Bout Of Intense Exercise Research Articles

The Effects of Sport Massage and Foam Rolling on Running Efficiency in Female Collegiate Distance Runners

Foam Rolling and Sport Massage techniques have become increasingly popular methods to help athletes prepare for and recover from bouts of intense exercise. Distance runners in particular use Foam Rolling prior to and after strenuous workouts potentially to improve athletic performance and flexibility, reduce workout-related soreness and decrease recovery time. While these activities are common in intercollegiate athletics (especially distance running circles), there is equivocal evidence that supports the effectiveness of either method, especially when used prior to exercise. PURPOSE: To compare running efficiency following a bout of Sport Massage and Foam Rolling in female Collegiate distance runners. METHODOLOGY: Nine healthy NCAA D-1 female Cross Country runners volunteered for the study (age=20.89±1.97yrs; WT=54.25±7.15kg; HT=163.02±5.67cm; Percent Fat=15.29±5.72; BMI=20.26±2.01). Volunteers reported to the laboratory and completed an initial VO2max test (7.0mph with a 3% grade increase every 3 minutes until exhaustion; VO2max=55.73±2.11 ml/kg/min). Subjects then performed three separate randomized treadmill runs (7.0mph at 3% grade for 10 minutes) following either no intervention (NI), Sport Massage (SM) or a Foam Rolling (FR) session. To estimate running efficiency, heart rate (HR), rate of perceived exertion (RPE) and lactate samples were taken every two minutes throughout the three 10-minute steady state runs. RESULTS: Results showed there were no significant differences (p>0.05) between NI, SM or FR for RPE (NI=10.25±2.31; SM=10.50±2.67; FR=10.63±2.56) or lactate (NI=2.7±1.23; SM=2.84±0.90; FR=2.90±0.97). However, there was a significant difference (p=0.028) for HR between NI (149.88±15.33) and FR (144.75±13.79). SM (147.50±14.43) was not significantly different (p>0.05) from NI or FR for HR. CONCLUSION: These results indicate that FR prior to a steady state submaximal run may have a beneficial cardiovascular effect (improved efficiency) in well trained female distance runners.

Ionized and Total Magnesium Levels Change during Repeated Exercise in Older Adults.

Magnesium is essential for health and performance. Sub-optimal levels have been reported for older persons. In addition, physical exercise is known to temporally decrease magnesium blood concentrations. To investigate these observations in conjunction we assessed total (tMg) and ionized magnesium (iMg) concentrations in plasma and whole blood, respectively, during 4 consecutive days of exercise in very old vital adults. 68 participants (age 83.7±1.9 years) were monitored on 4 consecutive days at which they walked 30-40km (average ~8 hours) per day at a self-determined pace. Blood samples were collected one or two days prior to the start of exercise (baseline) and every walking day immediately post-exercise. Samples were analysed for tMg and iMg levels. Baseline tMg and iMg levels were 0.85±0.07 and 0.47±0.07 mmol/L, respectively. iMg decreased after the first walking day (-0.10±0.09 mmol/L, p<.001), increased after the second (+0.11±0.07 mmol/L, p<.001), was unchanged after the third and decreased on the final walking day, all compared to the previous day. tMg was only higher after the third walking day compared to the second walking day (p=.012). In 88% of the participants, iMg levels reached values considered to be sub-optimal at day 1, in 16% of the participants values were sub-optimal for tMg at day 2. Prolonged moderate intensity exercise caused acute effects on iMg levels in a degree comparable to that after a bout of intensive exercise. These effects were not associated with drop-out or health problems. After the second consecutive day of exercise, levels were returned to baseline values, suggesting rapid adaptation/resilience in this population.

