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.

Handedness, Bilateral, and Interdigit Strength Asymmetries in Male Climbers

PURPOSE

To determine whether there are bilateral and interdigit differences in the maximal force production of experienced climbers and whether these differences are mediated by ability level or preferred style of climbing.

METHODS

Thirty-six male climbers (age 30 [9.4] y) took part in a single-session trial to test their maximal force production on both hands. The tests included a one-arm maximal isometric finger flexor strength test (MIFS) and a one-arm individual MIFS. Bilateral differences were analyzed by strongest hand (defined as the hand that produced the highest MIFS value) and dominance (defined as the writing hand).

RESULTS

A pairwise t test found that MIFS was significantly greater for the strongest hand (mean difference = 4.1%, 95% CI, -0.052 to 0.029, P < .001), with handedness explaining 89% of the variation. A 2-way mixed-model analysis of variance determined that there were no interactions between preferred style (bouldering or sport climbing) and MIFS or between ability level (advanced or elite) and MIFS.

CONCLUSIONS

Climbers have significant finger flexor strength bilateral asymmetries between their strongest and weakest hand. Moreover, when dominance is controlled, this difference in strength is present, with the dominant hand producing more force. Neither preferred style of climbing nor the ability level of the climbers could explain these asymmetries. As such, practitioners should consider regularly monitoring unilateral strength, aiming to minimize the likelihood of large bilateral asymmetry occurring.

Comparing low volume of blood flow restricted to high-intensity resistance training of the finger flexors to maintain climbing-specific strength and endurance: a crossover study

Introduction

It is acknowledged that training during recovery periods after injury involves reducing both volume and intensity, often resulting in losses of sport-specific fitness. Therefore, this study aimed to compare the effects of high-intensity training (HIT) and low-intensity training with blood flow restriction (LIT + BFR) of the finger flexors in order to preserve climbing-specific strength and endurance.

Methods

In a crossover design, thirteen intermediate climbers completed two 5-week periods of isometric finger flexors training on a hangboard. The trainings consisted of ten LIT + BFR (30% of max) or HIT sessions (60% of max without BFR) and were undertaken in a randomized order. The training session consisted of 6 unilateral sets of 1 min intermittent hanging at a 7:3 work relief ratio for both hands. Maximal voluntary contraction (MVC), force impulse from the 4 min all out test (W), critical force (CF) and force impulse above the critical force (W') of the finger flexors were assessed before, after the first, and after the second training period, using a climbing-specific dynamometer. Forearm muscle oxidative capacity was estimated from an occlusion test using near-infrared spectroscopy at the same time points.

Results

Both training methods led to maintaining strength and endurance indicators, however, no interaction (P > 0.05) was found between the training methods for any strength or endurance variable. A significant increase (P = 0.002) was found for W, primarily driven by the HIT group (pretest-25078 ± 7584 N.s, post-test-27327 ± 8051 N.s, P = 0.012, Cohen's d = 0.29). There were no significant (P > 0.05) pre- post-test changes for MVC (HIT: Cohen's d = 0.13; LIT + BFR: Cohen's d = -0.10), CF (HIT: Cohen's d = 0.36; LIT + BFR = 0.05), W` (HIT: Cohen's d = -0.03, LIT + BFR = 0.12), and forearm muscle oxidative capacity (HIT: Cohen's d = -0.23; LIT + BFR: Cohen's d = -0.07).

Conclusions

Low volume of BFR and HIT led to similar results, maintaining climbing-specific strength and endurance in lower grade and intermediate climbers. It appears that using BFR training may be an alternative approach after finger injury as low mechanical impact occurs during training.

Metabolic demands of slacklining in less and more advanced slackliners

HIGHLIGHTS

Balancing on a slackline is metabolically demanding and slackline training is suitable not only to develop neuromuscular control but also to meet cardiovascular fitness demands.Improved postural control demonstrated by skilled slackliners reduces by ∼25% metabolic cost of balancing tasks on a slackline when compared to less skilled counterparts.Falls during slacklining increase the metabolic demands of the activity. Three falls per minute during walking on a slackline increase the oxygen uptake by ∼50%.

