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Climbing Critical Force Calculator

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New! - Sport Climbing Level Calculator!

If you're a sport/lead climber, there's a new tool available! The Sport Climbing Level Calculator!

The Sport Climbing Level Calculator is designed specifically for sport/lead climbers. It analyzes the athlete's finger strength and forearm endurance profile to estimate the expected climbing grade accurately.

The Sport Climbing Level Calculator will:

  • Let you know how hard you could be climbing at your current fitness level
  • Pinpoint your biggest weaknesses and help you effectively target them
  • Give you an instant automatic assessment and help you design a training plan tailored to your exact needs!

If you're a sport/lead/trad climber, and you're looking for an automatic in-depth climbing performance assessment, follow this link.

Critical Force Calculator

The Critical Force Calculator will help you determine where you stand with your forearm aerobic endurance. If you’re a strong sport’s or trad climber, but end up pumped on your way to the crux, it means that your forearm aerobic endurance likely requires some attention. The Critical Force Calculator will also allow you to find the optimum load at which you should train so that you will soon breeze up through those endurance routes! 

The calculator provides a basic assessment of your climbing endurance level. If you would like to get a detailed personal climbing performance evaluation like this one, just send your input numbers to me directly at [email protected], and I’ll get back to you with an in-depth lead climbing level evaluation. I will analyze your current performance and give you hints on what to train to quickly improve your climbing!

For best results, train exactly at CF intensity and try to maximize the total work done.


To determine your forearm aerobic endurance Critical Force, you can use the calculator below. Input your body weight and your 7-second MVC on a 10 – 35 mm edge, followed by respective times to failure for the 7/3 Endurance Repeaters at 80% MVC-7 and 60% MVC-7. For the last measurement you may choose 45%, 50% or 55% MVC-7 load, just make sure that you fail in under 1200 seconds. 

The calculator will output your CF and the weight you need to subtract in order to exercise exactly at CF load. You will also receive a brief assessment of your strength and forearm aerobic endurance. The calculator is calibrated for the half crimp grip on a 20 mm edge, to enable a direct comparison with the results published in 1. The bouldering level prediction is based on the results of the survey published at 2.

You can find more detailed information regarding the role of the Critical Force in sport’s and climbing endurance training in 3.

Example Critical Force test

Let’s say you weigh 68 kg, and you take the MVC-7 test on a 20 mm edge. You can add 32 kg to the bodyweight and hang for 7 seconds, so the MVC-7 load is 100 kg. Now we can calculate your 80%, 60% and 45% loads, which are 80 kg, 60 kg and 45 kg respectively.

  1. Test your T80% :
    • To set the 80% load, you must add 12 kg to the harness.
    • Execute a set of 7/3 Repeaters until failure.
    • Add the hanging times together. This means that if you were able to execute 10 full hangs and failed at hang 11 in the 4-th second, then your T80% is 74 seconds.
    • Rest 15 minutes before the next test.
  2. Test your T60%
    • To set the 60% load, you must remove 8 kg using a pulley system.
    • Execute a set of 7/3 Repeaters until failure.
    • Add the hanging times together. This means that if you were able to execute 15 full hangs and failed at hang 16 in the 4-th second, then your T60% is 109 seconds.
    • Rest 30 minutes before the next test.
  3. Test your T45%:
    • To set the 45% load, you must remove 23 kg using a pulley system.
    • Execute a set of 7/3 Repeaters until failure.
    • Add the hanging times together. This means that if you were able to execute 60 full hangs and failed at hang 61 in the 4-th second, then your T45% is 424 seconds.
    • If your aerobic endurance is very good, and you are able to last more than 20 minutes at the 45% load, you should change the load to 50% or even 55% of your MVC-7 and redo the test.
  4. Enter your data into the form and press calculate.
Your Input - Demo Version







Results - Demo Version

The calculator lets you compare your finger strength and endurance with data from hundreds of other climbers, which I collected over more than four years of doing climbing research and running the site. It outputs the climbing grade you should be able to send with your current results and gives you precise suggestions regarding what aspects of your climbing you should focus on to move forward.

Register and get 1-month access to the full version of the calculator, together with all Premium Content on In the sections below, you'll find detailed instructions on using the tool to leverage its full potential and to get an accurate automatic assessment.

Unregistered users can try out the demo version of the calculator to get a glimpse of its capabilities. In addition, I've prepared a set of trial values that you can input to see how it works!

Demo version test

To test the Demo Version of the Sport Climbing Level Calculator, please input the demo dataset:

  • Body Weight: 65 kg or 144.4 lbs
  • Test edge: 20 mm
  • MVC-7: 105 kg or 233.3 lbs
  • T80: 77 s
  • T60: 136 s
  • T45: 323 s

Identify your climbing weaknesses

I often ask other climbers why they love climbing and usually get similar answers. It's about hanging around with buddies, being in nature, and living an adventure. But it's also about focusing on a challenge, the act of self-improvement, and being able to surpass their weaknesses. Yes, climbing is a great sport, and we spend much of our time trying to get better at it to impress our friends and even ourselves by achieving what we thought was impossible.

