuel: Fats, which form your aerobic foundation.
- The reality: This is the bedrock of premium endurance performance. Zone 2 optimises fat oxidation, increases mitochondrial density and builds the aerobic engine you need to sustain race pace across a long-distance triathlon or cycling event.
- The catch: Pushing even a little bit too hard here can completely undermine the intended adaptation, adding systemic fatigue without the fitness benefits.
Medium intensity (Zones 3 – 4)
- Primary fuel: Carbohydrates (or a combination of fat and carbohydrate for those with a lower VLaMax), which power threshold and race pace.
- The reality: Zone 3 tempo establishes sustainable, heavy-tempo paces. Zone 4 directly targets and raises your Functional Threshold Power (FTP).
- The catch: This is where the black hole lives. Spend too much accidental time here and you will burn out or break down
High intensity (Zones 5 – 6)
- Primary fuel: Glycogen, which fuels your anaerobic capacity.
- The reality: These are short, highly concentrated intervals designed to maximise your stroke volume, cardiac output and top-end torque.
- The catch: They require massive recovery windows, anywhere from 48 to over 72 hours.
Why consistency beats intensity: The 80/20 rule
To understand why chronic intensity is a flawed strategy, we only need to look at elite sports science. Data collected from modern professional endurance fields – including Tour de France cyclists – demonstrates a strict, highly polarized or pyramidal distribution of training intensity.
Even the world's most elite endurance athletes spend 80% or more of their total training volume strictly in Zones 1 and 2. They understand that consistency beats intensity every single day. And that, for endurance athletes, intensity has to be built on top of a huge (VO2) aerobic base.
If elite athletes with massive recovery capacity limit their high-intensity work to a tiny fraction of their week, everyday athletes juggling jobs and families must be even more disciplined. If you decide to push your Zone 2 recovery ride up into Zone 3, you are actively undermining your program.
Insight from Matt: If your 'Zone 2' ride involves a sprint to beat your mate to a signpost, you're not training your aerobic system. You're just feeding your ego.
How do you accurately calculate your individual training zones?
Training zones are completely meaningless if they are based on generic, age-calculated internet formulas. They have to be hyper-individualized to you.
Fortunately, we now have highly accessible pathways to establish your baseline data right in your own training environment.
- Swimming (Critical Swim Speed): Conducted in a standard pool. You perform a 400m max-effort time trial, rest completely with some easy active recovery swimming and follow it immediately with a 200m max-effort time trial. The goal is a steady, sustainable pace. Enter those times into an online CSS calculator and you’ll get your CSS (think of this as your swim FTP) and your zones (expressed as pace per 100m).
- Cycling (Power Diagnostics): While a standard 20-minute field test is common (FTP calculated as 0.95 x the average power you can hold for a 20 minute max effort), it is often difficult for athletes to pace properly so, if you are newer to the sport, I highly recommend a Ramp Test for producing much cleaner data.
There are various protocols but, on a smart trainer, you could start at 100W and increase the resistance by 20W every one minute until failure. Your FTP is 0.75 x the power you held for the final full one minute segment.
For advanced athletes, a lactate test or remote metabolic profile like an INSCYD test is highly preferred because it maps your actual internal metrics, calculating VO2Max, VLaMax, Maximum Lactate Steady State, Carb/Fat burn etc rather than just a static number. As a coach, this arms me with a lot more information for fine-tuning training. - Running (Threshold Pace): A recent race-paced effort such as a 5k or 10km is a great starting point for calculating your zones. Rather than destroying yourself in a 5km or 10km time trial, I again prefer lactate testing or advanced remote profiling as it allows me to capture lab-accurate performance data on a standard run track, replacing guesswork with exact internal metrics.
As a rule of thumb, you want to re-test every 4 to 6 weeks depending on your training phase and recovery status to keep your metrics accurately aligned with your physical adaptations.
“The single most technical piece of equipment you own is your own body and physiology. Learn how to get the most out of that before you spend thousands on disc wheels and ceramic bearings.” - Matt Warnock
The two most common training mistakes
- Bleeding aerobic sessions into no-man's land: Pushing the pace on long runs or extended base rides because you feel good that day. This creates the wrong training effect, undermines your training mix and multiplies your injury risk.
- Succumbing to the group effect: Letting yourself get drawn into accidental match-sprinting and ego-driven pacing during club rides or Masters swims. This completely blunts the structured impact of your training week.
Before you start your next workout, step back and ask yourself the golden question posed by legendary coach Joe Friel: “What is the purpose of this workout?”
Don't start the session until you can answer that question. And it’s ok if sometimes the answer is “to do what makes me feel good,” “to race my mates” or “to test my limits.” Just as long as you’re aware of that and you ensure these sessions are the exceptions and not the norm.
Ready to build a smarter engine?
If you’re tired of guessing and ready to take the handbrake off your performance, let's chat. Training should fit your real life – it should add to it, not take away from it.
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