Short-duration Exercise Research Articles

Short-Duration Swimming Exercise after Myocardial Infarction Attenuates Cardiac Dysfunction and Regulates Mitochondrial Quality Control in Aged Mice.

Background Exercise benefits to cardiac rehabilitation (CR) following stable myocardial infarction (MI). The suitable exercise duration for aged patients with coronary heart disease (CHD) remains controversial, and the underlying molecular mechanism is still unclear. Methods and Results 18-Month-old mice after stable MI were randomly submitted to different durations of exercise, including 15 and 60 min swimming training (ST) once per day, five times a week for 8 weeks. Compared to sedentary mice, 15 min ST, rather than 60 min ST, significantly augmented left ventricular function, increased survival rate, and suppressed myocardial fibrosis and apoptosis. 15 min ST improved mitochondrial morphology via regulating mitochondrial fission-fusion signaling. 15 min ST regulated mitophagy signaling via inhibiting LC3-II and P62 levels and increasing PINK/Parkin expression. 15 min ST also inhibited ROS production and enhanced antioxidant SOD2 activity. Notably, 15 min ST significantly increased sirtuin (SIRT) 3 level (2.7-fold) in vivo while the inhibition of SIRT3 exacerbated senescent H9c2 cellular LDH release and ROS production under hypoxia. In addition, SIRT3 silencing impairs mitochondrial dynamics and mitophagy in senescent cardiomyocytes against simulated ischemia (SI) injury. Conclusion Collectively, our study demonstrated for the first time that sustained short-duration exercise, rather than long-duration exercise, attenuates cardiac dysfunction after MI in aged mice. It is likely that the positive regulation induced by a short-duration ST regimen on the elevated SIRT3 protein level improved mitochondrial quality control and decreased apoptosis and fibrosis contributed to the observed more resistant phenotype.

Does time of day and short-duration high-intensity exercise effect haemostasis?

Does time of day and short-duration high-intensity exercise effect haemostasis?

A Novel Electromyographic Approach to Estimate Fatigue Threshold in Maximum Incremental Strength Tests.

Evaluation of muscular fatigue thresholds in athletes performing short-duration and explosive exercises is difficult because classic parameters do not suffer large variations. Therefore, the aim of this study was to develop a new method to estimate the fatigue threshold in single muscles. Our approach is based on electromyographic data recorded during a maximum incremental strength test until the one repetition maximum is reached. Ten men and 10 women performed a half-squat strength test consisting of five incremental intensities of one repetition maximum. Neither heart rate nor blood lactate concentrations showed significant differences at the various intensities tested. Surface electromyographic activities of vastus lateralis, vastus medialis, and rectus femoris were recorded, finding a break point corresponding to the fatigue threshold occurring in men at 70.74%, 71.48%, and 72.52% of one repetition maximum, respectively. In women, break-point values were 76.66% for vastus lateralis, 76.27% for vastus medialis, and 72.10% for rectus femoris. In conclusion, surface electromyography could be a useful, rapid, and noninvasive tool to determine the fatigue threshold of independent muscles during a maximal half-squat strength test.

Effect of tapering after a period of high-volume sprint interval training on running performance and muscular adaptations in moderately trained runners.