Effect of listening to music during a warmup on anaerobic test performance

Many studies have investigated the effect of listening to music during exercise on performance, but the influence of music during a warmup on subsequent exercise performance is unknown. The primary purpose of this study was to determine whether or not listening to self-selected music before an intense bout of anaerobic exercise would positively affect performance. We also sought to explore the effect of music on psychological variables including rating of perceived exertion (RPE). 16 participants (8 males, 8 females; age 23.6 ± 4.8 years, BMI 18.9 ± 3.2 kg/m2) listened to pre-selected music, self-selected music or white noise during a warmup, which consisted of cycling at 50 rpm for 10 min with a resistance of 1 kg. Once the warmup was completed, they performed a Wingate Anaerobic Test (WAnT) against a flywheel resistance of 7.5% body mass. Immediately after the WAnT, they were asked to complete the Subjective Exercise Experience Scale (SEES) and RPE was assessed. One-way repeated-measures ANOVAs were used to determine the effect of music condition on both physiological and psychological variables. There were no significant differences in mean or peak power, relative power, fatigue index, or RPE (all p > 0.05). There were also no differences in any SEES variables (positive well-being, psychological distress, or fatigue) or in RPE (all p > 0.05). This study suggests that listening to music during a warmup has no positive effect on performance during the actual event, even when the music is self-selected.

183 - Mitochondria-localized lactate dehydrogenase is not a biologically significant contributor to bioenergetic function in striated muscle

Previous studies indicate that mitochondrial lactate dehydrogenase (mLDH) might be a significant contributor to metabolism. The presence of mLDH could provide mitochondria with a higher capacity to generate reducing equivalents for respiration, especially during exercise when circulating lactate levels are high. Furthermore, mitochondrial lactate oxidation could support cardiac output or skeletal muscle function, both of which contribute to exercise capacity. We measured lactate-, pyruvate-, and glutamate-supported respiration in mitochondria isolated from heart and skeletal muscle of sedentary, acutely exercised, and exercise-adapted mice. We modeled the acute effects of exercise by subjecting male FVB/NJ mice to one, 60 min bout of treadmill running. Exercise adaptation was modeled with progressive treadmill training at 40-60 min/d for 2 weeks, with adaptation determined by measuring exercise capacity and indices of cardiac growth. We performed immunoblotting to assess relative abundance of LDH isoforms in isolated mitochondria. Two weeks of treadmill running increased running distance by 1.3-fold. Compared with sedentary mice, exercise training increased cardiac mass by 15% (n=5/group, p<0.01). Cardiac mitochondria energized with 5 mM pyruvate+2.5 mM malate, and skeletal muscle mitochondria provided with 5 mM glutamate+2.5 mM malate, showed approximately 10-fold higher respiration rates compared with mitochondria provided 5 mM lactate+2.5 mM malate. Exercise training did not significantly affect respiration on either substrate. We performed similar studies on mitochondria isolated immediately after one intense bout of exercise. In both sedentary and exercised conditions, cardiac and skeletal muscle mitochondria provided with lactate showed 10-fold lower respiration rates than those supplied with pyruvate or glutamate (n=3/group). Western blotting indicated low levels of LDHB in mitochondrial fractions from heart and low levels of LDHA in mitochondrial fractions from skeletal muscle. Lactate metabolism in striated muscle is primarily a cytosolic phenomenon; mLDH is of minimal biological significance.

A Review of the Effects of Leucine Metabolite (β-Hydroxy-β-methylbutyrate) Supplementation and Resistance Training on Inflammatory Markers: A New Approach to Oxidative Stress and Cardiovascular Risk Factors.

β-hydroxy β-methylbutyrate (HMB) is a bioactive metabolite formed from the breakdown of the branched-chain amino acid, leucine. Given the popularity of HMB supplements among different athletes, specifically, those who participate in regular resistance training, this review was performed to summarize current literature on some aspects of HMB supplementation that have received less attention. Because of the small number of published studies, it has not been possible to conclude the exact effects of HMB on cardiovascular parameters, oxidative stress, and inflammatory markers. Thus, the interpretation of outcomes should be taken cautiously. However, the data presented here suggest that acute HMB supplementation may attenuate the pro-inflammatory response following an intense bout of resistance exercise in athletes. Also, the available findings collectively indicate that chronic HMB consumption with resistance training does not improve cardiovascular risk factors and oxidative stress markers greater than resistance training alone. Taken together, there is clearly a need for further well-designed, long-term studies to support these findings and determine whether HMB supplementation affects the adaptations induced by resistance training associated with the body’s inflammatory condition, antioxidative defense system, and cardiovascular risk factors in humans.

Intense aerobic exercise lowers blood pressure in individuals with metabolic syndrome taking antihypertensive medicine.

