Reliability of Time to Exhaustion Above the Power Output at VO2peak in Trained Mountain Bikers.

To our knowledge, no study has investigated the reliability of the time to exhaustion (TTE) test during constant-load trials in Olympic distance cross-country mountain bike (XCO-MTB) athletes. Thus, the aim was to analyze the reliability of the TTE test at intensities above peak oxygen uptake (VO2peak) in trained XCO-MTB athletes. Fifteen male XCO-MTB athletes (mean ± SD: age 31.5 ± 6.6 years, stature 174.0 ± 5.4 cm, body mass 67.2 ± 5.1 kg, VO2peak 64.5 ± 4.7 mL·kg-1·min-1) completed 2 TTE tests on the cycle ergometer with 4 different intensities above the maximal work rate in the incremental test (Wmax) (105%, 120%, 130%, and 140% of Wmax). There was moderate reliability between TTE tests at 105% (intraclass correlation coefficient (ICC) = 0.81, p ≤ 0.001; coefficient of variation (CV) = 9.1%; standard error of measurement (SEM) = 18.3%), and 120% (ICC = 0.88, p ≤ 0.001; CV = 6.6%; SEM = 9.3%) Wmax. For intensities of 130% (ICC = 0.53, p = 0.018; CV = 9.2%; SEM = 15.8%) and 140% (ICC = 0.56, p = 0.012; CV = 12.2%; SEM = 13.5%) Wmax, the reliability results proved to be questionable. In addition, no significant differences were found between the 2 TTE tests in all intensities (p > 0.05). Caution should be taken when assessing TTE above VO2peak or when using it as a performance indicator, given its moderate to questionable reliability.

Is There a Dose-Response Relationship between High-Intensity Interval Exercise (HIIE) Intensity and Affective Valence? Analysis of Three HIIE Sessions Performed with Different Amplitudes.

The inverse relationship between exercise intensity and affective valence is well established for continuous exercise but not for high-intensity interval exercise (HIIE). The objective was to verify the dose-response relationship between exercise intensity and affective valence in HIIE sessions. Eleven young men underwent a vigorous-intensity continuous exercise (VICE) and three HIIE sessions at the same average intensity (70% of peak power-WPeak) and duration (20 min) but with different amplitudes: 10 × [1 min at 90% WPeak/1 min at 50% WPeak]-HIIE-90/50; 10 × [1 min at 100% WPeak/1 min at 40% WPeak]-HIIE-100/40; 10 × [1 min at 110% WPeak/1 min at 30% WPeak]-HIIE-110/30. During the exercise sessions, psychophysiological variables were recorded (VO2, VCO2, heart rate, perceived exertion CR10, and Feeling Scale (FS)). Higher correlations were found between CR10 and FS for all conditions (VICE = -0.987; HIIE-90/50 = -0.873; HIIE-100/40 = -0.908; HIIE-110/30 = -0.948). Regarding the physiological variables, the %HRMax presented moderate inverse correlations with FS for all exercise conditions (VICE = -0.867; HIIE-90/50 = -0.818; HIIE-100/40 = -0.837; HIIE-110/30 = -0.828) while the respiratory variables (%VO2Peak and %VCO2Peak) presented low-to-moderate correlations only for VICE, HIIE-90/50, and HIIE-100/40 (ranging from -0.523 to -0.805). Poor correlations were observed between the %VO2Peak (r = -0.293) and %VCO2Peak (r = -0.020) with FS. The results indicated that perceived exertion is more sensible than physiological variables to explain the intensity-affective valence relationship in HIIE sessions. RPE should be used for HIIE prescription with a focus on affect.

Internal Training Load Perceived by Athletes and Planned by Coaches: A Systematic Review and Meta-Analysis.