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.

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

PURPOSE

Sport climbing requires high-intensity finger flexor contractions, along with a substantial whole-body systemic oxygen uptake ([Formula: see text]O₂) contribution. Although fatigue is often localised to the finger flexors, the role of systemic ̇[Formula: see text]O₂ and local aerobic mechanisms in climbing performance remains unclear. As such, the primary purpose of this study was to determine systemic and local muscle oxygen responses during both isolated finger flexion and incremental exhaustive whole-body climbing tests. The secondary aim was to determine the relationship of isolated and whole-body climbing endurance tests to climbing ability.

METHODS

Twenty-two male sport climbers completed a series of isometric sustained and intermittent forearm flexor contractions, and an exhaustive climbing test with progressive steepening of the wall angle on a motorised climbing ergometer. Systemic [Formula: see text]O₂ and flexor digitorum profundus oxygen saturation (StO₂) were recorded using portable metabolic analyser and near-infra red spectroscopy, respectively.

RESULTS

Muscle oxygenation breakpoint (MOB) was identifiable during an incremental exhaustive climbing test with progressive increases in angle (82 ± 8% and 88 ± 8% [Formula: see text]O₂ and heart rate climbing peak). The peak angle from whole-body treadwall test and impulse from isolated hangboard endurance tests were interrelated (R² = 0.58-0.64). Peak climbing angle together with mean [Formula: see text]O₂ and StO₂ from submaximal climbing explained 83% of variance in self-reported climbing ability.

CONCLUSIONS

Both systemic and muscle oxygen kinetics determine climbing-specific endurance. Exhaustive climbing and isolated finger flexion endurance tests are interrelated and suitable to assess climbing-specific endurance. An exhaustive climbing test with progressive wall angle allows determination of the MOB.

The Effect of Traditional and Stabilization-Oriented Exercises on Deep Stabilization System Function in Elite Futsal Players

Background: This study aimed to compare the effect of traditional and stability-oriented strength exercises on trunk stability and deep stabilization system (DSS) activation in elite futsal players. Methods: Twenty elite futsal players (21–34 years, 180 ± 13 cm, 79 ± 15 kg) were randomly divided into a group that performed stability-oriented exercises and a group that performed traditional strength exercises. Both interventions lasted for 10 weeks and included 25 strength training sessions. Main outcome measures: The DSS pretest and posttest included the diaphragm test, trunk flexion test, back extension test, hip flexion test, intraabdominal pressure test, and a side plank test on a 1–5 point scale. Results: Both groups had similar initial test results, where the stability-oriented exercise group had significantly improved intraabdominal pressure test (p = 0.004, by lower quartile rate), trunk flexion (p = 0.036, by 0.5 grade in median), and side plank (p = 0.002, by 1 grade in median) in posttest results. Traditional exercise did not change the results of any of the included DSS function tests. Conclusions: Stabilization-oriented exercises effectively activate the functions of the DSS and should be prioritized over traditional strength exercises in injury prevention training programs. The use of stabilization-oriented exercises might prevent injury and overloading in elite futsal players.

New Zealand blackcurrant extract enhances muscle oxygenation during repeated intermittent forearm muscle contractions in advanced and elite rock climbers

