Athletes and coaches believe that adequate sleep is essential for peak performance. There is ample scientific evidence which support the conclusion that sleep loss seems to stress many physiological functions in humans. The aim of this study was to determine the effect of one night's sleep deprivation on intermittent exercise performance in the evening of the following day. Ten male Taekwondo players performed the Yo-Yo intermittent recovery test (YYIRT) in three sleep conditions (reference sleep night [RN], partial sleep deprivation at the beginning of night [PSDBN], partial sleep deprivation at the end of night [PSDEN]) in a counterbalanced order, allowing a recovery period ≥36 hr in between them. Heart rate peak (HRpeak), plasma lactate concentrations (Lac) and rating of perceived exertion (RPE) were measured during the test. A significant effect of sleep restriction was observed on the total distance covered in YYIRT (P<0.0005) and Lac (P<0.01) in comparison with the RN. In addition, performance more decreased after PSDEN (P<0.0005) than PSDBN (P<0.05). Also, Lac decreased significantly only after PS-DEN (P<0.05) compared with RN. However, there were no significant changes in HRpeak and RPE after the two types of partial sleep deprivation compared to RN. The present study indicates that short-term sleep restriction affect the intermittent performance, as well as the Lac levels of the Taekwondo players in the evening of the following day, without alteration of HRpeak and RPE.

Coronavirus 2019 (COVID-19) is an infectious viral disease that has spread globally, resulting in the ongoing pandemic. Currently, there is no vaccine or specific treatment for COVID-19. Preventive measures to reduce the chances of contagion consist mainly of confinement, avoiding crowded places, social distancing, masks, and applying strict personal hygiene as recommended by the World Health Organization (WHO). After the first wave of infection in many countries, the potential effects of relaxing containment and physical distancing control measures suggest that as a result of these measures, a second wave of COVID-19 appears probable in these countries. In sport, the period of self-isolation, and quarantine, for COVID-19 affects the physical preparation of athletes as well as their mental health and quality of life to an even greater extent (i.e., nutrition, sleep, healthy lifestyle), and thus, relevant and practical recommendations are needed to help alleviate these physical and mental health concerns. Our review aims to summarize the physiological and psychological effects of detraining associated with athletes’ confinement during the proposed second wave of COVID-19. This article also proposes answers to questions that concern the advantages and disadvantages of different types of social media platforms, the importance of nutrition, and the effects of sleep disturbance on the health and modified lifestyle of athletes during this worldwide pandemic. Thus, this review provides some general guidelines to better manage their modified lifestyle and optimally maintain their physical and mental fitness with respect to measures taken during this restrictive proposed second wave of the COVID-19 confinement period.

This study investigated the two different time-of-day effect on team-handball-related short-term maximal physical performances. At two different time-of-day, fifteen young female team handball players performed different physical tests: HandGrip (HG) test, Ball-Throwing Velocity (BTV) test, Modified Agility T-test (MAT) and Repeated Shuttle-Sprint and Jump Ability (RSSJA) test. Rating of perceived exertion (RPE) scale was determined following the termination of the last test. Measurements were performed at two separate testing sessions (i.e., in the morning (7:00–8:30 h) and in the early evening (17:00–18:30 h)) in a randomised and counter-balanced setting on non-consecutive days. The results showed that HG (P = 0.0013), BTV (P = 0.0027) and MAT (P < 0.001) performances were better in the evening compared with the morning. During RSSJA, both best and mean sprint times were shorter in the evening compared to the morning (P < 0.001). Moreover, during the latter test, mean jump performance was higher in the evening compared to the morning (P = 0.026). However, there was no morning–evening difference in the best jump performance during RSSJA. Likewise, jump performance decrement was not affected by the time-of-day of testing. On the other hand, RPE fluctuated, with morning nadirs and afternoon/early evening highest values. The findings suggest that in female team handball players, team-handball-related short-term maximal physical performances were better in the afternoon than in the morning.