BACKGROUND: Rating of perceived exertion (RPE) and session RPE (sRPE) has been widely used to verify the internal load in athletes. Understanding the agreement between the training load prescribed by coaches and that perceived by athletes is a topic of great interest in sport science. OBJECTIVE: This systematic review and meta-analysis aimed to investigate differences between the training/competition load perceived by athletes and prescribed/intended/observed by coaches. METHODS: A literature search (September 2020 and updated in November 2021) was conducted using PubMed, Web of Science, Embase, and SPORTDiscus databases. The protocol was registered in the Open Science Framework (osf.io/wna4x). Studies should include athletes and coaches of any sex, age, or level of experience. The studies should present outcomes related to the RPE or sRPE for any scale considering overall training/competition sessions (physical, strength, tactical, technical, games) and/or classified into three effort categories: easy, moderate, and hard. RESULTS: Twenty-seven studies were included in the meta-analysis. No difference was found between coaches and athletes for overall RPE (SMD = 0.19, P = 0.10) and overall sRPE (SMD = 0.05, P = 0.75). There was a difference for easy RPE (SMD = - 0.44, small effect size, P = 0.04) and easy sRPE (SMD = - 0.54, moderate effect size, P = 0.04). No differences were found for moderate RPE (SMD = 0.05, P = 0.74) and hard RPE (SMD = 0.41, P = 0.18). No difference was found for moderate (SMD = -0.15, P = 0.56) and hard (SMD = 0.20, P = 0.43) sRPE. CONCLUSION: There is an agreement between coaches and athletes about overall RPE and sRPE, and RPE and sRPE into two effort categories (moderate and hard). However, there were disagreements in RPE and sRPE for easy effort category. Thus, despite a small disagreement, the use of these tools seems to be adequate for training monitoring.

Comparison of coach-athlete perceptions on internal and external training loads in trained cyclists.

ABSTRACTThe aim was to compare the rating of perceived exertion (RPE), duration and session-RPE (S-RPE) prescribed by the coaches to those perceived by the cyclists in training sessions. The classification of RPE, duration and S-RPE of 14 male road cycling and mountain biking athletes were compared with the planned values of five coaches. The results revealed no differences for average RPE (P = 0.586), duration (P = 0.717) and S-RPE (P = 0.738) between coaches and cyclists. When comparing the three categories of effort, the results of the intensity of training sessions designed to be easy were perceived as significantly harder by cyclists compared to coaches (3.0 [2.0] vs. 2.0 [0.0] a.u.; P = 0.013). In addition, the correlations between coaches and cyclists on RPE (r = 0.73), duration (r = 0.95) and S-RPE (r = 0.87) were large, almost perfect and very large (P < 0.0001) respectively. In conclusion, our results indicate a mismatch between coaches (prescription) and cyclists (perception) of easy RPE training sessions, where the cyclists perceived the session harder. However, the S-RPE can be used to prescribe and quantifying the internal training load of trained cyclists.

Correlation between economy/efficiency and mountain biking cross-country race performance.

This study investigated the correlation between cycling economy (CE) and gross efficiency (GE) in Olympic cross-country mountain biking (XCO-MTB) race performance. Also was examined the correlation between CE, GE, and peak oxygen uptake (VO2peak). Sixteen male XCO-MTB athletes (30.9 ± 5.2 years, 68.7 ± 5.6 kg, 175.0 ± 5.7 cm, and VO2peak: 65.4 ± 4.9 mL·kg-1 min-1) completed two experimental sessions. On the first, anthropometric assessments and a maximal incremental test were performed. The maximal incremental test was performed in the cycle ergometer to determine VO2peak, CE, and GE. A week later, an XCO-MTB race was performed in the second visit, where the official race time was used as a performance indicator. An inverse, significant moderate correlation was found between race time (8318.3 ± 459.0 s) and both CE (r = -0.53; CI95% = -0.84 to -0.10; p = 0.0008), and GE (r = -0.67; CI95% = -0.89 to -0.22; p = 0.0001). However, the moderate correlation between CE and race time showed low power. No significant correlation was found between VO2peak and either CE (r = -0.45; CI95% = -0.77-0.06; p = 0.08) or GE (r = -0.47; CI95% = -0.78-0.04; p = 0.07). In conclusion, gross efficiency is an important component of XCO-MTB race performance. The VO2peak was not related to CE and GE. The evaluation of GE may be a useful addition to the battery of physiological tests in mountain bikers.Highlights The gross efficiency can be a performance indicator related to the Olympic cross-country mountain biking race;The cycling economy has a moderate association with race time, but its use as a measure related to Olympic cross-country mountain biking race performance should be carried out with caution;Despite VO2peak's influence on both cycling economy and gross efficiency measures, our results do not show a relationship with Olympic cross-country mountain biking athletes.

Association between movement patterns and risk of musculoskeletal injuries in navy cadets: A cohort study.

