Florian Azad Engel

Hormonal, metabolic, and cardiorespiratory responses of young and adult athletes to a single session of high-intensity cycle exercise.

This study aimed to determine the effects of a single high-intensity interval training (HIIT) session on salivary cortisol (SC) levels, physiological responses, and performance in trained boys and men. Twenty-three boys (11.5 ± 0.8 years) and 25 men (29.7 ± 4.6 years) performed HIIT (4 consecutive Wingate Anaerobic Tests). SC in boys and men increased after HIIT from 5.55 ± 3.3 nmol/l to 15.13 ± 9.7 nmol/l (+173%) and from 7.07 ± 4.7 nmol/l to 19.19 ± 12.7 nmol/l (+171%), respectively (p < .01). Pretest SC as well as posttest changes were comparable in both groups (both p < .01). Peak blood lactate concentration was significantly lower in boys (12.6 ± 3.5 mmol/l) than in men (16.3 ± 3.1 mmol/l; p < .01). Throughout the HIIT, mean heart rates in boys were higher (p < .001) but relative peak oxygen uptake (ml·min-1·kg-1; p < .05) and performance were lower (p < .001) in boys than in men. HIIT in young athletes is associated with a higher activation of the hormonal stress axis than other types of exercise regimes as described in the literature. This study is the first to show a pronounced SC increase to HIIT in trained boys accompanied by elevated levels of blood lactate concentrations and heart rate suggesting a high cardio-respiratory, metabolic, and hormonal response to HIIT in 11-year-old boys.

The kinetics of blood lactate in boys during and following a single and repeated all-out sprints of cycling are different than in men.

This study characterized the impact of high-intensity interval training on the kinetics of blood lactate and performance in trained boys and men. Twenty-one boys (11.4 ± 0.8 years) and 19 men (29.4 ± 5.0 years) performed a set of four 30-s sprints with 2-min of rest and a single 30-s sprint on 2 separate occasions (randomized order) with assessment of performance. Blood lactate was assayed after each sprint and during 30 min of recovery from both tests. The individual time-curves of blood lactate concentration were fitted to the biexponential function as follows: [Formula: see text], where the velocity parameters γ1 and γ2 reflect the capacity to release lactate from the previously active muscle into the blood and to subsequently eliminate lactate from the organism, respectively. In both tests, peak blood lactate concentration was significantly lower in the boys (four 30-s sprints: 12.2 ± 3.6 mmol·L(-1); single 30-s sprint: 8.7 ± 1.8 mmol·L(-1)) than men (four 30-s sprints: 16.1 ± 3.3 mmol·L(-1); single 30-s sprint: 11.5 ± 2.1; p < 0.001). The boys exhibited faster γ1 (1.4531 ± 0.65 min; p < 0.001) and γ2 (0.059 ± 0.023 min; p = 0.01) in the single 30-s sprint and faster γ2 (0.049 ± 0.016 min; p = 0.01) in the four 30-s sprints. The worsening of performance from the first to the last of the four 30-s sprints was less pronounced in boys (9.2% ± 13.9%) than men (19.2% ± 11.5%; p = 0.01). In the present study boys, when compared with men, exhibited lower Peak blood lactate concentration; less pronounced decline in performance during the sprints concomitantly with more rapid release and elimination during the single 30-s sprint; and faster elimination of lactate following the four 30-s sprints.

Effects of Active and Passive Recovery on Blood Lactate and Blood pH After a Repeated Sprint Protocol in Children and Adults

The aim of this study was to compare the effect of active (AR) and passive recovery (PR) after a high-intensive repeated sprint running protocol on physiological parameters in children and adults. Blood lactate (La) and blood pH were obtained during two sets of 5 × 5 s all-out sprints and several times during subsequent 30-min recovery in 16 children and 16 adults. End-exercise La was significantly lower and pH significantly higher in children (La: 5.21 ± 2.73 mmol·L-1; pH: 7.37 ± 0.06) compared with adults (La: 10.35 ± 5.76 mmol·L-1; pH: 7.27 ± 0.10) (p < .01). La half-life during postexercise recovery was significantly shorter in children (AR: 436 ± 371 s, PR: 830 ± 349 s) than in adults (AR: 733 ± 371 s, PR: 1361 ± 372 s), as well as in active compared with passive recovery for both age groups (p < .01). The age x recovery interaction for La half-life only approached statistical significance (p = .06). The results suggest a faster lactate disappearance and an earlier return to resting pH after a repeated sprint running protocol in children compared with adults and a less pronounced advantage of active recovery in children.

