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Calculate your sport climbing grade with the new Tindeq setting!

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Blood Flow Restriction (BFR) Training for Rock Climbing - Introduction

Blood Flow Restriction is one of the most recent innovations in climbing training. I first encountered this finger strength training method in the 2021 Nugget Climbing interview with Tyler Nelson [nugget]. I tried it, and I was amazed with the results. After one training cycle of about 6 - 8 weeks, my 7-second finger strength (MVC-7) measured on a 20 mm edge hit an all-time peak of 124 kg! Moreover, I could repeat this result in 2022 with another BFR cycle.

At that point, I started focusing more on endurance training, and my finger strength declined to 109.5 kg in August 2023. But now, I did another quick BFR cycle to see if I could quickly boost my finger strength. Read on if you're curious to find out what the results were!

Sport climbing level calculator for Tindeq Progressor

Below you'll find a simple calculator that makes estimating your current redpoint level possible based on the Peak Load and Critical Force measurements done with the Tindeq Progressor. The calculator also lets you compare the result obtained with the model developed by Lattice Training and the model I’ve created for this post. Still, at this early development stage, I believe the calculations based on the earlier 4-trial method are more reliable, although the tests are more time-consuming. To get a detailed automatic sport climbing performance analysis based on the 4-trial method, please try my Sport Climbing Level Calculator.

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The concept of Critical Force in rock climbing endurance training

The concept of finger flexor Critical Force and its role in determining sport climbing performance has been discussed extensively on my blog, and I've been using it regularly to assess climbers 12. However, looking at it again from the perspective of the new all-out test makes sense.

In theory, finger flexor Critical Force is the force a climber can generate on and off for a very long time. You may compare that to Critical Speed. For example, there is a certain walking speed with which a person could go on for many kilometers, but as soon as they start running fast, they’ll quickly get exhausted and need to rest. Critical Speed is the maximum speed they could walk theoretically unlimitedly 3. Finger flexor Critical Force in climbing is similar; it is the theoretical load you can endure intermittently and infinitely on your fingers. The higher this force is relative to your body weight, the better your expected sport climbing performance.

To determine the Critical Force of my clients, I typically use the three separate repeaters tests at 80%, 60%, and 45% MVC-7, as described in the earlier paper by Lattice Training 4. Based on this method, I built an extensive database of results, letting me determine the athlete’s climbing level 1. Because the 80%, 60%, and 45% MVC-7 loads roughly represent the anaerobic alactic, anaerobic lactic, and aerobic endurance systems, the results allow insight into the performance of the entire spectrum of the endurance profile.

However, the original test has drawbacks. First of all, four separate trials are required, often split into two individual testing sessions because fatigue accumulation would negatively impact the test results. Moreover, you need to have added weight at your disposal and a pulley unloading system behind your hangboard. Finally, the 60% and 45% MVC-7 tests can take up to 20 minutes, which can be grueling and mentally challenging, preventing some climbers from completing the measurements. In contrast, the new test proposed by Lattice Training allows the determination of Critical Force in one relatively quick trial, lasting only 4 minutes, which is a huge advantage and enables us to assess the client very quickly.

Figure 1: Typical Critical Force curves made with the original Lattice Training method - my personal 1-year training progress.

Brief overview of the climbing grade models

In this blog post, you’ll find a simple calculator letting you approximately predict your sport climbing level based on the Tindeq Progressor measurements. Here, I’m comparing two different models - the first is a model developed by Lattice Training and published in their 2021 paper. The second is my alternative model, which includes Peak Load measurements as a parameter.

Model 1: Lattice Training

The first model was developed by Lattice Training, based on the research done for their 2021 paper 5. In the article the model is named CF% BM Unadjusted - see Figure 2. The model considers the relationship between the climber’s CF and body mass (BM). The results from the tests are recalculated to the numerical IRCRA scale, as explained in the 2016 article by Draper et al. 6 According to the authors, The CF as a % body mass was positively associated with both sport climbing and bouldering performance, and the Lattice Training model enables predicting the tested athlete’s sport climbing redpoint grade.

Even better results were reported after combining the W’ relative to body weight with CF relative to body weight. Unfortunately, the Tindeq Progressor software cannot extract W’ from the measurements yet, so I didn’t consider this model in the calculator. In any case, the reported accuracy of both models is similar.

Figure 2: Linear regression model S2 - Critical Force (% Body mass) adapted from the 2021 Lattice Training paper 5.