OBJECTIVE: To investigate the association of movement patterns evaluated by the Dynamic Movement Assessment (DMA) with the occurrence of musculoskeletal injuries in navy cadets. DESIGN: Cohort study. SETTING: Participants were filmed performing the six functional tests of the DMA (deep squat, step up, single-leg squat, hop, plank and side-plank tests). PARTICIPANTS: 240 navy cadets. MAIN OUTCOME MEASUREMENTS: Depending on the number of certain movement patterns on the Dynamic Movement Assessment (DMA), participants were classified as high, moderate, medium or low risk of developing injuries. Predictive associations between injuries and risk classification were examined using logistic regression analysis. RESULTS: Considering sex, previous injuries and the type of secondary school as covariates, participants who were classified as high risk were not more likely to develop injuries. Non-military high school was an independent risk factor for any injuries (OR = 3.14, 95% CI [1.43,6.91]; OR = 4.57, 95% CI [1.92,10.83]), overuse injuries (OR = 2.58, 95% CI [1.05,6.30]; OR = 2.55, 95% CI [1.06, 6.14]) and acute injuries (OR = 4.88, 95% CI [1.19,19.99]), respectively. Previous musculoskeletal symptoms also increased the chance of AI (OR = 4.45, 95% CI [1.15,17.18]; OR = 5.91, 95% CI [1.13,30.88]). CONCLUSIONS: Movement patterns evaluated by DMA are not associated with an increased risk of injuries. However, attendance of a non-military high school and previous musculoskeletal symptoms are associated with musculoskeletal injuries.

The Impact of Sex and Performance Level on Pacing Behavior in a 24-h Ultramarathon.

Purpose: We analyzed the impact of sex, performance level and substantial speed reductions (SSR) on pacing in the VI Rio 24-h Marines Ultramarathon. This will provide insights into the importance of minimizing speed variations in relation to optimal pacing in endurance events. Methods: Runners (30 males and 21 females), classified as high- (HP) and low-performance (LP) ran the race while having their time recorded every 400 m. The pacing was analyzed as the first 10% (initial epoch), the following 80% (intermediate epoch) and the last 10% of the race (final epoch). The time percentage spent at speeds <3.5 km·h-1 (SSR), 3.5 to 5.9 km·h-1 (walking speed), 6.0 to 8.0 km·h-1 (walk-to-running transition speed) and > 8.0 km·h-1 (running speed) was calculated. Results: Runners showed a reverse J-shaped pacing (P < 0.001) regardless of sex and performance level, although male (P < 0.004) and HP runners (P < 0.001) have preserved a higher mean speed throughout the race. Male and HP runners spent more time at running speed (P < 0.001) and less time at SSR (P < 0.001) than female and LP runners. Total distance was inversely correlated with the number of SSR and speed CV in male (r = -0.47 and r = -0.64, respectively) and female (r = -0.61 and r = -0.47, respectively). Conclusion: Male, HP runners showed less SSR, conserving a higher mean speed with less variation throughout the race. Results suggest that conservative pacing strategies, with lower speeds in the beginning and higher speeds toward the end, may be the most adequate for different endurance running disciplines. Results also show different competition dynamics between men and women, which warrants further exploration in ultramarathons as well as other IAAF events.

Pacing Strategy During Simulated Mountain Bike Racing.

Cross-country mountain biking (XCO) is a popular high-intensity endurance cycling event, but XCO pacing strategy has not been fully examined. This study examined the pacing strategies of different XCO athletes during a laboratory-simulated XCO performance test. Brazilian cyclists classified as performance-cohort level 3 performed an XCO race simulation. The simulation consisted of four 10-km laps with a gradient of 0-10%. No group-vs-time interaction was found in lap time (P = .169), absolute (P = .719) and relative (P = .607) power output, ratings of perceived exertion (P = .182), or heart rate (P = .125). There was a time main effect, as athletes decreased power output by 0.3 W/kg throughout the XCO simulation, thereby resulting in a 1.6-min decrement per lap. The power output corresponding to the onset of blood lactate accumulation adequately represented the mean power of the first lap. These results showed that 2 groups of cyclists with different training status adopted similar pacing strategies during an XCO race simulation, as they both used a fast-starting pacing strategy followed by positive pacing that resulted in a linear decrease in power output at every lap.

Effects of Sprint versus High-Intensity Aerobic Interval Training on Cross-Country Mountain Biking Performance: A Randomized Controlled Trial.

