Isolated finger flexor vs. exhaustive whole-body climbing tests? How to assess endurance in sport climbers?

Importance of shoulder girdle and finger flexor muscle endurance in advanced male climbers

Aim

This study aimed to: (a) assess the relationships between climbing performance and finger and shoulder girdle muscle endurance; and (b) provide evidence on the validity of the specialized exercise tests used for the purpose.

Materials and methods

28 male sport climbers (climbing ability 23 ± 2.43 IRCRA scale) performed four tests muscle failure, including two-finger hang tests (using 2.5 and 4 cm holds) and two variants of pull-up exercises (classical pull-ups and a combination of dynamic and isometric actions - the so-called Edlinger). Climbing performance and test results were subjected to correlation, taxonomic and regression analysis.

Results

The correlations between the results from all tests and climbing performance were notably strong ( r between 0.54 and 0.61) and statistically significant ( p < 0.05 ). The taxonomic analysis indicated that the two variants of each test type reflect two different latent variables 2.5 cm and 4 cm finger hang durations were highly correlated ( r = 0.76 , p < 0.01 ). A similar correlation was found between the results from the pull-up tests ( r = 0.72 , p < 0.01 ). Thus, the finger hang and pull-up test results were determined to a high extent (43% and 49%, respectively) by factors that cannot be assessed when only one test of each type is used. The regression model of the two-finger tests allowed individual endurance profiles to be assessed.

Conclusions

The muscular endurance of the elbow flexors and shoulder girdle muscles predicts climbing performance within the specific sport level studied to a comparable degree as finger flexor endurance.The use of two variants of a test intended to assess one physical ability provided important details on a climber's fitness.

Muscle Oximetry in Sports Science: An Updated Systematic Review

BACKGROUND

In the last 5 years since our last systematic review, a significant number of articles have been published on the technical aspects of muscle near-infrared spectroscopy (NIRS), the interpretation of the signals and the benefits of using the NIRS technique to measure the physiological status of muscles and to determine the workload of working muscles.

OBJECTIVES

Considering the consistent number of studies on the application of muscle oximetry in sports science published over the last 5 years, the objectives of this updated systematic review were to highlight the applications of muscle oximetry in the assessment of skeletal muscle oxidative performance in sports activities and to emphasize how this technology has been applied to exercise and training over the last 5 years. In addition, some recent instrumental developments will be briefly summarized.

METHODS

Preferred Reporting Items for Systematic Reviews guidelines were followed in a systematic fashion to search, appraise and synthesize existing literature on this topic. Electronic databases such as Scopus, MEDLINE/PubMed and SPORTDiscus were searched from March 2017 up to March 2023. Potential inclusions were screened against eligibility criteria relating to recreationally trained to elite athletes, with or without training programmes, who must have assessed physiological variables monitored by commercial oximeters or NIRS instrumentation.

RESULTS

Of the identified records, 191 studies regrouping 3435 participants, met the eligibility criteria. This systematic review highlighted a number of key findings in 37 domains of sport activities. Overall, NIRS information can be used as a meaningful marker of skeletal muscle oxidative capacity and can become one of the primary monitoring tools in practice in conjunction with, or in comparison with, heart rate or mechanical power indices in diverse exercise contexts and across different types of training and interventions.

CONCLUSIONS

Although the feasibility and success of the use of muscle oximetry in sports science is well documented, there is still a need for further instrumental development to overcome current instrumental limitations. Longitudinal studies are urgently needed to strengthen the benefits of using muscle oximetry in sports science.

Muscle Cooling Before and in the Middle of a Session: There Are Benefits on Subsequent Localized Endurance Performance in a Warm Environment