Model 2: StrengthClimbing

Based on my experience with Critical Force measurements and redpoint climbing grade prediction,
I developed my own model that considers the Critical Force relative to body mass as well as the Peak Force relative to body mass. I believe that evaluating the finger flexor endurance in the context of finger strength improves the accuracy of the analysis. However, this is still an experimental model, and for reliable results, please use my Sport Climbing Level Calculator, which is based on the original 4-test method 1.

Please try out both models and let me know which one works better for you!

Finger flexor Critical Force measurements in practice

The first mention of a single-bout forearm Critical Force test was published in 2014 by Kellawan and Tschakovsky 7. But it wasn’t until the test consisting of four separate trials was described by Giles in 2019 that the concept of Critical Force became more widely recognized in the climbing community 4.

To carry out the test proposed by Lattice Training in 2019, you first measure the 7-second maximum finger strength (MVC-7). Then, you calculate 80%, 60%, and 45% of that value and perform three separate endurance tests with the respective loads. High-level amateurs and professional climbers, whose CF may be higher than 45% MVC-7, typically use 50% or even 55% MVC-7 loads in the final trial. During each test, you perform 7/3 Repeaters until failure.

Typically, for the 80% test, you need to add some weight to your harness, and for the 45% - 60% tests, you need to subtract some of your weight using a pulley setup. That may pose additional complications, especially for heavy climbers with poor finger strength, because using a heavy counterweight may be necessary.

After performing each test, you note the Time Under Tension (TUT), the total hanging time at each load. For example, if during your 60% MVC-7 endurance test, you performed 21 full 7-second hangs and failed at the third second of your 22nd hang, then the TUT is 7 s *21 + 3 = 150 s. Finally, you input your test results into a spreadsheet or a calculator 1. The test results serve as input, and based on the equations explained by Giles in his 2019 paper, the extrapolated Critical Force is calculated.

The procedure may seem complex and often impossible to complete within a single testing session. That's why Giles and the Lattice Training team developed a simpler alternative approach and published it in the second paper from 2021. According to the new procedure, we need to perform only one short test instead of four separate tests. The new CF measurement consists of 24 all-out one-arm pulls. CF was defined as the mean end-test force, using the last six contractions of the test. A typical result plot from the Tindeq measurement is shown in Figure 3 below. I explain the entire procedure in Video 1.

Typical Critical Force plot registered with the Tindeq Progressor load cell dynamometer.

Figure 3: Example of a Critical Force curve registered with the Tindeq Progressor.

Video 1: Critical Force (CF) measurement with the Tindeq Progressor instructional video.

Peak Load/Peak Force measurements

The Peak Force or the Peak Load is the force/load that your fingers can generate statically on a given hold. The most commonly used holds are 20 mm edges in half crimp/open hand positions, such as the Tindeq V-Rings. However, the procedure can be done for any hold, including pinches and pockets.

Although the Lattice Training model does not rely on Peak Load measurements, I’m proposing an alternative model with Peak Load as the second parameter. Below, you’ll find brief instructions on how to measure the Peak Load with the Tindeq Progressor. You will find additional information in the RFD article and video 8. Before you engage in any measurements or climbing-specific activity, please ensure you're properly warmed up, including your fingers, elbows, shoulders, and back.

  • Hang your Tindeq Progressor above your head with the V-Ring, or any other portable edge attached, so that your arm is slightly bent when holding the edge.
  • Turn on and tare your Tindeq Progressor.
  • Select the Peak Load setting and start a new session.
  • Load the edge slowly, trying to put as little load as possible on your feet. Strong climbers may need to use an additional load to avoid lifting off.
  • Save your results for future reference.
  • Repeat the procedure with your other hand.

Perform the Peak Load measurements one or two more times for both hands to ensure your fingers are fully recruited.

What can we learn from CF measurements?

We can obtain a lot of valuable information from Critical Force measurements. First, knowing the Critical Force lets us decide whether we should train finger flexor endurance at all or whether it’s better to invest our time in finger strength training. As a rule of thumb, you can use Table 1 below to make that decision.

Table 1: Critical Force vs. maximum finger strength training criteria.