Anthocyanin-rich New Zealand blackcurrant (NZBC) may improve forearm muscle oxygenation and enhance performance in high-level rock climbers. As such, using a double-blind, randomised, cross-over design study, twelve participants performed an oxidative capacity assessment, and two successive exhaustive exercise trials (submaximal forearm muscle contractions at 60% of their maximal volitional contraction). Each visit was conducted following 7-days intake of 600 mg·day^-1 NZBC extract or placebo. Oxidative capacity was estimated by calculating the oxygen half time recovery using near infrared spectroscopy. Time to exhaustion (s), impulse (kg·s), and minimum tissue saturation index (min-TSI %) were assessed during both the exercise trials. Muscle oxidative capacity was greater with NZBC (mean difference [MD] = 5.3 s, 95% confidence intervals [95% CI] = 0.4-10.2 s; p = 0.036; Cohen's d = 0.94). During the exercise trials, there was an interaction for min-TSI % (time x condition, p = 0.046; ηp2= 0.372), which indicated a greater level of oxygen extraction during trial two with NZBC extract (MD = 9%, 95% CI = 2-15%) compared to the placebo (MD = 2%, 95% CI = 1-7%). There was a decrease in time to exhaustion (p <0.001, ηp2 = 0.693) and impulse (p = 0.001, ηp2 = 0.672) in exercise trial two, with no effect of NZBC extract. In high-level rock climbers 7-days NZBC extract improves forearm muscle oxygenation with no effect on isolated forearm muscle performance.

Effect of Height on Perceived Exertion and Physiological Responses for Climbers of Differing Ability Levels

Purpose

The purpose of this study was to examine differences in perceived exertion (RPE) and physiological responses for climbers of different abilities completing an identical route low and high above the ground.

Materials and Methods

Forty-two male (N = 18) and female (N = 24) sport climbers divided into three groups, lower-grade (N = 14), intermediate (N = 14), and advanced climbers (N = 14), completed two visits to a climbing gym, separated by 7 days. In a random order, the climbers completed a close-to-the-ground ascent (treadwall) and climb to height (climbing gym). Immediately after the test, climbers provided their RPE (6–20). Indirect calorimetry was used to assess physiological response during the ascent and recovery.

Results

The mean (±standard deviation) RPE was higher for lower-grade climbers when ascending the route on the wall (RPE = 12 ± 1) when compared to the treadwall route (RPE = 11 ± 1, P = 0.040; d = 0.41). For all ability groups, the physiological response was higher on the climbing gym wall as opposed to the treadwall: ventilation (P = 0.003, η_p² = 0.199), heart rate (HR) (P = 0.005, η_p² = 0.189), energy cost (EC) (P = 0.000, η_p² = 0.501). The RPE demonstrated a moderate relationship with physiological variables (R² = 0.14 to R² = 0.45).

Conclusion

Climbing to height induced a greater metabolic stress than climbing at a low height (treadwall) and led to higher RPE for lower-grade climbers. In this study, RPE appeared to be a good proxy measure of the physiological demands for advanced climbers but not for intermediate and lower-grade climbers. Therefore, using RPE in climbing with less experienced athletes may perhaps overestimate actual exercise intensity and should be interpreted carefully.

Males benefit more from cold water immersion during repeated handgrip contractions than females despite similar oxygen kinetics

The purpose of the present study was to assess the effect of different water immersion temperatures on handgrip performance and haemodynamic changes in the forearm flexors of males and females. Twenty-nine rock-climbers performed three repeated intermittent handgrip contractions to failure with 20 min recovery on three separate laboratory visits. For each visit, a randomly assigned recovery strategy was applied: cold water immersion (CWI) at 8 °C (CW8), 15 °C (CW15) or passive recovery (PAS). While handgrip performance significantly decreased in the subsequent trials for the PAS (p < 0.05), there was a significant increase in time to failure for the second and third trial for CW15 and in the second trial for CW8; males having greater performance improvement (44%) after CW15 than females (26%). The results indicate that CW15 was a more tolerable and effective recovery strategy than CW8 and the same CWI protocol may lead to different recovery in males and females.

Reliability and Validity of Finger Strength and Endurance Measurements in Rock Climbing

PURPOSE

An advanced system for the assessment of climbing-specific performance was developed and used to: (a) investigate the effect of arm fixation (AF) on construct validity evidence and reliability of climbing-specific finger-strength measurement; (b) assess reliability of finger-strength and endurance measurements; and (c) evaluate the relationship between finger flexor all-out test scores and climbing ability.