The effect of tapering following a period of high-volume sprint interval training (SIT) and a basic volume of aerobic training on performance and muscle adaptations in moderately trained runners was examined. Eleven (8 men, 3 women) runners [maximum oxygen uptake (V̇o2max): 56.8 ± 2.9 ml·min-1·kg-1; mean ± SD] conducted high-volume SIT (HV; 20 SIT sessions; 8-12 × 30 s all-out) for 40 days followed by 18 days of tapering (TAP; 4 SIT sessions; 4 × 30 s all-out). Before and after HV as well as midway through and at the end of TAP, the subjects completed a 10-km running test and a repeated running test at 90% of vV̇o2max to exhaustion (RRT). In addition, a biopsy from the vastus lateralis muscle was obtained at rest. Performance during RRT was better ( P < 0.01) at the end of TAP than before HV (6.8 ± 0.5 vs. 5.6 ± 0.5 min; means ± SE), and 10-km performance was 2.7% better ( P < 0.05) midway through (40.7 ± 0.7 min) and at the end of (40.7 ± 0.6 min) TAP than after HV (41.8 ± 0.9 min). The expression of muscle Na+-K+-ATPase (NKA)α1, NKAβ1, phospholemman (FXYD1), and sarcoplasmic reticulum calcium transport ATPase (SERCA1) increased ( P < 0.05) during HV and remained higher during TAP. In addition, oxygen uptake at 60% of vV̇o2max was lower ( P < 0.05) at the end of TAP than before and after HV. Thus short-duration exercise capacity and running economy were better than before the HV period together with higher expression of muscle proteins related to Na+/K+ transport and Ca2+ reuptake, while 10-km performance was not significantly improved by the combination of HV and tapering. NEW & NOTEWORTHY Short-duration performance became better after 18 days of tapering from ~6 wk of high-volume sprint interval training (SIT), whereas 10-km performance was not significantly affected by the combination of high-volume SIT and tapering. Higher expression of muscle NKAα1, NKAβ1, FXYD1, and SERCA1 may reflect faster Na+/K+ transport and Ca2+ reuptake that could explain the better short-duration performance. These results suggest that the type of competition should determine the duration of tapering to optimize performance.

Maternal exercise during pregnancy reduces the risk of preterm birth through the mediating role of placenta

Objective: The extent of research on maternal exercise during pregnancy and the risk of preterm birth (PTB) have grown substantially, but conclusions still remained controversial. Thus, this study aims to examine the relationship of maternal exercise during pregnancy and PTB and explore whether placenta mediates their relationship. Study design: We investigated 849 pregnant women delivering PTB newborns (cases) and 1306 delivering full-term appropriate for gestational age newborns (controls) in this case–control study. Information concerning maternal exercise during pregnancy, sociodemographics and obstetric characteristics were collected at Women and Children’s Hospitals of Shenzhen and Foshan in Guangdong, China. A series of logistic and linear regressions were used to examine the relationships of maternal exercise during pregnancy, placenta, and PTB. Results: After adjusting for the potential confounders, maternal exercise frequency and duration during pregnancy were negatively associated with PTB. Moreover, compared with mother taking no exercise during pregnancy, those taking exercise lowered the risk of PTB except those taking low/medium frequency and short duration exercise, and their adjusted ORs ranged from 0.43 to 0.65. Furthermore, mediation analysis illustrated that placental weight partially mediated 65.20% of the effects of maternal exercise frequency on PTB, as well as 41.98% of the association between maternal exercise duration and PTB. Conclusions: Maternal exercise during pregnancy is beneficial for lowering the risk of PTB, especially when taking appropriate and enough exercise. Placenta weight may partially mediate the association between maternal exercise during pregnancy and PTB.

Effect of water-based recovery on blood lactate removal after high-intensity exercise.

This study assessed the effectiveness of water immersion to the shoulders in enhancing blood lactate removal during active and passive recovery after short-duration high-intensity exercise. Seventeen cyclists underwent active water- and land-based recoveries and passive water and land-based recoveries. The recovery conditions lasted 31 minutes each and started after the identification of each cyclist’s blood lactate accumulation peak, induced by a 30-second all-out sprint on a cycle ergometer. Active recoveries were performed on a cycle ergometer at 70% of the oxygen consumption corresponding to the lactate threshold (the control for the intensity was oxygen consumption), while passive recoveries were performed with subjects at rest and seated on the cycle ergometer. Blood lactate concentration was measured 8 times during each recovery condition and lactate clearance was modeled over a negative exponential function using non-linear regression. Actual active recovery intensity was compared to the target intensity (one sample t-test) and passive recovery intensities were compared between environments (paired sample t-tests). Non-linear regression parameters (coefficients of the exponential decay of lactate; predicted resting lactates; predicted delta decreases in lactate) were compared between environments (linear mixed model analyses for repeated measures) separately for the active and passive recovery modes. Active recovery intensities did not differ significantly from the target oxygen consumption, whereas passive recovery resulted in a slightly lower oxygen consumption when performed while immersed in water rather than on land. The exponential decay of blood lactate was not significantly different in water- or land-based recoveries in either active or passive recovery conditions. In conclusion, water immersion at 29°C would not appear to be an effective practice for improving post-exercise lactate removal in either the active or passive recovery modes.

