Strength and endurance testing for efficient climbing training

This article is about the importance of finger and arm strength and endurance assessment in climbing. Simple but useful tests are presented along with a new comprehensive testing methodology that includes force-measuring technology and can contribute more to the optimization of training.

Climbing has reached an advanced stage of development. Any further development of climbing requires science-based training, technology and the use of reliable and valid exercise tests that evaluate and track performance-limiting factors in a precise and objective manner. Climbing training can be optimized by assessing key climbing abilities such as finger and arm strength and endurance. This can be done using simple tests such as finger and bent-arm hang tests which are adequately useful for assessing both strength and endurance and for predicting climbing performance. Climbing specific force-measuring devices (dynamometers) allow for different abilities to be assessed separately and a comprehensive evaluation of climbers’ physical condition. Climbing specific dynamometric tests can be designed to evaluate both physical capabilities (such as strength and muscle endurance) and the capacity of the physiological functions to deliver energy (e.g. local muscle aerobic and anaerobic capacity). Such details about our physical condition let us know exactly what type of training is most needed to maximize performance. This article is about a testing methodology for comprehensive performance evaluation that includes four dynamometric tests: a maximal strength test, continuous and intermittent muscle endurance tests, and RFD test. The muscle endurance tests are performed at intensities assigned as percentage of the maximal force. Each test measures various parameters that carry information on different abilities. The continuous test evaluates muscle endurance and local anaerobic capacity. The intermittent test evaluates muscle endurance and local aerobic capacity. The RFD test evaluates the ability of the finger flexor muscles to generate high force in a short time. This testing methodology is a new performance evaluation approach in sport and exercise science and practice and has been already used by many elite and recreational climbers.

Introduction

Sport climbing has reached an advanced stage of development and has been included in the Olympic Games. Due to the advanced stage of development, new climbing records will be set less frequently and climbing performance gains will become smaller and smaller (Fig 1). In addition, millions of recreational climbers enjoy sending at their limit and aim to improve their grades. All this places higher demands upon sport climbers’ preparation and surely requires science-based training.

Fig 1. Climbing records in the redpoint style.

The purpose of performance evaluation and monitoring

One important condition to train based on science is the application of sport-specific exercises and methods for which there is evidence that they maximally improve sport performance limiting factors with minimum loss of time and energy. However, performance evaluation and monitoring are needed in order for an athlete to fully realize his or her motor potential. The most important fitness indicator in climbing is our climbing ability level (i.e. our hardest current onsight and redpoint ascents). Although important, knowing our climbing ability level is not enough to optimize training. Changes in climbing ability provide information on the combined effect of various factors (biological, psychological, biomechanical, social, etc.). Therefore, onsight or redpoint grades cannot help us assess the state of the various performance limiting factors and identify strengths and weaknesses. Climbers and especially coaches can guess which ability is underdeveloped. However, informative tests should be used to estimate the exact levels of key performance factors in an objective manner as well as to provide details on the training state that even the most experienced coaches may not think of. This will provide objective feedback on the effect of the applied training. On the one hand, assessing different performance factors can show the level of our progress and whether the performance gains are satisfactory. On the other hand, it shows the athletes profile (i.e. strengths and weaknesses).

What determines the usefulness of exercise tests?

The tests for the assessment of climbers’ physical fitness would be useful in case they reflect climbing specificity and provide reliable, valid, objective and comprehensive feedback. Therefore, the tests should meet a number of conditions. Testing should be standardized (i.e. identical: climbing hold size; body, arm and finger positions; and workload parameters setting). This will make the tests more reliable. A test is reliable if a group of climbers repeats it and the results of the first and second trials are consistent. Results of reliable tests reflect the actual state of the measured abilities and can be compared between and within climbers over time. To be valid, the workload during tests for assessment of climbers should be climbing specific. For example, strength measurements done with standard hand dynamometers or cycle and treadmill ergometer tests do not assess climbing specific strength and work capacity, respectively. Such tests cannot serve for analysing the effectiveness of climbing training. At the same time, the efforts during testing should not be exactly the same as during lead or boulder climbing. The workload of a test should be assigned according to the ability it is intended to assess. For example, during a maximal strength test, the muscles should overcome or counteract maximal external resistance and the effort should be short. Aerobic muscle endurance tests should be longer than anaerobic muscle endurance tests. The use of sport-specific dynamometers is another important condition for assuring specificity and higher reliability, validity and objectivity of the measurements. Such devices can also provide comprehensive feedback because they measure various mechanical parameters.

Climbing specific strength and endurance tests

Finger and arm strength and endurance are key climbing performance factors. That is why this article is focused on tests that assess these abilities. Muscle strength and endurance can be assessed through two types of tests: 1) simple tests such as finger and bent-arm hang tests, 2) and climbing-specific dynamometric tests. The advantages of the simple tests are that every climber can easily perform them and the necessary equipment is affordable (e.g. climbing holds or fingerboards). Their disadvantage is that they cannot provide all necessary information for training plans.