And yet, one of the most frustrating things about climbing is when we hit a plateau. After a few years of training, most of us have been there. You climb a lot, have a fixed training routine that works, progress continuously, and suddenly boom - your progress stalls.

That's a clear sign that you need to change how you train. Maybe you were focusing too much on finger strength training or completely neglected it and relied solely on aerobic endurance. On the other hand, it's also possible that your anaerobic endurance is poor, and you get pumped quickly after a few hard moves. You may lack technique and tactics because you need to climb outdoors more. Or, contrary to that, you might be overtraining by combining long weekends at the crag with hard weekly training at the gym during the summer.

Getting a clear perspective can be challenging when trying to find your own weaknesses, so the best solution is to find a coach, get him to take a closer look at your climbing, and ask for a training program tailored to your goals. The second best option is to run a series of tests and send them to an experienced climbing analyst for a remote assessment. However, both these options can be costly and time-consuming.

That's why I created the Sport Climbing Performance Analyzer tool, which can quickly pinpoint what's holding you back and see what improvements you can expect if you address the issue. Of course, nothing can replace a good climbing coach, but the tool will quickly show you how to eradicate your most significant climbing deficits and get back on track with your progress.

Sport Climbing Level Calculator instructions

In the paragraphs below, you will find detailed instructions on how to perform the measurements safely and accurately. But, again, remember that thorough preparation is essential.

Equipment required for performing the measurements

To perform the Sport Climbing Level Calculatoe measurements, you'll need the following:

  • A hangboard with a wooden 10 - 35 mm edge
  • Some additional load
  • A pulley setup for reducing your body weight
  • Bathroom scales or a crane scale
  • A means to measure test time

As far as the hangboard is concerned, if you're going for the standard 20 mm test, you have the following options:

For weaker climbers, performing the test with a 30 mm edge or a 33 mm edge (BM2K default) might be better. That will also enable smaller load reductions when designing the Endurance Repeaters exercise protocol 5. Of course, you must ensure that you use the same edge for the MVC-7 measurements and the following endurance measurements.

Be well rested

To correctly test your finger strength and endurance with the Sport Climbing Level Calculator, ensure that you are well rested from your previous climbing activities. That typically means resting for 24 - 72 after your last training session, depending on its intensity.

Warm up and recruit

Before engaging in any climbing activities, you should warm up thoroughly. Pay special attention to your back, shoulders, forearms, and fingers. Then, top up your warm-up with a series of 3 - 5 progressively heavier 7 - 10 second hangs. For detailed information on warming up for climbers, you may look at my article, this video from Dr. Tyler Nelson, or this video on how to warm up your fingers specifically 678.

Determine your weight

To perform an accurate measurement, you should prepare a bathroom scale, a hook scale, or a dedicated tool, such as the Tindeq Progressor 9. It is recommended to weigh yourself in full gear with the added load before each test hang. However, it is also helpful to know your body's weight to relate it to the total hang load.

Select the tested hold position

The Sport Climbing Level Calculator is designed for tests on flat wooden edges in the half-crimp or open-hand position - you may choose the stronger hold position. The tests can be performed on any edge depth between 10 - 35 mm. Typically the tests are performed on 20 mm edges, but weaker climbers will find deeper edges more useful.

Test your MVC-7

The MVC-7 test is the first test you must run to assess your finger strength and get the point of reference for your other tests. If this is your first time doing this, please refer to this article to familiarize yourself with maximum finger strength testing and weighted hangs 10. Here you'll find tons of helpful information on how to run the test safely and accurately.

Let's say you weigh 68 kg, and you take the MVC-7 test on a 20 mm edge. You can add 32 kg to the body weight and hang for 7 seconds, so the MVC-7 load is 100 kg. Now we can calculate your 80%, 60% and 45% loads, which are 80 kg, 60 kg and 45 kg respectively.

Test your T80%

The 80% MVC-7 test is like doing a Heavy Repeaters until failure. It lets you check the efficiency of your anaerobic alactic/lactic system, which is critical for sending routes with hard bouldery cruxes. To set the 80% load, you must add 12 kg to the harness. Execute a set of 7/3 Repeaters until failure. Add the hanging times together. This means that if you were able to execute 10 full hangs and failed at hang 11 in the 4-th second, then your T80% is 74 seconds. Rest 15 minutes before the next test.

Test your T60%

The 60% MVC-7 test specifically targets your anaerobic lactic system, which is heavily taxed when climbing through sustained sequences of moderately hard moves. To set the 60% load, you must remove 8 kg using a pulley system. Execute a set of 7/3 Repeaters until failure. Add the hanging times together. This means that if you were able to execute 15 full hangs and failed at hang 16 in the 4-th second, then your T60% is 109 seconds. Rest 30 minutes before the next test.

Test your T45/50/55%

The 45/50/55% MVC-7 test lets you verify how well your aerobic endurance system works. To set the 45% load, you must remove 23 kg using a pulley system. Execute a set of 7/3 Repeaters until failure. Add the hanging times together. This means that if you were able to execute 60 full hangs and failed at hang 61 in the 4-th second, then your T45% is 424 seconds.

