Sports Science Made Easy · Endurance Lab
You set out for an easy run. Halfway through, you notice you are a little faster than last week. You hold that pace, push the final hill and finish pleased with the time.
Before calling it a successful session, ask a different question: did you do the session you planned?
An easy run should have a clear purpose. A faster average pace can be interesting, but it does not tell you whether the effort matched that purpose. Start with the workout target, then judge the session against it.
What does the science say?
In a study of 11 well-trained junior cross-country skiers, Seiler and Kjerland observed that most endurance sessions were performed at low intensity, with a smaller share at high intensity. They used three physiological zones defined by ventilatory thresholds. That is useful evidence about those athletes; it does not prescribe the same weekly split for every runner. [1]
A later review of elite endurance training found both pyramidal and polarized distributions, with variation between sports and season phases. The authors highlighted differences in measurement methods and missing contextual information. The practical lesson is to examine the athlete and the way intensity is counted before treating a percentage as a universal rule. [2]
Our seven training zones
At Endurance Lab, our training zones are numbered 1, 2, 3, 4, 5, 6 and 7. Targets must follow the Endurance Lab method for the relevant sport and metric.
The number alone is not enough. Research using three zones, a watch using five zones and your seven-zone plan can use the same number for different intensity ranges. Check the model before comparing them.
We are not giving universal heart-rate, pace or power boundaries here. Your individual targets need their own setup.
A simple coaching example
Imagine a runner with an easy Tuesday session, planned intervals on Thursday and a longer run on Sunday. This is a fictional example, not an athlete’s results.
Tuesday turns into a pace challenge. Sunday’s group goes faster than the runner intended. The calendar still shows three completed workouts, but it no longer describes the week the athlete set out to do.
The useful coaching conversation starts with what changed: the goal, the effort, the conditions or the decision to follow the group. That gives us something practical to adjust next week.
Four checks for your next easy run
- Read the purpose before starting. Can you describe it in one sentence? If the notes are unclear, ask your coach.
- Check the target and the model. Make sure the watch and workout use the intended running zones. Do not copy a training partner’s numbers.
- Record more than the average pace. Include the conditions and how the run felt. That helps explain a session when a number alone leaves questions.
- Write honest feedback. If you followed a faster group or changed the session, say so. Your coach needs the session you actually did.
You do not need to turn every easy run into a test. Choose one this week, follow its intended target and write a short note afterwards. Use that note to start a better conversation about your training.
Would testing help you set your targets?
If your current targets no longer fit your sessions, ask what information would help. An appropriate assessment can be part of that discussion; it should answer a question rather than simply produce a score.
Explore performance testing at Endurance Lab. See the current testing options and booking links for our Dun Laoghaire lab.
For help turning your targets into a plan, explore our coaching options.
References
- Seiler KS, Kjerland GO. Quantifying training intensity distribution in elite endurance athletes: is there evidence for an optimal distribution? Scandinavian Journal of Medicine & Science in Sports. 2006. DOI: 10.1111/j.1600-0838.2004.00418.x.
- Sperlich B, Matzka M, Holmberg HC. The proportional distribution of training by elite endurance athletes at different intensities during different phases of the season. Frontiers in Sports and Active Living. 2023. DOI: 10.3389/fspor.2023.1258585.
