Introduction
The load profile describes the total external and internal demands that athletes experience during a bouldering competition. It represents the result of a comprehensive load analysis, which forms a key part of competition diagnostics.
The goal of such an analysis is to determine both the specific structure of external load and the individual physiological responses of the athletes, providing the foundation for evidence-based training design that reflects the requirements of competition.
But what is known about the load profile in competitive bouldering? To answer this question, we performed a literature review, including only studies that analyzed the load profile in actual competitions or in simulations that were equal or similar to the format of current international bouldering competitions.
External Load Structure
Bouldering competitions are characterized by a two-folded intermittent load structure, shaped by the official IFSC competition format. On one level, athletes alternate between climbing periods and rest periods as they move from one boulder to the next. On another level, each climbing period itself consists of repeated short attempts interspersed with brief pauses, resulting in an additional intra-boulder alternation between effort and recovery. This dual pattern creates a complex load profile that combines high-intensity efforts with both short and long recovery intervals.
In qualification and semifinal rounds, athletes compete in a rotation format. Each competitor faces five boulders (four in semifinals) and has five minutes to attempt each boulder, followed by five minutes of rest before moving on. Within these five-minute windows, athletes can make multiple attempts, resting self-paced between efforts. This structure results in rapid alternation between brief bouts of maximal bouldering and short rest periods between attempts, superimposed on the longer inter-boulder rest phases defined by the rotation schedule.
In the final round, the format changes to an athlete-by-athlete system, where climbers attempt each boulder sequentially while the others wait in isolation. Each finalist has four minutes to complete a problem but then rests for an extended period—usually 20–25 minutes—while the remaining athletes take their turns.
To analyze this external load structure, Winkler et al. (2022) examined video recordings from two international competitions — the 2018 IFSC Bouldering World Cup and the 2018 IFSC World Championships: Within each climbing period, athletes, on average, performed 3–4 attempts per boulder, each lasting approximately 27 seconds, separated by 32 seconds of rest. The total climbing time per boulder averaged about 70 seconds, while rest intervals between boulders were around 8 minutes in qualification & semifinals and up to 22 minutes in finals.
A different approach was undertaken by Künzell et al. (2021), who examined how elite climbers adapt their strategy following unsuccessful attempts. The authors found that the likelihood of success increases when athletes change their beta (men: 23 % vs. 5 %; women: 22 % vs. 4 %), and that climbers who changed strategies more often occupied higher positions in the world ranking. Thus,elite climbers tend to modify their beta more frequently and display pronounced creative problem-solving, adapting effectively to route-specific challenges.
Although no standardized classification system for boulder types exists, consistent trends emerge in the literature. Augste et al. (2021) analyzed the semifinals and finals 2017 & 018 Bouldering World Cups, to determine the frequency distribution and success rates of different boulder types. Their classification included five main types—dynamo, volume, crimp, slab, and mantle—with dynamic problems representing the largest share (≈ 52 %), followed by volume (≈ 25 %), crimp (≈ 10 %), slab (≈ 7 %), and mantle (≈ 6 %). The top-20 ranked athletes were significantly more successful than lower-ranked climbers, particularly in dynamic boulders, indicating that performance level strongly influences success in highly coordinative tasks. Consequently, the authors emphasized that optimizing dynamic movement execution should be a primary training focus for elite boulderers.
Complementary findings from Ochoa-Marcos (2024), who analyzed semifinal and final rounds of international competitions 2019 – 2023. The study categorized problems according to wall inclination (slap), intensity, coordination, and complexity demands. Complexity was defined as demanding movements due to the size of the holds, physical demand, or reading difficulty, regardless of jumps or coordination. Among female athletes, the most frequent boulder type was intensity-focused (43 %), with dominant difficulties in coordination (45 %) and complexity (42 %). Coordinative demands were distributed across hand coordination (40 %), hand–foot coordination (35 %), dynamic jumps (16 %), and foot coordination (8 %). Open-hand grips (63 %) were used more often than closed grips (37 %). Among male athletes, intensity (39 %), coordination (32 %), and slab problems (27 %) were most common in semifinals, while complexity (41 %) and coordination (44 %) dominated finals. The coordinative profile was similar—hand coordination (44 %), hand–foot coordination (27 %), jumps (19 %), and foot coordination (8 %). Open-hand grips were used predominately (64 %) and the boulders had a slight rightward movement orientation (60 %).
Internal Load Structure
While the external load describes the observable structure of performance, the internal load reflects the athlete’s physiological response to that external demand. Studies analyzing heart rate, oxygen uptake, and blood lactate concentration provide valuable insights into the cardiovascular and metabolic stress induced by competitive bouldering.
La Torre et al. (2009) were among the first to measure these responses during simulated bouldering competitions, while Callendar et al. (2021) later extended this work using laboratory and field-based analyses more closely aligned with current IFSC competition formats. Both studies consistently demonstrate that bouldering, despite its brief climbing phases, elicits high cardiovascular activation and substantial anaerobic energy contributions.
Peak heart rates during competition reach approximately 93 ± 8 % of the age-predicted HR_max, indicating near-maximal cardiovascular strain. Time-motion data show that athletes spend about 25.9 % of total climbing time in the 70–85 % HR_max zone and 12 % above 86 % HR_max. Heart rate increases progressively across repeated attempts within the same boulder, reflecting the accumulating load of successive efforts. Across rounds, female athletes exhibit a gradual rise in heart rate, while male athletes maintain relatively stable values, suggesting different recovery and pacing dynamics between sexes.