If your aerobic endurance is very good, and you are able to last more than 10 minutes at the 45% load, you should change the load to 50% or even 55% of your MVC-7 and redo the test. Enter your data into the form and press calculate.

The idea of Critical Force

Critical Speed (CS) and Critical Power (CP) are well-known concepts used in sports training. Imagine yourself walking at about 6 km/h – you could probably carry on like this for hours. On the other hand, unless you’re an elite marathon runner, you probably couldn’t run at 20 km/h for very long. This means that your running critical speed, which is the speed at which you could theoretically run for an unlimited time, lies somewhere between 6 – 20 km/h. Cycling coaches use the term Critical Power, which defines the power output, at which you could cycle for hours. For climbing, the term Critical Force (CF) is more relevant, meaning the maximum load at which you should be able to climb indefinitely without falling off.

The Critical Force determines the performance on endurance routes, and it is directly related to the forearm aerobic capacity. Critical Force is usually expressed as a percentage of the climber’s body weight, or their maximum voluntary contraction (MVC). For elite sport climbers, it could reach up to 60% of their MVC, while for boulderers and poorly conditioned route climbers, it could be below 30% MVC. Knowing your CF is important because it was shown that aerobic capacity is trained most efficiently exactly at critical loads 11.


  1. 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)[]
  2. (link)[]
  3. J. Banaszczyk, StrengthClimbing – Endurance Repeaters, May 2, 2019. (link)[]
  4. r/climbharder, Beastmaker 1000 and 2000 edge/hold sizes, Jul. 18, 2019. (link)[]
  5. J. Banaszczyk, StrengthClimbing – Endurance Repeaters – Forearm Aerobic Endurance Hangboard Routine, May 2, 2019.(link)[]
  6. J. Banaszczyk, StrengthClimbing - 9 Powerful Reasons To Warm-Up For Rock Climbers (Review), Dec. 4, 2020. (link)[]
  7. Dr. T. Nelson, C4HP, Connective tissue warm-up drill, Jan. 31, 2020. (link)[]
  8. A. MacFarlane, Finger Warm Up for Climbers, Oct. 4, 2020. (link)[]
  9. (link)[]
  10. J. Banaszczyk, StrengthClimbing – Finger Strength Measurements For Rock Climbers Made Easy!, Feb. 17, 2023.(link)[]
  11. McGawley, K., 2010. The application of the critical power construct to endurance exercise. University of Brighton. Student thesis: Doctoral Thesis. (link)[]
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66 thoughts on “Climbing Critical Force Calculator”

  1. Hi Jędrzej.
    Thank you so much for the article and the calculator.

    I tested my CF with tindeq and my results are 24kg for the right hand and 20kg for the left.
    My MVC-7 on a hangboard 20mm both hands 127kg.
    I weigh 80kg.
    How do I calculate my CF, CF/BW%, and CF/MVC-7%? And compare them with your test. I mean, this calculator uses both hands and tindeq only one. Do I add 24+20? Or results from your calculator are average for one hand?

    1. Hello Volodymyr,

      The Sport Climbing Level calculator was not specifically designed for Tindeq type one arm measurements, but you may try to introduce the Tindeq data and see what output you get.

      There are some significant differences between the two measurement methods. For example, there’s the bilateral deficit phenomenon, where the sum of the forces generated by the hands in separate measurements is higher than when both hands pull together. Moreover, all-out pulling differs from hanging with the same load every time.

      However, next week I plan to release a calculator that will let you calculate your Sport Climbing Level directly from the Tindeq measurement, which might be more helpful for you.


    I would love to hear about your opinion.
    Here are the results, where does it put me according to your data when it comes to sport climbing and bouldering?
    In your opinion, what type of training should I prefer to improve rope climbing?

    My results are:
    BW: 62kg
    MVC-7: 91 Kg
    T80%: 78″
    T60%: 546″
    T45%: 1050″
    If I understood correctly, I only entered the actual suspension times. I use for test beastmaker 1000.
    Thank you

    1. Hi Emanuele,

      I looked at your data. Your finger strength is average, but your endurance is quite ok, which makes up for it.

      At this point, you’re likely able to climb in the 8a+/8b+ range, depending on the route’s character. If you want to improve quickly, you should address your finger strength first. Try to reach a stable 160% MVC-7 on a 20 mm edge. Bechtel’s Ladders could be an excellent place to start. Regular bouldering and system board training is also a good idea.

      Once you’ve improved your finger strength, you may return to address forearm endurance specifically. You may use Endurance Repeaters at Critical Force load. Currently, your CF lies at 42% MVC-7. Improving beyond 45% would give you an extra edge on longer routes.

      I hope this helps,

      1. Hi Jędrzej
        thanks for your advice.
        Currently I have climbed maximum on 7c+. Glad to know I could do more.
        I will try to follow your advice.