METHODS

To determine the effect of AF, 22 male climbers performed 2 maximal strength and all-out tests with AF (shoulder and elbow flexed at 90°) and without AF (shoulder flexed at 180° and elbow fully extended). To determine reliability, 9 male climbers completed 2 maximal strength tests with and without AF and an all-out and intermittent test without AF.

RESULTS

The maximal strength test without AF more strongly determined climbing ability than the test with AF (r² = .48 and r² = .42 for sport climbing; r² = .66 and r² = .42 for bouldering, respectively). Force and time variables were highly reliable; the rate of force development and fatigue index had moderate and low reliability. The maximal strength test with AF provided slightly higher reliability than without AF (intraclass correlation coefficient [ICC] = 0.94, ICC = 0.88, respectively). However, smaller maximal forces were achieved during AF (484 ± 112 N) than without AF (546 ± 132 N). All-out test average force had sufficiently high reliability (ICC = 0.92) and a relationship to sport climbing (r² = .42) and bouldering ability (r² = .58).

CONCLUSION

Finger strength and endurance measurements provided sufficient construct validity evidence and high reliability for time and force parameters. Arm fixation provides more reliable results; however, the position without AF is recommended as it is more related to climbing ability.

The Reliability of Parkour Skills Assessment

The aim of the study was to determine the reliability of parkour skills assessment in field conditions. Twenty young men completed three trials of a parkour obstacle course on two separate days. The tested group consisted of 10 beginners (age 16 ± 1 years, body mass = 65 ± 12 kg, height = 177 ± 7 cm) and 10 advanced traceurs (age 18 ± 2 years, body mass = 68 ± 14 kg, height = 178 ± 6 cm). The performance was video-recorded and subsequently analyzed by three raters (total score 0–45). Median and percentiles were used to characterize results from all sessions by all raters. Inter-rater, intra-session and inter-session reliability were assessed using Krippendorff’s α for ordinal data. The Mann-Whitney test was used to assess the differences between beginners and advanced traceurs. Advanced traceurs obtained a total score from 41 to 44 whilst beginners achieved 27 to 33 points. Krippendorff’s α for total score ranged from 0.910 to 0.916 between raters, 0.828 to 0.874 between trials, and from 0.839 to 0.924 between days. The proposed parkour course differentiated two different ability levels and the skills assessment demonstrated excellent reliability between raters, trials, and days.

Differences in forearm strength, endurance, and hemodynamic kinetics between male boulderers and lead rock climbers

This study examined differences in the oxygenation kinetics and strength and endurance characteristics of boulderers and lead sport climbers. Using near infrared spectroscopy, 13-boulderers, 10-lead climbers, and 10-controls completed assessments of oxidative capacity index and muscle oxygen consumption (m⩒O₂) in the flexor digitorum profundus (FDP), and extensor digitorum communis (EDC). Additionally, forearm strength (maximal volitional contraction MVC), endurance (force-time integral FTI at 40% MVC), and forearm volume (FAV and ΔFAV) was assessed. MVC was significantly greater in boulderers compared to lead climbers (mean difference = 9.6, 95% CI 5.2-14 kg). FDP and EDC oxidative capacity indexes were significantly greater (p = .041 and .013, respectively) in lead climbers and boulderers compared to controls (mean difference = -1.166, 95% CI (-3.264 to 0.931 s) and mean difference = -1.120, 95% CI (-3.316 to 1.075 s), respectively) with no differences between climbing disciplines. Climbers had a significantly greater FTI compared to controls (mean difference = 2205, 95% CI= 1114-3296 and mean difference = 1716, 95% CI = 553-2880, respectively) but not between disciplines. There were no significant group differences in ΔFAV or m⩒O₂. The greater MVC in boulderers may be due to neural adaptation and not hypertrophy. A greater oxidative capacity index in both climbing groups suggests that irrespective of climbing discipline, trainers, coaches, and practitioners should consider forearm specific aerobic training to aid performance.