There is a growing tendency for physicians to prescribe exercise in accordance with the 'exercise is medicine' global health initiative. However, the exercise-pharmacologic interactions for controlling blood pressure are not well described. Our purpose was to study whether angiotensin II receptor type 1 blocker (ARB) antihypertensive medicine enhances the blood pressure-lowering effects of intense exercise. Fifteen hypertensive individuals with metabolic syndrome chronically medicated with ARB underwent two exercise trials in a blind randomized order. One trial was conducted after taking their habitual dose of ARB (ARB MED trial) and another after 48 h of placebo medicine (i.e. dextrose; PLAC trial). After placebo medication, brachial systolic blood pressure increased by 5.5 mmHg [P=0.009; effect size (ES)=0.476] and diastolic by 2.5 mmHg (P=0.030; ES=0.373). Exercise reduced systolic and diastolic blood pressures to the same extent in ARB MED and PLAC trials (7 and 8 mmHg, respectively, for systolic and 5 and 4 mmHg, respectively, for diastolic, all P<0.05). Pulsatile measures of arterial stiffness did not reveal an interaction effect between exercise and medication. However, postocclusion reactive hyperemia increased after exercise only in the ARB MED trial (361±169 to 449±240% from baseline; P=0.033; ES=0.429). ARBs and a bout of intense exercise each have an independent effect on lowering blood pressure in hypertensive individuals, and these effects are additive.

Repressed Exercise-Induced Hepcidin Levels after Danggui Buxue Tang Supplementation in Male Recreational Runners.

This study was to investigate the protective and recovery effects of Danggui Buxue Tang (DBT) supplementation on exercise performance, hepcidin, iron status, and other related biochemical parameters after being challenged by a single bout of intense aerobic exercise. A total of 36 recreationally active males were pair-matched and randomly assigned to receive DBT or a placebo for 11 days, while using clusters based on their aerobic capacities. On the eighth day of the supplementation, the participants performed a 13-km run with maximal effort. Blood and urine samples were collected and analysed before treatment (Pre-Tre) and immediately after (Post-Ex), 24 h after (24-h Rec), and 72 h after (72-h Rec) the run. DBT supplementation dramatically shortened the finish times by 14.0% (12.3 min) when compared with that in the placebo group. Significant group × time effects were observed in serum hepcidin and iron levels. DBT supplementation repressed hepcidin levels at Post-Ex and 24-h Rec, thereby causing a significant increase in iron levels by 63.3% and 31.4% at Post-Ex and 72-h Rec, respectively. However, DBT supplementation had no significant anti-inflammatory or haemolysis-preventative effects. Short-term DBT supplementation shortened the running time and repressed exercise-induced hepcidin levels, thereby boosting iron levels and accelerating iron homeostasis during recovery.

Effects of intense aerobic exercise and/or antihypertensive medication in individuals with metabolic syndrome.

We studied the blood pressure lowering effects of a bout of exercise and/or antihypertensive medicine with the goal of studying if exercise could substitute or enhance pharmacologic hypertension treatment. Twenty-three hypertensive metabolic syndrome patients chronically medicated with angiotensin II receptor 1 blockade antihypertensive medicine underwent 24-hr monitoring in four separated days in a randomized order; (a) after taking their habitual dose of antihypertensive medicine (AHM trial), (b) substituting their medicine by placebo medicine (PLAC trial), (c) placebo medicine with a morning bout of intense aerobic exercise (PLAC+EXER trial) and (d) combining the exercise and antihypertensive medicine (AHM+EXER trial). We found that in trials with AHM subjects had lower plasma aldosterone/renin activity ratio evidencing treatment compliance. Before exercise, the trials with AHM displayed lower systolic (130±16 vs 133±15mm Hg; P=.018) and mean blood pressures (94±11 vs 96±10mm Hg; P=.036) than trials with placebo medication. Acutely (ie, 30min after treatments) combining AHM+EXER lowered systolic blood pressure (SBP) below the effects of PLAC+EXER (-8.1±1.6 vs -4.9±1.5mm Hg; P=.015). Twenty-four hour monitoring revealed no differences among trials in body motion. However, PLAC+EXER and AHM lowered SBP below PLAC during the first 10 hours, time at which PLAC+EXER effects faded out (ie, at 19 PM). Adding exercise to medication (ie, AHM+EXER) resulted in longer reductions in SBP than with exercise alone (PLAC+EXER). In summary, one bout of intense aerobic exercise in the morning cannot substitute the long-lasting effects of antihypertensive medicine in lowering blood pressure, but their combination is superior to exercise alone.

