Rest day mobility: what the engine changes

Rest day mobility is the one context in this whole cluster where a stretching session has the day to itself. Every other page has to argue about interference: whether a long hold before a heavy set costs you five per cent, whether the warm-up rescues it, where in a session the holds belong. On a rest day none of that applies. Nothing follows the session, so nothing can be blunted by it, and the only limits are your own patience and how much time you have.

That makes it worth describing exactly rather than vaguely. This page sets out what Limber changes on a rest day, rule by rule, including the one protocol the app will not run on any other day.

The short answer

• A rest day removes the only real objection to long static holds: nothing follows them.
• Limber changes two things on one: a reason code, and contract-relax becomes available.
• The contract-relax gate has six conditions and all of them must pass.
• Seven of the 56 moves are flagged for it; five can actually receive it today.
• A five-minute routine has no contract-relax in it, on any day.
• A rest day never triggers a streak warning. That is deliberate.

Why a rest day is different

The acute performance cost of stretching is the reason most of this cluster is careful about ordering. Simic, Sarabon and Markovic found in the Scandinavian Journal of Medicine & Science in Sports in 2013 that static stretching immediately before a maximal effort reduces strength, power and explosive performance by around 5 per cent. Behm and colleagues put the practical threshold at about 60 seconds per muscle group in Applied Physiology, Nutrition, and Metabolism in 2016, and Blazevich and colleagues showed in Medicine & Science in Sports & Exercise in 2018 that a full dynamic warm-up afterwards removes the decrement entirely.

Grade: solid, across all three.

Every one of those findings is about what happens next. On a rest day nothing happens next. You can hold anything for as long as you like, at whatever depth you can tolerate, and the only consequence is the range work itself.

The dose does not change, though. Bandy and Irion found in Physical Therapy in 1994 that 30 seconds beat 15 and matched 60 over six weeks, their 1997 follow-up found one hold a day matched three, and Thomas and colleagues reported in the International Journal of Sports Medicine in 2018 that total weekly stretching time is what tracks the gain. Grade: solid, and narrow. A rest day is a good slot, not a magic one — it does not buy more per minute than a Tuesday evening does.

Rest day mobility, exactly

Here is what the app does differently, taken from the engine rather than from the marketing.

One: the lead step carries a different reason code. On a rest day with no training logged, the group the routine leads with is tagged with the engine's rest-day-gains code, and that code has a line in the why-sheet explaining itself. Every move in a Limber routine carries at least one reason code; this is one of nine.

Two: contract-relax becomes available. On every other day it is off. This is the only setting in the app that opens a protocol rather than changing a selection.

And that is the whole list. The session shape does not change, the holds are not lengthened by the engine, and the downshift still comes last. Anywhere you read that a rest day makes the holds longer, that is copy running ahead of the code, and it is being said here rather than quietly left alone.

There is one more thing a rest day does, outside the routine. A rest day outranks the streak warning: the app will not tell you your record is at risk on a day it did not expect you to practise. Warning you on your own rest day would be the app inventing a threat.

The contract-relax gate

Six conditions, all of which must pass before a hold becomes a contract-relax block.

• It is a rest day.
• Your feel level is 2 or higher.
• The session budget is more than five minutes — a five-minute routine skips the warm-up, runs all-gentle, and never runs this.
• The move is a hold, flagged as contract-relax-capable, and is itself level 2 or above.
• At most two such blocks in one session.
• Never in a warm-up, under any setting.

The protocol itself is a hold, then about 6 seconds of contraction at roughly 40 per cent effort, about 2 seconds of release, then 15 to 20 seconds deeper. Two rounds, or three at the top feel level. What is PNF stretching covers the technique in general.

One honest note about the evidence. The dose research this site leans on — 30 seconds, most days, total weekly time — was done with static holds. This page does not assert that contract-relax beats a long static hold over six weeks, because that is not a claim the sources above will carry. It is offered as a protocol you may prefer, gated to the day where it cannot interfere with anything.

Seven flagged, five reachable

The catalogue flags seven of its 56 moves as contract-relax-capable. The engine also requires the move itself to sit at level 2 or above, which quietly excludes two of them.

That table is printed because the difference between "seven moves support it" and "five moves can get it" is exactly the kind of gap this site exists to close. Two of the seven are flagged and unreachable.

Work to a mild stretch, never at sharp pain. Come out of a position that pinches rather than pushing through it, and treat any sharp, electric or numb sensation as a signal to stop rather than a stretch. Pain that persists, wakes you at night, radiates down a limb or followed a specific incident is a matter for a clinician who can examine you.

