How long to rest, and when to leave
A rest pays back quickly at first and then less and less. The right moment to leave is when the payback has flattened, not when you feel fully fresh.
In plain words
When you start resting, oxygen floods back into your forearm fast. After a while the refill slows, and staying longer gives you less and less. On a good hold you can keep recovering for a long time. On a poor hold the arm doing the holding loses almost as much as the shaking arm gains, so the refill stops early. So the question isn't how long you can stay. It's whether you're still getting better. When you stop getting better, go.
Memory hookStay while it's paying, go when it flattens.
The refill curve
Half-times, in numbers you can count
Refill is often described by its half-time: the time to win back half of what was lost (new to half-times? start with half-times explained). If refill followed one simple curve, you'd be back:
| After | Share of the lost oxygen regained |
|---|---|
| 1 half-time | 50 % |
| 2 half-times | 75 % |
| 3 half-times | 87.5 % |
| 4 half-times | 94 % |
Each extra half-time buys half as much as the one before. With the half-times measured after a sustained hold to failure, three-quarters back would take about 16 s for elite climbers, 94 s for intermediate climbers and 190 s for non-climbers. These are model numbers built on measured half-times, not measurements themselves.
Why a poor rest flattens early
On a rest you hold with one hand and shake the other, then swap. The shaking hand gets full blood flow. The holding hand gets less the harder it grips, and none once it grips hard enough to squeeze its blood vessels shut. On a poor hold the holding hand drains while the shaking hand refills, and the two cancel out. The curve flattens below full, and staying longer does nothing.
See it
Set the rest hold to Poor and watch the weaker arm level off. Then try Jug, or change the half-time.
Signs it's time to go
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Am I still getting better?Check
Compare each shake with the last: is the pump easing?
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No change for a few cyclesFlat
The refill has flattened on this hold. Leave now.
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Still improvingBetter
Stay, keep switching hands, and check again in a few cycles.
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On a timed routeClock
Count the holds left and leave enough time for them.
The evidence
Numbers from adults only.
- Measured Half recovery of forearm oxygen took about 8 s (elite), 47 s (intermediate) and 95 s (non-climbers) after a sustained 40 % grip to failure, and 8, 83 and 93 s after repeated grips to failure. Fryer et al. 2015: 38 adult men analysed, in four groups. J Strength Cond Res 29(6):1633–1639.
- Measured Forearm blood flow is cut off at roughly 45–75 % of maximum grip force (Barnes 1980, Ergonomics 23(4):351–357, as cited by MacLeod et al. 2007).
- Model The "three-quarters back" times above assume a single exponential curve with those half-times. Real recovery has fast and slow parts.
- Coaching practice Leave a rest when the improvement stops, not when you feel fresh.
Model assumptions
The forearm model is described on Why resting works. In short: full flow below 20 % of maximum grip, falling to none at 60 %. Oxygen use is proportional to grip. Refill runs toward full with the chosen half-time, 1.32 times faster when the arm hangs low. The "levels off" and "flattens" readouts use the weaker arm's average over the last 30 s of a 3-minute run.
Try it
Common mistakes
on most rest holds you never get there. Leave when the improvement stops.
the first seconds of a rest are the most valuable ones.
harder grip means less blood flow to the holding arm. Hold as lightly as the hold allows.
a jug can keep paying for a minute or more; a poor hold may stop paying after a few seconds.