Effect of prepartum exercise, pasture turnout, or total confinement on hoof health

Lameness is a major welfare concern in the dairy industry, and access to physical activity during the dry period may improve hoof health. The objective of this study was to determine the effects of forced exercise, pasture turnout, or total confinement of dry cows on horn growth and wear and sole thickness. Twenty-nine primiparous and 31 multiparous, pregnant, nonlactating Holstein (n = 58) and Jersey-Holstein crossbred (n = 2) dairy cows were assigned to either total confinement (n = 20), exercise (n = 20), or pasture (n = 20) treatments at dry-off using rolling enrollment from January to November 2015. Cows were managed with a 60-d dry period (58.5 ± 5.4 d) divided into far-off (dry-off to 2 wk before parturition) and close-up periods (2 wk before projected parturition). Cows were housed in a naturally ventilated, 4-row freestall barn at the University of Tennessee's Little River Animal and Environmental Unit (Walland, TN) with concrete flooring and deep-bedded sand freestalls. Cows assigned to confinement remained in the housing pen. Exercise cows were walked for a targeted 1.5 h at 3.25 km/h, 5 times/wk until calving. Pasture cows were turned out for a targeted 1.5 h, 5 times/wk until calving. Hoof growth and wear and sole thickness of the rear hooves were measured on d 2 and 44, relative to dry-off. Data were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC). Cranial and caudal horn wear was greater for exercise cows than confinement and pasture cows. Exercise cows experienced more equal rates of horn growth and wear cranially. Confined cows tended to increase sole thickness from d 2 to 44, relative to dry-off. Frequent, short duration exercise on concrete did not impair the hoof health of late-gestation dry cows. Further, exercise may improve overall hoof health, potentially improving cow welfare.

Acute ethanol and taurine intake affect absolute alpha power in frontal cortex before and after exercise.

Taurine and alcohol has been popularly ingested through energy drinks. Reports from both compounds shows they are active on nervous system but little is known about the acute effect of these substances on the frontal cortex in an exercise approach. The aim of this study was to determine the effects of 0,6mldL-1 of ethanol (ET), 6g of taurine (TA), and taurine with ethanol (TA+ET) intake on absolute alpha power (AAP) in the frontal region, before and after exercise. Nine participants were recruited, five women (22±3years) and four men (26±5years), for a counterbalanced experimental design. For each treatment, the tests were performed considering three moments: "baseline", "peak" and "post-exercise". In the placebo treatment (PL), the frontal areas showed AAP decrease at the post-exercise. However, in the TA, AAP decreased at peak and increased at post-exercise. In the ET treatment, AAP increased at the peak moment for the left frontal electrodes. In the TA+ET treatment, an AAP increase was observed at peak, and it continued after exercise ended. These substances were able to produce electrocortical activity changes in the frontal regions after a short duration and low intensity exercise. Left and right regions showed different AAP dynamics during peak and post-exercise moments when treatments were compared.

The Influence of Short Duration Exercise on the Concentration of C-Reactive Protein and Selected Haematological and Biochemical Parameters in the Blood of German Shepherd Dogs

Abstract Short-term intensive exercise may be associated with many short-lasting metabolic changes. These changes depend on the duration and intensity of the exercise. The aim of our study was to determine potential changes in C-reactive protein (CRP) and selected haematological and biochemical parameters in clinically healthy German shepherd dogs before short duration high-intensity exercise and 6 hours after the exercise. During the study, the dogs were subjected to the following defensive training: detaining a figurant running away from a dog (2×) and detaining with a counterattack (2×). The running distance was 200 m at a mean speed of 28 km.h-1. The investigation of haematological parameters revealed a significant decrease in the mean values of platelet haematocrit (PCT) 6 hours after the training. Significant differences in the levels determined before and after exercise were observed also for phosphorus (P) and for iron (Fe). At the same time, we observed a significant increase in the mean calcium (Ca) level and a significant decrease in sodium (Na) and chlorides (Cl). The activity of aspartate aminotransferase (AST) significantly increased after exercise. Concentrations of acute phase C-reactive proteins were increased 6 hours after exercise in comparison to those before exercise but the difference was insignificant. Although the concentration of CRP was increased insignificantly after the exercise, when interpreting concentrations of this nonspecific indicator of inflammation, one should keep in mind that intensive exercise may also affect its concentrations.