  3. Hello!
    The results,
    BW: 59.5kg
    MVC: 119.5kg
    T80: 54s
    T60: 88s
    T50: 105s
    Was curious, where would this put me for sport climbing? Also, thanks for all the great training content!

    1. Hi James,

      Wow, your finger strength is outstanding – that puts you in a top-class bouldering league, that’s for sure! However, your aerobic endurance is relatively poor, so unless you’re trying short bouldery routes, you might have a hard time at anything harder than 7c+. It’s difficult to say because your results are typical for people who only do bouldering, not lead climbing.

      I hope this helps,

  4. Hi there,
    So it looks like I have extrimaly weak fingers( I am not surprised I started climbing 19 months ago) BW 72kg + 3kg
    And my T60 is 156sec.
    According to the calculator I should be bale to climb 6A+, I don’t do boulders but so far I claimed few 7a’s indoors and flashed one 7a in Greece ( non of them were slabbs) … So am confused about the results

    1. Hi Mateusz!
      Yes, your fingers seem pretty weak, but your T60 is decent. You may be able to make up for your weak fingers with other qualities, like flexibility, core strength, tactics, etc. You may contact me directly through the email if you’d like a more in-depth analysis.

  5. Really appreciate your tools. I wonder how much time under tension would be an appropriate amount of volume for someone training at their CF to improve it? 30min/week, 60min/week. Is there any research available indicating what a minimal effective dose would be for training at CF to improve it?

    1. Hello Yoni!
      Thank you for your message. It depends on how much endurance climbing you’re doing on a regular basis. However, during the pandemic, I used to do 2 hangboard endurance sessions per week with a TUT of about 25 minutes at CF per session, and my endurance improved significantly.

  6. Hi Jedrzej,

    Thanks for this resource. Should assist in understanding where to put my focus in training.

    It also would be good to see what you think about my current ‘stats’

    BW: 65kg
    MVC: 95kg

    T80%: 120s
    T60%: 250s
    T50%: 505s

    1. Hello Arlo!
      Thank you for your message. Your endurance looks pretty good, but your finger strength may be a bit low, so it might be worth investing time into some recruitment or hypertrophy protocols. It’s difficult to make solid recommendations without looking a bit deeper into your strengths and weaknesses. Don’t hesitate to email me if you’re interested in a thorough performance assessment.

  7. Hey! Thank you for the wonderful article, I wanted to ask for some clarification on the weight reduction. Is that weight supposed to be subtracted from bodyweight or from the total MVC-7 load? Thanks!

    1. Hello Alan!
      Yes, the weight reduction is supposed to be subtracted from your bodyweight. The calculator gives you the total load at which you should train. So if you weigh 70 kg and your CF is 50 kg, you need to unload 20 kg.

  8. Hi Jedrzej,

    Cheers for this resource. Based on the information available it seems to be a really interesting way of measuring endurance progress. It appears to me, based on available media published by lattice, that they have abandoned this method of estimating CF and now use a 4min continuous max effort 7×3 repeater protocol measuring the force time relationship with a force plate. Which testing methodology do you think is most relevant for assessing CF/aerobic endurance?

    It would also be great to hear what you think my current physical capacity is for sport climbing (i.e. what grade I could climb with perfect technique and tactics).

    My results are:
    BW: 80kg
    MVC: 125kg

    T80%: 56s
    T60%: 139s
    T45%: 525s

    1. Hi Roger!

      It took a while – sorry for that. Yes, I think Lattice use a force plate, but not everyone has access to a Tindeq or other similar tools. I never compared these methods directly, but I suppose they are equivalent. Your climbing level should be around 8a, I think.


  9. Hi JĘDRZEJ it’s been a while !
    This year, I struggle a bit to train properly, and I would love to hear about your opinion.
    Here are the results, where does it put me according to your data when it comes to sport climbing and bouldering?

    BW: 74kg
    MVC-7: 145kg = 196% BW
    T80%: 156,8% BW = 65s TUT
    T60%: 117,6% BW = 186s TUT
    T50%: 97,8% BW = 441s TUT

    1. Hi Karl-Jean!
      It’s always great to hear from you! In terms of strength and endurance, you’re practically where we left off last year. Your endurance profile tilted toward aerobic endurance at the cost of anaerobic endurance, which is a good sign, but the change is insignificant. It looks like you still have a lot of potential to build aerobic endurance, so I think you should focus on that – run laps on easy routes, like 7c, or if you don’t have regular access to a climbing wall, keep doing endurance repeaters. Try getting creative with them and address other finger positions, like the 3-finger drag.

      I’m not sure about your bouldering performance – on paper, you should be able to climb 8A+/8B, but if you don’t go bouldering regularly, it would probably not be easy.
      Please let me know if you need any more help!

