TRAINING ZONES

Your body does different things at different intensities. Easy riding grows capillaries, mitochondria and fat-burning machinery. Threshold work raises the ceiling on sustainable power. Short maximal efforts stretch your oxygen uptake. Zones are simply labels for those distinct adaptations so you can aim at one on purpose instead of riding everything at a vague medium-hard.

That vague medium-hard — commonly called the grey zone — is the single most common mistake in amateur cycling. It is hard enough to leave you tired but too easy to force real adaptation. Zones exist to keep your easy rides genuinely easy and your hard rides properly hard.

Use power to control what you do and heart rate to understand what it cost you. If you only have one, power is the more useful for training indoors; heart rate is still excellent for keeping easy rides honest.

The polarised approach

Roughly 80% of your riding time easy (zone 2 and below) and 20% genuinely hard (zone 4 and above), with very little in between. This is broadly what the best endurance athletes in the world actually do, and it works well for anyone riding eight hours a week or more.

The time-crunched approach

On four to six hours a week, pure polarised wastes your limited hours. Sweet spot and tempo work — zone 3 to low zone 4 — delivers a lot of aerobic stimulus per minute, so most time-crunched riders do well with two quality sessions and one or two easy rides each week.

• 6 hours/week: 2 quality sessions, 2-3 easy rides, 1 rest day.
• 10 hours/week: 2 quality sessions, the rest zone 2 with one long ride.
• Always: one genuinely easy week every fourth week. Fitness arrives during recovery.