Athletes competing in ultra-endurance events are advised to meet energy requirements, to supply appropriate amounts of carbohydrates (CHO), and to be adequately hydrated before and during exercise. In practice, these recommendations may not be followed because of satiety, gastrointestinal discomfort, and fatigue. The purpose of the study was to assess energy balance, macronutrient intake and hydration status before and during a 1,230-km bike marathon. A group of 14 well-trained participants (VO2max: 63.2 ± 3.3 ml/kg/min) completed the marathon after 42:47 hr. Ad libitum food and fluid intake were monitored throughout the event. Energy expenditure (EE) was derived from power output and urine and blood markers were collected before the start, after 310, 618, and 921 km, after the finish, and 12 hr after the finish. Energy intake (EI; 19,749 ± 4,502 kcal) was lower than EE (25,303 ± 2,436 kcal) in 12 of 14 athletes. EI and CHO intake (average: 57.1 ± 17.7 g/hr) decreased significantly after km 618 (p < .05). Participants ingested on average 392 ± 85 ml/hr of fluid, but fluid intake decreased after km 618 (p < .05). Hydration appeared suboptimal before the start (urine specific gravity: 1.022 ± 0.010 g/ml) but did not change significantly throughout the event. The results show that participants failed to maintain in energy balance and that CHO and fluid intake dropped below recommended values during the second half of the bike marathon. Individual strategies to overcome satiety and fatigue may be necessary to improve eating and drinking behavior during prolonged ultra-endurance exercise.
Bjoern Geesmann, Joachim Mester and Karsten Koehler
Bjoern Geesmann, Jenna C. Gibbs, Joachim Mester and Karsten Koehler
Ultraendurance athletes often accumulate an energy deficit when engaging in ultraendurance exercise, and on completion of the exercise, they exhibit endocrine changes that are reminiscent of starvation. However, it remains unclear whether these endocrine changes are a result of the exercise per se or secondary to the energy deficit and, more important, whether these changes can be attenuated by increased dietary intake. The goal of the study was to assess the relationship between changes in key metabolic hormones after ultraendurance exercise and measures of energy balance. Metabolic hormones, as well as energy intake and expenditure, were assessed in 14 well-trained male cyclists who completed a 1230-km ultraendurance cycling event. After completion of the event, serum testosterone (–67% ± 18%), insulin-like growth factor-1 (IGF-1) (–45% ± 8%), and leptin (–79% ± 9%) were significantly suppressed (P < .001) and remained suppressed after a 12-h recovery period (P < .001). Changes in IGF-1 were positively correlated with energy balance over the course of the event (r = .65, P = .037), which ranged from an 11,859-kcal deficit to a 3593-kcal surplus. The marked suppression of testosterone, IGF-1, and leptin after ultraendurance exercise is comparable to changes occurring during acute starvation. The suppression of IGF-1, but not that of other metabolic hormones, was strongly associated with the magnitude of the energy deficit, indicating that athletes who attained a greater energy deficit exhibited a more pronounced drop in IGF-1. Future studies are needed to determine whether increased dietary intake can attenuate the endocrine response to ultraendurance exercise.
Michael Behringer, Andreas vom Heede, Maria Matthews and Joachim Mester
The recent literature delineates resistance training in children and adolescents to be effective and safe. However, only little is known about the transfer of achieved strength gains to athletic performance. The present meta-analysis revealed a combined mean effect size for motor skill types jumping, running, and throwing of 0.52 (95% CI: 0.33–0.71). Effect sizes for each of aforementioned skill types separately were 0.54 (95% CI: 0.34–0.74), 0.53 (95% CI: 0.23–0.83), and 0.99 (95% CI: 0.19–1.79) respectively. Furthermore, it could be shown that younger subjects and nonathletes showed higher gains in motor performance following resistance training than their counterparts and that specific resistance training regimes were not advantageous over traditional resistance training programs. Finally, a positive dose response relationship for “intensity” could be found in subgroups using traditional training regimens. These results emphasize that resistance training provides an effective way for enhancing motor performance in children and adolescents.
Michael Behringer, Sebastian Neuerburg, Maria Matthews and Joachim Mester
The purpose of the current study was to evaluate the transferability of 2 different resistance training protocols on service velocity and its precision consistency in junior tennis players. Thirty-six male athletes (15.03 ± 1.64 years) were randomly assigned to a machine-based resistance-training group (RG, n = 12), a plyometric training group (PG, n = 12), and a control group (CG, n = 12). For a period of 8 weeks, both intervention groups resistance trained 2 days per week in addition to their regular tennis training, whereas the CG had no extra training. Mean service velocity over 20 maximum-velocity serves increased significantly more in PG (3.78%; p < .05) when compared with CG, whereas no such changes could be found in the RG (1.18%; p > .05). Service precision did not change from pre- to posttest in all three groups (p > .05). Only the plyometric training program tested, improved mean service velocity over 20 maximum-velocity serves in junior tennis players but did not affect service precision.