ABSTRACT

Baláš, J, Kodejška, J, Procházková, A, Knap, R, and Tufano, JJ. Muscle cooling before and in the middle of a session: there are benefits on subsequent localized endurance performance in a warm environment. J Strength Cond Res 38(3): 533-539, 2024-Localized cold-water immersion (CWI) has been shown to facilitate recovery in the middle of a session of exhaustive repeated forearm contractions. However, it has been suggested that these benefits may be attributed to "precooling" the muscle before an activity, as opposed to cooling a previously overheated muscle. Therefore, this study aimed to determine how precooling and mid-cooling affects localized repeated muscular endurance performance in a warm environment. Nineteen subjects completed a familiarization session and 3 laboratory visits, each including 2 exhaustive climbing trials separated by 20 minutes of recovery: PRE CWI (CWI, trial 1; passive sitting [PAS], trial 2); MID CWI (PAS, trial 1; CWI, trial 2); and CONTROL (PAS, trial 1; PAS, trial 2). Climbing trial 1 in PRE CWI was 32 seconds longer than in CONTROL ( p = 0.013; d = 0.46) and 47 seconds longer than in MID CWI ( p = 0.001; d = 0.81). The time of climbing trial 2 after PAS (PRE CWI and CONTROL) was very similar (312 vs. 319 seconds) irrespective of the first trial condition. However, the time of the second trial in MID CWI was 43 seconds longer than in PRE CWI ( p < 0.001; d = 0.63) and 50 seconds longer than in CONTROL ( p < 0.001; d = 0.69). In warm environments, muscle precooling and mid-cooling can prolong localized endurance performance during climbing. However, the effectiveness of mid-cooling may not be as a "recovery strategy" but as a "precooling" strategy to decrease muscle temperature before subsequent performance, delaying the onset of localized heat-induced neuromuscular fatigue.

The Connection Between Resistance Training, Climbing Performance, and Injury Prevention

BACKGROUND

Climbing is an intricate sport composed of various disciplines, holds, styles, distances between holds, and levels of difficulty. In highly skilled climbers the potential for further strength-specific adaptations to increase performance may be marginal in elite climbers. With an eye on the upcoming 2024 Paris Olympics, more climbers are trying to maximize performance and improve training strategies. The relationships between muscular strength and climbing performance, as well as the role of strength in injury prevention, remain to be fully elucidated. This narrative review seeks to discuss the current literature regarding the effect of resistance training in improving maximal strength, muscle hypertrophy, muscular power, and local muscular endurance on climbing performance, and as a strategy to prevent injuries.

MAIN BODY

Since sport climbing requires exerting forces against gravity to maintain grip and move the body along the route, it is generally accepted that a climber`s absolute and relative muscular strength are important for climbing performance. Performance characteristics of forearm flexor muscles (hang-time on ledge, force output, rate of force development, and oxidative capacity) discriminate between climbing performance level, climbing styles, and between climbers and non-climbers. Strength of the hand and wrist flexors, shoulders and upper limbs has gained much attention in the scientific literature, and it has been suggested that both general and specific strength training should be part of a climber`s training program. Furthermore, the ability to generate sub-maximal force in different work-rest ratios has proved useful, in examining finger flexor endurance capacity while trying to mimic real-world climbing demands. Importantly, fingers and shoulders are the most frequent injury locations in climbing. Due to the high mechanical stress and load on the finger flexors, fingerboard and campus board training should be limited in lower-graded climbers. Coaches should address, acknowledge, and screen for amenorrhea and disordered eating in climbers.

CONCLUSION

Structured low-volume high-resistance training, twice per week hanging from small ledges or a fingerboard, is a feasible approach for climbers. The current injury prevention training aims to increase the level of performance through building tolerance to performance-relevant load exposure and promoting this approach in the climbing field.

Wearable and Non-Invasive Sensors for Rock Climbing Applications: Science-Based Training and Performance Optimization

Rock climbing has evolved from a method for alpine mountaineering into a popular recreational activity and competitive sport. Advances in safety equipment and the rapid growth of indoor climbing facilities has enabled climbers to focus on the physical and technical movements needed to elevate performance. Through improved training methods, climbers can now achieve ascents of extreme difficulty. A critical aspect to further improve performance is the ability to continuously measure body movement and physiologic responses while ascending the climbing wall. However, traditional measurement devices (e.g., dynamometer) limit data collection during climbing. Advances in wearable and non-invasive sensor technologies have enabled new applications for climbing. This paper presents an overview and critical analysis of the scientific literature on sensors used during climbing. We focus on the several highlighted sensors with the ability to provide continuous measurements during climbing. These selected sensors consist of five main types (body movement, respiration, heart activity, eye gazing, skeletal muscle characterization) that demonstrate their capabilities and potential climbing applications. This review will facilitate the selection of these types of sensors in support of climbing training and strategies.

