Mark Turnbull - Cycling Coach

Cycling Coach and Personal Trainer
Ambassador @TORQfitness

[Mark Turnbull - Cycling Coach @MarkJudeT]

Come join SparksIntoLife on Zwift https://t.co/AIQcTNIprY
Weekly training sessions in addition to regular INSCYD test days. Complete the test protocol with my guidance. Should you want to receive the INSCYD metabolic report you can contact me to schedule a consultation.

[Iñigo San Millán @doctorinigo]

30 years ago I was working with elite athletes and drawing training zones on paper based on blood lactate curves.
No substrate data. No indirect calorimetry. Just the conviction that something metabolically distinct was happening at each intensity — and that Zone 2 was where the most important adaptation was taking place.

In 2005 I began adding fat and carbohydrate oxidation rates to the picture, and what the substrate data revealed confirmed what the lactate curves had been suggesting all along: each intensity represents a distinct metabolic state, not just a point on a continuum of effort.

That work became the Metabolic Map in 2013. Then the metabolic flexibility paper with George Brooks in 2018. And now the updated 2026 framework, which maps four metabolic states onto classical threshold models and asks a question the older models never quite posed:
Is the system in optimal metabolic balance, or is it drifting away from it?

Lactate turns out to be the best real-time proxy we have for answering that question. It tracks metabolic equilibrium, the onset of drift, and the progression toward overload better than any other single variable we can measure in the field.

Thirty years of work. One molecule. One central question.

My last substack article

https://t.co/hvNuIVnH6b

[Mark Turnbull - Cycling Coach @MarkJudeT]

Another great thread from @jem_arnold 💪🏽

[Jem Arnold @jem_arnold]

When does resistance exercise become endurance exercise? 🏋️↔️🏃

It might depend on the critical occluding tension in our muscles 💪🩸

🧵/ 📚link👇

A Critical Occluding Tension Phase Transition Occurs Between 30-40% 1RM in Dynamic Knee Extension Exercise

[Mark Turnbull - Cycling Coach @MarkJudeT]

See this Instagram post by @cheshirecyclingsnaps https://t.co/IRfF07PPzH MBC 4up last night, a bit wet!

[Mark Turnbull - Cycling Coach @MarkJudeT]

Thinking of incorporating heat acclimation into your training program? This thread may be of interest.

[Mark Turnbull - Cycling Coach @MarkJudeT]

🧐

[Inigo Mujika (En) @inigomujika_en]

OPEN ACCESS! Mechanistic influence of the torque cadence relationship on power output duringexhaustive all-out field tests in professional cyclists
With @peter__leo @bmgsport @AndreaGiorgiDoc

https://t.co/HGlaIruC6S

[Mark Turnbull - Cycling Coach @MarkJudeT]

Interesting research into understanding the torque-cadence-power relationship https://t.co/WMJbawc5YG

[Mark Turnbull - Cycling Coach @MarkJudeT]

See this Instagram post by @inscyd_ https://t.co/h1vYPP4dUk

[Mark Turnbull - Cycling Coach @MarkJudeT]

https://t.co/5muv2uCJeL

[Dan Lorang 🇱🇺 @Danlorang]

Simplicity is the key to successful coaching, believe it or not. Simplicity doesn't mean that you don't give attention to details but that you are capable of breaking complex input down into what truly matters in the end.

[Jem Arnold @jem_arnold]

In our recent meta-analysis we found:
🔴Higher level competitive athletes improved VO2max modestly more with Polarised training
🔷Lower level recreational athletes modestly more with Pyramidal training

This is what those differences looks like 👇
But is this meaningful? 🤔1/🧵

[Hilkka Kontro @HilkkaKontro]

@MartinMacInnis https://t.co/hDGkmn1o1o

[Hilkka Kontro @HilkkaKontro]

Tom's Weekend Warrior study is out! Training either 4x (short) or 2x (long) weekly resulted in the same adaptations, when overall volume and content of training was fixed.

Performance, thresholds, efficiency, Hbmass, and ox cap ↑ equally in both groups.

@MartinMacInnis

[Mark Turnbull - Cycling Coach @MarkJudeT]

Great training model 🧵 from @jem_arnold and co.

[Jem Arnold @jem_arnold]

Polarised🆚Pyramidal🆚Threshold

Which training model is best?🏆
It might matter how trained you are🤔

Our new meta-analysis tries to answer which training intervention produces the greatest improvements in endurance performance in trained athletes

Thread🧵 & 🔗links below👇

[Mark Turnbull - Cycling Coach @MarkJudeT]

Can fasting make or break your performance?

A new study reveals 7 days of fasting:
⚡ Maintains muscle strength
🔥 Doubles fat oxidation
📉 Reduces VO₂ max by 13%

Fasting boosts fat metabolism but limits high-intensity efforts. Read more here: 🏃‍♂️🚴‍♀️https://t.co/LhTiwk9fk0

[Mark Turnbull - Cycling Coach @MarkJudeT]

New data shows that the biggest difference between elite and middling runners is how much time they spend jogging. https://t.co/FK3cS1WNLW

[Mark Turnbull - Cycling Coach @MarkJudeT]

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[Mark Turnbull - Cycling Coach @MarkJudeT]

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[Mark Turnbull - Cycling Coach @MarkJudeT]

Strava's Big Changes Aim To Kill Off Apps https://t.co/61eY2oglfo via @dcrainmakerblog