Effects of minimal dose of strength training on running performance in female recreational runners

BACKGROUND

The purpose of this study was to analyze the extent to which minimal dose strength training would elicit improvements in running performance for female recreational runners.

METHODS

Forty-one female recreational runners were randomly assigned to one of three groups (endurance running [E] N.=14; combined endurance running and strength training program once [ES30] N.=14 and twice a week [ES60] N.=13, respectively). During the 10-week training program, the E group completed 3 hours of continuous endurance running per week; ES30 completed 2 ½ hours of continuous endurance running and 1 x 30 min of strength training per week, while ES60 group completed 2 hours of continuous endurance running and 2x30 min of strength training per week. Body composition, standing long jump, running economy and maximal endurance performance characteristics were assessed using ANOVA with repeated measures.

RESULTS

Both concurrent training groups significantly improved their maximum treadmill test performance, ES30 from 168.5±43.2 to 191.3±43.8 s, ES60 from 203.1±47.8 to 249.3±49.7 s. No significant differences were detected between and within groups for body composition, power output (standing long jump), exercise economy and V̇O2max.

CONCLUSIONS

The findings suggest strength training in volume 30 min or 1 hour per week was sufficient to increase maximal running performance, however it did not lead to improvement in running economy or aerobic capacity.

The effect of potential fall distance on hormonal response in rock climbing

The aim of this study was to examine the effect of alterations in potential lead fall distance on the hormonal responses of rock climbers. Nine advanced female climbers completed two routes while clipping all (PRO-all) or half (PRO-½) of the fixed points of protection. Venous blood samples were analysed for total catecholamines, noradrenaline (norepinephrine), adrenaline (epinephrine), dopamine, lactate, cortisol and serotonin. Differences between the two conditions pre, immediately post and 15 min post climbing were assessed using a 2 × 3 repeated measures ANOVA. All hormones and blood lactate concentrations increased significantly (P < 0.05) immediately post climb, except for cortisol. Peak cortisol concentrations did not occur until 15 min post ascent. Further, significant interactions between climbing and clipping conditions were found for total catecholamines (890% of basal concentration in PRO-½ vs. 568% in PRO-all), noradrenaline (794% vs. 532%) and dopamine (500% vs. 210%). There were no significant interactions for adrenaline (1920% vs. 1045%), serotonin (150% vs. 127%) or lactate (329% vs. 279%). The study showed a greater catecholamine response with an increase in potential lead fall distance. The most pronounced increases seen in catecholamine concentration were reported for dopamine and noradrenaline.

Effect of paddle grip on segmental fluid distribution and injuries occurrence in elite slalom paddlers

AIM

The aim of this current study was to assess the segmental fluid distribution, grip strength and injury occurrence in elite slalom kayakers and canoeists.

METHODS

Ninety three world-cup competitors (72 males; 21 females) took part in the study. Impedance analysis assessed segmental fluid asymmetry and a questionnaire evaluated injury occurrence during the three previous years. The effect of paddle grip (loose/fixed hand in kayakers, lower/upper hand in canoeists), morphological dominance (dominant/non-dominant) and discipline (canoe/kayak) was evaluated by repeated measures ANOVA.

RESULTS

The findings indicated a significant effect of paddle grip in male canoeists on morphological asymmetry in the upper limbs (arm of lower paddle hand, mean fluid distribution 3.17, s=0.47 litres; arm of upper paddle hand mean fluid distribution 3.08, s=0.45 litres; P<0.001, ωp2=0.32). Significant morphological asymmetry was found also in kayakers but the effect of paddle grip was not substantial. Grip strength was not related to paddle grip. Paddlers with arm morphological asymmetry reported upper limb injury occurrence in 60% of cases, which was 3 times more than in paddlers without arm morphological asymmetry.

CONCLUSION

As upper-limb asymmetry was directly associated with paddle grip in male canoeists, canoe paddling may lead to higher bilateral morphological asymmetry and therefore, injury occurrence.