Case Study (Diagnostic): Elite Road Cyclist - When 18–20h/Week Still Creates Junk Miles

Problem

An elite road cyclist came to GritLab wanting to train more efficiently. He was already doing,

So the goal was not simply to “do more.”

The priority was to reduce junk miles, train with clearer purpose, and ensure his intensity zones matched his current physiology.

Diagnosis

Lactate testing was used to determine his current Zone 2 ceiling and identify where intensity became significantly more fatiguing.

Zone 2 Power

Lactate and Rate of Perceived Exertion (RPE) remained stable through his Zone 2 power output, but rose sharply once power output exceeded his Zone 2 ceiling - as seen in the green arrow.

The arrow marks the jump in lactate value - signaling the transition from Zone 2 into Zone 3.

Lactate Spike and Rapid Fatigue Explanation

The below chart highlights the point where lactate spiked from an already elevated level to a very high value. This suggests the athlete had moved well beyond his FTP and into a high-fatigue intensity zone such as Vo2max (Zone 5) or Anaerobic (Zone 6) power outputs.

The green arrow highlights the spike in lactate values. This indicates a costly intensity zone that should be used intentionally, not accidentally accumulated during base training.

This will be a bottleneck when surging in road racing situation - such as attacking or responding to attacks, as any power output above his FTP results in rapid fatigue.

Solution

For his base phase, the key recommendation was to keep Zone 2 rides strictly below his tested ceiling, rather than drifting into unnecessary moderate-intensity / Tempo work.

This allows accumulation of larger volume of Zone 2 work while minimizing fatigue, it is known that more volume typically results in greater endurance performance - as long as athlete is then able to recover from training.

The sharper lactate response above this range also gave a clear target for the upcoming build phase, where VO₂max intervals, micro-intervals, and over-under work could be used intentionally.

Outcome

The athlete left with a tested Zone 2 ceiling to guide his base rides more precisely.

This helped separate productive endurance work from unnecessary moderate-intensity fatigue, especially important when training 18–20 hours per week.

It also gave clearer direction for the next build phase, where higher-intensity work could be added intentionally instead of accumulated by accident.

Key Takeaway

When training volume is already high, the answer is not always more work. Accurate training zones help ensure each session has a purpose, so endurance work stays productive instead of drifting into unnecessary fatigue.

This is especially important for serious cyclists, where small intensity errors can compound quickly across a full training week.

Note: Absolute power values have been withheld to protect athlete privacy and competitive confidentiality.

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