Comparative Analysis of Two Grip Strength Training Protocols in Experienced Climbers

Alejandra Ruiz-López

Alejandro Padilla-Crespo

Álvaro Bustamante-Sánchez

Abstract

The aim of this study was to compare the effects of the traditional weighted dead-hang method (HIMA) and the effects of the active pull training method using a dynamometer (PIMA). Additionally, the strength difference between hands and its evolution after the proposed protocols was analyzed. Eleven climbers were randomly divided into a Control Group, CG (n = 5) 33.20 (8.7) years, 14.40 (0.548) climbing level IRCRA, and a Dinamo Group, DG (n = 6) 31.50 (6.56) years, 14.67 (1.366) IRCRA climbing level. CG followed HIMA protocol, while DG followed PIMA protocol. The common characteristics of both groups’ protocols were: 4 weeks duration, working on a 14 mm wooden strip, 3 series of dead-hang in the first week, 4 series in the second and third, and 5 series in the last week; 10 second efforts at 85% intensity, with 3-minute rests. An ANOVA analysis showed significant differences (p ≤ .05) after training protocols for both groups in all the variables studied: the peak force, the RFD200ms, the ST, and the MHT_14. No significant differences in strength were found between hands. Despite that, active pull with a dynamometer method reduced the differences in strength values between hands after training. Both grip strength methods (PIMA and HIMA), seem to be effective for improving key factors in climbing performance. Future research should analyze the influence of both training methods with larger samples and with higher level athletes, as well as with female samples.

Introduction

The popularity of climbing has continued growing since the debut of the sport at the Olympic Games (Michael et al., 2019). Despite many new climbing gyms being built over the last few years (Climbing Business Journal, 2023), the increasing number of athletes suggests that new climbing centers will be opened in the future. This interest from the general population has had an impact on the emergence of new elite athletes [International federation of sport climbing (IFSC], 2025] and an increase in the number of competitions. This has led the scientific world to also become interested in the discipline and, thus, a multitude of new studies are being carried out on this sport. 

The need for new research and training strategies has motivated the creation of new compact and portable devices that can be used to measure determining variables in climbing performance (Breen et al., 2023). Among these devices, force sensors stand out, such as the Progressor Tindeq (Tindeq, Trondheim Norway) (Labott et al., 2022) or Chronojump (Chronojump Boscosystem, Barcelona España) (Colomar et al., 2020; Moreno-Pérez et al., 2020). These new devices allow us to explore new forms of training based on quantitative data with high levels of validity and reliability. These methods contrast with traditional methodologies based on imprecise and subjective measurements, sometimes based on the athlete’s own perception (Michailov, 2014). Sensors measure grip strength, the key performance indicator in climbing  (Bergua et al., 2018; Consuegra, 2020; López-Rivera, 2014; López-Rivera & González-Badillo, 2012, 2019). Among the factors that explain the production of grip force in climbing, the maximum grip force and the Rate of Force Development (RFD) are considered the most adequate for measuring performance  (Consuegra, 2020). 

There are currently two main training methods to improve finger grip strength in climbers; the traditional dead-hang method conceived by Eva López (López-Rivera, 2014; López-Rivera & González-Badillo, 2012), which has been the most commonly used, and training with force sensors with active pull (Breen et al., 2023) which allows athletes to train unilaterally, even when not supporting body weight, and quantifying the load at all times. While the traditional dead-hang method involves a passive effort on the finger structures, the force sensor training method involves an active voluntary tensile effort. At the same time, the terms Holding Isometric Muscular Action (HIMA) and Push Isometric Muscular Action (PIMA) (Schaefer & Bittmann, 2017) describe two types of isometric contractions which we could relate to them respectively. In HIMA, the effort is passively supported, while in PIMA, although there is no movement, an active attempt is made to overcome resistance. Objective measures show that these two types of contractions are physiologically different (Dech et al., 2022; Oranchuk et al., 2024; Schaefer & Bittmann, 2021) which makes both types of training different.