Malte Krüger, Markus de Mareés, Karl-Heinrich Dittmar, Billy Sperlich and Joachim Mester
To examine the effects of a whole-body cryotherapy (WBC) protocol (3 min at –110°C) on acute recovery and key variables of endurance performance during high-intensity intermittent exercise in a thermoneutral environment.
Eleven endurance athletes were tested twice in a randomized crossover design in which 5 × 5 min of high-intensity running (HIR) were followed by 1 h of passive rest at ~22°C, including either 3 min of whole-body exposure to –110°C (WBC) or a placebo intervention of 3 min walking (PBO). A ramp-test protocol was performed before HIR (R1) and after the 1-h recovery period (R2). Time to exhaustion (t lim) was measured along with alterations in oxygen content of the vastus lateralis (TSI), oxygen consumption (VO2), capillary blood lactate, heart rate (HR), and rating of perceived exertion (RPE) during submaximal and maximal running.
The difference in t lim between R1 and R2 was lower in WBC than in PBO (P < .05, effect size d = 1.13). During R2, TSI was higher in WBC during submaximal and maximal running (P < .01, d = 0.68−1.01). In addition, VO2, HR, and RPE were lower at submaximal level of R2 after WBC than in PBO (P = .04 to <.01, d = 0.23−0.83).
WBC improves acute recovery during high-intensity intermittent exercise in thermoneutral conditions. The improvements might be induced by enhanced oxygenation of the working muscles, as well as a reduction in cardiovascular strain and increased work economy at submaximal intensities.
Hans Braun, Karsten Koehler, Hans Geyer, Jens Kleinert, Joachim Mester and Wilhelm Schänzer
Little is known about the prevalence and motives of supplement use among elite young athletes who compete on national and international levels. Therefore, the current survey was performed to assess information regarding the past and present use of dietary supplements among 164 elite young athletes (16.6 ± 3.0 years of age). A 5-page questionnaire was designed to assess their past and present (last 4 weeks) use of vitamins, minerals, carbohydrate, protein, and fat supplements; sport drinks; and other ergogenic aids. Furthermore, information about motives, sources of advice, supplement sources, and supplement contamination was assessed. Eighty percent of all athletes reported using at least 1 supplement, and the prevalence of use was significantly higher in older athletes (p < .05). Among supplement users, minerals, vitamins, sport drinks, energy drinks, and carbohydrates were most frequently consumed. Only a minority of the athletes declared that they used protein/amino acids, creatine, or other ergogenic aids. Major motives for supplement use were health related, whereas performance enhancement and recommendations by others were less frequently reported. Supplements were mainly obtained from parents or by athletes themselves and were mostly purchased in pharmacies, supermarkets, and health-food stores. Among all athletes, only 36% were aware of the problem of supplement contamination. The survey shows that supplement use is common and widespread among German elite young athletes. This stands in strong contrast to recommendations by leading sport organizations against supplement use by underage athletes.
Billy Sperlich, Karsten Koehler, Hans-Christer Holmberg, Christoph Zinner and Joachim Mester
The aim of the study was to determine the cardiorespiratory and metabolic characteristics during intense and moderate table tennis (TT) training, as well as during actual match play conditions.
Blood lactate concentration (Lac), heart rate (HR, beats per minute [bpm]), oxygen uptake (VO2), and energy expenditure (EE) in 7 male participants of the German junior national team (age: 14 ± 1 y, weight: 60.5 ± 5.6 kg height; 165 ± 8 cm) were examined during six training sessions (TS) and during an international match. The VO2 was measured continuously with portable gas analyzers. Lac was assessed every 1 to 3 min during short breaks.
Mean (peak) values for Lac, HR, VO2, and EE during the TS were 1.2 ± 0.7 (4.5) mmol·L–1, 135 ± 18 (184) bpm, 23.5 ± 7.3 (43.0) mL·kg–1· min–1, and 6.8 ± 2.0 (11.2) METs, respectively. During match play, mean (peak) values were 1.1 ± 0.2 (1.6) mmol·L–1, 126 ± 22 (189) bpm, 25.6 ± 10.1 (45.9) mL·kg–1·min–1, and 4.8 ± 1.4 (9.6) METs, respectively.
For the frst time, cardiorespiratory and metabolic data in elite junior table tennis have been documented demonstrating low cardiorespiratory and metabolic demands during TT training and match play in internationally competing juniors.