Simple tests

The finger and bent-arm hangs measure both muscle endurance and strength. The hanging time can be used to estimate your progress and adequately predict your climbing ability. For example, on a 3 cm rung intermediate climbers hang around 20-40 s and elite climbers hang around 90-110 s. A disadvantage of the simple tests is that they cannot assess muscle endurance and strength separately. The hanging time depends predominantly on muscle endurance but is also influenced by strength and body mass. A longer hanging time does not necessarily mean better endurance. For example, the finger hang scores of two climbers with similar finger endurance and body mass will differ if one of the climbers has stronger fingers. The intensity at which the stronger climber’s forearms would act would be lower and this climber’s hanging time would be longer.

Fig 2. The finger and bent-arm hang tests are simple, easy to organize and can satisfactorily predict climbing performance.

You can use the reference values in the tables below to compare your finger and bent-arm hang test scores with the results of other climbers.

Finger hang (men and women)

Fig 3. Reference values for evaluating climbers’ finger hang scores – men and women.

Bent-arm hang (men)

Fig 4. Reference values for evaluating climbers’ bent-arm hang scores – men.

Bent-arm hang (women)

Fig 5. Reference values for evaluating climbers’ bent-arm hang scores – women.

Dynamometric tests

The climbing specific dynamometric tests require force-measuring devices (Fig 6) that are more expensive than fingerboards. The big advantage is that these tests allow comprehensive evaluation of climbers’ physical condition. The most useful force-measuring devices provide real time feedback on the applied force and allow assigning test parameters (i.e. muscle contraction intensity, work and rest intervals etc.). Test parameters can be set in a way that will place each tested climber in a desired working regime that will activate similar energy delivery pathways. This allows different abilities to be assessed separately. Work capacity depends on physiological functions and energy delivery pathways (with or without using oxygen). Dynamometric tests can be designed in a way to assess not only the levels of strength or endurance but also muscle aerobic or anaerobic capacity. Using tests that allow both functional diagnostics and assessment of physical qualities are much more helpful for optimizing training. They let us know exactly what type of training to focus on to improve our performance significantly. This is not possible if we analyze our hanging test scores and climbing performance only. For example, a climber that copes well with long routes may think that his aerobic endurance is very good. However, without performing dynamometric strength and endurance tests, one can’t say that for sure as he could manage to climb on long routes because of compensating with much higher strength and anaerobic endurance levels.

Fig 6. The Climbro Smart Hangboard force-measuring device providing a real-time feedback of the applied force.

A methodology for comprehensive climbing performance evaluation

How to design strength and endurance tests to get comprehensive feedback about the physical condition? We have presented our approach in this paragraph. We have taken into account the scientific evidence on climbing physiology and performance to develop and validate a combination of dynamometric tests that evaluate key climbing abilities and are part of a new methodology for functional diagnostics on a local muscle level. This is done by measuring physiological parameters such as muscle oxygenation as well as calculating the relative energy system contribution during the performance of the tests.

The testing methodology comprises four tests: a maximal finger strength test, continuous and intermittent finger endurance tests and test for assessing the rate of force development (RFD). These tests should be performed when fully recovered from training or other type of fatigue and after a good warm-up. In all tests, one should attempt to reach one’s maximum as when making a serious attempt to send a project on the rocks or when participating in a climbing competition. Otherwise, the results might be unrealistically lower and useless for performance diagnostics and training optimization.

All tests are performed while standing facing a climbing force measuring device on which a 23 mm rounded edge is mounted. One hand at a time should be used to apply force on the hold. The hold should be loaded by flexing the knees which lowers the body. At the same time, the fingers should act to resist body weight. The arm should be slightly bent and the shoulder engaged to avoid injuries. In other words, this technique is a one-arm finger hang with the feet on the ground (Fig 7).

Fig 7. One-arm hang technique used to apply force on a climbing specific force measuring device.

Maximal strength test

This test evaluates climbing specific strength. It is undertaken by applying the maximal force that the fingers can produce on a 23 mm rounded edge, one-arm at a time. The test consists of two 5 s long attempts for each hand to pull as hard as possible. The rest between attempts should be 1 – 3 min long. The highest force value from the two attempts is used to determine the maximal strength of each hand. Climbers who can hang with one-arm from the 23 mm hold with feet off the ground (climbers with finger force that is more than their body weight) should use additional weight that will make them stay on the ground and apply their maximum. Otherwise, the dynamometer will measure body mass instead of maximal strength. The test score is presented in kilograms and as a percentage of body mass (e.g. Fmax = 65 kg = 93% body mass).

Continuous endurance test

This test evaluates anaerobic capacity of the forearm muscles. The test is undertaken by loading the 23 mm hold continuously applying 60% of the maximal force. The target force should be maintained for as long as possible. The test ends automatically when the force drops more than 5%. An intensity of 60% of maximal force is activating significantly the forearm muscles. Such an intensive muscle contraction makes the muscles stiff and they compress the blood vessels, which restricts oxygen delivery. All this makes the effort predominantly anaerobic (Fig 8). The anaerobic energy is delivered by two systems: glycolytic and alactic. The anaerobic glycolytic system delivers energy without oxygen using carbohydrates, which leads to lactic acid accumulation. The anaerobic alactic system delivers energy without oxygen using fuel from high-energy phosphate molecules, which does not lead to lactic acid accumulation. For the forearm muscles, the continuous test anaerobic energy was slightly more glycolytic than alactic. The continuous test performance indicators are the time spent in the target zone, force-time integral (force multiplied by time) and force-time integral relative to body mass. Each indicator carries different information. The force-time integral is a good indicator of anaerobic endurance (both glycolytic and alactic). The time in the target zone depends more on the anaerobic glycolytic capacity. The force-time integral relative to body mass correlates significantly with climbing performance.