      1. Actually yes,
        Can you tell me where does it put me in terms of route redpointing ?
        As always, I’m far stronger with 4 fingers drag. Around 10kg but the test needs to be done in a half crimp position 😉

        1. Hi Karl-Jean!
          Sorry for the late reply. As I mentioned in response to your comment, your assessment result would still be about 8c, at least for the half-crimp grip. I suppose if we tested for your extended grip, the result would sit comfortably in the 8c+ range. Your anaerobic endurance decreased since last year, but your Critical Force improved by about 2%, so you’re becoming an endurance climbing expert 🙂 How did that transition to your climbing? Have you improved your personal best?

    Thank you very much for your interesting work.
    just a question:
    when you talk about “make sure that you fail in under 1200 seconds”, do you mean total time , including 3 seconds of rest? or just the time hanging?

    1. Hi Alessandro!
      Thank you for the question. Yes, here in this case I meant the total time, so that would be 120 repetitions, which is 840 seconds TUT. In principle, it shouldn’t matter if it’s 1200 seconds or 1300 seconds, or even more, but we need to have some limit to satandardize the measurments. If you’re exceeding 150 seconds TUT on your 60% test, then it’s a safe bet to use 50% loads for your last tests.

  11. Samuel Peccoud

    Here are my results: I have climbed V12 and 5.13c.
    MVC-7 52kg BW=65kg on 20mm all in all 117kg

    1. Hello Samuel!

      Thank you for the results! They’re very interesting! Your V12 personal best result is above what is expected from your measurements in terms of pure finger strength for bouldering. However, when it comes to sport climbing, it looks like you could be ready to tackle 5.13d or even 5.14a. Maybe it’s a matter of what you’re currently focusing on. What do you think?

  12. Hi Jędrzej,

    I did both tests (MVC-7 and CF) today. I took 15-20 minutes between the MVC-7 and T80%, then maybe 90 minutes (thanks, life) until I did the T60% test, without doing a proper warmup, as I still felt warm. However, I’m not sure if my pulley system was truly taking the full amount of weight off or not; the pulleys I used are… not great, and angled slightly. I’m wondering if my results seem normal or if I should re-make my pulley system.
    BW: 73kg
    MVC-7: 90kg
    T80%: 40s
    T60%: 110s
    T50%: 133s

    Thanks for creating this, and for your help!

    1. Hi Yoav! Thanks for these results. Yout T80% and T60% tests look ok, but your T50% result is way too low – take a look at the attached plot. Your results should form an almost straight line, as in the corrected version, where I increased your T50% to 210 s (we’re talking about TUT, of course).

      critical force measurement results

      If you want to take accurate measurements, you should definitely invest in good pulleys and fix them properly. I also like to take the last test in a separate session, because after testing MVC-7, T80% and T60% the fatigue begins to accumulate and it shows in the last test.

      Have a great year!

  13. Hi, just some results from 6a climber after no training at all (RP 6b+ some years ago). This was my entry level test before training season.
    BW – 80kg
    MVC-7 – 92kg (20mm)
    T80% – 58s
    T60% – 131s
    T50% – 186s

    Both tests was taken different days.

    1. Hi Lukas!
      Thanks for the input! It’s surprising that you should climb only 6a/b, though? These results seem good enough for at least 7a? Did you give total exercise times or the Time Under Tension?

      1. Its TUT. There might be also “head” factor, fear of falling etc. in my climbing. Also climbing once a 2 weeks might be a problem. We will see in new season after classic endurance protocol (7/3). I will let you know about my training progress after 4 months and climbing grade in first few sessions outside.

        Thanks for this site, very helpfull!

  14. Hey JĘDRZEJ!
    Thank you for taking the time to answer all my questions!
    For question 4, yes it’s Time under Tension + duration of the last failed rep.
    Thanks again

    1. Hi Yann!
      Based on your finger strength and endurance, it looks like you’re a versatile climber and your sport redpoint level should be around 7c+ already. However, you need to address both strength and endurance if you want to break into higher grades. Fortunately, it looks like you still have some potential to work with. Please let me know if you need a more detailed analysis.

      1. Hello!
        Thank you!
        Yes your prediction is accurate, I’ve been onsighting 7a+ and 7b regularly and so projecting on 7c+ should be realistic.
        If you have the time of course I would like to have more details of the analysis.
        Also my goal is to not climb 4-5times a week outdoors so I should be including strenght trainings on the same days (early mornings), would you recommend doing a reduced amount of steve betchel ladders to improve strenght on the long term (twice a week)?

        Thanks a lot!


        1. I think you meant that your goal is to climb 4 – 5 days outdoors? Is that correct? In any case, that’s a tremendous amount of climbing in itself – I don’t think that adding additional hangboard sessions in the morning is a good idea. Unless you’re a professional athlete training with a coach.

          For an amateur climber, the optimum volume would be 3 – 4 training days per week. That could mean three days of climbing + one hangboard session or two days of climbing supplemented with two hangboard sessions.

          If done by the book (three hold positions per session), Bechtel’s Ladders are a surprisingly high-volume training routine, so if you’re going to pair that with a lot of climbing, you should indeed consider doing a reduced protocol.