Motivational State Does Not Affect All-Out Short Duration Exercise Performance

Introduction: The preferred motivational state (telic or paratelic), i.e., dominance, has been linked to the type of activity sports people participate in. As such, positive or negative performance may occur if there is a mismatch between the activity and the required state. This study set out to examine the effects of altering telic or paratelic motivational states and thus induce the “misfit effect” in order to quantify the influences on emotions and performance during allout, short duration cycle performance. Methods: Based on paratelic dominance scale (PDS) scores participants completed the Wingate anaerobic test (WAT) on two separate occasions in their preferred and non-preferred motivational state. Special video display method was used to manipulate participants to their non-preferred motivational state and verified via the telic state measure (TSM) test prior to performing the Wingate test (WT). Changes in emotion and stress levels were recorded using the tension and effort stress inventory (TESI) along with heart rate variability (HRV) data obtained from electrocardiogram (ECG). Peak power (PP), mean power (MP) and fatigue index (FI) obtained from the WT were used to assess all-out athletic performance. Results: The main findings show that there was no link between dominant motivational state and anaerobic cycle performance (p&gt;0.05) and that successful manipulation of motivational state (p&lt;0.05) did not influence perceived levels or physiological levels of stress (p&gt;0.05) and did not affect all-out, short duration cycle performance (p&lt;0.05). Conclusion: As such, coaches, support staff and athletes do not have to worry about a particular state in regards to telic or paratelic in an acute time frame, as long as the athlete’s arousal levels and emotional conditions are optimal.

Effects of different durations of aerobic exercise on the cardiovascular health in untrained women: a meta-analysis and meta-regression.

Women's cardiovascular health is a hot topic. Exercise intervention is an effective method to improve the cardiovascular functions. The aim of this study was to systematically assess effects of aerobic exercise at different durations on the cardiovascular health of untrained women. Published articles from January 1989 to March 2016 were identified using electronic databases (PubMed, Cochrane Library, Embase and Web of Science) for randomized controlled trials. Weighted mean differences and 95% confidence intervals (CI) were calculated using fixed-effects and random-effects models. Meta-regression and subgroup analysis were performed to explore the possible heterogeneity. Data from 26 published studies with a total of 518 untrained women were identified. The subgroup analysis and meta-regression were performed according to age (under 40, and from 41 to 60 years old) and exercise durations. Maximal oxygen consumption significantly increased at short-duration exercise (95% CI: -2.51 to -1.57; I2=0%) and mid-duration exercise (95% CI: -8.23 to -5.18; I2=0%). While HR (95% CI: 4.72 to 5.60; I2=0%) and SBP (95% CI: 5.55 to 7.52; I2=0%) significantly decreased at mid-duration exercise. Total cholesterol (N.=242, 95% CI: 0.07 to 0.16, I2=13%), HDL-C (N.=242, 95% CI: -0.11 to -0.06, I2=11%) and low-density lipoprotein cholesterol levels (N.=238, 95% CI: 0.07 to 0.16, I2=37%) significantly improved with short-duration, mid-duration and long-duration. Improvement of cardiovascular functions decreases with age in untrained women. Short-duration exercise has significant effects on aerobic capacity. Mid-duration exercise significantly improves on aerobic capacity, heart rate and systolic blood pressure. All the different durations of aerobic exercise improve the cholesterol metabolism.

Sugar-Sweetened Beverages And Short-duration Exercise On Glycemic Response And Subjective Appetite In Young Boys

PURPOSE: Sugar-sweetened beverage consumption is thought to be a contributor to weight gain through its effects on the control of food intake and glucose homeostasis. It has been suggested that energy from sugar-sweetened caloric beverages bypass physiologic systems regulating food intake, leading to weight gain. Despite a lack of reported evaluation, short-duration exercise is promoted in schools as a means of achieving energy balance and glucose homeostasis. The purpose of the present study was to investigate the interaction between sugar-sweetened beverage consumption and short-duration exercise on glycemic response and subjective appetite in young boys. METHODS: Eight normal weight boys (age: 11.25 ± 0.7 years) consumed isovolumetric amounts (240mL) of either a commercial fruit drink or 1% chocolate milk, matched for available carbohydrates (25g) two hours after a standardized breakfast. The boys then exercised on a motorized treadmill at their ventilatory threshold or sat quietly for 15min, followed by 45min of quiet sitting. Subjective appetite and capillary blood glucose were assessed at baseline, and at 15 and 60min during the test condition. RESULTS: There was a beverage (fruit drink vs. chocolate milk) x test condition (exercise vs. rest) x time (0, 15, 60min) interaction for blood glucose response (p<0.01). There was a main effect of beverage on glucose response (p<0.01). Exercise increased subjective average appetite to 60min compared to quiet sitting (p<0.05). CONCLUSIONS: Fifteen minutes of moderate-intensity exercise attenuates the rise in blood glucose following sugar-sweetened beverage consumption. Chocolate milk has the lowest glycemic response, which may be due its milk protein and fat content and effect on gut hormone release. Further investigations are required to determine whether increased subjective appetite following short duration exercise would result in greater next-meal food intake.

