Rate of Force Development for Climbers
Rate of force development (RFD) is how quickly you reach high force: the steepness of the force curve at the start of a pull. Two climbers with the same maximum finger strength can differ in it, and the one who reaches full strength a moment too late misses the hold.
RFD can matter as much as maximum strength when you have only a fraction of a second to load a hold, as on a deadpoint, a catch or a quick crimp.
What is rate of force development?
RFD is the slope of the force curve at the start of a pull. Your maximum force is the height of the curve; RFD is how steeply it rises. On a deadpoint, a catch or a quick crimp, you often have only a fraction of a second to load the hold, so RFD can matter as much as maximum strength.
Peak force is the height of the curve. RFD is the slope of its rising part, often analysed over the first 50% of the time to peak.
What does the research show on RFD?
Elite climbers stand out most in RFD. A Norwegian group has tested climbers of different levels with an isometric pull on a 23 mm rung, half crimp, elbows at 90°.
- In 57 male lead climbers, elite climbers had much higher peak force and RFD than intermediate and advanced climbers, while intermediate and advanced climbers did not differ from each other. The authors recommend analysing RFD over relative time windows (for example the first 50% of the time to peak force) rather than fixed milliseconds.
- In a larger sample, elite climbers produced 74.9% higher RFD than advanced climbers, compared with 39.7% higher peak force.
RFD responds quickly to training. Four weeks of hangs on small holds, twice a week, improved early RFD in elite French competition climbers by 27.5 to 32%, with an 8% gain in maximum force on a sloping crimp. Such rapid gains point to changes in how the nervous system recruits muscle, not to bigger muscles.
The nervous system plays a big part. In a 2023 study, a sudden loud sound sped up force development in both climbers and untrained people, but climbers’ advantage in early force appeared only after the startle, which the authors tentatively link to training adaptations in the nervous-system pathways that drive fast, powerful contractions.
Not every strength program improves it. Five weeks of weighted one-arm finger pulls improved dynamic finger strength in boulderers but did not change RFD. Slower, heavier strength work and fast, explosive work are different stimuli.
How do you measure RFD?
- Warm up thoroughly; explosive pulls on cold fingers are a bad idea.
- Hang or stand with your hands relaxed on a 20 mm edge, half crimp.
- On your own count, pull as hard and as fast as you can, holding for about 3 seconds.
- Rest a full 2 to 3 minutes. Do three attempts and keep the best.
- Keep the starting position the same every time: fully relaxed, no pre-tension. Pre-tensioning inflates the number.
RFD needs a device that samples quickly and shows the force curve: research setups record at 200 samples per second or more. Check the sample rate in our device comparison, and see the testing guide for how RFD fits with maximum force and critical force.
How do you train RFD?
The studies above suggest a few principles:
- Intent is the stimulus. Every rep should be a maximal-intent, as-fast-as-possible pull, not a slow squeeze.
- Short efforts, full rest. A few seconds of pulling with 2 to 3 minutes of rest keeps the quality high.
- Small or specific holds. The French study used suspensions on small holds; training on the grips you need on the wall keeps it specific.
- Low volume, twice a week. Four weeks was enough to see changes in elite climbers.
- Fresh fingers only. Put RFD work at the start of a session, after the warm-up, never after hard climbing.
Explosive loading is demanding on pulleys. If you are new to hangboarding or returning from a finger injury, build a base with max hangs or no-hangs first.
Seeing it improve
Because RFD changes over weeks and depends on a clean starting position, it is easy to fool yourself by feel. A force sensor that shows the curve lets you check your technique and see whether the slope actually gets steeper. On a ground force plate like Entralpi, the app records each pull at up to 100 samples per second, so you can compare the rising part of the curve from one session to the next.
More on finger strength and testing: max hangs and how to test finger strength.
Do this in Entralpi
The app counts the speed of a pull (RFD) over the first 200 milliseconds of the pull, and shows it in your unit per second (What each test measures). The tests are on Take a test. Without the plate, the timer runs a session but measures no force.
Sources
- Stien N, et al. (2021). Upper body rate of force development and maximal strength discriminates performance levels in sport climbing. PLOS ONE.
- Vereide V, et al. (2022). Differences in upper-body peak force and rate of force development in male intermediate, advanced, and elite sport climbers. Frontiers in Sports and Active Living.
- Levernier G, Laffaye G (2019). Four weeks of finger grip training increases the rate of force development and the maximal force in elite and top world-ranking climbers. Journal of Strength and Conditioning Research.
- Colomer-Poveda D, et al. (2023). Differences in the effects of a startle stimulus on rate of force development between resistance-trained rock climbers and untrained individuals. Scandinavian Journal of Medicine & Science in Sports.
- Saeterbakken AH, et al. (2024). Five weeks of dynamic finger flexor strength training on bouldering performance and climbing-specific strength tests. Frontiers in Physiology.
