This study investigated the effects of 4-weeks repeated sprint (RST) vs. repeated high-intensity-technique training (RTT) on physical performance. Thirty-six adolescent taekwondo athletes (age: 16 ± 1 yrs) were randomly assigned to RST (10 × 35 m sprint, 10 s rest), RTT (10 × 6 s Bandal-tchagui, 10 s rest) and control (control group (CG): no additional training) groups. Additionally, to their regular training, RST and RTT trained 2×/week for 4 weeks. Training load (TL), monotony, and strain were calculated using the rating of perceived exertion scale. The progressive specific taekwondo (PSTT), 20 m multistage shuttle run (SRT_20m), 5 m shuttle run, agility T-test, taekwondo-specific agility (TSAT) and countermovement jump (CMJ) tests were performed before and after 4 weeks of training. Additionally, taekwondo athletes performed specific taekwondo exercises (i.e., repeated techniques for 10 s and 1 min). From week 1, mean TL increased continuously to week 4 and monotony and strain were higher at weeks 3 and 4 (p < 0.001). VO_2max calculated from SRT_20m and PSTT increased for RST and RTT in comparison to CG (p < 0.001). Agility performance during T-test and TSAT (p < 0.01) improved in RTT. The number of performed techniques during the 10 s specific exercise increased in RTT and RST (p < 0.01) for the dominant leg and in RTT for the non-dominant leg (p < 0.01). The number of techniques during the 1 min specific exercise was higher in RST and RTT compared to CG for the dominant leg (p < 0.001). Delta lactate at post-training was lower for RTT for both legs compared to RST and CG (p < 0.01). It is important to include a low-volume high-intensity training based on repeated sprint running or repeated technique in the training programs of adolescent taekwondo athletes.

Ego-depletion describes a state of mind, where the capacity for self-control is temporarily depleted after a primary self-control action. The aim of this study was to investigate whether a brief virtual reality-based mindfulness breathing meditation with integrated biofeedback can be considered an effective strategy to counteract the detrimental effects of ego depletion on motor skill performance under pressure. The study included two experiments, each of them designed as counterbalanced cross-over trials and based on an a priori sample-size calculation. Within each experiment, participants completed two appointments in a randomly assigned order, during which they were asked to perform 20 basketball free throws (N = 18; Experiment 1) or 20 penalty kicks at a football goal in four target squares (N = 16; Experiment 2) under pressure pre and post the following conditions: Stroop-test-induced ego depletion followed by a 15 min resting break, Stroop-test-induced ego depletion followed by a 15 min virtual reality-based mindfulness breathing meditation with integrated biofeedback. Results indicate that, in comparison to a resting break, a brief virtual reality-based mindfulness meditation with integrated biofeedback can counteract the detrimental effects of ego-depletion (Experiment 2) and enhance motor skill performance under pressure (Experiment 1, 2) Implications for researchers and practitioners are derived in light of the identified methodological limitations.

Nowadays, self-tracking and optimization are widely spread. As sleep is essential for well-being, health, and peak performance, the number of available consumer technologies to assess individual sleep behavior is increasing rapidly. However, little is known about the consumer wearables’ usability and reliability for sleep tracking. Therefore, the aim of the present study was to compare the sleep measures of wearable devices with a standardized sleep diary in young healthy adults in free-living conditions. We tracked night sleep from 30 participants (19 females, 11 males; 24.3 ± 4.2 years old). Each wore three wearables and simultaneously assessed individual sleep patterns for four consecutive nights. Wearables and diaries correlated substantially regarding time in bed (Range CCC_Lin: 0.74–0.84) and total sleep time (Range CCC_Lin: 0.76–0.85). There was no sufficient agreement regarding the measures of sleep efficiency (Range CCC_Lin: 0.05–0.34) and sleep interruptions (Range CCC_Lin: −0.02–0.10). Finally, these results show wearables to be an easy-to-handle, time- and cost-efficient alternative to tracking sleep in healthy populations. Future research should develop and empirically test the usability of such consumer sleep technologies.

Zusammenfassung Wearable Devices versprechen durch ihre motivierende Wirkung einen wichtigen Beitrag zur Bindung des Individuums an körperlich-sportliche Aktivitäten und somit zum Aufbau und Erhalt von Gesundheit und Leistungsfähigkeit in Zeiten des digitalen gesellschaftlichen Wandels. Übergeordnetes Ziel der vorliegenden Untersuchung war die Beurteilung der Testgüte von Wearable Devices anhand eines marktrelevanten Gerätes, der Garmin fēnix® 5. Als Forschungsdesiderat wurde der Reliabilitätsaspekt der Methodenkonkordanz identifiziert. Zur Überprüfung der Methodenkonkordanz wurden das Stresslevel bei kognitiver Stressinduktion, der Kalorienverbrauch bei moderater Ausdauerlaufbelastung sowie die maximale Sauerstoffaufnahme bei Laufausbelastung von 30 männlichen Probanden (Alter: 23,13 ± 2,5 Jahre; BMI: 24,95 ± 2,45 kg/m²) mit der Garmin fēnix® 5 bestimmt und die Ergebnisse mit denen im Feld gängigen Referenzmethoden Elektrokardiographie, Indirekte Kalorimetrie bzw. Spiroergometrie verglichen. Zur rechnerischen Überprüfung der Methodenkonkordanz diente Lin’s Konkordanzkorrelationskoeffizient (CCC_Lin). Die Ergebnisse zeigen eine hohe Präzision der Garmin fēnix® 5 im Vergleich mit der Referenzmethode Elektrokardiographie hinsichtlich der Messung des notwendigerweise z-standardisierten Stressparameters (p = 0,89) sowie eine gerade mittlere exakte intrainidividuelle Konkordanz mit der Referenzmethode Indirekte Kalorimetrie bzw. Spiroergometrie hinsichtlich der Messung des Parameters Kalorienverbrauch (CCC_Lin = 0,43 [p = 0,52, C_b = 0,82]) bzw. maximale Sauerstoffaufnahme (CCC_Lin = 0,50 [p = 0,77, C_b = 0,66]). Die Garmin fēnix® 5 kann somit zumindest bei erstmaliger Verwendung nicht als hinreichend konkordante Alternative zu den gängigen aktivitäts- und leistungsbezogenen Referenzmethoden empfohlen werden.

Gaming is a global phenomenon often associated with impaired health and sleep patterns. Although the research activities are growing, the evidence to date is rare due to the various gaming titles and inconsistent study designs. Thus, this study aimed to examine the impact of excessive gaming in the evening on subjective as well as objective sleep parameters by focusing on specific game titles and assessing several evenings/nights using a mixed-methods approach. A total of 33 experienced young male adults (23.00 ± 3.53 years old, ranked players in League of Legends or Counter-Strike: Global Offensive) took part. The individuals' sleep parameters were assessed via diary and actigraphy. In randomized order, one week apart and for a duration of 120 min each, two study evenings were spent gaming, while the other two evenings were spent without digital media and gaming, but instead watching a nature documentary. No significant difference between the conditions were found (p > 0.05) in either the sleep duration nor the sleep quality. Daytime sleepiness was significantly increased after watching the documentary movie, when compared to gaming (p < 0.001). These results indicate that, one the one hand, the gaming activity leads to higher arousal and alertness as it requires concentration and dedication. On the other hand, this impact seems only short-term and does not necessarily affect sleep patterns. Future studies are needed to gain deeper insights, especially regarding the long-term health effects of gaming.