Running15 min
How to Prepare for Your First Marathon
How long to train, weekly mileage, the long run, race pace and tapering, built on the Jack Daniels method. A complete first marathon roadmap.
Read articleLatest Articles
Tips, guides, and news to optimize your training.
Swimming11 min
What Is SWOLF? How to Improve Swim Efficiency
What is SWOLF, what is a good score, and how to improve it with better front crawl technique. Read your Garmin and Apple Watch SWOLF right.
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Science11 min
The 80/20 Rule: Why 80% of Training Should Be Easy
Why 80% of training should be easy and 20% hard, how to calculate your split, and how to dodge the moderate-intensity trap.
Read articleTraining Zones Explained
From active recovery to all-out sprints - each zone triggers different adaptations to optimize your performance.
Metric
1Recovery
2Endurance
3Tempo
4Threshold
5VO₂max
Heart Rate
50–60%
60–70%
70–80%
80–90%
90–100%
Perceived Exertion (RPE)
1–2
3–4
5–6
7–8
9–10
Breathing
Easy conversation
Can hold conversation
Short sentences only
A few words only
Unable to speak
Running
Very easy jog
Easy, steady pace
Sustained pace, half-marathon
10K pace, hard effort
Sprint, all-out effort
Cycling (% FTP)
< 55%
56–75%
76–90%
91–105%
> 105%
Swimming (% CSS)
< 75%
75–85%
86–95%
96–105%
> 105%
Energy System
Fat oxidation
Fat + some carbs
Carbs + fat
Mostly carbohydrates
Anaerobic (ATP-CP + glycolysis)
Sustainable Duration
Trained: > 7 hBeginner: < 3 h
Trained: > 5 hBeginner: < 2 h
Trained: 2–3 hBeginner: < 45 min
Trained: 20–60 minBeginner: < 20 min
Trained: 5–7 minBeginner: < 3 min
Key Benefit
Active recovery, blood circulation
Aerobic base, fundamental endurance
Lactate threshold, running economy
VO₂max, maximal aerobic power
Maximum speed, anaerobic power
HR= % HRmaxFTP= Functional Threshold PowerCSS= Critical Swim SpeedRPE= Rate of Perceived Exertion (1–10)
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