OBJECTIVES: The current study compared the effects of high-intensity aerobic training (HIT) and sprint interval training (SIT) on mountain biking (MTB) race simulation performance and physiological variables, including peak power output (PPO), lactate threshold (LT) and onset of blood lactate accumulation (OBLA). METHODS: Sixteen mountain bikers (mean ± SD: age 32.1 ± 6.4 yr, body mass 69.2 ± 5.3 kg and VO2max 63.4 ± 4.5 mL∙kg(-1)∙min(-1)) completed graded exercise and MTB performance tests before and after six weeks of training. The HIT (7-10 x [4-6 min--highest sustainable intensity / 4-6 min-CR100 10-15]) and SIT (8-12 x [30 s--all-out intensity / 4 min--CR100 10-15]) protocols were included in the participants' regular training programs three times per week. RESULTS: Post-training analysis showed no significant differences between training modalities (HIT vs. SIT) in body mass, PPO, LT or OBLA (p = 0.30 to 0.94). The Cohen's d effect size (ES) showed trivial to small effects on group factor (p = 0.00 to 0.56). The interaction between MTB race time and training modality was almost significant (p = 0.08), with a smaller ES in HIT vs. SIT training (ES = -0.43). A time main effect (pre- vs. post-phases) was observed in MTB race performance and in several physiological variables (p = 0.001 to 0.046). Co-variance analysis revealed that the HIT (p = 0.043) group had significantly better MTB race performance measures than the SIT group. Furthermore, magnitude-based inferences showed HIT to be of likely greater benefit (83.5%) with a lower probability of harmful effects (0.8%) compared to SIT. CONCLUSION: The results of the current study suggest that six weeks of either HIT or SIT may be effective at increasing MTB race performance; however, HIT may be a preferable strategy. TRIAL REGISTRATION: ClinicalTrials.gov NCT01944865.

Correlates of Mood and RPE During Multi-Lap Off-Road Cycling.

This study examined the relationship between mood and rating of perceived exertion (RPE) during a simulated multiple-lap time trial (MLTT). Nineteen male cyclists performed a MLTT consisting of four 9.9 km laps, each lap with a gradient ranging from 0 to 10 %. Mood as measured by the Profile of Mood States Questionnaire (POMS) and perceived exertion as measured by the Borg CR100 scale (RPE) were obtained at the end of each lap. A categorical multiple regressive model, having median of POMS subscales as independent variables, was obtained to explain the variance in median RPE responses. Increases in POMS fatigue scores and decreases in POMS vigour scores were observed throughout the MLTT (P < 0.001). A linear increase in RPE during the MLTT was also observed (P < 0.001). POMS fatigue subscale scores accounted for 88 % of the variance in RPE during the MLTT (R(2) = 0.88, P = 0.002), and no other POMS subscale improved the final predictive model. With the exception of fatigue these results suggest that most aspects of mood do not have a discernable effect on RPE during a MLTT. The rate of increase in RPE can predict the MLTT endpoint.

Validade preditiva da medida e estimativas do VO2máx no desempenho de Mountain Bikers / Predictive validity of VO2máx measurement and estimates in Mountain Bikers' performance / Validez predictiva de la medida y estimativas del VO2máx en el desempeño de Mountain Bikers

INTRODUÇÃO: considerando o racional para a utilização das equações preditivas na estimativa do VO2máx em atletas, nenhum estudo estabeleceu sua validade para o desempenho no mountain bike cross-country (XCO). OBJETIVO: comparar diferentes estratégias de determinação do VO2máx, de forma direta ou indireta, para a predição do desempenho em uma prova real e outra simulada. MÉTODOS: 20 atletas de XCO do sexo masculino (31,6 ± 6,8 anos; 68,1 ± 6,5 kg; 175,5 ± 5,7cm; 64,9 ± 4,4 mL. kg-1.min-1), foram submetidos a três sessões experimentais. A primeira visita consistiu na estratificação de risco, avaliação antropométrica e teste progressivo máximo. Na segunda, foi realizada a prova simulada e, na terceira, foi realizada a competição de XCO. RESULTADOS: a correlação entre a prova simulada e as equações preditivas do VO2máx de forma absoluta alcançaram relação quase perfeita (r ≥ 0,9). As correlações entre a competição real e as estimativas de VO2máx relativizadas à massa corporal alcançaram resultados classificados como muito altos (r = 0,7-0,89). As associações entre a medida direta do VO2máx e a simulação apresentaram uma classificação baixa para valores relativos à massa corporal (r = 0,10, IC95% -0,35 a 0,51). Para o desempenho real, a classificação foi moderada (r = 0,48, IC95% 0,009 a 0,78). CONCLUSÃO: o presente estudo foi o primeiro a demonstrar a validade preditiva das estimativas do VO2máx para o desempenho simulado e real de MTB. Em complemento, confirmou a baixa validade preditiva da medida direta do VO2máx para o mesmo propósito. .

