Relationship of an equivalence point for change in V[combining dot above]CO2 and V[combining dot above]O2 to endurance performance.

There are many tests available to coaches and practitioners who seek to identify a point during exercise when excess lactate is being produced or hyperventilation stimulated as a result of metabolic acidosis. This investigation sought to determine the relationship between performance and the first occurrence of excess CO2 production because of increased ventilatory buffering. For this investigation, 2 separate studies were conducted, each examined the predictive value of the 2 standard ventilatory threshold (VT) assessments (V-Slope and examination of ventilatory equilvalents) and the point of equivalence in change (PEC) against performance in an endurance race. The PEC was determined by examining the third-order trend for V[Combining Dot Above]CO2 and V[Combining Dot Above]O2 and determining where the change by time was equivalent (ΔV[Combining Dot Above]O2/ΔV[Combining Dot Above]O2 = 1). The first study examined the assessments of PEC vs. VT in a population of 10-km race competitors (study 1) and the second a population of National Collegiate Athletic Association Division 1 crosscountry runners (study 2). Partial correlations (controlled for weight) were used to assess the relationships with performance. In study 1, the partial correlations revealed that the PEC had the highest correlation to race performance (r = 0.961, p < 0.001) compared with the other techniques (V-slope r = 0.890, p < 0.001, ventilatory equivalents r = 0.733, p = 0.01). Analyses of difference in strength of correlations within study 1 demonstrated differences between PEC and mean race speed as compared with V-slope or ventilatory equivalents and mean race speed. In study 2, a similar trend was observed (PEC r = 0.863, p = 0.001, V-slope (r = 0.828, p = 0.002, ventilatory equivalents r = 0.750, p = 0.008). The results of this study suggest that determination of PEC is more related to 10-km race performance than 2 well-established methods for VT determination.

Energy systems efficiency influences the results of 2,000 m race simulation among elite rowers.

HYPOTHESIS: Energy efficiency within an elite group of athletes will ensure metabolic adaptation during training. OBJECTIVES: To identify energy system efficiency and contribution according to exercise intensity, and performance obtained during a 2,000 m race simulation in an elite group of rowers. METHOD: An observational cross-sectional study was conducted in February 2016 in Bucharest, Romania, on a group of 16 elite rowers. Measurements were performed through Cosmed Quark CPET equipment, and Concept 2 ergometer, by conducting a VO2max test over a standard rowing distance of 2,000 m. The analyzed parameters during the test were: HR (bpm), Rf (b/min), VE (l/min), VO2 (ml/min), VCO2 (ml/min), VT (l), O2exp (ml), CO2exp (ml), RER, PaCO2 (mmHg), PaO2 (mmHg), Kcal/min, FAT (g), CHO (g), from which we determined the ventilatory thresholds, and the energy resource used during the specific 2,000 m rowing distance (ATP, ATP+CP, muscle glycogen). RESULTS: We performed an association between HR (180.2±4.80 b/min), and carbohydrate consumption during the sustained effort (41.55±3.99 g) towards determining the energy systems involved: ATP (3.49±1.55%), ATP+CP (18.06±2.99%), muscle glycogen (77.9±3.39%). As a result, completion time (366.3±10.25 s) was significantly correlated with both Rf (p=0.0024), and VO2 (p=0.0166) being also pointed out that ≥5 l VO2 value is associated with an effort time of ≤360 s. (p=0.040, RR=3.50, CI95%=1.02 to 11.96). Thus, the average activation time among muscle ATP (12.81±5.70 s), ATP+CP (66.04±10.17 s, and muscle glycogen (295±9.5 s) are interrelated, and significantly correlated with respiratory parameters. CONCLUSIONS: Decreased total activity time was associated with accessing primary energy source in less time, during effort, improving the body energy power. Its effectiveness was recorded by early carbohydrates access, as a primary energy source, during specific activity performed up to 366 seconds.

Secondary elements of blood pH variation can influence the effort effectiveness based on adaptive changes within a group of elite athletes.

AIM: pH is the direct indicator of the body reaction following the activities performed. Establishing precise correlations between pH and blood biochemical parameters might support the balancing of values during periods of marked physical activity. METHOD: We conducted a case study in a group of elite rowers. Twelve athletes were included in the study. Monitoring was carried out by collecting biological samples several times a day: in the morning, 80 minutes pre-workout, 12 hours after the last physical effort performed, at two different times, 10 days apart. Determinations were aimed at adapting the reported biochemical parameters depending on the effort performed. The following parameters were monitored: pH, HCO3, pCO2, pO2, BE, SBE, SBC, Ca++, Mg++, LDH, GPT, T-Pro, and Alb. RESULTS: The mean value of pH found in athletes was 7.41±0.024. The value obtained was significantly correlated to biochemical parameters such as BE (2.32±1.79), SBC (1.67±1.45), SBE (2.70±1.75). However, bicarbonate (HCO3) was statistically significantly related with SBE, SBC, SBE, and pO2, but did not present a strong association with the pH value (p=0.094). However, values such as Alb, Ca++, LDH, BE, SBC are related to pH value as a result of variations in the data submitted. CONCLUSIONS: The processed data evidence the fact that blood pH, in this case, is significantly influenced by a number of indices that correlate energy system activity, individual adaptation to effort, and the recovery process. The parameters under investigation (SBE, SBC, SBE, CPK, LDH) are associated with pH changes that could confirm the recovery efficiency of the athlete, along with a possible metabolic acidosis/alkalosis.