Fig 8. Relative energy system contribution during the continuous and intermittent muscle endurance tests. This figure is based on a study that collected metabolic data during the performance of the tests.

Intermittent endurance test

This test evaluates aerobic capacity of the forearm muscles. During this test, 8 s work phases at an intensity of 60% of the maximal force are alternated by 2 s rests for as long as possible. This work and rest ratio is chosen because observations of lead climbing competitions proved its specificity. During the 2 s rests, the climber should shake the tested hand down near the body quickly. It has been shown that intermittent testing with shaking rather than without shaking better reflects aerobic capacity. The 2 s rests induce reperfusion and enhanced muscle re-oxygenation in climbers with better forearm aerobic capacity, which leads to a much longer effort compared to the continuous test. That is why this test is predominantly aerobic (Fig 8). The intermittent test performance indicators are the number of repetitions, the time spent in the target zone, force-time integral and force-time integral relative to body mass (Fig 9). The number of repetitions and the time in the target zone are pure measures of aerobic capacity. The force-time integral depends on the aerobic capacity and to a small extent to the anaerobic capacity. The force-time integral related to body mass strongly correlates with climbing performance.

Fig 9. Results of an intermittent test. Up: evaluation scores (climbing grades). Down: quantitative test scores (time in target zone, average force and muscle performance expressed as a force-time integral value).

RFD test

This test evaluates the ability of the finger flexor muscles to generate high force in a limited time frame. This ability is required for example during the take-off when making a dyno and during grabbing the next hold (especially when it is a small one). During the RFD test climbers should pull the 23 mm hold as fast and as hard as possible while abruptly bending their knees. Similarly, as in the maximal strength test, climbers who can hang on one arm from the 23 mm hold with feet off the ground should hold a weight with the other hand that is not performing the test. The fingers should be placed on the hold and no pressure should be applied until the effort is initiated (which should be done after the start signal). The indicators provided by the RFD test are: RFD at 200 ms; time to reach 25%, 50%, 75% and 100% body weight; and time to reach 50% and 100% of the maximal force for each hand (Fig 10).

Fig 10. Results of an RFD test. Up: evaluation scores (climbing grades). Down: quantitative test scores (RFD at 200 ms; time to reach 25%, 50%, 75% and 100% body mass; peak force; peak force expressed as % Fmax; time to reach 50% and 100% peak force).

Analysis of test results

After completing the tests, we will have several quantitative values that characterize our athlete profile. They can be used to monitor the progress of each ability. However, the quantitative test scores do not allow for comparison between the levels of the different abilities assessed through the tests. This is because the strength and endurance measurement units are different and interpretation of how good or bad the results are is not possible without referring to the scores of other climbers. Therefore, the raw scores should be converted to qualitative evaluation scores (e.g. poor, fair, good, very good and excellent). The evaluation scores of the current methodology are based on the relationships between the test scores and lead climbing and bouldering performance. In particular, we convert the raw test scores to French grades. This way we enable anonymous comparison of one’s own scores with the results of hundreds of climbers at different ability levels. On the one hand, the grades allow for identification of strengths and weaknesses (Fig 11). On the other hand, the grades show how difficult a route you could possibly climb with your current strength and endurance levels. If you climb more than predicted, you probably compensate with a better technique, mental skills or other abilities. If you climb less than predicted, you probably have not pushed yourself to fully realize your physical potential on a route or you are less technically and mentally experienced than the average climber at your climbing ability level.

Fig 11. Evaluation scores. These scores enable: 1) comparison of one’s own results with those of other climbers, 2) estimation of strengths and weaknesses), and 3) progress monitoring.

Successful training management is a cycle of several important steps: 1) initial analysis of athlete’s profile and his or her potential for improvement, 2) setting training goals and predicting the highest possible future level of key sport performance factors, 3) planning training accordingly, 4) application of the training plan, and 5) getting feedback on how effective the training has been. Evaluating and tracking the improvement of sport performance limiting factors starts and closes the training management cycle and helps optimize the next training plan. The testing methodology presented in this article is specially developed for maximizing the effect of climbing training. It is supporting the Czech and Bulgarian National Climbing teams as well as many other elite and recreational climbers over the world. Climbing specific strength and endurance measuring devices and tests for comprehensive performance evaluation are very needed nowadays for further development of sport climbing.

Fig 12. Peter Ivanov from the Bulgarian Climbing Team is а two-time European youth bouldering champion and winner of the European bouldering youth cup. For years, the coaches of the Bulgarian and Czech climbing teams have optimized their training plans using the present testing methodology. (photo by Vassil Kirov)

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