The Performance Margin 

Ask any experienced marathon runner what went wrong in a race that unravelled and the answer is usually one of two things: they went out too fast, or they did not fuel adequately. Often both. The two problems are related; poor fuelling accelerates the consequences of even modest early pacing errors. Getting nutrition right in the marathon is not complicated, but it requires understanding, planning, and (critically) practice. Race day is not the time to experiment. By the time

The London Classics is one of those challenges most people finish before they realise they have started it. Created in 2017 by London Marathon Events, it brings together three of the country's biggest mass participation events - the London Marathon, the RideLondon 100 and the two-mile distance at Swim Serpentine. Complete all three, in any order and over any timeframe, and you receive an outsized medal engraved with the Latin "Et ego Londinium vici", meaning "I too have conqu

VO2 max is one of the most frequently cited metrics in endurance sport. Garmin watches estimate it, coaches reference it, and athletes compare values as a proxy for fitness. But what it actually represents, and what its limitations are, is less well understood than the number itself. This post explains what VO2 max measures, how it relates to race performance, and how to structure training to develop it effectively. What VO2 Max Actually Measures VO2 max is the maximum volume

Almost every training session ends with a feedback form, and almost every one of them is wasted. Not because feedback has no value, but because of what we ask for. Did you enjoy it. Was the room comfortable. Rate the facilitator out of five. We collect a mood, file it, and learn nothing we could act on. In the trade these are called happy sheets, and the name is the whole criticism. A happy sheet can only ever return a compliment, which means it can never tell you what to cha

Two runners with identical VO2 max values can produce very different performances. One runs a 3:15 marathon. The other manages 3:45. The difference is often running economy; the oxygen cost of running at a given pace. Running economy is one of the most important yet least discussed factors in endurance running performance. Unlike VO2 max, which is partly constrained by genetics and responds relatively slowly to training, running economy can be meaningfully improved through ta

In my work in human factors, a lot of what I do comes down to a single idea: you cannot manage what you cannot see. Before anyone makes a good decision, they first have to perceive the situation accurately. Pilots call that situational awareness, and most of the errors we study do not start with a bad choice. They start with an incomplete picture. So when I had the chance to see something I normally only guess at, my own blood glucose, I was always going to take it. Why I did

There is a spectrum of training-related fatigue in endurance sport. At one end sits the normal tiredness of a hard week that resolves after a rest day. Further along is functional overreaching; planned and temporary fatigue that, with adequate recovery, produces a supercompensation response. At the far end is overtraining syndrome; a prolonged state of performance degradation and systemic dysfunction that can take months to fully resolve. Most athletes will experience functio

I've spent a large part of my working life watching people perform under pressure. Not in a gym, and not at a finish line - in aviation, where the quality of someone's thinking under load isn't measured in seconds off a PB. The stakes are rather higher than that. That's where my coaching philosophy comes from. Not from a textbook on periodisation, and not from my own race results. From human factors; the discipline that studies how capable people make poor decisions when they

Bank Holiday weekend here in the UK was unseasonally sunny, and I was away with my family camping in the Peak District. As it was my 30th birthday weekend, I was free to exercise as I pleased, and I definitely took advantage of that! On the Saturday, I took part in the Monsal Trail parkrun in Bakewell. This out and back route along the trail brought the challenge of narrow paths, slightly uneven, gravel terrain and a chance to test my lactate threshold after spending a lot

Athletes will spend significant time and money on training equipment, nutrition products, recovery tools, and coaching - and then routinely get six hours of sleep. It is one of the most consistent patterns in amateur sport, and it undermines every other investment made in performance. Sleep is not passive recovery. It is the period during which the majority of the body's repair and adaptation processes occur - the reason training produces fitness gains at all. Shortchange sle

Of all the physiological concepts that underpin endurance performance, lactate threshold is the one that correlates most strongly with race performance across distances from 5k to the marathon. Yet it remains poorly understood by most recreational athletes, who often confuse it with maximum effort, anaerobic threshold, or simply 'the point where it starts hurting'. Understanding lactate threshold properly - what it is, where yours sits, and how to develop it - is one of the m

Triathlon has a reputation for being a sport for serious, seasoned athletes. The reality is that most triathlon events - particularly sprint and Olympic distance - are remarkably accessible to anyone who is willing to swim, ride, and run with reasonable consistency for several months beforehand. The challenge is not usually fitness. It is logistics. Triathlon involves more moving parts than any single-sport event, and the unfamiliarity of those moving parts is what causes mos

Heart rate variability (HRV) has moved from elite sports science laboratory into the mainstream over the past decade. Most modern GPS watches now measure it nightly. Apps like Whoop, Garmin Connect, and Oura have made HRV scores a regular part of how athletes plan their training. Yet for many people, HRV remains a number they look at without fully understanding what it is telling them. This post explains what HRV actually measures, why it is a useful metric for endurance athl

Most training advice is written for athletes with unlimited time. Long warm-ups, two sessions on the same day, careful periodisation across a 24-week cycle - all sensible in theory, and entirely impractical when you are trying to fit training around a full-time job, a family, and the unpredictability of real life. The challenge for the amateur endurance athlete is not usually fitness. It is structure. Specifically, building a training week that is consistent enough to produce

Ask most recreational runners what their training looks like and the answer follows a familiar pattern. A few runs per week, mostly at a moderate effort, with a longer one at the weekend. It feels productive. It feels like training. The problem is that for many athletes, this approach is building fitness slowly, generating more fatigue than necessary, and leaving the most valuable adaptation on the table. That adaptation is aerobic base fitness - the fundamental capacity that

If there is one pattern that connects almost every recreational endurance runner I work with, it is this: their easy runs are too fast, and their hard sessions are not hard enough. It sounds like a contradiction. Athletes who are motivated, who train consistently, who care about their performance - running too hard on recovery days and not hard enough on quality sessions. But it is one of the most common and most damaging training habits in amateur endurance sport, and it has

Most runners don't have a speed problem in the marathon. They have a pacing problem. I see it regularly with athletes I coach - and I've made the mistake myself. The first 15 kilometres feel easy. The pace feels generous. The crowd is loud, the legs are fresh, and the effort feels well within range. So the pace creeps slightly. Then a little more. By 28 or 30 kilometres, something starts to unravel, and the final 10 becomes a very different race from the one that was planned.

February is always a nice month. January feels like a year in its own right, then we’re graced with a 28 day month to skip us straight into Spring. The weather also turns, generally, as we move away from the consistent rainy days and find some breaks with some sun. But February hasn’t been all sunshine and rainbows in my world. My almost one year old has been having an amazing time at nursery, so much so that he’s decided to collect every illness possible and share with us at

I’m currently coaching an athlete to sharpen his 5k time before we move to a Tough Mudder focus from Spring. It’s early days, even though we’ve been training together since November, but the ‘serious’ coaching has started since being back at work in the New Year. When we started off, I was prescribing his workouts on a spreadsheet. It was the same way his last coach did it, and it’s a free, uncomplicated way to tabulate his training plan. It had his paces, distances and an

In safety critical work, fatigue is a hot topic of discussion. Risk management often identifies it as a threat to safety and leaders are beginning to understand (and appreciate) that actively managing peoples’ rest is key. The same applies to performance. Athletes train regularly, subjecting their body to increased physical loads, with the aim of improving their performance. This improvement comes from the body’s ability to rebuild stronger, and where does that rebuild occur?