        2. Adrian Huttenberger

          Back from from a climbing weekend with tired muscles, i did the test today.
          MVC7 132kg (66kg + 66kg)
          T80 27sec
          T60 175sec
          T50 255sec
          Guess the low T50 is much related to the climbs on the weekend.
          What to improve best? Apart from all 🙂

          1. Hi Adrian!

            Your T60 and T50 are fairly normal. However, it’s your T80 that’s way below average and may have been influenced by either the MVC-7 measurements (very good result by the way), or by your weekend climbing. I suggest that you retry the endurance tests, the T80 in particular when you’re fully recovered. I will then be able to answer your question.

  15. Hello!
    First of all, thanks a lot of the work and science your adding to the climbing community!
    1- What is the formula to calculate the critical force? and to reproduce the graph?
    2- To know the CF progress over 4 weeks for example, we should retest the MVC-7 right? Because I assume that progressing in CF % means endurance dominant macrocycle and loss of MVC-7, unless MVC-7 is maintained by doing 1 session a week of maxhangs or finger strenght work.
    3- If CF is really the maximum power we can maintain from the aerobic endurance system, we should be able to maintain it for much more than 20 min no?
    4- My results were :
    MVC-7: 115KG, MY WEIGHT IS 73KG
    T80: 83sec
    T60: 135 sec ( it was more like T57 because the friction of the carabineer used as a pulley was 50 % of the 3.75kg I wanted to take off of my weight…)
    T45: 355 sec
    I’ve been climbing for 2 years and want to get to the elite level: 8c-9a in sport climbing. I actually didn’t project anything outside so my max grade is 7c sport, 7b+ onsight and 7a flash bouldering.
    Thanks again

    1. Hi Yann, thank you for the comment! I will try to address your questions one by one:

      1- You can find the exact formula in the cited paper by the guys from Lattice training. If you go to Researchgate, they even have the excel spreadsheet with the formulas implemented to calculate the CF (link). To make the plots, you need to calculate the function for every time instant in excel.

      2- Yes, you need to retest MVC-7 eventually. I typically know mine because I combine MaxHangs with endurance Repeaters. I suppose it’s enough to do the full test every 12 weeks or so. If it’s a dominant endurance macrocycle, you’re indeed likely to lose some strength. I usually manage to progress both at the same time, albeit perhaps at a slower rate.

      3- In reality, at these loads, there is still a strong anaerobic component present. That’s why you can last only 20 minutes or less. Anyway, 20-minute CF is just a metric. You can have 5-minute CF, 10-minute CF, or 30-minute CF just as well. At 20 minutes, you’re striking a good balance between the anaerobic and aerobic components, which makes the test meaningful.

      4- The times you provided are Time Under Tension (number of reps*7 seconds + plus the duration of the last failed rep) or the Total exercise time? I want to make sure to give you the right level prediction.

      You’re perfectly right about the bigger edges. I actually believe that it’s better to train on a 30 mm edge unless you’re aiming for routes with small holds.

  16. I finally made it to this test and my results are :
    Mvc-7 : 118kg. (83kg+35kg)
    T80 = 63 sec
    T60 = 112sec
    T45 = 196sec

    So the calculator says i have pretty poor aerobic endurance wich is what i know is my weakest link…what would be a route grade with these stats?

    thx for that:)

    1. Hi Rene!

      Yes, it does look like your aerobic capacity is a bit on the low side, but your strength endurance is pretty ok. Maybe you didn’t recover from the previous tests? I always recommend to do the final test in a separate session.

      In any case, it looks like you could manage a technical, vertical 7b/+, but I think you might struggle with steeper routes, which give you little chance to rest, unless they’re short. If you need a more detailed analysis, you can always write me an email.

      1. Hi,i just remembered to have a look if you‘d answered and want to give some feedback.Your Analysis pretty on point,my main project is a vertical techy 7b+ ,on steeper terrain i‘m having a hard time goin over 7a/+.
        Thx and greets

  17. Hi i did that test,what i suppose to climb?
    My bodyweight is around 66-70 my MVC-7 is( BW 67+65kg)
    80% 78s
    50% 287s
    I also test my weighted pull up and my 1 rm is 55kg
    Great website,awesome test!

    1. Hi Alex!
      I’m glad you like the site, thanks! It looks like you’re a pretty strong climber. Your average redpoint level should be around 8b+, but could be more if the route fits your style. It seems that you still have a big potential to improve your endurance, so work on that and you’ll be golden!

  18. Hi Jędrzej
    First of all, great website, great idea to publish so much knowledge. I started last December with my serious hang board training, using the zlagboard. I did some research as well and find out that it is important to grow the force you bring in your training. I had the simple idea to do 7/3 repeaters always till I fall off. This I do 3 times per training day. First with 90% BW an 100%BW. If I could do more than 4-5 minutes I went to a higher BW percentage or from 20mm to a 12mm hold. This week I found your website and start too study it. Find out I have the similar data that you measure.
    Here are my results
    13 Dez 2020 : MVC7 max 150% BW, 90%BW 54sec, 100%BW 59sec, 120%BW,
    Mar 2021: MVC7max 164%BW, 90%BW 1200sec, 100% BW 660sec, 120%BW 290sec, 135% BW 90sec
    My hardest boulder 7a (not really a boulder guy)
    My hardest sport rout 7c+ (what I always do)
    Body 59kg 160cm

    May I get it wrong but on some part of the website your “100%” point is the MVC7, on other part is your ”100%” point the BW. From this point you start to calculate your curve. I guess the 100 BW should be the “100%” point. Because your bodyweight is the only “constant” what you “can’t” change. For example, if you start January at BW 60kg and your MVC7 is 80kg and CF 40kg and after a month max force training (February) your MVC7 will rise 10kg to 90kg. the CF is sill 40kg your endurance is now lower because you lift your “100%” point, but in reality your endurance is the same as a month ago.

