High-dose short-term creatine supplementation without beneficial effects in professional cyclists: a randomized controlled trial.

BACKGROUND: Growing evidence supports the ergogenic effects of creatine supplementation on muscle power/strength, but its effects on endurance performance remain unclear. We assessed the effects of high-dose short-term creatine supplementation in professional cyclists during a training camp. METHODS: The study followed a double-blind, randomized parallel design. Twenty-three professional U23 cyclists (19 ± 1 years, maximum oxygen uptake: 73.0 ± 4.6 mL/kg/min) participated in a 6-day training camp. Participants were randomized to consume daily either a recovery drink (containing carbohydrates and protein) with a 20-g creatine supplement (creatine group, n = 11) or just the recovery drink (placebo group, n = 12). Training loads and dietary intake were monitored, and indicators of fatigue/recovery (Hooper index, countermovement jump height), body composition, and performance (10-second sprint, 3-, 6-, and 12-minute time trials, respectively, as well as critical power and W') were assessed as study outcomes. RESULTS: The training camp resulted in a significant (p < 0.001) increase of training loads (+50% for total training time and + 61% for training stress score, compared with the preceding month) that in turn induced an increase in fatigue indicators (significant time effect [p < 0.001] for delayed-onset muscle soreness, fatigue, and total Hooper index) and a decrease in performance (significant time effect [p = 0.020] for critical power, which decreased by -3.8%). However, no significant group-by-time interaction effect was found for any of the study outcomes (all p > 0.05). CONCLUSIONS: High-dose short-term creatine supplementation seems to exert no consistent beneficial effects on recovery, body composition or performance indicators during a strenuous training period in professional cyclists.

Time-course Changes of Field- and Laboratory-based Performance Indicators in Junior Cyclists Through a Season.

This study aimed to assess the seasonal evolution of field-based and laboratory-based performance indicators in cyclists. Thirteen Junior male road cyclists (age 17.4±0.5 years) were followed up during a season, which was divided in three phases: early season (involving mainly training sessions), mid-season (including the first competitions), and late season (including the major competitions of the season). During each phase, field-based power output data were registered for the assessment of maximum mean power values, and laboratory-based endurance (ramp test and simulated 8-minute time trial), muscle strength/power (squat, lunge, hip thrust) and body composition indicators (dual-energy X-ray absorptiometry) were also assessed. A progressive (p<0.01) increase in maximum mean power values (e.g., 3.8±0.3 and 4.5±0.4 watts/kg in early and late season, respectively, for 60-minute efforts) and on 8-minute time trial performance (i.e., 5.3±0.3 and 5.6±0.4 watts/kg, respectively) was observed through the season. Yet, more "traditional" endurance indicators (i.e., ventilatory threshold, respiratory compensation point, or maximum oxygen uptake) seemed to show a ceiling effect beyond the mid-season. In addition, neither peak power output, body composition, nor muscle strength indicators followed a similar pattern to the aforementioned field-based indicators. In summary, in Junior cyclists field-based indicators seem more sensitive to monitor endurance cyclists' changes in actual fitness and performance capacity than more "traditional" laboratory-based markers in Junior cyclists.

Laboratory-based determinants of simulated time trial performance in cyclists.

Different laboratory-based variables are individually associated with cycling performance, but scarce evidence exists on which of them, when all assessed in combination, could best explain cycling performance. The present study aimed to examine the combined association between laboratory-based endurance, strength/power and body composition indicators with time trial performance in high-level cyclists. Ninety-four male cyclists were recruited (age: 20 ± 3.5 years, maximum oxygen uptake [V̇O2max]: 77.7 ± 5.4 ml · kg-1 · min-1). Participants performed a maximal incremental cycling test for the assessment of endurance indicators (peak power output [PPO], V̇O2max, ventilatory threshold [VT] and respiratory compensation point [RCP]), and an incremental loading test to assess muscle strength and power-related outcomes (1-repetition maximum, mean maximal power) in the squat, lunge and hip-thrust exercises. Body composition was assessed by dual energy X-ray absorptiometry. On a separate visit, participants performed a simulated 8-minute time trial to assess cycling performance (determined as the mean power output attained). Strong-to-very-strong correlations were found between all endurance indicators and time trial performance (most r-values ranging between 0.68-0.92), whereas weaker correlations were found for strength/power (r-values < 0.5) or body composition (r-values < 0.7) indicators. Multivariate regression analyses revealed that VT, RCP and PPO explained together 92% of the variance in time trial performance (p < 0.001), with no significant contribution of the remaining variables. Although different endurance, strength/power and body composition individually correlate with simulated time trial performance in high-level cyclists, the former (and particularly VT, RCP and PPO) show the strongest association when all studied in combination. These findings underscore the importance of endurance capabilities (above strength/power or body composition) for maximizing time trial performance.