Postural Induced Changes in Plasma Volume Inversely Influences Plasma Nitrite Concentration in Humans

Moving from a supine to a standing position typically reduces plasma volume (PV) and while this increases the concentration of some molecules in the blood, the effect on plasma nitrate [NO3-] and nitrite [NO2-] has not been reported. PURPOSE: To determine the change (Δ) in PV, [NO3-] and [NO2-] while lying supine, sitting, standing, and following short-duration exercise. METHODS: Fourteen participants (9 male, age 27 ± 4 yr, body mass 71 ± 11 kg) completed two trials. The first was conducted with no dietary intervention (control; CON) and the second was preceded by ingestion of 3 x 70 ml of NO3--rich beetroot juice the day before and 2 x 70 ml two hours before the trial (BR; total of ~31 mmol NO3-). Both trials comprised 30 min lying supine followed by 2 min of standing, 2 min of sitting, and then 5 min of cycling at 60% of the age-predicted maximal heart rate. Repeated blood samples were collected to allow measurements of haemoglobin and haematocrit in whole blood and plasma [NO3-] and [NO2-] by chemiluminescence. The ΔPV was calculated using the Dill and Costill formula. RESULTS: Following the supine phase, PV increased from baseline in both trials (CON Δ12.6 ± 10.3 %; BR Δ12.5 ± 7 %, both P 0.05). CONCLUSIONS: Plasma [NO2-] changes in the opposite direction to PV during changes in posture, both in the presence and absence of prior dietary NO3- supplementation. Given that [NO2-] offers the best approximation of nitric oxide bioavailability, researchers must be cognisant of these outcomes when designing and interpreting dietary NO3- research.

The mediating role of placenta in the relationship between maternal exercise during pregnancy and full-term low birth weight

Objective: To explore the association of maternal exercise during pregnancy with full-term low birth weight (FT-LBW) and whether placenta mediates their association. Study design: We investigated 326 pregnant women delivering FT-LBW weight newborns (cases) and 1644 delivering full-term normal birth weight newborns (controls) in this case-control study. Information concerning maternal exercise during pregnancy, socio-demographics and obstetric characteristics were collected at Women and Children’s Hospitals of Shenzhen and Foshan in Guangdong, China. Results: After adjusting for the potential confounders, maternal exercise frequency and duration during pregnancy were significantly negatively associated with FT-LBW, respectively. Moreover, compared with mothers taking no exercise during pregnancy, those taking exercises were significantly negatively associated with FT-LBW except those taking low/medium frequency and short duration exercise and high-frequency and long duration exercise, and their adjusted ORs ranged from 0.30 to 0.62. Furthermore, mediation analysis illustrated that placental weight partially mediated 27.20% of the association between maternal exercise frequency during pregnancy and FT-LBW, but not the association between maternal exercise duration during pregnancy and FT-LBW. Conclusions: Maternal exercise during pregnancy is beneficial for lowering FT-LBW risk, especially when taking appropriate and enough exercise. Placenta weight partially mediates the association between maternal exercise frequency during pregnancy and FT-LBW.