Even though few studies look at the differences between both types of contractions, it has been suggested that HIMA could be used for injury prevention and rehabilitation, while PIMA could be a better option for prolonged activations and for stimulating agonist adaptations (Oranchuk et al., 2024). 

It is for these reasons that studying the differences between both methods in the sport performance framework seems particularly relevant. Additionally, climbing has traditionally used a grip strength training protocol following HIMA’s characteristics (traditional dead-hang method) which makes studying the differences between both HIMA and PIMA protocols more interesting for this sport. 

Therefore, the present study aimed to compare the effects of two different grip strength training methods (traditional weighted dead-hang as a HIMA, and force-sensing active pulls as a PIMA) on key markers of climbing performance: peak grip strength, RFD200ms, strength test (ST), and maximum dead-hang time (MHT_14).  The secondary aim was to analyze the differences in peak strength of each hand and to analyze the differences after training.

We hypothesized that both training methods would be effective in improving all the key factors in climbing performance studied (peak grip strength, RFD200ms, ST, and MHT_14); but grip strength training through the active method using the Chronojump device would present better results.

For our second aim, we hypothesized that the dynamometer training method, not being bilateral, would help reduce the differences in strength between hands after the training period.

Methods

Participants

Twenty climbers training twice per week participated in this study. The inclusion criteria are shown in Table 1. Finaly eleven climbers could finish the protocol. 

Table 1

Inclusion criteria defined

See Table

The sample was divided into two groups using stratified random sampling, based on self-determined climbing level. Main anthropometric and training characteristics are depicted in Table 2.  Every climber in our sample self-identified as either boulderer or lead climber. The IRCRA scale (Draper et al., 2015) was used to determine the level of climbing.

Table 2

Main characteristics of the sample and of each of the groups, mean and standard deviation

See Table

The study sessions took place on Monday and Wednesday afternoons at the same time, after which the participants attended their guided climbing sessions. They carried out identical sessions with the same climbing trainer, who focused the sessions on maximum strength work, in accordance with the objectives of the study.

The participants were informed of the procedure through an informative email and signed a consent form. The study was designed in compliance with the recommendations for clinical research of the Declaration of Helsinki and approved by the Ethics Committee of the University (Universidad Europea de Madrid, CIPI/23.105).

Participants were asked to:

• Attend all protocol training sessions. 
• Do not modify their sports habits related to climbing.
• Refrain from any intense physical activity 24h before the test sessions.

The study took place from May to July 2023.

Procedures

The intervention consisted of 4 weeks of training, with 2 training sessions per week. A familiarization session with the Chronojump device was also held, along with two evaluation sessions: one prior to and one after the training period. The warm-up was the same for both groups, and it is described in Table 3, in line with previous warm-ups used in research (Hermans et al., 2022; López-Rivera, 2014; Pérez, 2021).

Table 3

Warm-up prior to testing and training for both CG and DG

See Table

Two training protocols were used: maximum passive weighted dead-hang (HIMA) for the control group (CG); and unilateral active pulls with a force sensor (PIMA) for the dynamometer group (DG).

The common characteristics for both protocols were the following:
• A 14 mm thick wooden edge was used (Bergua et al., 2018; López-Rivera, 2014).
• The series were distributed as follows: 3 series in the first week, 4 series on the second and third weeks, and 5 series on the last week; with 3-min rests between series.
• Using a half-crimp or open-crimp type of grip (Bergua et al., 2018; Quaine & Vigouroux, 2004) was allowed throughout the study.

The specific characteristics of the HIMA protocol were the following: 
• An intensity of 85%  (Devise et al., 2022; López-Rivera, 2018; Pérez, 2021) calculated from the total weight (adding loaded weight + body weight) measured on the pre-assessment. 
• The series consisted of 10-second weighted dead-hang efforts with two hands, as described in Eva López’s maximum dead-hang method (López-Rivera, 2014; López-Rivera & González-Badillo, 2012).
• The grip and placement instructions described by Baláš et al. (2014); y Michailov et al. (2018) were followed.