Critical Force vs. Peak Force training criteria
CF/PF > 50%Train finger strength
35% < CF/PF < 50%Train both
CF/PF < 35%Train finger endurance

Second, you can optimize hangboard endurance training once you measure your CF. For example, as a rule of thumb, climbing coaches may recommend performing hangboard endurance training exercises at 40% MVC intensity. However, for some climbers, that means exercising in the aerobic regime, while others will already be in the anaerobic intensity range. That means the two groups will be subjected to different training stimuli, and various intervention outcomes will be observed 54. Knowing the Critical Force of the athlete allows the coach to prescribe exercises at the intensity precisely targeting the right adaptation.

Furthermore, knowing W’ makes it possible to calculate the exact training load to allow you to continue the exercise for a certain target time. For example, let’s say you’re projecting an endurance route that takes 5 minutes to climb. Based on the result of your CF measurement, you may calculate the 7/3 Repeaters training load to improve your 5-minute endurance. After several weeks of training, you will find that you have more finger strength remaining for the final moves of the route.

Finally, with the models developed by researchers such as Lattice Training and myself, it’s possible to predict the athlete’s potential redpoint performance based on the CF measurement. That, in turn, makes it possible to establish whether the climber requires more physical conditioning (if they’re overperforming for their calculated grade) or more outdoor climbing and technical drills if they’re underperforming on the rock.

Rock Climbing Critical Force measurements with the Tindeq Progressor - Summary

In this article, I’ve discussed a method that allows us to directly perform finger forearm flexor Critical Force measurements with the new Tindeq Progressor feature. Furthermore, I’ve included a simple calculator that makes estimating your current redpoint level possible based on the Peak Load and Critical Force measurements. The calculator also lets you compare the result obtained with the model developed by Lattice Training and the model I’ve created for this post. Still, at this early development stage, I believe the calculations based on the earlier 4-trial method are more reliable, although the tests are more time-consuming. To get a detailed automatic sport climbing performance analysis based on the 4-trial method, please try my Sport Climbing Level Calculator.

Interestingly, in the conclusions of the 2021 Lattice Training paper, we read that:

“Further research is necessary to determine if ff-CF and W’ are trainable characteristics in climbers and the efficacy of interventions based on exercise intensities determined relative to ff-CF end-test force.”

This question is relatively easy to answer since Critical Force is a measure of endurance, and we know that endurance can be trained. In fact, over the years, I’ve been tracking my Critical Force measured with the original 4-test method, and I’ve found beyond all doubt that I could significantly improve it in absolute numbers (kg), relative to my body weight, and relative to my MVC-7. For example, in the period between July 2019 and July 2020, I increased my CF/MVC-7 ratio from 30% to 40% by doing Endurance Repeaters Pyramids - see Figure 1 2.

What is more interesting is how impactful Critical Force training is on improving the athlete’s sport climbing performance at the crag. From my own experience and the experience of the athletes I’ve trained, I can say that working on your Critical Force gives you more confidence and makes it possible to climb longer, with less pump and, consequently, better technique. It also improves the recovery rate between burns and allows you to perform more hard tries during the climbing day. From this perspective, finger flexor Critical Force training can potentially affect many different aspects of your climbing, including technique and tactics.

If you’re new to sport climbing, or you’ve been stuck in a rut trying to figure out why your lead climbing level is not improving despite you doing body weight 7/3 Repeaters, you might try to evaluate your Critical Force with any of the methods described in this post and see if you can get interesting insight into your climbing performance. Please let me know about your experiences in the comments!


  1. J. Banaszczyk, StrengthClimbing – Sport Climbing Level Calculator – Automatic Climbing Assessment!, Apr. 09, 2023. (link)[][][][]
  2. J. Banaszczyk, StrengthClimbing – The Best Hangboard Endurance Training For Rock Climbing – Pyramids, Mar. 02, 2023. (link)[][]
  3. Smyth, B., Muniz-Pumares, D., 2020. Calculation of Critical Speed from Raw Training Data in Recreational Marathon Runners. Medicine & Science in Sports & Exercise. (link)[]
  4. Giles, D., Chidley, J.B., Taylor, N., Torr, O., Hadley, J., Randall, T., Fryer, S., 2019. The Determination of Finger-Flexor Critical Force in Rock Climbers. International Journal of Sports Physiology and Performance 1–8. (link)[][][]
  5. Giles, D., Hartley, C., Maslen, H., Hadley, J., Taylor, N., Torr, O., Chidley, J., Randall, T., Fryer, S., 2021. An All-Out Test to Determine Finger Flexor Critical Force in Rock Climbers. International Journal of Sports Physiology and Performance. (link)[][][]
  6. Draper, N., Giles, D., Schöffl, V., Konstantin Fuss, F., Watts, P., Wolf, P., Baláš, J., Espana-Romero, V., Blunt Gonzalez, G., Fryer, S., Fanchini, M., Vigouroux, L., Seifert, L., Donath, L., Spoerri, M., Bonetti, K., Phillips, K., Stöcker, U., Bourassa-Moreau, F., Garrido, I., Drum, S., Beekmeyer, S., Ziltener, J.-L., Taylor, N., Beeretz, I., Mally, F., Mithat Amca, A., Linhart, C., Abreu, E., 2015. Comparative grading scales, statistical analyses, climber descriptors and ability grouping: International Rock Climbing Research Association position statement. Sports Technology. (link)[]
  7. Kellawan, J.M., Tschakovsky, M.E., 2014. The Single-Bout Forearm Critical Force Test: A New Method to Establish Forearm Aerobic Metabolic Exercise Intensity and Capacity.(link)[]
  8. J. Banaszczyk, StrengthClimbing – All You Need To Know For Perfect RFD Measurements With Tindeq Progressor!, June 02, 2023.(link)[]
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21 thoughts on “Calculate your sport climbing grade with the new Tindeq setting!”

