scholarly journals Comparison and Performance Validation of Calculated and Established Anaerobic Lactate Thresholds in Running

Medicina ◽  
2021 ◽  
Vol 57 (10) ◽  
pp. 1117
Author(s):  
Sanghyeon Ji ◽  
Aldo Sommer ◽  
Wilhelm Bloch ◽  
Patrick Wahl
Keyword(s):  
Lactate Production ◽  
Endurance Performance ◽  
Cycle Ergometer ◽  
Threshold Concepts ◽  
Endurance Running ◽  
Maximal Deviation ◽  
Physiological Profiles ◽  
Good Concordance ◽  
And Performance ◽  
Performance Validation

Background and Objectives: This study aimed to compare the calculated running velocity at the anaerobic lactate threshold (cLTAn), determined by a mathematical model for metabolic simulation, with two established threshold concepts (onset of blood lactate accumulation (OBLA; 4 mmol∙L−1) and modified maximal deviation method (mDmax)). Additionally, all threshold concepts were correlated with performance in different endurance running events. Materials and Methods: Ten sub-elite runners performed a 30 s sprint test on a cycle ergometer adjusted to an isokinetic mode set to a cadence of 120 rpm to determine maximal lactate production rate (VLamax), and a graded exercise test on a treadmill to determine maximal oxygen uptake (VO2max). Running velocities at OBLA, mDmax, and cLTAn were then compared with each other, and further correlated with running performance over various distances (3000 m, 5000 m, and 10,000 m). Results: The mean difference in cLTAn was −0.13 ± 0.43 m∙s−1 and −0.32 ± 0.39 m∙s−1 compared to mDmax (p = 0.49) and OBLA (p < 0.01), respectively. cLTAn indicated moderate to good concordance with the established threshold concepts (mDmax: ICC = 0.87, OBLA: ICC = 0.74). In comparison with other threshold concepts, cLTAn exhibited comparable correlations with the assessed running performances (cLTAn: r = 0.61–0.76, mDmax: r = 0.69–0.79, OBLA: r = 0.56–0.69). Conclusion: Our data show that cLTAn can be applied for determining endurance performance during running. Due to the consideration of individual physiological profiles, cLTAn offers a physiologically justified approach to assess an athlete’s endurance performance.

scholarly journals Lactobacillus plantarum PS128 Improves Physiological Adaptation and Performance in Triathletes through Gut Microbiota Modulation

Nutrients ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2315 ◽  
Author(s):  
Wen-Ching Huang ◽  
Chun-Hsu Pan ◽  
Chen-Chan Wei ◽  
Hui-Yu Huang
Keyword(s):  
Lactobacillus Plantarum ◽  
Exercise Performance ◽  
Maximal Oxygen Consumption ◽  
Endurance Performance ◽  
Short Chain Fatty Acids ◽  
Physiological Adaptation ◽  
Endurance Running ◽  
Supplement Group ◽  
Significant Difference ◽  
And Performance

A triathlon is an extremely high-intensity exercise and a challenge for physiological adaptation. A triathlete’s microbiome might be modulated by diet, age, medical treatments, lifestyle, and exercise, thereby maintaining aerobiosis and optimum health and performance. Probiotics, prebiotics, and synbiotics have been reported to have health-promoting activities (e.g., immunoregulation and cancer prevention). However, few studies have addressed how probiotics affect the microbiota of athletes and how this translates into functional activities. In our previous study, we found that Lactobacillus plantarum PS128 could ameliorate inflammation and oxidative stress, with improved exercise performance. Thus, here we investigate how the microbiota of triathletes are altered by L. plantarum PS128 supplementation, not only for exercise performance but also for possible physiological adaptation. The triathletes were assigned to two groups: an L. plantarum 128 supplement group (LG, 3 × 1010 colony-forming units (CFU)/day) and a placebo group (PG). Both groups continued with their regular exercise training for the next 4 weeks. The endurance performance, body composition, biochemistries, blood cells, microbiota, and associated metabolites were further investigated. PS128 significantly increased the athletes’ endurance, by about 130% as compared to the PG group, but there was no significant difference in maximal oxygen consumption (VO2max) and composition between groups. The PS128 supplementation (LG) modulated the athlete’s microbiota with both significant decreases (Anaerotruncus, Caproiciproducens, Coprobacillus, Desulfovibrio, Dielma, Family_XIII, Holdemania, and Oxalobacter) and increases (Akkermansia, Bifidobacterium, Butyricimonas, and Lactobacillus), and the LG showed lower diversity when compared to the PG. Also, the short-chain fatty acids (SCFAs; acetate, propionate, and butyrate) of the LG were significantly higher than the PG, which might be a result of a modulation of the associated microbiota. In conclusion, PS128 supplementation was associated with an improvement on endurance running performance through microbiota modulation and related metabolites, but not in maximal oxygen uptake.