Physical performance testing in climbing-A systematic review

Due to the increasing popularity of climbing, the corresponding diagnostics are gaining in importance for both science and practice. This review aims to give an overview of the quality of different diagnostic testing- and measurement methods for performance, strength, endurance, and flexibility in climbing. A systematic literature search for studies including quantitative methods and tests for measuring different forms of strength, endurance, flexibility, or performance in climbing and bouldering was conducted on PubMed and SPORT Discus. Studies and abstracts were included if they a) worked with a representative sample of human boulderers and/or climbers, b) included detailed information on at least one test, and c) were randomized-controlled-, cohort-, cross-over-, intervention-, or case studies. 156 studies were included into the review. Data regarding subject characteristics, as well as the implementation and quality of all relevant tests were extracted from the studies. Tests with similar exercises were grouped and the information on a) measured value, b) unit, c) subject characteristics (sex and ability level), and d) quality criteria (objectivity, reliability, validity) were bundled and displayed in standardized tables. In total, 63 different tests were identified, of which some comprised different ways of implementation. This clearly shows that there are no uniform or standard procedures in climbing diagnostics, for tests on strength, endurance or flexibility. Furthermore, only few studies report data on test quality and detailed information on sample characteristics. This not only makes it difficult to compare test results, but at the same time makes it impossible to give precise test recommendations. Nevertheless, this overview of the current state of research contributes to the creation of more uniform test batteries in the future.

Time Management Strategies of Rock Climbers in World Cup Bouldering Finals

Competitive rock climbing recently made its Olympic debut, but minimal published research exists regarding training and competition strategies. Time management strategies define the structured approach climbers take in bouldering competitions to successfully obtain a “top” or a “zone” hold. During finals rounds of the International Federation of Sport Climbing bouldering competitions, climbers are allotted 240 s to complete a boulder. Variables influencing a climber’s time management strategies include their work-to-rest intervals, and the frequency of their attempts or rests. Video analysis of International Federation of Sport Climbing competitions was used to collect time management strategy data of professional climbers. Fifty-six boulders (28 female and 28 male boulders) over the 2019 International Federation of Sport Climbing season were analyzed. Time management strategies variables were compared between slab/slab-like and non-slab bouldering styles using generalized estimating equations with significance set to p < 0.05. Additionally, we determined trends in success rates for various styles of boulders. There were no differences in the number of attempts taken per boulder between slab/slab-like and non-slab boulders (3.7 ± 2.3 and 3.8 ± 2.4, p = 0.97), but climbers spent more time actively climbing on slab/slab-like (92 ± 36 s) compared to non-slab boulders (65 ± 26 s, p < 0.001). Trends in the success rate suggest climbers who take more than 6 attempts on any boulder style are unsuccessful. The results of this study provide practical information that can be used by coaches and athletes to guide training and competition strategy.

Validity and Reliability of a Commercial Force Sensor for the Measurement of Upper Body Strength in Sport Climbing

Recreational and professional climbing is gaining popularity. Thus, valid and reliable infield strength monitoring and testing devices are required. This study aims at assessing the validity as well as within- and between-day reliability of two climbing-specific hanging positions for assessing the maximum force with a new force measurement device. Therefore, 25 experienced male (n = 16) and female (n = 9) climbers (age: 25.5 ± 4.2 years, height: 176.0 ± 9.9 cm, weight: 69.7 ± 14.5 kg, body composition: 11.8 ± 5.7% body fat, climbing level: 17.5 ± 3.9 International Rock Climbing Research Association scale) were randomly tested with climbing-specific hang board strength tests (one-handed rung pulling and one-handed bent arm lock-off at 90°). The Tindeq, a load cell-based sensor for assessing different force-related variables, was employed together with a force plate (Kistler Quattro Jump) during both conditions. Data analysis revealed excellent validity for assessment with Tindeq: The intra-class correlation coefficient (ICC) was 0.99 (both positions), while the standard error of the measurement (SEM), coefficient of variation (CV), and limits of agreement (LoA) showed low values. Within day reliability for the assessment with Tindeq was excellent: rung pulling showed an ICC of 0.90 and arm lock-off an ICC of 0.98; between-day reliability was excellent as well: rung pulling indicated an ICC of 0.95 and arm lock-off an ICC of 0.98. Other reliability indicators such as SEM, CV, and LoA were low. The Tindeq progressor can be applied for the cross-sectional and longitudinal climbing strength assessment as this device can detect training-induced changes reliably.