    I would love to share my data’s with you, I use it all in google sheets.
    Cheers Daniel

    1. Hi Daniel!
      Thank you for your comment! It’s exciting to know that others are also exploring the idea of Critical Force! I think that the knowledge related to climbing training is growing fast in recent years within the community, and I believe that we can all contribute – keep it up!

      Regarding the CF measurements, it’s helpful to know both the relationship with your BW and with your MVC-7. Measuring CF against your BW is indeed what matters the most. However, measuring against your MVC-7 gives you valuable insight into your endurance profile.

      Coming back to our example, if you improve your MVC-7 is 80 kg, and your CF is 40 kg, then the ratio is 50%, which is an excellent result for a sport climber. At 133% MVC-7/BW, the climber is not very strong but can maintain a decent amount of strength for a very long time. Once the climber improves the MVC-7 to 90 kg and the CF stays at 40 kg, the MVC-7 becomes 150%, which is decent, and the CF becomes 44%. That’s still a pretty good result regarding endurance, but the climber’s profile changes to a more powerful athlete, capable of climbing cruxy and bouldery routes. For boulderers, it’s not uncommon to have the CF/MVC-7 relationship as low as 25 – 30%, but it could still be quite high relative to their BW if they’re strong.

      Training for sport climbing is tricky because you want to develop both strength and endurance, and the two often get in the way of each other. There are a lot of useful routines and training programs to develop concurrently. Some drills focus on the anaerobic system and help build strength (like 7/3 Repeaters at 80% MVC-7), and some target the aerobic system and may be detrimental to strength and contact force. It’s good to cycle through them and mix things up to avoid hitting a plateau.

      Sure, you can share your data with me through google sheets. I promise to take a look.

  19. Hi what is good time on 60%?
    My test is
    MVC-7 50kg BW=68kg on 17mm all in all 118kg

    1. Hi Marco!

      173% BW on a 17 mm edge? Wow, that’s very strong! However, endurance at 60% MVC-7 is a relative value, so it’s independent of the edge depth, and we can have a general analysis. An excellent result would be anything above 200 seconds TUT, so roughly 280 seconds T_total. Yours is decent (if we’re talking TUT). If you want a detailed analysis of your endurance profile, please let me know in an email.


  20. Great website.
    Is Critical Force another term for what some people call ‘anaerobic threshold’ or ‘lactate threshold’? (Although depending on who you’re talking to anaerobic threshold and lactate threshold are not necessarily synonymous)

    1. Hi Malcolm!
      Thanks a lot! As you wrote, there is some confusion around the nomenclature here. I addressed a similar question in an earlier comment. Please have a look here. According to the definitions in the Ph.D. thesis of Kerry McGawley, Critical Force lies above the lactic threshold and also above the MLSS.

  21. Hi Jędrzej,

    Thanks for your work and reply. My boulder grade is 8A and the lead is 8a+ you are right.

    I have noticed that roughly after 4 months block of training I get the best adaptations from strength/power training. No surprise as that is the biological adaptation period.

    Last couple of years I took too much time off from training in Summers and just climbed lots. Over the next year I will try not to have longer than 2 week performance period for roped climbing. Then back to base training. I hope I will be getting to the next level. It seems that when I was climbing whole summer, after I need to do a lot of catching up in the strength department.


  22. Hello there, you have created very interesting resource here. I have just finished 60% 9 weeks of my base training. Just to give extra info. I have another 6 weeks left of it.

    My results are:
    MVC7 109kg(Body weight 68kg + 41kg)
    T80: 90s
    T60: 139s
    T50: 349s it felt like it is not going to end then – boom.

    1. Hi!
      Thanks! I’m trying my best! Based on your results, I did a little rough assessment. Your level seems to be about 8a+, I think. It looks like you’re a versatile climber with a good balance between strength and endurance. I believe that in order to progress you need to develop both facets, but I think focusing more on finger strength should help you quickly reach the next level. Anyway, I hope this helps. If you need a training program, don’t hesitate to let me know!

  23. Hi jedrzej.
    I tried training at cf load and managed sets of 15 repeaters before having to stop to rest. I then repeated this until i managed to do all 120 reps, the equivalent of 840s TUT. Ive yet to do it for a decent time to see results, but it is very pumpy.
    Earlier you mentioned increasing cf from 45 to 50% mvc-7. To do this do you train at cf load until you can complete the 20min of repeaters with no rest, and then reduce the cf load slightly or recalculate the whole thing, ie mvc-7,t80,t60,t45, or does it involve strength gains and trying to improve your mvc-7? Thanks for your time.