scholarly journals Sporting myths: the REAL role of lactate during exercise

2016 ◽  
Vol 19 (5) ◽  
Author(s):  
T Mann
Keyword(s):  
Lactate Concentration ◽  
Lactate Production ◽  
Blood Lactate Concentration ◽  
Endurance Performance ◽  
Post Exercise ◽  
Early Exercise ◽  
Important Intermediate ◽  
Lactate Formation ◽  
Exercise Muscle

Background. Lactate or, as it was customarily known, ‘lactic acid’ was one of the first molecules to attract the attention of early exercise scientists, mainly because blood lactate concentration could be measured and was shown to increase with increasing exercise intensity. This connection resulted in lactate being associated with numerous other events associated with high-intensity exercise including muscle cramps, fatigue, acidosis and post-exercise muscle soreness. Nobel prize-winning research by AV Hill and Otto Meyerhof provided a rational explanation linking lactate to anaerobiosis and acidosis, which resulted in this relationship being widely accepted as fact. It was only following isotopic tracer studies of George Brooks and others that the true role of lactate during rest and exercise was revealed. Conclusions. Lactate is now acknowledged as an important intermediate of carbohydrate metabolism, taken up from the blood by tissues such as skeletal and cardiac muscle as a substrate for oxidation. Furthermore, lactate formation consumes a proton, thereby buffering against muscle acidosis. For this reason, lactate production forms an essential aid to endurance performance rather than a hindrance.

Effects of the Menstrual Cycle on Serum Carnitine and Endurance Performance of Women

2020 ◽  
Vol 41 (07) ◽  
pp. 443-449
Author(s):  
Tomoka Matsuda ◽  
Tamaki Furuhata ◽  
Hazuki Ogata ◽  
Kayoko Kamemoto ◽  
Mizuki Yamada ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Endurance Performance ◽  
Cycle Ergometer ◽  
Free Carnitine ◽  
Blood Levels ◽  
Serum Free ◽  
Ergometer Exercise ◽  
Early Follicular Phase ◽  
Total Carnitine ◽  
Midluteal Phase

AbstractThis study aimed to investigate the effect of the menstrual cycle on serum carnitine and the endurance performance of healthy women. Fifteen eumenorrheic women underwent cycle ergometer exercise at 60% maximal oxygen uptake (V̇ O2max) for 45 min, followed by exercise at an intensity that was increased to 80% V̇ O 2max until exhaustion, during two menstrual cycle phases, including the early follicular phase (FP) and the midluteal phase (LP). The blood levels of estradiol, progesterone, total carnitine, free carnitine, and acylcarnitine were assessed. Compared with the FP, the LP had significantly lower serum total carnitine (p<0.05) and free carnitine (p<0.01). Moreover, the group with decreased endurance performance in the LP than in the FP showed a significantly higher change in serum free carnitine compared with the group that showed improved endurance performance in the LP than in the FP (p<0.05). The results of this study suggested that the changes in serum free carnitine during the menstrual cycle might influence endurance performance.

