scholarly journals Peripheral Modulators of the Central Fatigue Development and Their Relationship with Athletic Performance in Jumper Horses

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 743
Author(s):  
Francesca Arfuso ◽  
Claudia Giannetto ◽  
Elisabetta Giudice ◽  
Francesco Fazio ◽  
Michele Panzera ◽  
...  

The current study aimed to investigate whether peripheral modulators of serotoninergic function and neurohumoral factors’ changes in athletic horses during an official jumping competition, and to evaluate their relationship with the physical performance of competing horses. From 7 Italian Saddle mares (6–9 years; mean body weight 440 ± 15 kg), performing the same standardized warm-up and jumping course during an official class, heart rate (HR) was monitored throughout the competition. Rectal temperature (RT) measurement, blood lactate and glucose concentration, serum tryptophan, leucine, valine, the tryptophan/branched-chain amino-acids ratio (Try/BCAAs), dopamine, prolactin, and non-esterified fatty acids (NEFAs) were assessed before the exercise event (T0), at the end of the competition stage (5 min ± 10 s following the cessation of the exercise, TPOST5), and 30 min after the end of competition (TPOST30). Highest HR values were recorded during the course and at the outbound (p < 0.0001); blood lactate concentration and RT increased after exercise with respect to the rest condition (p < 0.0001). Lower leucine and valine levels (p < 0.01), and higher tryptophan, Try/BCAAs ratio, and NEFAs values were found at TPOST5 and TPOST30 with respect to T0 (p < 0.0001). A higher prolactin concentration was found at TPOST5 and TPOST30 compared to T0 (p < 0.0001), whereas dopamine showed decreased values after exercise compared to rest (p < 0.0001). Statistically significant correlations among the peripheral indices of serotoninergic function, neurohumoral factors, and athletic performance parameters were found throughout the monitoring period. The findings provide indirect evidence that the serotoninergic system may be involved in fatigue during jumper exercise under a stressful situation, such as competition, in which, in addition to physical effort, athletic horses exhibit more passive behavior.

2020 ◽  
Vol 19 (1) ◽  
pp. 32
Author(s):  
Gustavo Taques Marczynski ◽  
Luís Carlos Zattar Coelho ◽  
Leonardo Emmanuel De Medeiros Lima ◽  
Rodrigo Pereira Da Silva ◽  
Dilmar Pinto Guedes Jr ◽  
...  

The aim of this study was to analyze the influence of two velocities of execution relative to blood lactate concentration in strength training exercise until the momentary concentric failure. Fifteen men (29.1 ± 5.9 years), trained, participated in the experiment. The volunteers performed three bench press sessions, with an interval of 48 hours between them. At the first session, individuals determined loads through the 10-12 RMs test. In the following two sessions, three series with 90 seconds of interval were performed, in the second session slow execution speed (cadence 3030) and later in the third session fast speed (cadence 1010). For statistical analysis, the Student-T test was used for an independent sample study and considered the value of probability (p) ≤ 0.05 statistically significant. By comparing the number of repetitions and time under tension of the two runs, all series compared to the first presented significant reductions (p < 0.05). The total work volume was higher with the fast speed (p < 0.05). The study revealed that rapid velocities (cadence 1010) present a higher concentration of blood lactate when compared to slow runs (cadence 3030). The blood lactate concentration, in maximum repetitions, is affected by the speed of execution.Keywords: resistance training, cadence, blood lactate.


1993 ◽  
Vol 75 (6) ◽  
pp. 2727-2733 ◽  
Author(s):  
K. H. McKeever ◽  
K. W. Hinchcliff ◽  
D. F. Gerken ◽  
R. A. Sams