  1. That’s a great article!
    Just got my Tindeq and did a PL and CF test. With the following results (just right arm on 20mm edge):
    PL: ~49 kg
    CF: 29.44 kg

    Which resulted to 8a climbing level. This is quite spot on. I climbed 8 8a routes on the rock so far and no 8a+ yet. Also, this confirms that I have quite low finger strength compared to my endurance.

      1. My wife also tested it in the evening. I can’t remember the numbers right now, but it resulted in 8b+. Her max grade is 8a+.

        But she always had strong fingers and flexibility + upper body strength is her weakness. If you like I can send you her numbers the next time she tests.

        1. Sure, that’d be great. It’s also possible that she has good endurance – women often have high Cf/MVC ratio.

          1. The numbers were:
            BW: 50kg
            PL: 42kg
            CF: 27.74kg
            on the 20mm edge of the V-Rings from Tindeq.

            As a remark: We don’t hangboard a lot and also got the Tindeq quite recently. So I suspect the numbers will be higher if we get used to the testing procedure, even without getting stronger. If you like to collect data (I do as a fellow engineer), I can give you some updates over the next months. But maybe not in form of spamming your article with comments 😉

          2. Hi! Thanks for the data! I think her CF is very high compared to max strength and that explains the calculation result and her high performance on the rock.

  2. Hey Jędrzej,
    i don’t understand your Table 1…. CF and PF are to different things (especially the numbers after testing). How can be 50 % of CF be in the same column as 50% of PF. ?
    Or how should i unterstand the criteria for training?

    1. Hi Lucas,

      Thank you for the question. It’s about the relationship between the measured CF and PF. If your CF is low compared to your PF, then you should train endurance, and if your CF is high, like above 50% of your PF, then you should focus on finger strength. Does this answer your question?

  3. Hi there
    Great article, thank you!
    I am wondering if the measurement with a lifting from the ground- setup is equally useful as the overhead setup?

    1. Hi, thanks for the question. I can’t say if the results of the two different tests can be compared directly. Probably not. However, such a lifting test can definitely be helpful. There are some things to keep in mind though:

      – Are you fixing the Tindeq to the ground (all-out effort), or are you lifting a certain weight?
      – Are you just flexing your fingers, or are you pulling with your back?

      The best thing to do would be to run a test in all possible configurations and compare the results.

      1. Hi, thanks for the reply.
        I guess to really be able to compare results I will have to use the same setup.
        Traveling for work, I do the 100% resistance, fixing the tindeq to a fixed object type of training. A pull up bar can´t be found all the time, so sometimes it´s a handrail, a pole, or simply sling over the shoe. So angles are very different and it´s hard to track differences. Tindeq is still helpful inside a session of course.
        For tracking progress I will have to define a testing setup at home.

        Regarding flexing fingers vs. pulling with the back – what is more helpful in your opinion for building strength as well as stronger connective tissue?

        1. Hi,

          Pulling with your back is not optimal because you could even injure yourself. Try flexing your fingers to incorporate elements of active recruitment into your training routine.

