No Combined Effect of Caffeinated Chewing Gum and Priming Exercise on Oxygen Uptake and Muscle Near-Infrared Spectroscopy-Derived Kinetics: A Double-Blind Randomized Crossover Placebo-Controlled Trial in Cyclists.

This study aimed to investigate the effects of caffeine ingestion by chewing gum (GUMCAF) combined with priming exercise on pulmonary oxygen uptake (V˙O2) and near-infrared spectroscopy-derived muscle oxygen extraction (HHb + Mb) kinetics during cycling performed in a severe-intensity domain. Fifteen trained cyclists completed four visits: two under a placebo gum (GUMPLA) and two under GUMCAF ingestion. Each visit consisted of two square-wave cycling bouts at Δ70 intensity (70% of difference between the V˙O2 at first ventilatory threshold and V˙O2max) with duration of 6 min each and 5 min of passive rest between the bouts. The GUMPLA or GUMCAF (400 mg) was chewed for 5 min, 12 min before the first Δ70 bout in a randomized double-blind procedure. The fundamental phase and slow component of HHb + Mb and V˙O2 kinetics were evaluated. For HHb + Mb kinetics, regardless of ingested gum, priming exercise effects occurred on the time constant (GUMCAF 16.0 ± 4.0 vs. 13.9 ± 2.9 s; GUMPLA 15.7 ± 6.1 vs. 13.2 ± 2.5 s), amplitude, slow component, time delay, and mean response time parameters (p ≤ .032). For V˙O2 kinetics, there were significant effects of bouts on the amplitude, slow component, end V˙O2, and the gain kinetics parameters (p < .017). Baseline V˙O2 was higher during GUMCAF than GUMPLA (p = .020). No significant effects occurred for the interaction between gum and bout in any parameter of V˙O2 or HHb + Mb kinetics. Therefore, unlike the priming exercise in severe-intensity exercise, GUMCAF is not an effective strategy for improving V˙O2 or HHb + Mb kinetics acceleration.

Nuevo test incremental para patinadores velocistas sobre una superficie plana deslizante: análisis de fiabilidad y comparación con un test de ciclismo / A novel incremental slide board test for speed skaters: Reliability analysis and comparison with a cycling test

Introducción: No parece ser adecuada la prescripción de ejercicio a patinadores a partir de los índices obtenidos en la bicicleta estática o la cinta rodante. Sin embargo, todavía no se ha establecido una valoración específica de laboratorio para patinadores. Objetivo: El objectivo de este estudio fue valorar la fiabilidad del test-retest de un test incremental ejecutado sobre una superficie plana deslizante (SB, del inglés slide board) y se comparó su validez, con un protocolo de ciclismo, para determinar el rendimiento aeróbico de los patinadores velocistas. Métodos: Diez patinadores de velocidad en línea de alto nivel ejecutaron 2 tests incrementales, uno en una SB y otro de ciclismo. La intensidad del test sobre SB fue determinada mediante cadencia, empezando por 30 impulsos/min y aumentando en 3 impulsos/min cada minuto hasta el agotamiento. Se midieron los valores máximo y submáximo relacionados con el umbral anaeróbico (AT), el consumo de oxígeno (VO2), la ventilación pulmonar (VE), la tasa de intercambio respiratorio (RER), la frecuencia cardíaca (FC), la escala de percepción del esfuerzo (RPE), la cadencia (CAD) y la concentración de lactato sanguíneo ([Lac]max).Resultados: No se encontraron diferencias significativas entre test y retest en la SB en ninguna de las variables. Se obtuvieron elevados niveles de fiabilidad relativa y absoluta (ICC > 0,9) (error típico de medida CVTEM < 3,5%) del VO2max, FCmax, [Lac]max, CADmax, VO2AT, CADAT y RPEAT. En comparación con el test de SB, el [Lac]max fue significativamente más alto durante el test de ciclismo y la RPTAT fue más baja. En VO2max, FCmax, CADmax, VO2AT y CADAT tuvieron una correlación alta entre el test de ciclismo y el SB (r > 0,8).Conclusión: Los resultados sugieren que el test de SB es fiable y adecuado para evaluar los índices de rendimiento aeróbico de patinadores velocistas

Introduction: Exercise prescription from indices obtained from cycling or running treadmill incremental tests does not seem suitable for speed skaters. However, the specificity of laboratory skating assessments remains to be established. Purpose: This study intended to assess the test-retest reliability of an incremental test performed on a slide board (SB), and its validity compared with a cycling protocol in order to determine aerobic performance indices in speed skaters. Methods: Ten competitive inline speed skaters performed two incremental tests on an SB and one cycling incremental test. The intensity of SB test was determined by cadence, starting at 30 push-offs/min and increasing by three push-offs/min each minute, until volitional exhaustion. Maximal and submaximal values related to the anaerobic threshold (AT) of oxygen uptake (VO2 ), pulmonary ventilation (VE), respiratory exchange (RER), heart rate (HR), rating of perceived effort (RPE), cadence (CAD), and blood lactate concentration ([Lac]max) were measured. Results: No significant differences were found in any of the variables between testretest on SB. High relative (ICC > 0.9) and absolute reliability (typical error of measure as CVTEM < 3.5%) were found for VO2max, HRmax, [Lac]max, CADmax, VO2AT, CADAT and RPEAT. In comparison to SB test, the [Lac]max was significantly higher during cycling, and the RPEAT was lower. VO2max, HRmax, CADmax, VO2AT and CADAT were largely correlated between cycling and SB (r > 0.8). Conclusions: The findings suggest that SB test is reliable and adequate to evaluate aerobic performance indices of speed skaters