Four mature horses were used to test the effects of two doses (50 and 200 mg) of intravenously administered cocaine on hemodynamics and selected indexes of performance [maximal heart rate (HRmax), treadmill velocity at HRmax, treadmill velocity needed to produce a blood lactate concentration of 4 mmol/l, maximal mixed venous blood lactate concentration, maximal treadmill work intensity, and test duration] measured during an incremental treadmill test. Both doses of cocaine increased HRmax approximately 7% (P < 0.05). Mean arterial pressure was 30 mmHg greater (P < 0.05) during the 4- to 7-m/s steps of the exercise test in the 200-mg trial. Neither dose of cocaine had an effect on the responses to exertion of right atrial pressure, right ventricular pressure, or maximal change in right ventricular pressure over time. Maximal mixed venous blood lactate concentration increased 41% (P < 0.05) with the 50-mg dose and 75% (P < 0.05) with the 200-mg dose during exercise. Administration of cocaine resulted in decreases (P < 0.05) in the treadmill velocity needed to produce a blood lactate concentration of 4 mmol/l from 6.9 +/- 0.5 and 6.8 +/- 0.9 m/s during the control trials to 4.4 +/- 0.1 m/s during the 200-mg cocaine trial. Cocaine did not alter maximal treadmill work intensity (P > 0.05); however, time to exhaustion increased by approximately 92 s (15%; P < 0.05) during the 200-mg trial.(ABSTRACT TRUNCATED AT 250 WORDS)


2011 ◽  
Vol 6 (3) ◽  
pp. 419-426 ◽  
Author(s):  
Dale I. Lovell ◽  
Dale Mason ◽  
Elias Delphinus ◽  
Chris McLellan

Purpose:The aim of this study was to compare asynchronous (AS Y) arm cranking (cranks at 180° relative to each other) with synchronous (SYN) arm cranking (parallel crank setting) during the 30 s Wingate anaerobic test.Methods:Thirty-two physically active men (aged 22.1 ± 2.4 y) completed two Wingate tests (one ASY and one SYN) separated by 4 d in a randomized counterbalanced order. The Wingate tests were completed on a modified electromagnetically braked cycle ergometer. Performance measures assessed during the two tests include peak power, mean power, minimum power, time to peak power, rate to fatigue and maximum cadence (RPMmax). Blood lactate concentration was also measured before and 5 min after the tests.Results:Peak and mean power (both absolute and relative to body weight) during SYN arm cranking were significantly (p < 0.001) less than during ASY arm cranking. Rate to fatigue and RPMmax were also significantly (p = 0.012) lower during SYN arm cranking compared with ASY arm cranking. No significant difference was found between test conditions for minimum power, time to peak power or blood lactate concentration.Conclusions:These findings demonstrate that ASY arm cranking results in higher peak and mean anaerobic power compared with SYN arm cranking during the Wingate test. Therefore, an ASY arm crank configuration should be used to assess anaerobic power in most individuals although specific population groups may require further testing to determine which crank configuration is most suitable for the Wingate test.


2017 ◽  
Vol 12 (4) ◽  
pp. 527-532 ◽  
Author(s):  
F. Javier Núñez ◽  
Luis J. Suarez-Arrones ◽  
Paul Cater ◽  
Alberto Mendez-Villanueva

The aim of this study was to examine the kinematics and kinetics (force, velocity, and acceleration) and blood lactate concentration with the VersaPulley (VP) device in comparison with free-weight (FW) exercise at a similar external load. Fifteen rugby players randomly performed 2 training sessions of 6 sets of 6 repetitions with 20 s of recovery between sets of the high-pull exercise with the VP and the FW. The training sessions were separated by 72 h. Barbell displacement (cm), peak velocity (m/s), peak acceleration (m/s2), mean propulsive velocity (m/s), mean propulsive acceleration (m/s2), propulsive phase (%), and mean and maximal force (N) were continuously recorded during each repetition. Blood lactate concentration was measured after each training session (end) and 3 min and 5 min later. Barbell displacement (+4.8%, small ES), peak velocity (+4.5% small ES), mean propulsive acceleration (+8.8%, small ES), and eccentric force (+26.7, large ES) were substantially higher with VP than with FW. Blood lactate concentration was also greater after the VP exercise (end +32.9%, 3 min later +36%, 5 min later +33.8%; large ES). Maximal concentric force was substantially higher with FW than VP during the 6th set (+6.4%, small ES). In the cohort and exercise investigated in the current study, VP training can be considered an efficient training device to induce an accentuated eccentric overload and augmented metabolic demands (ie, blood lactate concentration).