The specific characteristics of the PIMA protocol were the following: 
• An intensity of 85%(Devise et al., 2022; López-Rivera, 2018; Pérez, 2021) calculated from the maximum newtons measured on the pre-assessment.
• The series consisted of 10-second pull efforts with unilateral maintained pull with dynamometer (Baláš et al., 2012; Rokowski et al., 2021).
• The grip and placement instructions described by Giles et al. (2021) were followed.

Both groups performed the same test for the pre- and post-assessment.

The order of the tests used for the evaluation was as follows: MHT_14, ST, and Maximal force peak and RFD. There were 5-min rests between every test.

Chalk was allowed during testing, and the edge was brushed between participants.

MHT_14: Maximum hanging time with both hands (Bergua et al., 2018) measured on a 14 mm thick wooden edge, until the climber lost contact of any finger with the hold, flexed their arms or hips, or extended their shoulders. Only one measurement was made (Hermans et al., 2022).

ST: Maximum added weight that was supported in dead-hang with both hands for 5 s (López-Rivera & González-Badillo, 2012, 2019) measured in a 14 mm thick wooden edge. The maximum weight supported was found through the minimum number of attempts, and rests of a minimum of 3 min were allowed between each attempt. ST was used to calculate the CG training loads, 85% of the maximum weight (adding loaded weight + body weight). 

Peak force and RFD with each hand: Measured with the dynamometer through a maximum pull (maximum voluntary contraction) (Levernier & Laffeye, 2019). After the sentence “pull as fast and hard as you can”  (Maffiuletti et al., 2016), and with a countdown, each participant recorded the maximum force value and RFD200ms they could. 3 attempts were made with 1 min of rest between them. From the average force values recorded, the loads for each hand were adjusted for the dynamometer group; calculating 85% of the newtons achieved and rounding to the nearest ten.

The maximum value of peak force (Hermans et al., 2022), the average of the 3 attempts, as well as the average of the RFDs (Maffiuletti et al., 2016) were recorded.

A 5-min rest period was allowed between each test and after warm-up.

The dynamometer used was Chronojump Boscosystem, which has been validated (de Blas et al., 2012) and even used to validate other instruments (Gaudet & Handrigan, 2020). The main characteristics of the instrument are shown in Table 4.

Table 4

Specifications of the force sensor used, Chronojump Boscosystem

See Table

Before using the device, it was calibrated, as described in the user manual (Foix & Padull, 2021).

The device software Chronojump Boscosystem version 2.3.0 was used for data collection and analysis. The software is free to download on its website.

To extract the values of maximum force and RFD200ms, the modeled function offered by the software was used, thus ensuring that the values varied less between each of the measurements (Pérez; 2021). To calculate the data, the initial point was used as the one at which the tangent of the maximum RFD intersected the x axis; and as a final point the one suggested by the application, which corresponds to the moment in which the maximum force is stable for 1 s. With this procedure, valid data is obtained in which the error is less than 5%.

Statistical Analysis 

The statistical analysis was performed with the data analysis package SPSS for Windows version 27.0; IBM, Armonk, NY, USA. A study of the sample was carried out through several descriptive statistics functions, such as the mean and standard deviation. 

Regarding the data obtained during the study (PRE and POST measurements of the dependent variables described in the previous section), the means obtained from all the measurements carried out were used, which were 3 in all cases except for the ST and MHT_14 tests, where  only a single measurement was used, the one with the highest values. The assumptions of normality were tested with the Shapiro-Wilk test.

Once the normality of each of the groups into which the sample was divided was confirmed, a two-factor mixed ANOVA test was used (Table 5); proposing time as an intra-participant factor (PRE and POST tests) and groups (CG and DG) as an inter-participant factor. With this test it was possible to compare the effect of the type of training, the difference between groups and the interaction between the type of training and the difference between groups. The effect size was assessed by the eta squared value (η²) as specified in previous research (Fritz et al., 2012). The effect size was determined based on the values recommended in the article by Cárdenas Castro & Arancibia Martini (2014); establishing a small effect η² =.01, a medium effect η² =.06, and a great effect η² =.14.