Acute cardiovascular exercise promotes functional changes in cortico-motor networks during the early stages of motor memory consolidation

A single bout of cardiovascular exercise performed immediately after practicing a visuo-motor tracking task has been shown to improve the long-term retention of this motor skill through an optimization of the memory consolidation process. The mechanisms underlying the time-dependent effects of acute cardiovascular exercise on motor memory consolidation, however, remain poorly understood. In this study, we sought to determine the impact of a single bout of cardiovascular exercise performed immediately after motor skill practice on those mechanisms using electroencephalography (EEG) and electromyography (EMG). Specifically, we assessed exercise-induced changes in the activity and connectivity of cortico-motor networks during early consolidation and the impact of these changes on skill retention. Participants practiced a visuo-motor tracking task followed by either a short bout of intense exercise or a rest period. EEG along with EMG data of hand muscles were collected during the production of low-force isometric contractions. Event-related desynchronization, functional connectivity and corticomuscular coherence were measured at baseline, 30, 60 and 90 min after the bout of exercise or the rest period. Improvements in motor memory were inferred via retention tests of the motor skill performed 8 and 24 h after motor practice. We found that participants who performed the single bout of exercise showed better motor skill retention 24 h after motor practice. This improvement in skill retention in the exercise group was associated with significant decreases in beta-band event-related desynchronization in EEG electrodes located over the left sensorimotor areas. We also found that after exercise, alpha-, and even more significantly, beta-band functional connectivity, increased between EEG electrodes located over left and right sensorimotor areas. The exercise group also showed greater beta-band corticomuscular coherence but only in a small number of electrodes. Neither functional connectivity nor corticomuscular coherence measures correlated with skill retention scores. This is the first study exploring brain mechanisms underlying the summative effects of motor learning and cardiovascular exercise on motor memory consolidation. We have identified potential neural substrates through which a single bout of acute exercise, when performed in close temporal proximity to motor practice, strengthens motor memories. Our findings provide new mechanistic insights into a better understanding of the complex temporal relationship existing between cardiovascular exercise and motor memory consolidation.

Exploring the effects of mental and muscular fatigue in soccer players’ performance

This study examined the effects of induced mental and muscular fatigue on soccer players’ physical activity profile and collective behavior during small-sided games (SSG). Ten youth soccer players performed a 5vs5 SSG under three conditions: a) control, playing without any previous activity; b) muscular fatigue, playing after performing a repeated change-of-direction task; c) mental fatigue, playing after completing a 30 min Stroop color-word task. Players’ positional data was used to compute time-motion and tactical-related variables. The muscular fatigue condition resulted in lower distances covered in high speeds (∼27%, 0.3; ±0.5) than the control condition. From the tactical perspective, the muscular fatigue condition resulted in lower distance between dyads and players spent ∼7% more time synchronized in longitudinal displacements than the control condition (0.3; ±0.3). Additionally, players spent ∼14% more time synchronized with muscular fatigue than with mental fatigue (0.7; ±0.3). The mental fatigue condition resulted in a very likely more predictable pattern in the distance between dyads than in muscular fatigue condition (0.4; ±0.2). Also, the mental fatigue possibly decreased the teams’ stretch index when compared with control (0.2; ±0.3) and likely increased compared with muscular fatigue (0.5; ±0.5). The better levels of longitudinal synchronization after muscular fatigue, might suggest the usage of tactical-related tasks after intense exercise bouts. The lower physical performance and time spent longitudinally synchronized after mental fatigue, should alert to consider this variable before matches or training activities that aim to improve collective behavior.