What a rest day cannot buy

Three expectations that a rest day does not change, and they are the same three the whole cluster leads with.

Soreness. Herbert, de Noronha and Kamper's Cochrane review, updated in 2011, found stretching for post-exercise soreness produced an effect of the order of one to two points on a hundred-point scale. Grade: solid, and disappointing. A rest-day session does not lift yesterday's legs. Does stretching help DOMS is the long version.

Injury. Lauersen, Bertelsen and Andersen pooled the randomised injury-prevention trials in the British Journal of Sports Medicine in 2014: strength training reduced sports injuries to under a third and overuse injuries to about half, while stretching showed no significant protective effect. Grade: reasonably solid.

Tissue length. Konrad and Tilp, in Clinical Biomechanics in 2014, ran six weeks of stretching, confirmed the range gain, then measured muscle and tendon and found neither had changed detectably. And Willy and colleagues, in JOSPT in 2001, stopped a hamstring programme and watched the gains reverse. Grade: reasonably solid. What you are building is a tolerance, and a tolerance is maintained rather than banked.

The shape of every session

Rest day or not, the structure is fixed, and knowing it makes the app easier to read.

Warm-up. One dynamic move, or two on a longer session. Only 18 of the 56 moves are warm-up-eligible and every one of them is dynamic — a repetition per breath cycle rather than a hold.

Main block. Built from your area readings, your equipment and your flagged movements, walking a priority list and stopping when the time budget is met. Flagged movements are removed from the pool before selection rather than ranked lower inside it.

Weak-side extras. Limber calls an imbalance at 12 points and adds one extra move for the low side until the gap falls under 6.

Downshift, always last. Only three moves in the whole catalogue are downshift-eligible: Child's Pose, Supine Twist and Happy Baby. Default holds run 30 to 60 seconds.

What the score is doing meanwhile

The Range Score is the number a rest-day session is planned against. It averages the score groups that have a reading, drops the weight of an unread test rather than counting it as zero, and interpolates nothing.

Two limits worth carrying. Four of five stations is the ceiling — the spine group is fed only by a seated thoracic rotation test, and that test is not built in the app or here, so the score reports the gap instead of filling it. And the scale runs about 15 to 93 rather than 0 to 100, with the middle band on every test reading 63. No population has ever been measured against it, so there is no percentile, no projection, no date and no countdown anywhere in the app.

The deep squat test is the busiest single reading in the battery: four bands that feed the hips, the glutes and half the lower back at once. Warm-up versus stretching covers the day this one is not, mobility for lifters covers the training around it, and the cluster sits under mobility for training.

Questions

Should I stretch on rest days?

It is the best slot you have, if you want one. Nothing follows the session, so the small acute cost of long static holds cannot matter, and you can hold for as long as you like at whatever depth you tolerate. What it will not do is speed recovery or reduce soreness, so treat it as range work that happens to have found an empty afternoon.

What does Limber change on a rest day?

Two things in the routine. The group it leads with carries the engine's rest-day-gains reason code, which is written out in the why-sheet, and contract-relax becomes available on eligible holds. The session shape is otherwise identical, the holds are not lengthened, and the downshift still comes last. Outside the routine, a rest day also suppresses the streak warning.

Why can I not use contract-relax on a normal day?

Because it is the most demanding thing the app will ask of a joint, and the day with nothing after it is the day to do it. Six conditions have to pass: a rest day, your feel level at 2 or above, a session longer than five minutes, a hold that is flagged and itself level 2 or above, no more than two blocks in a session, and never in a warm-up.

How many moves can actually run the protocol?

Five, today. Seven of the 56 moves in the catalogue are flagged as capable, and the engine additionally requires the move itself to be level 2 or above, which excludes the half-kneeling hip flexor stretch and the seated hamstring strap stretch. That gap between what is flagged and what is reachable is printed here rather than left for you to discover.

Is a rest day session better than a training-day one?

Not for the range you build. The pooled evidence says total weekly stretching time tracks the gain rather than which day it falls on, so a rest-day session is worth exactly what an equivalent session on any other day is worth. What it has is room: no effort follows it, so nothing has to be kept short.

Does the app know it is my rest day?

Only from the rhythm plan you set, or from the week's goal already being met with nothing done today. It has no other source: the app writes a finished session to Health and never reads a workout back, so it cannot tell whether you trained, rested or did something else entirely. You tell it which days are practice days, and it treats the rest as rest.