Validity of Single Beam Timing Lights at Different Heights

Abstract Altmann, S, Spielmann, M, Engel, FA, Neumann, R, Ringhof, S, Oriwol, D, and Haertel, S. Validity of single-beam timing lights at different heights. J Strength Cond Res 31(7): 1994–1999, 2017—The purpose of this study was to quantify the effect of different timing light heights on sprint time and the validity of measurement. Two single-beam timing gate systems were used to measure 30-m sprint time (splits at 5 and 10 m) in 15 healthy and physically active male subjects. System 1 was set up at a height of 0.64 m and system 2 at 0.25 m (initial timing light) and 1.00 m (each following timing light), respectively. Participants performed 3 valid trials. The recordings of a high-speed video camera were used as a reference. Sprint times of system 1 and system 2 differed significantly between each other and from the reference system at all distances (p < 0.001). Intraclass correlation coefficients and Pearsons r values between both timing light systems and the reference system were low to moderate at 5 and 10 m and moderate to high at 30 m. Bland and Altman analysis revealed that the agreement intervals were considerably higher for the comparison between system 1 and the reference system than for system 2 and the reference system. A valid measurement of splits at 5 and 10 m via the systems used in this study is questionable, whereas 30-m times have an acceptable validity, especially when using system 2. This study confirms the influence of methodological approaches on sprint times. Coaches and researchers should consider that results gained by single-beam timing lights at different heights are not comparable.

Compression Garments in Sports: Athletic Performance and Recovery

Compression garments are popular among competitive and recreational athletes alike. The debate about the efficacy of compression garments in sport is similarly popular, spanning the scientific literature, public press, social media, and the sports field itself. In this chapter we aim to assist both researchers and the general reader by discussing the core elements of the compression garment story. First, we consider compression—the applied pressures and factors influencing those pressures. Knowing the applied pressures in vivo and characteristics of the pressures during use are important for building a clearer idea about what aspects of sports performance and recovery are affected by compression garments and why. Second, we consider garments—that, like other clothing, compression garments cover and interact with the body, establish a microenvironment, and influence variables such as heat and moisture exchanges. Understanding characteristics of the garments themselves can be useful for aiding interpretation of certain physiological and psychological effects, including heat balance, comfort, and wearer acceptability. We hope that the detail here helps the reader to contextualise and critically evaluate research on compression garments in sport. B.A. MacRae (&) Laboratory for Protection and Physiology, Empa—Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland e-mail: braid.macrae@empa.ch B.A. MacRae Exercise Physiology Laboratory, Institute of Human Movement Sciences and Sport, ETH Zurich—Swiss Federal Institute of Technology Zurich, Zurich, Switzerland R.M. Laing Clothing and Textile Sciences, University of Otago, Dunedin, New Zealand e-mail: raechel.laing@otago.ac.nz H. Partsch Medical University of Vienna, Vienna, Austria e-mail: hugo.partsch@meduniwien.ac.at

(Hoch-)intensives Intervalltraining mit Kindern und Jugendlichen im Nachwuchsleistungssport

A computer-based literature research during July 2013 using the electronic databases PubMed, MEDLINE, SPORTDiscus and Web of Science was performed to assess the effect of the high intensity interval training (HIIT) on sport performance in healthy children and adolescents. Studies examining the effect of HIIT on aerobic and anaerobic performance pre and post to HIIT-Interventions in children and adolescents (9-18 years) were included. The results indicate increased aerobic and anaerobic performance following two or three HIIT sessions per week for a period of five to ten weeks, additional to normal training. Results regarding long term effects following HIIT have not been documented so far. In addition, due to the physiological characteris-tics during HIIT protocols improved fatigue resistance has been demonstrated in children as compared to adults, which may be interpreted as a prerequisite for the applicability of HIIT in children.

Acute responses to forearm compression of blood lactate accumulation, heart rate, perceived exertion and muscle pain in elite climbers

Objectives: To evaluate the immediate responses to forearm compression of blood lactate concentration, heart rate, perceived exertion and local forearm muscle pain during severe climbing in elite climbers. Method: Seven elite climbers (18 ± 2 years; 164 ± 5 cm; 57.8 ± 5.3 kg) performed 3 × 3 climbing bouts with maximal intensity on a distinct 8 m boulder wall (lead grade: 7a–8b) in a single blinded, placebo-controlled cross-over design, wearing either forearm sleeves with compression (verum-compression) or placebo forearm sleeves with no compression (falsum-compression). Each climber’s heart rate was recorded during and capillary blood lactate concentration, perceived exertion and forearm muscle pain were assessed directly after climbing. Result: Heart rate (p = 0.45, ηp2 = 0.12), blood lactate concentrations (p = 0.44, ηp2 = 0.10), perceived exertion levels (p = 0.51, ηp2 = 0.08) and pain perception (p = 0.67, ηp2 = 0.03) were not affected by forearm compression. No condition × time interaction effect (compression × time) occurred for heart rate (p = 0.66, ηp2 = 0.04), blood lactate concentration (p = 0.70, ηp2 = 0.02), perceived exertion (p = 0.20, ηp2 = 0.26) and pain perception (p = 0.62, ηp2 = 0.04). Conclusion: In elite climbers performing severe climbing bouts, sleeves with forearm compression do not alter blood lactate concentration, heart rate, perceived exertion and local forearm muscle pain.