The Bonferroni post hoc test was performed to analyze the pairwise comparisons. The level of significance for all comparisons was set at p ≤ .05.

As a secondary analysis, the difference in strength between hands was studied through a T-test for paired samples. The evolution of these differences depending on the training method used was also studied, using the difference between the means of both hands.

Results 

The effect of the type of training, the difference between groups and the interaction between the type of training and the difference between groups is shown in Table 5.

Table 5

Results obtained in each of the interventions, PRE and POST, for each of the groups, CG and DG

See Table

Significant differences have been found between PRE and POST results for all variables (all tests) and for all groups. We observed a medium to large effect size in the MHT_14 tests (.242) and in the peak force measurement for the non-dominant hand (.081). Small to medium effect sizes were observed for the ST tests (.034), and for the peak force measurement for the dominant hand (.045). The effect sizes on the RFD measurements for the dominant and nondominant hand were very small (.001 and.008 respectively).  The comparison of the peak force and RFD of the dominant and non-dominant hand, for each training group and PRE and POST training is shown in Table 6. 

Table 6

Results obtained from the T test for related samples in the comparison of different variables depending on the hand used. Analysis carried out on the total sample and by groups

See Table

No significant differences were found in any of the analyses carried out regarding the differences between hands. Despite not finding significance, the difference between hands was 5.52% in the PRE tests and 3.90% in the POST tests, for the general sample. The dominant hand obtained better results in all tests, except in RFD PRE.

Discussion 

The main objective of the present study was to compare the effects of two different methods of grip strength training (traditional dead-hang training, HIMA, and active pull training with dynamometer, PIMA), on key performance indicators in climbing: peak grip strength, RFD, ST, and MHT_14.

The main hypothesis was fulfilled.  Both trainings, traditional dead-hang training and active pull training with a dynamometer; are effective in significantly improving all the key markers in climbing performance (peak grip strength, ST, MHT_14, and RFD). 

Results hint at better outcomes using the active pulling training methods but we should be cautious about the generalization of these results given the size of the sample used. We observed a medium to large effect size in the MHT_14 tests (0.242) and in the peak force measurements for the non-dominant hand (.081). A larger sample could provide more information which could follow the trend we see in these results, or not, elucidating this subject.

The secondary objective of this work was to analyze the differences in peak strength of each hand and see how these differences evolve with each of the training sessions. We hypothesized that grip strength training through the active method using the Chronojump device would present better results. This hypothesis was not fulfilled, since we did not find POST differences between training groups. 

Regarding the data obtained in the study, both training methods have been effective in improving the key markers of climbing performance studied in 4 weeks. As has been previously studied (Devise et al., 2022; Levernier & Laffeye, 2019; López-Rivera & González-Badillo, 2012) a 4-week exercise program is sufficient to observe improvements in grip strength. With regard of improvements in peak strength, the study by Levernier & Laffeye (2019) used one-handed dead-hang training; and observed improvements only with one type of grip and one of the hands. These improvements are smaller than those found in the present study. This may be due to the shorter duration of the dead-hangs (around 6 s), or a higher sample level (national and international climbers). 

In the study by Hermans et al. (2022) they used dead-hang training, and found significant differences in peak force, like the present study. Participants performed shorter dead-hang training (7 s) with shorter rests (3 s) within the same series. In this case the intervention was 10 weeks, with a sample level starting at score 11 on the IRCRA scale. Peak strength is measured in a pull-up position with arms flexed at 90º. In another study (Devise et al., 2022) a dynamometer was used for both testing and training, but the pull training was performed with two hands. If we look at the results obtained at the intensities closest to those of the present study (between 80% and 100%), significant improvements in peak force are observed, as in the present study. 

Regarding the improvements in RFD, in the study by Levernier & Laffeye (2019) and by Hermans et al. (2022) significant improvements are observed, in line with the results obtained. Hermans et al. (2022) analyzed maximum time in dead-hang with a larger edge, 23 mm, and significant improvements are found, as in the present investigation. In the study by Devise et al. (2022) resistance was measured with a different protocol than the one we used, making it difficult to compare their results with those obtained in our research.