The effects of short time monohydrate creatine supplementation on systemic stress homeostasis following repeated maximum swimming in young women

Introduction: This study aimed to evaluate the effect of short-term creatine supplementation on oxidative stress and antioxidant enzymes after six bouts of 50-meter sprint swimming. Methods: This quasi-experimental study recruited eight trained female swimmers with the mean age of 25±4.4 years and body mass index (BMI) of 21.8±4.2 kg/m2 to perform six bouts of 50-meter sprint swimming with a 120-second active recovery in water. Then, subjects consumed Cr supplement (capsules containing 5 g monohydrate creatine), four times a day for six days. Blood samples were taken in resting position after the sixth bout of swimming before and following Cr supplementation period. Protein carbonyl (PC) and superoxide dismutase (SOD) concentration were measured using ELISA method. Result: Sprint swimming significantly increased PC concentration compared to resting state, but an insignificant increase was detected after Cr supplementation. In addition, sprint swimming led to a significant reduction in SOD levels after creatine supplementation compared to pre-test. Swimmers’ records after creatine supplementation in sixth bout of sprint swimming was also lower compared to the first bout. Conclusion: Cr supplementation can inhibit increased oxidative stress markers induced by high-intensity and short-duration exercise in trained female swimmers.

Neuromuscular Fatigue during Prolonged Exercise in Hypoxia.

Prolonged cycling exercise performance in normoxia is limited because of both peripheral and central neuromuscular impairments. It has been reported that cerebral perturbations are greater during short-duration exercise in hypoxia compared with normoxia. The purpose of this study was to test the hypothesis that central deficits are accentuated in hypoxia compared with normoxia during prolonged (three bouts of 80 min separated by 25 min) whole-body exercise at the same relative intensity. Ten subjects performed two sessions consisting of three 80-min cycling bouts at 45% of their relative maximal aerobic power in normoxia and hypoxia (FiO2 = 0.12). Before exercise and after each bout, maximal voluntary force, voluntary activation assessed with nerve stimulation and transcranial magnetic stimulation, corticospinal excitability (motor evoked potential), intracortical inhibition (cortical silent period), and electrical (M-wave) and contractile (twitch and doublet peak forces) properties of the knee extensors were measured. Prefrontal and motor cortical oxygenation was also recorded during each cycling bout in both conditions. A significant but similar force reduction (≈-22%) was observed at the end of exercise in normoxia and hypoxia. The modifications of voluntary activation assessed with transcranial magnetic stimulation and nerve stimulation, motor evoked potential, cortical silent period, and M-wave were also similar in both conditions. However, cerebral oxygenation was reduced in hypoxia compared with normoxia. These findings show that when performed at the same relative low intensity, prolonged exercise does not induce greater supraspinal fatigue in hypoxia compared with normoxia. Despite lower absolute exercise intensities in hypoxia, reduced brain O2 availability might contribute to similar amounts of central fatigue compared with normoxia.

The effects of exercise load during development on oxidative stress levels and antioxidant potential in adulthood

The objective of this study was to elucidate the impact of physical activity during the growth period as well as on oxidative stress and antioxidative potential in adulthood. The experimental animals used were four-week old male Wistar rats, which were randomly divided into three groups. The exercise loads were as follows: control (CON), treadmill exercise (TE), and jumping exercise (JE). The exercise was performed at the same time of day, at a frequency of five days per week, for eight weeks. Derivatives of reactive oxygen metabolites (d-ROSs) and biological antioxidant potential (BAP) were measured during periods of rest prior to commencement of the experiment and after the experiment. Analysis was conducted using a Wilcoxon signed-rank test and Schaffer’s multiple comparison procedure and the significance level was set at p < 0.05. The percent increase in d-ROM levels in the JE group, which experienced short-duration intense exercise loads, was higher than that in the TE group, which experienced moderately intense exercise loads. However, BAP, which is an index of antioxidant potential, markedly decreased in adulthood in the CON group, as compared to that in the developmental period, whereas the exercise groups showed no notable changes in BAP levels. Oxidative stress levels and antioxidant potential are affected differently in adulthood, depending on the intensity of sustained exercise loads experienced during development. Results suggested that in order to increase antioxidant potential, while taking oxidative stress production into account, moderately intense exercise loads are more desirable than highly intense exercise loads.