Diurnal variation of short-term repetitive maximal performance and psychological variables in elite judo athletes

Objectives: The aim of this study was to examine the effect of time of day on short-term repetitive maximal performance and psychological variables in elite judo athletes. Methods: Fourteen Tunisian elite male judokas (age: 21 ± 1 years, height:172 ± 7 cm, body-mass: 70.0 ± 8.1 kg) performed a repeated shuttle sprint and jump ability (RSSJA) test (6 m × 2 m × 12.5 m every 25-s incorporating one countermovement jump (CMJ) between sprints) in the morning (7:00 a.m.) and afternoon (5:00 p.m.). Psychological variables (Profile of mood states (POMS-f) and Hooper questionnaires) were assessed before and ratings of perceived exertion (RPE) immediately after the RSSJA. Results: Sprint times (p > 0.05) of the six repetition, fatigue index of sprints (p > 0.05) as well as mean (p > 0.05) jump height and fatigue index (p > 0.05) of CMJ did not differ between morning and afternoon. No differences were observed between the two times-of-day for anxiety, anger, confusion, depression, fatigue, interpersonal relationship, sleep, and muscle soreness (p > 0.05). Jump height in CMJ 3 and 4 (p < 0.05) and RPE (p < 0.05) and vigor (p < 0.01) scores were higher in the afternoon compared to the morning. Stress was higher in the morning compared to the afternoon (p < 0.01). Conclusion: In contrast to previous research, repeated sprint running performance and mood states of the tested elite athletes showed no-strong dependency of time-of-day of testing. A possible explanation can be the habituation of the judo athletes to work out early in the morning.

Effects of Compression Garments on Performance and Recovery in Endurance Athletes

Athletes specializing in different endurance sports at various levels of performance wear compression garments to improve their performance and facilitate recovery. The purpose of this chapter is outline the effects of compression garments on performance and recovery in endurance disciplines. A computerized research of the electronic databases PubMed, MEDLINE, SPORTDiscus, and Web of Science (performed in December 2015) and articles published in peer-reviewed journals were analyzed. Studies examining effects on performance, recovery, physiological, and/or psychological parameters during or after endurance sports comparing experimental (compression) and control (non-compression) trials were investigated. A total of 55 articles involving 788 participants were included. Compression garments exerted no significant improvements on performance in running (400 m–42.195 km), triathlon, ice speed skating, cross country skiing, and kayaking. Maximal and submaximal oxygen uptake, blood lactate concentrations, blood gas analysis, cardiac parameters, and body temperature were not altered in most of the considered studies during endurance exercise. Also in most studies, perceived exertion as well as perceived temperature were not affected by compression. Compression clothing significantly increased cycling performance, post exercise blood lactate elimination and reductions in blood lactate concentration during running, cycling, and cross country skiing. Three studies observed improved muscular oxygenation following and during endurance exercise. Furthermore, compression garments reduced post-exercise muscle soreness following running and cycling in eight studies. We conclude that compression clothing has no significant impact on performance parameters during running, ice speed skating, triathlon, cross country skiing and kayaking. The wearing of compression clothing might improve cycling performance, reduce post-exercise muscle pain following running and cycling, and facilitate lactate elimination during recovery.

(Hoch-)intensives Intervalltraining mit Kindern und Jugendlichen im Nachwuchsleistungssport@@@High-intensity interval training for young athletes

A computer-based literature research during July 2013 using the electronic databases PubMed, MEDLINE, SPORTDiscus and Web of Science was performed to assess the effect of the high intensity interval training (HIIT) on sport performance in healthy children and adolescents. Studies examining the effect of HIIT on aerobic and anaerobic performance pre and post to HIIT-Interventions in children and adolescents (9-18 years) were included. The results indicate increased aerobic and anaerobic performance following two or three HIIT sessions per week for a period of five to ten weeks, additional to normal training. Results regarding long term effects following HIIT have not been documented so far. In addition, due to the physiological characteris-tics during HIIT protocols improved fatigue resistance has been demonstrated in children as compared to adults, which may be interpreted as a prerequisite for the applicability of HIIT in children.