Considering the levels of force between hands, in the present study no significant differences were found. Despite the lack of significant differences, the dominant hand was the one that presented higher levels for all tests except for the RFD PRE measurements. The dominant hand obtained an extra 5.52% of peak force in the PRE measurements, and 3.90% in the POST measurements, compared to the non-dominant hand. In the article by Vujic et al. (2021) no significant differences were found between the hands either, and these differences were less than 10%. In this case, higher levels of force were also recorded for the dominant hand. In the article by Levernier & Laffeye (2019), no significant differences were found between hands, and the right hand continued to record higher values in all grips except the extension grip.

In both studies, mean grip strength values higher than in the present study (320–380N) were recorded. In the study by Vujic et al. (2021), values of approximately 550–580N per hand were recorded, with a sample at levels 14–15 on the IRCRA scale, and in the study by Levernier and Laffeye (2019), values of 410–460N were recorded, with a sample at levels 24–26. Both studies obtained measurements using a manual dynamometer. These differences could be explained by the level differences between samples (Assmann et al., 2021), as well as the different ways of calculating force levels. It has been observed that these values vary depending on the surface and depth. (Bergua et al., 2018).

Regarding the secondary hypothesis of the work “dynamometer training, since it is not bilateral, helps to reduce the differences between hands”; the data seems to confirm the proposed hypothesis, but the results must be interpreted with caution. It is a superficial analysis in which only the differences in PRE and POST means between the two proposed interventions have been analyzed. Furthermore, the differences found are small.

In the study by Levernier & Laffeye (2019), a trend to increase the differences between hands with open grip after training was observed. In this case, the training followed is not bilateral but uses instead dead-hang, not active pull training. The results show no significant differences (less than a 10% difference) between hands in intermediate-high level climbers, although the right hand tends to present higher strength values. Regarding the proposed hypothesis, although the data from the present study suggest that active pull training with a non-bilateral dynamometer could help reduce differences between hands, the results are not conclusive, and more research would be necessary.

Conclusions

In response to the main objective, it is concluded that both grip strength training with active pulls and traditional dead-hang training seem to be effective methods to improve key factors in climbing performance in an intermediate level sample. Improvements in grip strength depend on both, the method (active pull or traditional dead-hang) and the established protocol (dead-hang time, intensity…).

In response to the secondary objective, it is concluded that the strength differences between the dominant and non-dominant hand decrease after applying non-bilateral active pulling training with a dynamometer. In the sample of the present study, as well as in the samples of the other studies analyzed, non-significant differences (less than 10%) are observed between the strength levels of each hand.

It should be noted that no studies have been found that compare the results of the two proposed protocols, and there are few articles in the scientific literature that propose interventions with exercises in climbing. Those that exist use very different training methods and systems, which makes it very complex to compare the results obtained across different articles.

As a practical application, climbing trainers could use this knowledge to improve their athletes’ grip strength in as little as 4 weeks.

Furthermore, this study suggests that using a force cell, specifically the Chronojump device, helps coaches quantify training load at all times, allowing customization of training for climbers to get the best out of their training time. 

Limitations of the study

One of the main limitations of the study was the small size of the sample. This prevented us from drawing generalizations from the results we obtained, such as the differences between hands. Another drawback was the relatively low climbing level of the participants, which may have affected the improvements observed. However, the difficulty of recruiting advanced climbers willing to undertake a 4-week experimental study should be taken into account. 

Additionally, more information related to the climbing habits of the participants could have been collected.

Future Research

Future lines of research should consider analyzing the two methods through larger samples of a higher climbing level to better explore these results, especially the effects of both methods in the differences between hands. Furthermore, some could focus on studying the differences through a larger female sample. Finally, comparing climbers from different disciplines like bouldering and sport climbing could be of interest. 

Funding

This study has been financed by the Universidad Europea de Madrid, through an internal competitive project with code CIPI/23.105 and 2024/UEM25.