Maximal-intensity exercise does not fully restore muscle pyruvate dehydrogenase complex activation after 3 days of high-fat dietary intake

Exercise activates muscle pyruvate dehydrogenase complex (PDC), but moderate intensity exercise fails to fully activate muscle PDC after high-fat diet [1]. We investigated whether maximal intensity exercise overcomes this inhibition. Quadriceps femoris muscle biopsy samples were obtained from healthy males at rest, and after 46 and 92 electrically-evoked maximal intermittent isometric contractions, which were preceded by 3 days of either low- (18%) or high- (69%) isocaloric dietary fat intake (LFD and HFD, respectively). The ratio of PDCa (active form) to total PDCt (fully activated) at rest was 50% less after HFD (0.32±0.01 vs 0.15±0.01; P<0.05). This ratio increased to 0.77±0.06 after 46 contractions (P<0.001) and to 0.98±0.07 after 92 contractions (P<0.001) in LFD. The corresponding values after HFD were less (0.54±0.06; P<0.01 and 0.70±0.07; P<0.01, respectively). Resting muscle acetyl-CoA and acetylcarnitine content was greater after HFD than LFD (both P<0.05), but their rate of accumulation in the former was reduced during contraction. Muscle lactate content after 92 contractions was 30% greater after HFD (P<0.05). Muscle force generation during contraction was no different between interventions, but HFD lengthened muscle relaxation time (P<0.05). Daily urinary total carnitine excretion after HFD was 2.5-fold greater than after LFD (P<0.01). A bout of maximal intense exercise did not overcome dietary fat-mediated inhibition of muscle pyruvate dehydrogenase complex activation, and was associated with greater muscle lactate accumulation, as a result of lower PDC flux, and increased muscle relaxation time.

Adaptation and Retention of a Perceptual-Motor Task in Children: Effects of a Single Bout of Intense Endurance Exercise.

We assessed the effect of an acute intense exercise bout on the adaptation and consolidation of a visuomotor adaptation task in children. We also sought to assess if exercise and learning task presentation order could affect task consolidation. Thirty-three children were randomly assigned to one of three groups: (a)exercise before the learning task, (b)exercise after the learning task, and (c)only learning task. Baseline performance was assessed by practicing the learning task in a 0° rotation condition. Afterward, a 60° rotation-adaptation set was applied followed by three rotated retention sets after 1hr, 24hr, and 7 days. For the exercise groups, exercise was presented before or after the motor adaptation. Results showed no group differences during the motor adaptation while exercise seemed to enhance motor consolidation. Greater consolidation enhancement was found in participants who exercised before the learning task. Our data support the importance of exercise to improve motor-memory consolidation in children.

The Effects of 10 Days of a Multi- Ingredient Supplement on Performance Lactate during Exercise and Post Exercise Muscle Damage, Oxidative Stress and Inflammation

Intense and prolonged bouts of intense exercise can cause metabolic acidosis due to the accumulation of intramuscular hydrogen ions. The purpose of the investigation was to assess the efficacy of a calcium bicarbonate sport supplement to enhance exercise performance and recovery. Sixteen healthy, active, college-aged males were recruited to participate in the investigation. Participants in this cross-over study had two tendaysupplementation periods separated by a ten-day washout period. Performance measures were tested and recorded via graded exercise tests on a cycle ergometer at baseline, as well as after both supplementation periods. Blood samples were acquired at baseline as well as pre- and post-exercise after both trial periods to assess levels of ammonia, 8-OHdG, creatine kinase, lactate dehydrogenase, and C-reactive proteins, IL-2, IL-6, and TNF-Alpha markers. ANOVA revealed significantly lower levels (treatment vs. placebo) by time (baseline, day ten) for 8-OHdG post exercise (main effect F=6.98, p=0.013). Creatine kinase levels demonstrated a significant interaction effect (main effect F=0.267, p=0.608; treatment * time: F=3.05, p=0.04). Additionally, a significant difference in peak lactate was noted by treatment (t=1.67, p=0.05, 3.8 mmol supplement vs. 4.8 mmol placebo). Significant differences were not found for aerobic performance measures, ammonia, C-reactive proteins, Interleukin-2, Interleukin-6, or TNF-alpha. The results of the present investigation provided initial evidence for the use of the multiingredient supplements. This preliminary evidence suggests the supplement may blunt lactate response to exercise and help provide some protection from muscle damage and oxidative stress.

