Predictors of Athlete's Performance in Ultra-Endurance Mountain Races.

BACKGROUND: In previous studies, ultra-endurance performance has been associated with training and psychological variables. However, performance under extreme conditions is understudied, mainly due to difficulties in making field measures. AIM: The aim of this study was to analyze the role of training, hydration, nutrition, oral health status, and stress-related psychological factors in athletes' performance in ultra-endurance mountain events. METHODS: We analyzed the variables of race time and training, hydration state, nutrition, oral health status, and stress-related psychological factors in 448 ultra-endurance mountain race finishers divided into three groups according to race length (less than 45 km, 45-90 km, and greater than 90 km), using a questionnaire. RESULTS: Higher performance in ultra-endurance mountain races was associated with better oral health status and higher accumulative altitude covered per week as well as higher positive accumulative change of altitude per week during training. In longer distance races, experience, a larger volume of training, and better hydration/nutrition prior to the competition were associated with better performance. CONCLUSIONS: Ultra-endurance mountain athletes competing in longer races (>90 km) have more experience and follow harder training schedules compared with athletes competing in shorter distances. In longer races, a larger fluid intake before the competition was the single best predictor of performance. For races between 45 and 90 km, training intensity and volume were key predictors of performance, and for races below 45 km, oral health status was a key predictor of performance. Psychological factors previously reported as ultra-endurance mountain race performance predictors were inconsistent or failed to predict the performance of athletes in the present research.

Hypoxanthine-Guanine Phosphoribosyltransferase/adenylate Kinase From Zobellia galactanivorans: A Bifunctional Catalyst for the Synthesis of Nucleoside-5'-Mono-, Di- and Triphosphates.

In our search for novel biocatalysts for the synthesis of nucleic acid derivatives, we found a good candidate in a putative dual-domain hypoxanthine-guanine phosphoribosyltransferase (HGPRT)/adenylate kinase (AMPK) from Zobellia galactanivorans (ZgHGPRT/AMPK). In this respect, we report for the first time the recombinant expression, production, and characterization of a bifunctional HGPRT/AMPK. Biochemical characterization of the recombinant protein indicates that the enzyme is a homodimer, with high activity in the pH range 6-7 and in a temperature interval from 30 to 80°C. Thermal denaturation experiments revealed that ZgHGPRT/AMPK exhibits an apparent unfolding temperature (Tm) of 45°C and a retained activity of around 80% when incubated at 40°C for 240 min. This bifunctional enzyme shows a dependence on divalent cations, with a remarkable preference for Mg2+ and Co2+ as cofactors. More interestingly, substrate specificity studies revealed ZgHGPRT/AMPK as a bifunctional enzyme, which acts as phosphoribosyltransferase or adenylate kinase depending upon the nature of the substrate. Finally, to assess the potential of ZgHGPRT/AMPK as biocatalyst for the synthesis of nucleoside-5'-mono, di- and triphosphates, the kinetic analysis of both activities (phosphoribosyltransferase and adenylate kinase) and the effect of water-miscible solvents on enzyme activity were studied.

Effectiveness of Psycho-Physiological Portable Devices to Analyse Effect of Ergogenic Aids in Military Population.

Caffeine is one of the ergogenic substances most used by warfighters in current operation areas, but the effect on the organic response and operational performed is already poor knowledge. This research aimed to study the acute effect of 400 mg of caffeine monohydrate on the psycho-physiological response and rifle marksmanship of warfighters during a close quarter combat simulation. We analysed parameter of heart rate, blood lactate, cortical arousal, state anxiety and marksmanship of 20 Spanish Army veteran warfighters before and after a close quarter combat simulation in a double-blind procedure, also a correlation analysis was conducted between all the study variables. Marksmanship of warfighters did not improve with the caffeine ingestion, but it produced an increase in blood lactate concentration (caffeine: 1.9 ± 0.5 vs. 9.2 ± 1.1 mmol.l-1; placebo: 1.8 ± 0.7 vs. 6.9 ± 2.2 mmol.l-1), cortical arousal (% of change: caffeine: 2.51; placebo: -1.96) and heart rate (caffeine: 80.0 ± 7.2 vs. 172.9 ± 28.2 bpm; placebo: 79.3 ± 6.4 vs. 154.0 ± 26.8 bpm). In addition, higher heart rate values correlated negatively with marksmanship in close quarter combat. We concluded that caffeine intake did not improve the warfighters rifle marksmanship in close quarter combat possibly due to the increase in the physiological response.

Psychophysiological Response and Fine Motor Skills in High-Altitude Parachute Jumps.

Clemente-Suárez, Vicente Javier, José Juan Robles-Pérez, Ketty Herrera-Mendoza, Beliña Herrera-Tapias, and Jesús Fernández-Lucas. Psychophysiological response and fine motor skills in high-altitude parachute jumps. High Alt Med Biol 18:392-399, 2017.-We analyzed the psychophysiological response and specific fine motor skill of an experienced jumper in HALO (high altitude low opening) and HAHO (high altitude high opening) parachute jumps. Eight HALO and eight HAHO jumpers were analyzed. They jumped at 5500 m, HALO jumpers opened the parachute at 500 m and HAHO jumpers at 4300 m of altitude. Before and after the jumps, parameters of muscle strength, cortical arousal, blood creatine kinase (CK) and glucose, blood oxygen saturation, rate of perceived exertion (RPE), and specific fine motor skills of an experienced jumper were assessed; during the jump, heart rate (HR), HR variability, and speed were evaluated. HALO and HAHO jumps produced a significant increase in CK, lactate, and RPE, and a decrease in glucose. HAHO decreased cortical arousal, presented a higher sympathetic modulation, and a higher HR during the jump than HALO. HALO and HAHO produced an increase in the physiological, sympathetic modulation and muscle destruction, and a decrease in cortical arousal and a higher blood lactate concentration only in the HAHO jump. Also, somatic and cognitive anxiety correlated with higher strength manifestation and muscle destruction. This novel research could be used to improve actual training systems in both civil and military parachute jumpers.