Mill Steam Inerting System Review and Performance Validation

2014 ◽  
Author(s):  
Qingsheng Lin ◽  
Todd Collins
Keyword(s):  
Inert Atmosphere ◽  
Tube Mill ◽  
Mill Operation ◽  
Start Up ◽  
Proper Design ◽  
System Review ◽  
System Requirements ◽  
And Performance ◽  
Performance Validation ◽  
Inerting System

NFPA 85, Chapter 9.5.4 states “A pulverizer that is tripped under load shall be inerted and maintained under an inert atmosphere until confirmation that no burning or smoldering fuel exists in the pulverizer or the fuel is removed”. Pulverizer systems with the potential for a resident inventory of combustible material upon trip must be designed and equipped with an inerting system that is capable of maintaining an inert atmosphere to meet this requirement. Proper design of the inerting system and operating procedure, integrated with the mill operation during start-up, shut down and emergency trip is critical for safe mill operation. This paper presents a mill steam inerting system review and performance validation. The technology has been applied to ball tube mill systems at Hoosier Energy’s Merom Generating Station. A testing technique, used to validate performance of the steam inerting system at this generating plant, is described. It quantifies the compliance of the steam inerting system to meet NFPA requirements during start-up and shut down of the pulverizer. This type of operation is considered to be the most difficult for inerting as the primary air is flowing through the system. The developed testing approach can be applied to evaluate the performance of either existing or newly installed steam inerting systems. The validation technology, developed based on a ball tube mill system, can be readily applied on other types of mill systems, since the steam inerting principle is the same and inerting system requirements are similar, regardless of different mill types.

scholarly journals Differences in the Effects of Carbohydrate Food Form on Endurance Performance to Exhaustion

1993 ◽  
Vol 3 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Scott D. Murdoch ◽  
Terry L. Bazzarre ◽  
Ian P. Snider ◽  
Allan H. Goldfarb
Keyword(s):  
Glucose Concentration ◽  
Blood Glucose Concentration ◽  
Endurance Performance ◽  
Performance Effects ◽  
Endurance Tests ◽  
The Mean ◽  
And Performance ◽  
Mean Blood Glucose ◽  
Mean Glucose ◽  
Placebo Drink

This investigation examined the metabolic and performance effects of ingesting solid compared to slurried carbohydrate food (bananas) between two prolonged exhaustive exercise bouts. Eight highly trained bale triathletes performed four exhaustive endurance tests (ET), each separated by at least 2 weeks. Each ET consisted of a 90-min run followed by 90 min of cycling, both at 70%. Workloads were then gradually increased on the cycle, and subjects continued to cycle until exhausted. They then rested for 20 min and ingested one of the following: an artificially sweetened placebo drink (P), slurried bananas (SL), or solid bananas (SO). Bananas were given in equal portions relative to each subject's body weight. Subjects cycled to exhaustion a second time at 70% of their, at which point the mean blood glucose concentration for the combined carbohydrate treatments was significantly higher than that from the P treatment. The mean glucose concentration from the SL treatment did not differ significantly from the SO treatment. These data demonstrate that solid bananas are as effective as slurried bananas in maintaining plasma glucose and in enhancing endurance exercise performance.

A Highly Efficient Integrated Silicon-Microchannel Cooler for Multi-Module Electronic Microsystems-Model Design, Optimization and Performance Validation

2020 ◽  
pp. 1-38
Author(s):  
Jiejun Wang ◽  
Tao Wang ◽  
Qiuyan Li ◽  
Yiming Li ◽  
Chuangui Wu ◽  
...  
Keyword(s):  
Heat Flux ◽  
Flow Distribution ◽  
Development Trend ◽  
High Heat ◽  
Coolant Flow ◽  
Maximum Temperature ◽  
High Heat Flux ◽  
Highly Efficient ◽  
And Performance ◽  
Performance Validation

Abstract Recently, the development trend of multi-module and multi-function in electronic microsystems makes the ever-increasing heat flux problem more serious. In this study, a highly efficient integrated single-phase microchannel cooler with four heat sources is presented for handling the challenges from both working independently of all electronic modules and the high heat flux. Numerical and experimental study are both conducted. By optimizing the structural design and the fabricated process, the presented microchannel cooler has outstanding cooling performance, which contains desired fluid flow distribution, pressure drop, heat transfer and combination thereof. Results reveals uniform coolant flow dissipates four individual heaters independently, and their maximal temperature difference below 4 °C. Beyond this, high heat flux removal (707.6 W/cm2) is realized with extremely low coolant flow rate (45 ml/min), and the maximum temperature rise is less than 60 °C. This study provides a referable solution for the thermal management of multi-module heat source and high heat flux in compact electronic microsystems.

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