Effects of Forearm Compression Sleeves on Muscle Hemodynamics and Muscular Strength and Endurance Parameters in Sports Climbing: A Randomized, Controlled Crossover Trial

Purpose: Wearing compression garments is a commonly used intervention in sports to improve performance and facilitate recovery. Some evidence supports the use of forearm compression to improve muscle tissue oxygenation and enhance sports climbing performance. However, evidence is lacking for an effect of compression garments on hand grip strength and specific sports climbing performance. The purpose of this study was to evaluate the immediate effects of forearm compression sleeves on muscular strength and endurance of finger flexor muscles in sports climbers.

Materials and Methods: This randomized crossover study included 24 sports climbers who performed one familiarization trial and three subsequent test trials while wearing compression forearm sleeves (COMP), non-compressive placebo forearm sleeves (PLAC), or no forearm sleeves (CON). Test trials consisted of three performance measurements (intermittent hand grip strength and endurance measurements, finger hang, and lap climbing) at intervals of at least 48 h in a randomized order. Muscle oxygenation during hand grip and finger hang measurements was assessed by near-infrared spectroscopy. The maximum blood lactate level, rate of perceived exertion, and forearm muscle pain were also determined directly after the lap climbing trials.

Results: COMP resulted in higher changes in oxy[heme] and tissue oxygen saturation (StO₂) during the deoxygenation (oxy[heme]: COMP –10.7 ± 5.4, PLAC –6.7 ± 4.3, CON –6.9 ± 5.0 [μmol]; p = 0.014, η_p² = 0.263; StO₂: COMP –4.0 ± 2.2, PLAC –3.0 ± 1.4, CON –2.8 ± 1.8 [%]; p = 0.049, η_p² = 0.194) and reoxygenation (oxy [heme]: COMP 10.2 ± 5.3, PLAC 6.0 ± 4.1, CON 6.3 ± 4.9 [μmol]; p = 0.011, η_p² = 0.274; StO₂: COMP 3.5 ± 1.9, PLAC 2.4 ± 1.2, CON 2.3 ± 1.9 [%]; p = 0.028, η_p² = 0.225) phases of hand grip measurements, whereas total [heme] concentrations were not affected. No differences were detected between the conditions for the parameters of peak force and fatigue index in the hand grip, time to failure and hemodynamics in the finger hang, or performance-related parameters in the lap climbing measurements (p ≤ 0.05).

Conclusions: Forearm compression sleeves did not enhance hand grip strength and endurance, sports climbing performance parameters, physiological responses, or perceptual measures. However, they did result in slightly more pronounced changes of oxy [heme] and StO₂ in the deoxygenation and reoxygenation phases during the hand grip strength and endurance measurements.

Optimization of an Intermittent Finger Endurance Test for Climbers Regarding Gender and Deviation in Force and Pulling Time

Performance diagnostics of finger strength is very relevant in climbing. The aim of our study was to find modalities for an intermittent finger flexor muscle endurance test that optimize the correlation of test performance with lead climbing performance. Twenty-seven female and 25 male climbers pulled with 60% MVC and a work-to-rest ratio of 7:2 s on a fingerboard until fatigue. The highest correlations, R = 0.429, were found for women when 9% deviation in the required force and 1 s deviation in the required pulling time was tolerated. For men, the optimum was reached with the same time deviation and a force deviation of 6%, R = 0.691. Together with maximum finger strength the repetitions explained 31.5% of the variance of climbing ability in women and 46.3% in men. Consequences from our results are to tolerate at least 7% force deviation for women and 5% for men and to terminate the finger endurance test quickly after the force falls below the threshold.