          You’ll find more information in this article

  4. Hi Jędrzej,

    Have you tried Tindeq CF with a portable hangboard and two arm hanging instead of one arm? Not surr how much that setup will be doable and comparable though.
    How would that turn out compared to the method where we measure max hang, 80%, 60% and 50% to calculate?
    Would this be different setup not comparable or should it more or less reflect the same and have similar outcome?
    I would like to test the Tindeq setup with two arm hang portable fingerboard setup to measure CF and then repeat the classical measurements and see how much it would differ. Hope to find some time in the following period and get back with results 🙂

    1. Hi Darko,

      Thanks for the great question! I have yet to try the Tindeq two-handed. What I did is I measured the left and right hand separately and averaged the results. I guess this should be similar to doing it with both hands simultaneously, but I haven’t confirmed it yet.

      Regarding comparison with the 80%, 60%, 50% method, the CF result should be similar – again, you might need to average the result for the left and right hand. However, I expect the curve for the Tindeq all-out measurements to be much steeper – it’ll converge to CF faster. The Tindeq measurement takes 240 seconds, and at the end of the measurement, we most likely reach CF. In contrast, it’s not uncommon to be able to do 7/3 Repeaters for more than 240 seconds at 60% MVC-7 if we measure with the “old” approach.

      Still, I’m sure that the all-out Tindeq measurements curve will differ depending on the endurance capability of the tested climber. Drawing meaningful conclusions from the Tindeq measurements is surely possible once the right methodology is applied.

      That said, I would very much appreciate it if you could send me your results once you complete the tests.

      Thank you very much for your ongoing support over the years – it means a lot 🙂


      1. Hi Jędrzej,

        I am following up with results as promised 🙂
        Disclaimer: Please take into account the multiple variables and error points that can significantly skew the end result.
        To name few: hangboard setup, edge, familiarity/novelty of testing/training method, correct form and detecting form failure, proper timing, pacing effort/max effort on each rep and many more.

        Now that I got that out of the way, lets have a look at the results, and add some context to better understand.

        1. Classical approach with MVC-7, 80%, 60%,50% hangs on ~20mm Beastmaker 1000 edge (fairly polished due to overuse and no maintenance. Please brush the holds on the hangboard. Everyone will benefit, incl. you 🙂
        CF result 43.6kg.

        2. Tindeq approach: portable hangboard, 20mm edge, Tindeq 24 reps all out max :
        CF result 35.88 kg.

        My takeaway:
        – use any preferred method to establish a baseline. Train with purpose and then repeat the same method to see if there is progress.
        – climbing is too complex to be narrowed down to only one number, but it can be a good indicator in which direction to take your training for improvement.
        – the setups are very different, and many other variables can skew the results. As I mentioned in the intro.
        – fatigue, rest, stress, recovery from previous sessions can have a major impact even on same method test.

        What are your thoughts?


        1. Hi Darko,

          Thanks for the results! Great job 🙂 Yes, the two methodologies are difficult to compare. I tried to divide your results by half to relate them to one-arm all-out tests; the result was 7b. Close enough, but not the same.

          I agree – one needs a set of benchmarks. It could be two-arm testing, one-arm testing, hanging, or active pulling. Then you try to monitor and improve them consequently.

          Hangboard training needs to be accompanied by regular climbing – this way, you can apply the improved strength and endurance and integrate them into your performance. Otherwise, you’re just weightlifting without a purpose.

          1. Climbed my first 7C indoor boulder. It is a commercial gym and does not compare to outdoors, but I guess it can be a good indicator.

  5. Félix Bamrounsavath

    Hello! 2 questions…

    1) Do you use results from single arm testing or do you use an avg of both arms? Or maybe I should do the CF test with both arms?

    2) Should I do the test pulling with my whole arm or only flexing the fingers – isolating the finger flexors muscle like Tyler Nelson advocate?

    Ty for the great content!

    1. Hi Félix,

      I’m glad you like the site!
      1) You can try both approaches. I think averaging could be more accurate – for example, my results differ significantly between the left and right hand. I even considered including an averaging option in the calculator, but I figured it would make it too complicated.

      2) You should lean into the hold as if you wanted to hang in it with your arm engaged. This is explained in the Lattice Training paper and in my article. Of course, you may try doing the same exercise concentrically, but the results will have a different meaning.

      Thanks for the questions!

  6. Hi, thanks for sharing your experience and work for free. As a coach, I’m using the Tindeq for a few months in France, and your article helps me a lot.

    1. Hello Fred,
      Thanks a lot for the positive feedback! There’s still a lot to discover! If you can, please let me know if the algorithm is accurate for your climbers!


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