Finger Extensor Training for Climbers
Climbers’ finger flexors are on average 6.3 times stronger than their extensors, and the ratio grows with climbing level. In a 4-week study, only dedicated high-intensity extensor training raised extensor strength, by 41.4%, in about 15 minutes per session.
Climbing trains the muscles that close your fingers and almost ignores the ones that open them. Whether the imbalance causes injuries is not proven, but it is measurable, and extensor strength responds quickly to training.
How big is the imbalance?
A 2023 study tested 78 experienced climbers on an instrumented hangboard, measuring finger flexion (pulling down on a 12 mm hold) and extension (pushing up against an inverted hold with the backs of the fingertips).
- Flexors were on average 6.3 times stronger than extensors (men 6.4, women 5.9).
- The ratio grew with climbing level: better climbers were more imbalanced.
- Flexor strength correlated with grade (r = 0.68); extensor strength did not (r = 0.04).
- About 8% of climbers had an “extreme” ratio above 8.75.
What rebalances the ratio?
The same team then trained 52 of the climbers for 4 weeks in four groups:
| Group | Training | Extensor strength | Flexor strength | Ratio |
|---|---|---|---|---|
| Flexors only | Isometric holds at 80% of max | No significant change | +8.4% | Unchanged |
| Extensors only | Isometric pushes at 80% of max | +41.4% | No change | −27.8% (a trend, not significant) |
| Paired | Alternating flexor and extensor work | No significant change | +11.9% | −1.9% |
| Control | Usual climbing | No change | No change | Unchanged |
Only dedicated, high-intensity extensor training raised extensor strength, and it took about 15 minutes per session. It also lowered the ratio by 27.8% on average, but after four weeks with ten climbers that drop was not statistically significant: the authors call it a potential to rebalance, not proof. Pairing extensor work with flexor work in the same session left the ratio where it was.
Does it prevent injuries?
We do not know yet. The authors are explicit that no study has linked the ratio to injury risk, and they call for long-term research. Extensor training is a plausible, low-cost addition, not a proven injury prevention method.
How do you train finger extensors?
What the study used:
- Isometric pushes: fingertips under a fixed hold, pushing up with the backs of the fingers.
- High intensity: 80% of your maximum push; a set stopped once you could no longer reach 70%.
- Its own session of about 15 minutes, not mixed into flexor sets.
- Sets: 5-second pushes with 6 seconds of rest, up to 10 per set, 4 sets with 2 minutes between them.
- Twice a week for four weeks.
Warm up with easier pushes first, since extensors are small muscles that fatigue quickly.
Rubber-band finger openers and reverse wrist curls are popular alternatives, but they are probably too light to reach the intensity the study used.
Measuring both directions
A force sensor can measure extension too: turn the hold upside down and push up against it. On a ground force plate like Entralpi, pushing up against a fixed hold makes the plate read heavier instead of lighter. The Entralpi app records pulls today, not pushes, so for now this side of the ratio needs another tool. Our testing guide covers the flexor side.
More on finger strength: max hangs and min edge vs added weight.
Do this in Entralpi
The app’s tests measure pulling force (Take a test), and The finger strength test measures each finger alone. For the flexor work of your week, pick a workout from the Train tab or build your own.
Sources
- Devise M, Pasek L, Goislard De Monsabert B, Vigouroux L (2023). Finger flexion to extension ratio in healthy climbers: a proposal for evaluation and rebalance. Frontiers in Sports and Active Living.