Tests and Procedures for Measuring Endurance, Strength, and Power in Climbing—A Mini-Review

The interest in climbing is rapidly growing among professional and recreational athletes and will for the first time be included in the 2021 Tokyo Olympics. The sport has also gained increased scientific attention in the past decades. Still, recommendations for testing procedures to predict climbing performance and measure training effects are limited. Therefore, the aim of this mini-review is to provide an overview of the climbing-specific tests, procedures and outcomes used to examine climbing performance. The available literature presents a variety of tests and procedures. While the reliability of some tests has been examined, measures of validity are scarce, especially for climbing-specific endurance tests. Moreover, considering the possible combinations of climbing performance levels, disciplines, and tests, substantial gaps in the literature exist. Vague descriptions of the participants in many studies (e.g., not specifying preferred discipline, performance level, experience, and regular climbing and training volume) further limit the current knowledge and challenge comparisons across studies. Regarding contraction types, dynamic strength- and power-tests are underrepresented in the literature compared to isometric tests. Studies exploring and reporting the validity and reliability of climbing-specific tests are warranted, and researchers should strive to provide a detailed description of the study populations in future research.

Comparison of Different Approaches Estimating Skeletal Muscle Oxygen Consumption Using Continuous-Wave Near-Infrared Spectroscopy at a Submaximal Contraction Level—A Comparative Study

Continuous-wave near-infrared spectroscopy (CW-NIRS) is a method used to non-invasively estimate skeletal muscle oxygen consumption (mVO2). Three different signals are provided by CW-NIRS devices: (1) oxygenated hemoglobin (O2Hb); (2) deoxygenated hemoglobin (HHb); and (3) tissue saturation index (TSI). Typically, the signal’s slope is interpreted with respect to high or low mVO2 during a muscle action. What signal (or combination of signals) is used for slope interpretation differs according to what approach is used, and there are several published in literature. It is unclear if resulting mVO2 estimates can be used interchangeably. Hence, this work aimed to compare five commonly used approaches on the same set of CW-NIRS data regarding their agreement in estimated mVO2. A controlled, lab-based study setting was used for this experiment. Data are based on isometric dorsiflexion contractions of 15 subjects at 30% of voluntary maximum torque, at two different ankle angles. CW-NIRS was placed on the m. tibialis anterior and blood flow was occluded. The approaches for mVO2 estimation included calculations based on (1) TSI, (2) the difference between O2Hb and HHb (Hbdiff), (3) the mean of slopes from O2Hb and HHb (Hbmean), (4) the HHb signal, and (5) the O2Hb signal. Linear regression modelling was used to calculate respective slopes (r2 > 0.99). Repeated measures ANOVA identified significant differences between the approaches (p < 0.001, ω2 = 0.258). Post-hoc tests revealed that only TSI vs. Hbmean and Hbdiff vs. HHb gave comparable results (p > 0.271). In addition, Bland–Altman plots showed good accuracy (mean bias ~2%) but low precision (±20%) between the comparisons. Thus, the different approaches to estimate mVO2 cannot be used interchangeably. The results from different studies using different approaches should be compared with caution.

The Estimation of Critical Angle in Climbing as a Measure of Maximal Metabolic Steady State

Purpose: Sport climbing is a technical, self-paced sport, and the workload is highly variable and mainly localized to the forearm flexors. It has not proved effective to control intensity using measures typical of other sports, such as gas exchange thresholds, heart rate, or blood lactate. Therefore, the purposes of the study were to (1) determine the possibility of applying the mathematical model of critical power to the estimation of a critical angle (CA) as a measure of maximal metabolic steady state in climbing and (2) to compare this intensity with the muscle oxygenation breakpoint (MOB) determined during an exhaustive climbing task.

Materials and Methods: Twenty-seven sport climbers undertook three to five exhaustive ascents on a motorized treadwall at differing angles to estimate CA, and one exhaustive climbing test with a progressive increase in angle to determine MOB, assessed using near-infrared spectroscopy (NIRS).

Results: Model fit for estimated CA was very high (R² = 0.99; SEE = 1.1°). The mean peak angle during incremental test was −17 ± 5°, and CA from exhaustive trials was found at −2.5 ± 3.8°. Nine climbers performing the ascent 2° under CA were able to sustain the task for 20 min with perceived exertion at 12.1 ± 1.9 (RPE). However, climbing 2° above CA led to task failure after 15.9 ± 3.0 min with RPE = 16.4 ± 1.9. When MOB was plotted against estimated CA, good agreement was stated (ICC = 0.80, SEM = 1.5°).

Conclusion: Climbers, coaches, and researchers may use a predefined route with three to five different wall angles to estimate CA as an analog of critical power to determine a maximal metabolic steady state in climbing. Moreover, a climbing test with progressive increases in wall angle using MOB also appears to provide a valid estimate of CA.