Effects of high-intensity interval and moderate-intensity continuous training on the anaerobic threshold of highly trained athletes in endurance sports: a systematic review with meta-analysis.

INTRODUCTION: The anaerobic threshold (AT) is an important physiological index used as a parameter for predicting performance and evaluating adaptations induced by training. The aim of this study was to carry out a systematic literature review to survey the randomized studies that compared the effects of high-intensity interval training (HIIT) with the effects of moderate intensity continuous training (MICT) on the anaerobic threshold of highly trained athletes in endurance sports. EVIDENCE ACQUISITION: The following databases were searched: MEDLINE, Embase, Cochrane Wiley, PubMed, SPORTDiscus, Web of Science, and ProQuest for randomized trials. The search terms covered the areas of HIIT and MICT. This study was registered in the International Prospective Register of Systematic under the number CRD42020155474. EVIDENCE SYNTHESIS: Three studies were included for the qualitative and quantitative synthesis, totaling 72 participants, of whom 28 belonged to the MICT group and 44 to the HIIT group. CONCLUSIONS: The summary result showed that HIIT promotes greater adaptation in the AT of highly trained athletes compared to continuous training (ES=0.73; 95% CI: 0.25-1.21); however, the certainty of evidence evaluated by the GRADE method is low and heterogeneity is high (I2=82%; P<0.01).

Perceived exertion and performance modulation: effects of caffeine ingestion and subject expectation.

BACKGROUND: It is well established that caffeine has ergogenic effects on endurance performance. This evidence often comes from studies in which subjects receive either caffeine or placebo in double-blind, randomized and counterbalanced order. Here, we propose a new methodology which aims to estimate the effects of participant expectancy of ergogenic or anti-ergogenic effects on performance. METHODS: Sixteen physically active participants (non-athletes engaged in systematic physical training >3 months, at least three times a week) performed three 30-minute running tests after being told they would be provided with either a harmful treatment (lactic acid), a beneficial treatment (caffeine) or a placebo. In each blinded case, subjects were given caffeine. The velocity and Rating of Perceived Exertion (RPE) during the time trial were examined in light of the participant's expectancy before and after the endurance event using Bayesian multilevel models. RESULTS: For pre-exercise expectancy, there is a 92% probability that caffeine expectation decreases RPE (posterior median±SD -0.65±0.36) and a 79% probability that lactic acid expectation increases RPE (posterior median±SD 0.58±0.47) with expectations for placebo and 'not sure' falling in between (posterior median±SD: -0.37±0.32 and -0.22±0.37, respectively). In general, our interventions suggest an 81% probability that caffeine lowers RPE. However, there was no effect of caffeine supplementation on running velocity (median±SD 0.04±0.08 km.h-1). CONCLUSIONS: When a participant believed they are under a potentially positive treatment, their RPE decreased but if they believed themselves to be under a harmful treatment, their RPE increased, regardless of the actual positive intervention; neither caffeine nor the expectancy of a particular intervention improved actual performance as measured by running velocity in a 30-minute period.

The relationship between the heart rate deflection point test and maximal lactate steady state.

BACKGROUND: The aim of this study was to investigate the use of the Heart Rate Deflection Point Test (HRDP) in the determination of the velocity at the Maximal Lactate Steady State (MLSS). METHODS: Fifteen untrained male participants took part in a 3000-m running performance on a 400-m track. The volunteers performed an incremental test for HRDP determination. The third test was constant velocity, which lasted around 30 minutes and was based around HRDP for MLSS determination. RESULTS: Performance velocity at HRDP was strongly correlated with the MLSS running velocity (r=0.84; R2=0.71; P<0.0001). HRDP running velocity (mean±SD 9.0±1.3-km.h-1) was not significantly different (P>0.05) from MLSS velocity (9.3±1.3km.h-1). A high agreement was observed between methods (Bland and Altman analysis) with a mean error of 0.47 km.h-1. CONCLUSIONS: We can conclude that the HRDP was able to predict MLSS velocity.

Airflow-Restricting Mask Reduces Acute Performance in Resistance Exercise.

BACKGROUND: The aim of this study was to compare the number of repetitions to volitional failure, the blood lactate concentration, and the perceived exertion to resistance training with and without an airflow-restricting mask. METHODS: Eight participants participated in a randomized, counterbalanced, crossover study. Participants were assigned to an airflow-restricting mask group (MASK) or a control group (CONT) and completed five sets of chest presses and parallel squats until failure at 75% one-repetition-maximum test (1RM) with 60 s of rest between sets. Ratings of perceived exertion (RPEs), blood lactate concentrations (Lac-), and total repetitions were taken after the training session. RESULTS: MASK total repetitions were lower than those of the CONT, and (Lac-) and MASK RPEs were higher than those of the CONT in both exercises. CONCLUSIONS: We conclude that an airflow-restricting mask in combination with resistance training increase perceptions of exertion and decrease muscular performance and lactate concentrations when compared to resistance training without this accessory. This evidence shows that the airflow-restricting mask may change the central nervous system and stop the exercise beforehand to prevent some biological damage.