Author(s):  
Giovanni Carpenè ◽  
Diletta Onorato ◽  
Riccardo Nocini ◽  
Gianmarco Fortunato ◽  
John G. Rizk ◽  
...  

Abstract Coronavirus disease 2019 (COVID-19) is an infectious respiratory condition sustained by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which manifests prevalently as mild to moderate respiratory tract infection. Nevertheless, in a number of cases the clinical course may deteriorate, with onset of end organ injury, systemic dysfunction, thrombosis and ischemia. Given the clinical picture, baseline assessment and serial monitoring of blood lactate concentration may be conceivably useful in COVID-19. We hence performed a systematic literature review to explore the possible association between increased blood lactate levels, disease severity and mortality in COVID-19 patients, including comparison of lactate values between COVID-19 and non-COVID-19 patients. We carried out an electronic search in Medline and Scopus, using the keywords “COVID-19” OR “SARS-CoV-2” AND “lactate” OR “lactic acid” OR “hyperlactatemia”, between 2019 and present time (i.e. October 10, 2021), which allowed to identify 19 studies, totalling 6,459 patients. Overall, we found that COVID-19 patients with worse outcome tend to display higher lactate values than those with better outcome, although most COVID-19 patients in the studies included in our analysis did not have sustained baseline hyperlactatemia. Substantially elevated lactate values were neither consistently present in all COVID-19 patients who developed unfavourable clinical outcomes. These findings suggest that blood lactate monitoring upon admission and throughout hospitalization may be useful for early identification of higher risk of unfavourable COVID-19 illness progression, though therapeutic decisions based on using conventional hyperlactatemia cut-off values (i.e., 2.0 mmol/L) upon first evaluation may be inappropriate in patients with SARS-CoV-2 infection.


Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 150
Author(s):  
Nico Nitzsche ◽  
Lutz Baumgärtel ◽  
Christian Maiwald ◽  
Henry Schulz

(1) Background: Maximum isokinetic force loads show strongly increased post-load lactate concentrations and an increase in the maximum blood lactate concentration rate ( V ˙ Lamax), depending on load duration. The reproducibility of V ˙ Lamax must be known to be able to better assess training-related adjustments of anaerobic performance using isokinetic force tests. (2) Methods: 32 subjects were assigned to two groups and completed two unilateral isokinetic force tests (210° s−1, Range of Motion 90°) within seven days. Group 1 (n = 16; age 24.0 ± 2.8 years, BMI 23.5 ± 2.6 kg m−2, training duration: 4.5 ± 2.4 h week−1) completed eight repetitions and group 2 (n = 16; age 23.7 ± 1.9 years, BMI 24.6 ± 2.4 kg m−2, training duration: 5.5 ± 2.1 h week−1) completed 16 repetitions. To determine V ˙ Lamax, capillary blood (20 µL) was taken before and immediately after loading, and up to the 9th minute post-load. Reproducibility and variability was determined using Pearson and Spearman correlation analyses, and variability were determined using within-subject standard deviation (Sw) and Limits of Agreement (LoA) using Bland Altman plots. (3) Results: The correlation of V ˙ Lamax in group 1 was r = 0.721, and in group 2 r = 0.677. The Sw of V ˙ Lamax was 0.04 mmol L−1 s−1 in both groups. In group 1, V ˙ Lamax showed a systematic bias due to measurement repetition of 0.02 mmol L−1 s−1 in an interval (LoA) of ±0.11 mmol L−1 s−1. In group 2, a systematic bias of −0.008 mmol L−1 s−1 at an interval (LoA) of ±0.11 mmol L−1 s−1 was observed for repeated measurements of V ˙ Lamax. (4) Conclusions: Based on the existing variability, a reliable calculation of V ˙ Lamax seems to be possible with both short and longer isokinetic force loads. Changes in V ˙ Lamax above 0.11 mmol L−1 s−1 due to training can be described as a non-random increase or decrease in V ˙ Lamax.


2017 ◽  
Vol 79 (3) ◽  
pp. 513-516 ◽  
Author(s):  
Takashi MURAKAMI ◽  
Shigeru NAKAO ◽  
Yohei SATO ◽  
Satoshi NAKADA ◽  
Akane SATO ◽  
...  

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