Effect of ubiquinol supplementation on biochemical and oxidative stress indexes after intense exercise in young athletes

ABSTRACTObjectives: Physical exercise significantly impacts the biochemistry of the organism. Ubiquinone is a key component of the mitochondrial respiratory chain and ubiquinol, its reduced and active form, is an emerging molecule in sport nutrition. The aim of this study was to evaluate the effect of ubiquinol supplementation on biochemical and oxidative stress indexes after an intense bout of exercise.Methods: 21 male young athletes (26 + 5 years of age) were randomized in two groups according to a double blind cross-over study, either supplemented with ubiquinol (200 mg/day) or placebo for 1 month. Blood was withdrawn before and after a single bout of intense exercise (40 min run at 85% maxHR). Physical performance, hematochemical parameters, ubiquinone/ubiquinol plasma content, intracellular reactive oxygen species (ROS) level, mitochondrial membrane depolarization, paraoxonase activity and oxidative DNA damage were analyzed.Results: A single bout of intense exercise produced a significant increase in most hematochemical indexes, in particular CK and Mb while, on the contrary, normalized coenzyme Q10 plasma content decreased significantly in all subjects. Ubiquinol supplementation prevented exercise-induced CoQ deprivation and decrease in paraoxonase activity. Moreover at a cellular level, in peripheral blood mononuclear cells, ubiquinol supplementation was associated with a significant decrease in cytosolic ROS while mitochondrial membrane potential and oxidative DNA damage remained unchanged.Discussion: Data highlights a very rapid dynamic of CoQ depletion following intense exercise underlying an increased demand by the organism. Ubiquinol supplementation minimized exercise-induced depletion and enhanced plasma and cellular antioxidant levels but it was not able to improve physical performance indexes or markers of muscular damage.

Diurnal Variation in Physiological and Immune Responses to Endurance Sport in Highly Trained Runners in a Hot and Humid Environment.

Purpose The purpose of this study was to investigate the physiological and immunological response of highly trained runners to an intense bout of exercise performed at two different times of day, in a hot, humid environment. Methods Using a crossover randomized design, 13 highly trained runners (range 64–79 ml·kg−1 min−1) performed a 10 km time trial run in hot (28°C) and humid conditions (70%), at 2 different times of day (09:00 hs and 18:00 hs). Venous blood samples were taken to determine WBCs (white blood cells), IL-6 (interleukin-6), CC16 (club cell protein 16), and HSP70 (heat shock protein-70) concentrations. Upper respiratory tract inflammation was additionally assessed using a nasal lavage procedure. Results A significant diurnal difference (p < 0.05) was found for core body temperature, total WBC, and neutrophil and lymphocyte concentrations with higher values at 18:00 hs. A phase response in IL-6, HSP70, WBC, neutrophil, lymphocyte, and CC16 was noted, being more pronounced at 18:00 hs, whilst core body temperature and HR phase responses were more pronounced at 09:00 hs. Conclusion In hot and humid conditions, athletes may wish to consider, when possible, racing and particularly training in the morning where the least homeostatic perturbation occurs.

The Right Heart: Acute and Chronic Issues.

Cardiovascular remodeling in response to sustained moderate and high-intensity exercise is a well-established phenomenon. Following more than a century of work focused on the left ventricle (LV), remodeling of the right side of the heart has recently become a topic of considerable scientific and clinical interest. Morphologic and functional changes have now been well documented in the right ventricle (RV) after isolated bouts of endurance exercise and in association with long-term sustained training. Although exercise-induced cardiac remodeling is classically viewed as an adaptive, clinically benign process, it has recently been hypothesized that repetitive bouts of intense exercise may trigger pathologic changes in the RV characterized by patchy fibrosis and a predisposition to arrhythmia. At present, this concept remains speculative due to the absence of definitive clinical data. While we await scientific clarification of this intriguing hypothesis, several practical clinical considerations are noteworthy. RV dilation is common among trained endurance athletes. As such, asymptomatic athletes with RV dilation do not require additional diagnostic evaluation unless dilation is accompanied by substantial decrements in systolic function or other structural abnormalities suggestive of genetic heart disease. In contrast, RV dilation among athletes with either symptoms or a family history of genetic heart disease requires extensive multi-modality assessment including maximal effort-limited exercise testing, ambulatory rhythm monitoring, advanced non-invasive imaging, and invasive electrophysiology study. This review will discuss the contemporary understanding of how the RV responds to exercise with an emphasis on the relevance of this phenomenon in clinical cardiovascular practice.