The aim of this study was to update the validity of the Taekwondo Anaerobic Intermittent Kick Test compared with the 30-s Wingate anaerobic test as the "Gold-Standard", squat jump and countermovement jump tests. The second objective was to examine whether this new specific test would be able to effectively discriminate between elite taekwondo athletes of different competitive levels. Twenty taekwondo athletes (15 males and 5 females) participated in the validation component, whereas 18 (14 males and 4 females) and 16 (13 males and 3 females) athletes participated in the reliability analysis of the Wingate anaerobic test and jumping tests, respectively. They performed these tests on two separate occasions (i.e., test-retest), in addition to the Taekwondo Anaerobic Intermittent Kick Test. To establish test’s discriminatory capability (i.e., construct validity), two subgroups were identified based on their international and national taekwondo performance: 10 elite (8 males and 2 females) and 9 sub-elite (7 males and 2 females) athletes. Wingate anaerobic test and jumping tests performances showed excellent reliability (ICC > 0.90, SEM < 5% for most variables). Significant correlations between Taekwondo Anaerobic Intermittent Kick Test, Wingate anaerobic test, and jumping tests’ variables were mostly "large". Elite taekwondo athletes showed greater taekwondo test performances compared with their sub-elite counterparts (p < 0.001). Receiving operating characteristic analysis indicated that the taekwondo specific test was able to effectively discriminate between elite and sub-elite taekwondo athletes. Overall, the findings of the current study support the concurrent validity of the Taekwondo Anaerobic Intermittent Kick Test. In particular, the Taekwondo Anaerobic Intermittent Kick Test showed good ability to effectively discriminate between taekwondo athletes of different competitive levels.

The aim of this study was to evaluate the effect of two types of partial sleep deprivation (PSD) on biomarkers of muscle and cardiac injuries in response to acute intermittent exercise in professional athletes. In a counterbalanced order, ten healthy male Taekwondo athletes were asked to perform the Yo-Yo Intermittent Recovery Test (YYIRT) in three conditions, allowing a 36 h recovery period in between: 1) following a full night of habitual sleep known as a reference sleep night (RN); 2) following PSD in the beginning of the night (PSDBN); and 3) following PSD in the end of the night (PSDEN). Heart rate (HR) and arterial oxygen saturation (SaO2) were measured during exercise. Blood samples were taken just before and 3 min after the YYIRT to measure biomarkers related to muscle and cardiac injuries (BRMCI). No significant effect of PSD was observed for physiological parameters (i.e., HR and SaO2). However, a significant alteration of resting ultra-sensitive C-reactive protein (us-CRP) (P<0.05) and myoglobin (MYO) (P<0.01) levels was detected after PSDEN. Furthermore, all BRMCI were altered by exercise. Likewise, compared to RN, PSD affected creatine phosphokinase (CPK) and MYO levels in response to exercise (P<0.05). The present study indicates that PSDEN increase the resting us-CRP and MYO levels, and that the two types of PSD increase the CPK and MYO levels in response to acute intermittent exercise, among Taekwondo athletes, in the evening of the following day. However, no rise of the physiological responses has been observed after the two types of PSD, at rest and in response to the exercise.

The aim of this study was to determine the relative and absolute test-retest reliability and criterion validity of a new Taekwondo Anaerobic Intermittent Kick Test (TAIKT). Twenty Tunisian elite Taekwondo athletes participated in this study (15 males and 5 females). Participants performed the TAIKT and the Running-based Anaerobic Sprint Test (RAST), twice (test and retest), on separate occasions three-week apart. Peak heart rate (HRpeak), blood lactate concentration [La־], and rating of perceived exertion (RPE) were measured during each session. There was no significant difference between the test and retest of TAIKT and RAST for all performances and physiological variables, except for the absolute mean power (Pmean) of RAST. Test-retest results showed that the TAIKT and RAST were reliable. All TAIKT and RAST parameters had an ICC>0.90, SEM<5%, with the smallest worthwhile change slightly higher than SEM, with very small limits of concordance. Strong significant correlations were found between TAIKT and RAST parameters (Ppeak (r=0.81; r=0.70), Pmean (r=0.72; r=0.60) in (W and W·Kg-67 respectively), fatigue index (r=0.81), [La־] (r=0.89) and RPE (r=0.78) at P<0.01, and HRpeak (r=0.55, at P<0.05)). The findings showed that the TAIKT can be considered as a valid and reliable specific test for assessing anaerobic power of Taekwondo athletes.