Rate of Force Development in Climbing: What Separates Elite Climbers?
Rate of Force Development in Climbers: What Does the Research Show?
We all spend a lot of time talking about finger strength, but maximal strength only tells gives us a force ceiling. But when you’re climbing at your limit, how quickly that force can be produced is likely more important.
This is called rate of force development (RFD).
RFD describes how rapidly force increases after a contraction begins. In climbing, it matters when catching a small hold, accelerating through a difficult move, or producing high force before the body position changes.
A 2021 study by Stien and colleagues compared maximal force and RFD between intermediate, advanced, and elite male sport climbers using a climbing-specific isometric pulling test. The results provide some useful information about climbing strength, but they also highlight several limitations of using RFD as a performance metric. PLOS
How was climbing strength tested?
The researchers tested 57 male climbers:
17 intermediate
25 advanced
15 elite
Climbing level was based on the climber's highest self-reported grade during the previous year using the IRCRA grading system. None of the participants were professional climbers, although several competed nationally.
The athletes performed an isometric pull-up on a 23 mm edge using a half-crimp grip without the thumb.
The elbow was held at approximately 90 degrees, while the climber wore a harness connected by a static rope to a force sensor anchored to the floor. After becoming stationary, the climber was instructed to pull as quickly and forcefully as possible and continue the maximal effort for three to five seconds.
Each climber completed three attempts with three minutes of rest between attempts.
This is important because the test wasn't measuring isolated finger strength. It was measuring the entire pulling system: fingers, elbow flexors, shoulder musculature, trunk stabilization and the athlete's ability to coordinate the task.
What is rate of force development?
Maximal force demonstrates how much force can you produce?
RFD demonstrates how quickly can you produce it?
The researchers calculated RFD during several periods after force production began:
50, 100, 150, 200 and 250 milliseconds
They also calculated RFD relative to each athlete's individual time to peak force:
25%, 50%, 75%, 95% and 100% of the force curve.
This distinction matters because climbers don't all reach peak force at the same speed. In this study, individual time to peak force varied substantially, from roughly 150 to 730 milliseconds.
Elite climbers produced more maximal force
Elite climbers produced significantly greater peak force than both the advanced and intermediate groups, with large effect sizes.
Interestingly, the advanced and intermediate groups were not significantly different from one another in this particular study.
That doesn't mean strength stops mattering between intermediate and advanced grades. It means this particular test, with this particular sample, didn't distinguish those two groups well.
The elite climbers also had substantially more climbing experience than the other groups, which makes cause and effect difficult to separate.
Elite climbers also produced force faster
The elite group demonstrated greater RFD than the other groups.
Using the absolute time intervals, differences appeared primarily during the first 50–150 ms of force production.
For example, using each athlete's best trial:
RFD intervals (50ms, 100ms, 150ms):
Intermediate = 801, 1,069, 1,364 N/s
Advanced = 799, 1,146, 1,495 N/S
Elite = 1,457, 1,928, 2,236 N/s
The differences between intermediate and advanced climbers were again small, while the elite group generally produced force substantially faster.
Importantly, elite climbers still demonstrated higher RFD after RFD was normalized to their greater maximal force.
So their higher RFD wasn't explained entirely by simply being stronger.
However, the effect sizes became smaller after normalization, suggesting that maximal strength still explains a meaningful portion of the difference in RFD.
That distinction is important. A climber who can produce substantially more maximal force will usually have more force available early in a contraction as well. RFD and maximal strength are related rather than completely separate physical qualities.
There is a problem with early RFD testing
The early RFD values are interesting, but they were also variable.
The researchers found relatively high coefficients of variation for many of the RFD measurements, particularly among intermediate and advanced climbers.
Reliability improved when longer portions of the force curve were used. The authors specifically noted that the early phase of RFD probably shouldn't be the preferred metric for monitoring individual athletes using this testing setup. I assume it’s because they all started in a deadhang position.
That is worth emphasizing because a difference between groups doesn't automatically make something a good athlete-monitoring metric.
If a measurement changes substantially from trial to trial, it becomes difficult to determine whether a climber actually improved or simply produced a different test result that day.
What does this mean for climbing training?
The study supports a fairly simple conclusion. Higher-level climbers tend to be capable of producing more force and producing that force quickly.
It does not tell us that climbers need a specific "RFD workout." And it certainly doesn't tell us that improving RFD alone will increase someone's climbing grade.
Elite climbing performance is influenced by finger strength, pulling strength, endurance, technique, movement efficiency, decision-making, psychological factors and years of exposure to difficult climbing.
RFD is one piece of that system.
For most climbers, I would still consider maximal force capacity the foundation. Heavy climbing-specific strength work can increase the ceiling from which rapid force is produced.
For athletes who already possess high maximal strength, exposing the fingers and pulling system to intentional high-rate force production may also make sense. But that training recommendation comes from the broader strength and conditioning literature, not directly from this study. This paper describes differences between climbers. It doesn't experimentally test which training method created those differences.
A later study strengthens the overall finding
A useful addition since this paper was published is a 2022 study from many of the same researchers involving 78 male climbers.
That study again found greater peak force and RFD at higher climbing levels. Unlike the 2021 study, the advanced climbers also performed better than the intermediate climbers.
Across all participants, climbing performance correlated strongly with peak force (r = 0.73) and moderately with RFD (r = 0.64).
That makes the broader conclusion more convincing. Maximal climbing-specific force appears to have a strong relationship with climbing level, while rapid force production is also associated with performance but is probably not independent of maximal strength.
Practical takeaway
I wouldn't interpret this research as evidence that every climber needs to chase an RFD number. Instead, it suggests that good climbers, particularly elite ones, possess both a large force ceiling and the ability to access force quickly.
For testing, maximal force remains relatively straightforward and reliable. RFD can provide additional information, but the testing setup, instructions, sampling rate, calculation method and athlete familiarity can all substantially influence the result. That makes RFD much more sensitive to methodology than a simple peak-force measurement.
For climbing training, the traditional order makes sense. Build force capacity first. Then consider how quickly that force can be expressed.
Reference
Stien N, Vereide VA, Saeterbakken AH, Hermans E, Shaw MP, Andersen V. Upper body rate of force development and maximal strength discriminates performance levels in sport climbing. PLOS ONE. 2021;16(3):e0249353. PMID: 33770128. PubMed
Vereide V, Andersen V, Hermans E, et al. Differences in Upper-Body Peak Force and Rate of Force Development in Male Intermediate, Advanced, and Elite Sport Climbers. Front Sports Act Living. 2022;4:888061. PMID: 35837246.