Average oxygen uptake (VO₂_peak) during bouldering reaches roughly 35–36 mL·kg⁻¹·min⁻¹, corresponding to 70–75 % of VO₂_max. Approximately 23 % of climbing time occurs above the ventilatory threshold, revealing a significant anaerobic contribution to energy supply even in short climbing bouts. Recovery, however, is rapid—heart rate and ventilation typically return to resting levels within 2–4 minutes after an attempt—underlining the importance of aerobic recovery capacity for repeated performance.
A specific feature of bouldering is the mechanical restriction of breathing. Due to body positions requiring high core tension and sustained isometric contractions, athletes often experience limited expansion of tidal volume, which transiently reduces ventilatory efficiency. This highlights the relevance of breathing technique and respiratory muscle conditioning in competition preparation.
Post-competition blood lactate concentrations average 5.6–6.9 mmol·L⁻¹, with a pronounced rise once climbing durations exceed about 20 seconds. These values are comparable to those observed in lead climbing but markedly lower than peak lactate concentrations of 14–25 mmol·L⁻¹ typically reported in other high-intensity sports. The moderate accumulation and rapid clearance confirm the hybrid metabolic profile of bouldering, characterized by explosive anaerobic efforts supported by well-developed aerobic recovery mechanisms.
In summary, bouldering imposes short, intense, and metabolically mixed loads, combining near-maximal cardiovascular responses with fast recovery kinetics. Effective performance therefore depends not only on maximal strength and power but also on the ability to restore physiological balance quickly, maintain efficient ventilation under muscular tension, and sustain repeated high-intensity efforts across multiple rounds.
Implications for Training Practice
The intermittent competition structure, short maximal climbing efforts, limited intra-attempt recovery, and high coordinative demands translate into a training approach that must specifically target explosiveness, recovery efficiency, technical variability, and tactical decision-making. The following recommendations are derived directly from the load characteristics observed in competition.
1. High-intensity training
Because competition attempts consist of short bouts of near-maximal climbing, training should regularly include high-intensity single efforts with an emphasis on maximal and explosive force production. Suitable formats include:
- 3–4 sets of 10–30 s high-intensity training
This approach directly reflects the physiological stress of competition and develops the capacity to repeat power-demanding sequences under fatigue.
2. Intermittent interval training to replicate competition rhythm
Interval structures are well-suited to simulate the short climbing periods followed by incomplete rest observed in bouldering competitions. Sessions should include repeated attempts with controlled rest to train the ability to recover quickly while maintaining movement quality.
3. Aerobic base conditioning for recovery
Although bouldering relies heavily on anaerobic power, both muscular and cardiopulmonary recovery depend on aerobic efficiency. Improving aerobic capacity supports lactate clearance and enables climbers to recover between attempts, between boulders, and across multiple rounds within a competition.
4. Competition simulations under metabolic and cognitive stress
To link physiological demands with performance execution, athletes should regularly train under competition-like conditions, reproducing the time structure, attempt limitations, and pressure of real rounds. This approach trains not only physical output but also technique, decision-making, and tactical pacing under elevated heart rate and metabolic load.
5. Respiratory mechanics under load
Because breathing is often restricted by body tension and isometric holds, training should include tasks that challenge ventilation control during high muscular load. This supports oxygen delivery during attempts and speeds recovery between efforts.
6. Technical Requirements and beta-flexibility
Success in bouldering depends on the ability to generate multiple solutions to the same movement task. Training should therefore prioritize:
- developing a large movement repertoire,
- practicing alternative betas,
- planning attempt strategy and anticipating a Plan B,
- consciously managing a “try budget” similar to competition pacing.
7. Boulder-type-specific coordination training
Since World Cup bouldering is dominated by intensity-, complexity- and coordination-based problems, training emphasis should reflect these patterns. Technical development should focus particularly on:
hand coordination > hand-foot coordination > dynamic jumps > foot coordination, matching the coordinative profile most frequently observed in competition settings.
References
Augste, C., Sponar, P., & Winkler, M. (2021). Athletes’ performance in different boulder types at international bouldering competitions. International Journal of Performance Analysis in Sport, 21(3), 409–420. https://doi.org/10.1080/24748668.2021.1907728
Callender, N. A., Hayes, T. N., & Tiller, N. B. (2021). Cardiorespiratory demands of competitive rock climbing. Applied Physiology, Nutrition, and Metabolism, 46(2), 161–168. https://doi.org/10.1139/apnm-2020-0566
Künzell, S., Thomiczek, J., Winkler, M., & Müller, E. (2021). Finding new creative solutions is a key component in world-class competitive bouldering. German Journal of Exercise and Sport Research, 51, 112–115. https://doi.org/10.1007/s12662-020-00680-9
La Torre, A., Crespi, D., Serpiello, F. R., & Merati, G. (2009). Heart rate and blood lactate evaluation in bouldering elite athletes. The Journal of Sports Medicine and Physical Fitness, 49(1), 19–24.
Ochoa-Marcos, I. (2024). Performance characteristics and movement classification in international competition bouldering [Unpublished manuscript]. https://drive.google.com/file/d/19XMjt0fcOf0-1LnqPaPzwMgGPCej_cNZ/view
Winkler, M., Künzell, S., & Augste, C. (2022). The load structure in international competitive climbing. Frontiers in Sports and Active Living, 4, 790336. https://doi.org/10.3389/fspor.2022.790336
