Effect of an Eleven-Day Altitude Training Program on Aerobic and Anaerobic Performance in Adolescent Runners

Peak Eccentric Cycling Exercise and Cardiorespiratory Responses to Normobaric Hypoxia Versus Normobaric Normoxia in Healthy Adults: A Randomized, Controlled Crossover Trial

Background/Objectives: Pulmonary rehabilitation clinics are traditionally located at higher altitudes (HAs), where lower PO2 reduces exercise capacity and blood oxygenation. Eccentric cycling exercise (ECC), with its lower cardiorespiratory demand compared to concentric cycling (CON), might therefore be a potential advantageous training modality at HAs, particularly for individuals with reduced exercise capacity. This study aimed to compare the cardiorespiratory responses of ECC while breathing normoxic versus hypoxic gas in healthy participants. Methods: This randomized, controlled crossover trial involved healthy participants performing CON in normoxia (FiO2 = 0.21), followed by two incremental ECC tests until 70-100% of peak exercise, one with normoxia and one with normobaric hypoxia (FiO2 = 0.15), in a randomized order. Oxygen uptake (V'O2) and additional outcomes were measured breath-by-breath. Endpoints were defined at rest, 50%, 70%, peak exercise, and isotime. The trial is registered on clinicaltrails.gov (NCT05185895). Results: Twelve healthy participants (age: 30 ± 11 years, six females) completed the study. During both interventions, V'O2 increased linearly with exercise intensity, with no significant differences between normoxic and hypoxic conditions. At peak exercise, SpO2 and peak work rate were significantly lowered by 5% (95%CI: 3 to 8%, p < 0.001) and by 22 W (95%CI: 8 to 36 W, p = 0.009) in hypoxia compared to normoxia. Other outcomes were unchanged. When comparing CON to ECC in normoxia, the mean differences in V'O2 increased with higher loads. Conclusions: This study demonstrated that V'O2 and other cardiopulmonary parameters remain unchanged when performing ECC in hypoxia compared to normoxia. Comparing CON to ECC in normoxia, participants achieved higher workloads and greater V'O2 consumption during CON compared to ECC at comparable watts, confirming the higher metabolic cost associated with CON. We identified that the optimal submaximal ECC intensities, with the highest difference in V'O2 between CON versus ECC, are around 40% of peak V'O2.

Circadian rhythm in sportspersons and athletic performance: A mini review

Circadian rhythms in the physiological and behavioral processes of humans play a crucial role in the quality of living and also in the magnitude of success and failure in various endeavors including competitive sports. The rhythmic activities of the body and performance in sportspersons do have a massive impact on their every cutthroat competition. It is essential to schedule sports activities and training of players according to their circadian typology and time of peak performance for improved performance and achievement. In this review, the focus is on circadian rhythms and diurnal variations in peak athletic performance in sportspersons. Accuracy and temporal variability in peak performance in an individual could be attributed to various factors, namely chronotype, time of the day, body temperature, jetlag, hormones, and prior light exposure. Circadian rhythm of mood, alertness, T-core, and ultimately athletic performance is not only affected by sleep but also by circadian variations in hormones, such as cortisol, testosterone, and melatonin. There are, however, a few reports that are not consistent with the conclusions drawn in this review. Nevertheless, circadian rhythm and performance among sportspersons and athletes are important areas of research. This review might be useful to the managers and policymakers associated with competitive sports and athletic events.

Warm-Up With Added Respiratory Dead Space Volume Mask Improves the Performance of the Cycling Sprint Interval Exercise: Cross-Over Study

Special breathing exercises performed during warm-up lead to hypercapnia and stimulation of mechanisms leading to increased exercise performance, but the effect of a device that increases the respiratory dead space volume (ARDSv) during warm-up has not been studied. The purpose of this study was to investigate the effect of 10 min warm-up with ARDSv on performance, physiological and biochemical responses during sprint interval cycling exercise (SIE). During four laboratory visits at least 72 h apart, they completed: (1) an incremental exercise test (IET) on a cycloergometer, (2) a familiarization session, and cross-over SIE sessions conducted in random order on visits (3) and (4). During one of them, 1200 mL of ARDSv was used for breathing over a 10-min warm-up. SIE consisted of 6 × 10-s all-out bouts with 4-min active recovery. Work capacity, cardiopulmonary parameters, body temperature, respiratory muscle strength, blood acid-base balance, lactate concentration, and rating of perceived exertion (RPE) were analyzed. After warm-up with ARDSv, P ET CO2 was 45.0 ± 3.7 vs. 41.6 ± 2.5 (mm Hg) (p < 0.001). Body temperature was 0.6 (°C) higher after this form of warm-up (p < 0.05), bicarbonate concentration increased by 1.8 (mmol⋅L-1) (p < 0.01). As a result, work performed was 2.9% greater (p < 0.01) compared to the control condition. Respiratory muscle strength did not decreased. Warming up with added respiratory dead space volume mask prior to cycling SIE produces an ergogenic effect by increasing body temperature and buffering capacity.

Superior Adaptations in Adolescent Runners Using Heart Rate Variability (HRV)-Guided Training at Altitude

We evaluated the efficacy of heart rate variability (HRV)-guided training in adolescent athletes during a 2-week, high altitude (≈1900 m) training camp. Sixteen middle- and long-distance runners (4 female/12 male, 16.9 ± 1.0 years, 65.44 ± 4.03 mL·kg-1·min-1) were divided into 2 matched groups, both of which received the same training plan, but one of which acquired postwaking HRV values that were used to tailor the training prescription. During the camp, seven athletes in the HRV-guided group combined for a total of 32 training adjustments, whereas there were only 3 runners combined for 14 total training adjustments in the control group. A significant group by time interaction (p < 0.001) for VO2max was driven by VO2max improvements in the HRV group (+2.8 mL·kg-1·min-1, +4.27%; pBonf = 0.002) that were not observed in the control condition (+0.8 mL·kg-1·min-1, +1.26%; pBonf = 0.643). After returning from the camp, all athletes in the HRV group set a personal best, and six out of eight achieved their best positions in the National Championship, whereas only 75% of athletes in the control group set a personal best and five out of eight achieved their best positions in the National Championship. These data provide evidence in support of HRV-guided training as a way to optimize training prescriptions in adolescent athletes.