The Effect of Exercise Treadmill of Rat Liver Tissue

Our study was designed to determine the level of oxidative stress parameters in rats consisting of treadmill exercise performed at different times. The rats in the treadmill exercise groups were subjected to run on a treadmill for 15 and 30 mins. once a day, seven times a week, continued for 28 days. Compliance with the normal distribution of variables was evaluated by Kolmogorov Smirnov Test. Comparisons between groups were analyzed using one-way ANOVA post hoc Least Significant Difference (LSD) Test. p < 0.05 was considered statistically significant differences. As a result, superoxide dismutase (SOD) 1.09 ± 0.23, 3.95 ± 2.26, glutathione (GSH) and malonic dialdehyde (MDA) was determined to be 1.46 ± 0.41. Short duration exercise group: 1.22 ± 0.14 SOD, GSH 3.12 ±0.17, and MDA 1.64 ± 0.58. Moderate exercise group: SOD 1.12 ± 0.19, GSH 2.49 ± 0.42, and MDA 1.16 ± 0.49 level was found in. As a result, it is more effective than moderate exercise on antioxidant activity, but the short-term exercise training performed in animals oxidant/antioxidant balance between energy systems said to be linked to the system.

Lactate-guided conditioning program using variable exercise intensities improves fitness and alters muscle enzyme activity but not inflammatory response in horses

Blood lactate concentration ([LA]) response to exercise challenges can be used to assess fitness in horses. Most equine conditioning programs (CP) that have been studied are based on regular bouts of exercise of similar to increasing levels of intensity. We hypothesised that a lactate-guided CP implementing 2× weekly short-duration high-intensity exercise bouts and 1× weekly low-intensity longer-duration exercise bout effectively increases fitness in horses. Six untrained adult horses followed a 12 week CP that consisted of 2× weekly exercise on an equine treadmill (6% incline) for 25 min at a velocity at which [LA] was 4.0 mmol/l (VLA4.0) and 1× weekly for 45 min at a velocity at which [LA] was 2.5 mmol/l (VLA2.5). VLA2.5 and VLA4.0 were determined by incremental-step standardised-exercisetest (SET) before the CP and adjusted every 3 weeks. Blood was collected for [LA], creatine kinase (CK), aspartate aminotransferase (AST), serum amyloid A (SAA), and fibrinogen (Fb) before each speed increase and 30 min, 2, 4, and 24 h after termination of the SET, when [LA] was ≥4.0 mmol/l. Repeated-measures ANOVA was used for analysis. During each SET horses showed increases in heart rate (P&lt;0.0001), packed cell volume (P=0.003), and [LA] (P=0.002). Throughout the CP, VLA2.5 increased from 5.6±0.2 to 6.7±0.3 m/s (P&lt;0.05) and VLA4.0 increased from 6.0±0.2 to 7.4±0.3 m/s (P&lt;0.01). CK, AST, SAA, and Fb did not increase following submaximal exercise. CK and AST activity were attenuated throughout the 12 week CP (P&lt;0.05). This lactate-guided CP was effective at increasing fitness based on achieving higher speeds during the SETs and did not appear to have deleterious effects on the horses’ muscular system or inflammatory state.

The Potentiating Effect of an Accentuated Eccentric Load on Countermovement Jump Performance.

Hughes, JD, Massiah, RG, and Clarke, RD. The potentiating effect of an accentuated eccentric load on countermovement jump performance. J Strength Cond Res 30(12): 3450-3455, 2016-Postactivation potentiation (PAP) following a bout of high-intensity exercise of short duration is known to produce both a fatigued and a potentiated state. There has been much research in the effectiveness of various PAP protocols, yet the type of dynamic muscle action utilized has seldom been investigated. Therefore, the present study aimed to assess whether an accentuated eccentric load (AE) could enhance subsequent performance. Eleven men (21 ± 2 years, 179.1 ± 6.9 cm, 83.2 ± 10.1 kg) performed 3 countermovement jumps (CMJs) before and 6 minutes after an AE and a back squat (BSq) PAP protocol. The participant's maximum CMJ height (cm) was determined before and after both protocol. A 2-way repeated measures analysis of variance was conducted to evaluate the effect of PAP condition and time on vertical jumping performance. A significant condition × time interaction was found (p = 0.02). Post hoc tests revealed that AE PAP had a significant (p = 0.03) potentiating effect on CMJ jump height. Whereas, the BSq PAP revealed no significant differences (p = 0.32). In conclusion, this study has shown that jump performance can be enhanced by eccentric muscle action when compared with a traditional BSq PAP protocol. This may provide a more practical method for coaches to enhance short-term explosive movements in athletic populations.