  24. I have retested the hangs on a different well known 20mm rung with rest days between attempts. Mvc-7 =110kg
    T80 = 55s. T60 = 98s T45 = 230s.
    With the calculated adjustment, is that designed to be used when doing a repeater form of hangboarding?

    1. Hi Tom!
      Thanks for the input! Yes, the calculated adjustment tells you how much weight you need to subtract from your body weight to perform 7/3 Endurance Repeaters exactly at Critical Force load. Training at CF load was found to be the most efficient way of improving endurance. At this load, you should be theoretically able to perform 7/3 Endurance Repeaters for at least 20 minutes (840 seconds TUT), but in my experience, it takes climbers at least a couple of sessions before they reach the 20-minute mark. You may also divide the Endurance Repeaters into various patterns, like 1 minute of exercise and 1 minute of rest, and repeat this 10 – 20 times. I found this training to be extremely effective in improving both the aerobic and anaerobic endurance.

  25. I am definitely an outlier. I just took the rest times that were given in the example. I also didnt try the t45 just because i had the right weight for t50. I was curious that my times were much much lower than the given examples. I have been sportclimbing 20 years and never really bouldered, the hardest i climbed was 5.13c/14a and maybe a small amount in the 5.13 range. My max hang used to be +50kg but i tried a different training tool and managed to surpass it. Im continuing to use it to make sure it is what is increasing my finger strength.

  26. My results are as follows:
    Mvc-7 115kg. (60kg bw +55kg)
    T80 = 23s
    T60 = 91s
    T50 = 112s
    I used to just be able to hang 50kg at a push, but the 55kg felt ok, and i failed at the 6th second for 60kg.

    1. Hi Tom!
      Thanks for posting your results! First of all, I need to congratulate you on your finger strength! At 55 kg added weight, you probably boulder around V11 🙂
      I took a closer look at the results of your Critical Force test. My guess is that you did the 50% test because, at 45% MVC, you were able to make it past the 20-minute mark, am I right? I plotted your results on the graph below.
      The green line is a typical characteristic measured for one of the climbers who follow my training plan. The person is a typical route climber, with a pretty decent CF score of 49% MVC-7.
      The red squares are your measured results, and the blue line is the endurance curve calculated for your measured T50%. The T50% result lies below the curve, which means that the result is too low – it does not fit the theoretical model. It should be around 190 seconds.
      The gray dashed line is the endurance curve, calculated assuming that your T45% result was 840 seconds, which is equivalent to completing full 20 minutes of the exercise. The curve is almost the same as the curve plotted using T50%. This confirms that your measured T50% result is too low.
      The T60% measurement seems just right, and the T80% measurement seems also slightly low – it should be at least 40 seconds.
      To sum up, it looks like you were still tired from the MVC-7 measurements when you did the 80% measurement. Then you took a good rest and measured T60% correctly, and then you were tired again when doing T50%. Perhaps you measured after testing for T45% first.
      Still, it’s obvious that you are a very strong boulderer and sport climber. Based on your results, I believe that you should be able to project in the 8b – 8b+ range. But there is certainly room for improvement when it comes to your endurance. If you could increase your CF from 45% MVC-7 to 50% MVC-7, which is common among sport climbers, you could make big progress.
      Anyway, I hope this helped.

    1. Hi Tom! Thanks for the question! Every time you execute a hang that’s close to your limit, you burn phosphocreatine (PCr), which is used to produce ATP that fuels your muscles. It takes between 3 – 5 minutes to replenish the PCr stores after such a maximum effort completely. The longer you hang, the more you deplete PCr, and the longer you need to rest. So, for example, after a single MVC-7 attempt, it might be enough to rest 3 minutes, but after a 30-second hang, it possible that you would have to rest even 10 minutes to recover fully.
      To determine the MVC-7 with reasonable accuracy, you need to perform at least 3 – 4 hangs, and the fatigue might start to accumulate, even if you rest for 5 minutes after each hang. To stay on the safe side, I think it’s better to wait 10 – 15 minutes after the MVC-7 tests and before moving on to the 80% Repeaters.

      1. Hi Jędrzej, can you send a link, for example to my private email, to the Excel file with the formula for calculating CF from Lattice.
        I tried to find it on the website but it is not available.

        1. Hi Radek!

          The excel spreadsheet for calculating the CF was provided by the authors toether with their paper, you can download it here. Please let me know if you need any additional help with the file or algorithm.

          1. Thank you for the fast reponse.
            Your work / website gave me a lot to think about.
            Good job.
            Currently working on a CF.
            I will let you know what the results will be and I honestly admit that I’m curious myself: D

          2. Hi Radek!
            No problem, thank you for the positive feedback! Sure, please let me know about your CF test results – I love discussing data with other climbers!
            All the best for 2022!

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