An unplanned group ride: what happens to your training plan.

On this page

1. The short answer
2. A group ride, in load terms
3. Fitness, fatigue and form
4. The rest of the week
5. How Summit handles it
6. Questions
7. Sources

The plan said one hour of endurance on Saturday. Then the club rolled out, the pace went up on the first climb, and three and a half hours later you were home with a ride the plan never asked for. That ride is not something to hide from your training. It is load, and the only question is what the rest of the week does with it.

What a group ride is, in load terms

A group ride is rarely steady. Long stretches on a wheel are broken by surges out of corners, climbs ridden at the pace of the strongest rider and the occasional sprint for a town sign. A load model scores all of it. Training Stress Score (TSS), the unit behind the Performance Manager model described by Allen, Coggan and McGregor, combines a ride's duration with its intensity relative to your threshold, and intensity enters it squared, so the surges cost more than their minutes suggest. Two rides of the same length can differ widely in TSS, and the group ride is usually the higher of the two.

It also tends to land in an awkward place for a structured week. Seiler and Kjerland (2006), studying elite cross-country skiers, found most training at low intensity, a smaller share at high intensity and little in between. A group ride often lands in that middle: too hard to count as an easy day, too unstructured to replace a specific session.

What it does to fitness, fatigue and form

Take a rider with a fitness (CTL) of 60 and a fatigue (ATL) of 65 whose plan had a 60 TSS endurance ride for the day. Instead they ride 180 TSS with the group. Run both days through the Performance Manager model of Allen, Coggan and McGregor, a slow exponentially weighted average of daily TSS for fitness and a fast one for fatigue, whose conventional time constants are about 42 and 7 days:

Illustrative, computed with the published model's conventional constants, not Summit's internals. Form (TSB) is the day's CTL minus its ATL, read the next morning.

Fitness moves by under three points, because one day is a small part of a six-week average. Fatigue jumps by seventeen, because the short average responds within days, and that gap is what the next morning feels like. It is also why the day after the ride matters more than the ride itself. The three numbers are worked through in full in CTL, ATL and TSB explained.

What to do with the rest of the week

The temptation is to make up what the plan had prescribed, which stacks two days of load into one and pushes the week's quality session onto tired legs. The better trade is to count the group ride as the week's hardest day, protect the next key session, and let an easy ride go if the week runs out of room.

That trade has one honest limit. A group ride delivers load, but not a specific stimulus: if the session it replaced was the week's threshold or VO2max work, the group ride did not do that job, however hard it felt. Keep the key session in the week if you can, and accept that the filler around it is what gives way.

If the ride happens every week, it has stopped being unplanned. Put it in the plan as what it is, a hard and unstructured day, and build the structured work around it. The base, build, peak piece covers how a week's load fits inside a season.

How Summit handles it

The ride is imported from Strava or a Hammerhead Karoo, which is free on every plan, and its load is computed from power when the ride has it. Without a power meter it is computed from heart rate against your LTHR, so the ride still counts. One honest limit: on long rides heart-rate load reads high, because cardiac drift raises heart rate at the same work (Coyle and González-Alonso, 2001).

Summit compares the ride with the session it replaces and tells you honestly how closely they matched.

The next morning, on Elite, today's session is decided against your recovery reading and your form. On an otherwise good reading, a one-off dip in recovery only softens the session when your form confirms the fatigue, and after a hard group ride that confirmation is likely. The response runs down a ladder from riding as planned, through capping the session or swapping it for an easier type, to soft activation or rest, and on the Apple Health route it usually happens before you open the app. What the recovery reading is made of is on the cycling recovery page.

For a club ride that happens every week, set that day in your weekly availability as one you ride your own way. Hard sessions stay off it, the quality work goes to the other days, and a missed key session is never moved onto it. When the group ride turns out hard, the plan takes that load off the rest of the week instead of stacking the planned training on top of it. All of this belongs to the adaptive plan described on the adaptive training page.

Imported rides and the daily recovery score are free, permanently. Fitness, fatigue and form, in the Performance Management Chart, are Pro. The adapted session and weekly availability are Elite. What each plan includes, with the price caveat, is on the pricing page.

Questions