Concordancia clínica e histopatológica de lesiones blancas en cavidad bucal

Introducción: Las lesiones blancas en cavidad bucal constituyen un problema de salud que responde a causas diversas y afectan a una cifra considerable de personas a nivel mundial. Las condiciones y resultados del diagnóstico clínico de las lesiones sin un basamento histopatológico solo exhiben deducciones empíricas basadas en la experiencia clínica acumulada, que pueden concordar o no con la real naturaleza de la enfermedad diagnosticada. El estudio de su concordancia permite evidenciar la certeza del diagnóstico clínico. Objetivo: Determinar la concordancia clínica e histopatológica de lesiones blancas presentes en cavidad bucal. Métodos: Se realizó un estudio observacional descriptivo de corte transversal en 193 pacientes con lesiones blancas en cavidad bucal seleccionados mediante muestreo no probabilístico de tipo intencionado, que acudieron al Servicio de Estomatología del Policlínico Arturo Puig Ruiz de Villa del municipio Minas, provincia Camagüey, en el período comprendido de enero de 2020 a enero de 2022. Se realizó biopsia de las lesiones para correlacionar el diagnóstico clínico y el diagnóstico histopatológico. Se evaluó la concordancia de los resultados mediante el índice de Kappa. Resultados: Predominó el grupo de edades de 40-49 años, los pacientes más afectados correspondieron al sexo femenino y el color de piel blanca, la lesión que predominó fue la leucoplasia con displasia, el subsitio anatómico más afectado es la mucosa del carrillo y más de la mitad de los pacientes se relacionaron con el tabaquismo como factor de riesgo. La fuerza de concordancia de la leucoplasia fue muy buena respecto al liquen plano y la candidiasis crónica hiperplásica (buena). El carcinoma espinocelular tuvo un nivel de concordancia moderado. Conclusión: Se promediaron los resultados de concordancia para las lesiones blancas presentes en cavidad bucal en los 193 pacientes de la investigación y de manera general el estudio mostró buena concordancia.

Introduction: White lesions in the oral cavity constitute a health problem that responds to diverse causes and affects a considerable number of people worldwide. The conditions and results of the clinical diagnosis of lesions without a histopathological basis only show empirical deductions based on accumulated clinical experience, which may or may not agree with the real nature of the clinically diagnosed entity. The study of their concordance allows evidencing the certainty of the clinical diagnosis. Objective: To determine the clinical and histopathological concordance of white lesions present in the oral cavity. Methods: A cross-sectional descriptive observational study was carried out in 193 patients with white lesions in the oral cavity selected by non-probabilistic purposive sampling who attended the Department of Dentistry of the Arturo Puig Ruiz de Villa Polyclinic from January 2020 to January 2022. The lesions were biopsied to correlate the clinical diagnosis and histopathological diagnosis. The concordance of the results was evaluated using the Kappa index. Results: The predominant age group was 40-49 years, the most affected patients were female and white skin color, the predominant lesion was leukoplakia with dysplasia, the most affected anatomical subsite was the cheek mucosa and more than half of the patients were related to smoking as a risk factor. The concordance strength of leukoplakia was very good with respect to lichen planus and hyperplastic chronic candidiasis (good). Squamous cell carcinoma had a moderate level of concordance. Conclusion: The concordance results for white lesions present in the oral cavity in the 193 patients of the study were averaged and in general the study showed a good concordance.

Comparative analysis of endurance, strength and body composition indicators in professional, under-23 and junior cyclists.

Purpose: To compare endurance, strength and body composition indicators between cyclists of three different competition age categories. Methods: Fifty-one male road cyclists classified as either junior (n = 13, age 16.4 ± 0.5 years), under-23 [(U23), n = 24, 19.2 ± 1.3 years] or professional (n = 14, 26.1 ± 4.8 years) were studied. Endurance (assessed through a maximal incremental test and an 8-minute time-trial), strength/power (assessed through incremental loading tests for the squat, lunge and hip thrust exercises) and body composition (assessed through dual energy X-ray absorptiometry) were determined on three different testing sessions. Results: U23 and, particularly professional, cyclists attained significantly (p < 0.05) higher values than juniors for most of the analyzed endurance indicators [time-trial performance, maximum oxygen uptake (VO2max), peak power output (PPO), respiratory compensation point (RCP), and ventilatory threshold (VT)]. Significant differences (p < 0.05) between U23 and professionals were also found for time-trial performance, PPO and VT, but not for other markers such as VO2max or RCP. Professional cyclists also showed significantly (p < 0.05) lower relative fat mass and higher muscle mass levels than U23 and, particularly, juniors. No consistent differences between age categories were found for muscle strength/power indicators. Conclusion: Endurance (particularly time-trial performance, PPO and VT) and body composition (fat and muscle mass) appear as factors that best differentiate between cyclists of different age categories, whereas no consistent differences are found for muscle strength/power. These findings might help in performance prediction and/or talent identification and may aid in guiding coaches in the design of training programs focused on improving those variables that appear more determinant.