INTRODUCCIÓN: considerando el racional para el uso de las ecuaciones predictivas en la estimativa del VO2máx en atletas de ciclismo, ningún estudio estableció su validez predictiva para el desempeño en el mountain bike cross-country (XCO). OBJETIVO: comparar diferentes estrategias de determinación del VO2máx, de forma directa o indirecta, para la predicción del desempeño en una prueba real y otra simulada. MÉTODOS: veinte atletas de XCO del sexo masculino (31,6 ± 6,8 años; 68,1 ± 6,5 kg; 175,5 ± 5,7cm; 64,9 ± 4,4 mL. kg-1.min-1), fueron sometidos a tres sesiones experimentales. La primera visita consistió en la estratificación de riesgo, evaluación antropométrica y test progresivo máximo. En la segunda, fue realizada la prueba simulada y en la tercera fue realizada la competición de XCO. RESULTADOS: la correlación entre la prueba simulada y las ecuaciones predictivas del VO2máx de forma absoluta alcanzaron relación casi perfecta (r ≥ 0,9). Las correlaciones entre la competición real y las estimativas de VO2máx relativizada a la masa corporal alcanzaron resultados clasificados como muy grande (r = 0,7-0,89). Las asociaciones entre la medida directa del VO2máx y la simulación presentaron clasificación pequeña para valores relativos a masa corporal (r = 0,10, IC95% -0,35 a 0,51). Para el desempeño real, la clasificación fue moderada (r = 0,48, IC95% 0,009 a 0,78). CONCLUSIÓN: el presente estudio fue el primero en demostrar la validez predictiva de las estimativas del VO2máx para el desempeño simulado y real de MTB. En complemento, confirmó la baja validez predictiva de la medida directa del VO2máx para el mismo propósito. .

INTRODUCTION: considering the rationale for the use of predictive equations to estimate VO2max in athletes, no study has established its validity for performance in mountain bike cross-country (XCO). OBJECTIVE: the aim was to compare different strategies for determining VO2max, directly or indirectly, for predicting performance in a simulated and in a real competition. METHODS: 20 XCO male athletes (31.6 ± 6.8 anos; 68.1 ± 6.5 kg; 175.5 ± 5.7cm; VO2max 64.9 ± 4.4 mL. kg-1.min-1), were submitted to three experimental sessions. In the first visit, there were risk stratification, anthropometric evaluation and maximum progressive test. In the second, a simulated race was performed and, in the third session, a XCO competition was performed. RESULTS: the correlation between the simulated competition and the predictive equations of VO2max in absolute values reached an almost perfect relationship (r ≥ 0.9). The correlations between the real competition and estimated VO2max relativized to body mass achieved results classified as very high (r = 0.7 to .89). The associations between the direct measurement of VO2max and the simulation were classified as small for values relative to body mass (r = 0.10, CI95% -0.35 to 0.51). For the actual performance, the classification was moderate (r = 0.48, CI95% 0.009 to 0.78). CONCLUSION: this study was the first to demonstrate the predictive validity of the estimates of VO2max for the simulated and real MTB performance. In addition, it confirmed the low predictive validity of direct measurement of VO2max for the same purpose. .

Relationship between anaerobic cycling tests and mountain bike cross-country performance.

Despite its apparent relevance, there is no evidence supporting the importance of anaerobic metabolism in Olympic crosscountry mountain biking (XCO). The purpose of this study was to examine the correlation between XCO race time and performance indicators of anaerobic power. Ten XCO riders (age: 28 ± 5 years; weight: 68.7 ± 7.7 kg; height: 177.9 ± 7.4 cm; estimated body fat: 5.7 ± 2.8%; estimated ·VO2max: 68.4 ± 5.7 ml·kg⁻¹·min⁻¹) participating in the Lagos Mountain Bike Championship (Brazil) completed 2 separate testing sessions before the race. In the first session, after anthropometric assessments were performed, the cyclists completed a single 30-second Wingate (WIN) test and an intermittent tests consisting of 5 × 30-second WIN tests (50% of the single WIN load) with 30 seconds of recovery between trials. In the second session, the riders performed a maximal incremental test. A significant correlation was found between race time and maximal power on the 5× WIN test (r = -0.79, IC(95%) -0.94 to -0.32, p = 0.006) and the mean average power on the 5× WIN test normalized by body mass (r = -0.63, IC(95%) -0.90 to -0.01, p = 0.048). The finding of the study supports the use of anaerobic tests for assessing mountain bikers participating in XCO competitions and suggests that anaerobic power is an important determinant of performance.