A maximal incremental effort alters tear osmolarity depending on the fitness level in military helicopter pilots

PurposeFitness level modulates the physiological responses to exercise for a variety of indices. While intense bouts of exercise have been demonstrated to increase tear osmolarity (Tosm), it is not known if fitness level can affect the Tosm response to acute exercise. This study aims to compare the effect of a maximal incremental test on Tosm between trained and untrained military helicopter pilots. MethodsNineteen military helicopter pilots (ten trained and nine untrained) performed a maximal incremental test on a treadmill. A tear sample was collected before and after physical effort to determine the exercise-induced changes on Tosm. ResultsThe Bayesian statistical analysis demonstrated that Tosm significantly increased from 303.72 ± 6.76 to 310.56 ± 8.80 mmol/L after performance of a maximal incremental test. However, while the untrained group showed an acute Tosm rise (12.33 mmol/L of increment), the trained group experienced a stable Tosm physical effort (1.45 mmol/L). There was a significant positive linear association between fat indices and Tosm changes (correlation coefficients [r] range: 0.77–0.89), whereas the Tosm changes displayed a negative relationship with the cardiorespiratory capacity (VO2 max; r = −0.75) and performance parameters (r = −0.75 for velocity, and r = −0.67 for time to exhaustion). ConclusionsThe findings from this study provide evidence that fitness level is a major determinant of Tosm response to maximal incremental physical effort, showing a fairly linear association with several indices related to fitness level. High fitness level seems to be beneficial to avoid Tosm changes as consequence of intense exercise.

Intake of a Ketone Ester Drink during Recovery from Exercise Promotes mTORC1 Signaling but Not Glycogen Resynthesis in Human Muscle.

Purpose: Ketone bodies are energy substrates produced by the liver during prolonged fasting or low-carbohydrate diet. The ingestion of a ketone ester (KE) rapidly increases blood ketone levels independent of nutritional status. KE has recently been shown to improve exercise performance, but whether it can also promote post-exercise muscle protein or glycogen synthesis is unknown.Methods: Eight healthy trained males participated in a randomized double-blind placebo-controlled crossover study. In each session, subjects undertook a bout of intense one-leg glycogen-depleting exercise followed by a 5-h recovery period during which they ingested a protein/carbohydrate mixture. Additionally, subjects ingested a ketone ester (KE) or an isocaloric placebo (PL).Results: KE intake did not affect muscle glycogen resynthesis, but more rapidly lowered post-exercise AMPK phosphorylation and resulted in higher mTORC1 activation, as evidenced by the higher phosphorylation of its main downstream targets S6K1 and 4E-BP1. As enhanced mTORC1 activation following KE suggests higher protein synthesis rates, we used myogenic C2C12 cells to further confirm that ketone bodies increase both leucine-mediated mTORC1 activation and protein synthesis in muscle cells.Conclusion: Our results indicate that adding KE to a standard post-exercise recovery beverage enhances the post-exercise activation of mTORC1 but does not affect muscle glycogen resynthesis in young healthy volunteers. In vitro, we confirmed that ketone bodies potentiate the increase in mTORC1 activation and protein synthesis in leucine-stimulated myotubes. Whether, chronic oral KE intake during recovery from exercise can facilitate training-induced muscular adaptation and remodeling need to be further investigated.

Increasing skeletal muscle carnitine availability does not alter the adaptations to high‐intensity interval training

Increasing skeletal muscle carnitine availability alters muscle metabolism during steady-state exercise in healthy humans. We investigated whether elevating muscle carnitine, and thereby the acetyl-group buffering capacity, altered the metabolic and physiological adaptations to 24weeks of high-intensity interval training (HIIT) at 100% maximal exercise capacity (Wattmax ). Twenty-one healthy male volunteers (age 23±2years; BMI 24.2±1.1kg/m2 ) performed 2×3minute bouts of cycling exercise at 100% Wattmax , separated by 5minutes of rest. Fourteen volunteers repeated this protocol following 24weeks of HIIT and twice-daily consumption of 80g carbohydrate (CON) or 3g l-carnitine+carbohydrate (CARN). Before HIIT, muscle phosphocreatine (PCr) degradation (P<.0001), glycogenolysis (P<.0005), PDC activation (P<.05), and acetylcarnitine (P<.005) were 2.3-, 2.1-, 1.5-, and 1.5-fold greater, respectively, in exercise bout two compared to bout 1, while lactate accumulation tended (P<.07) to be 1.5-fold greater. Following HIIT, muscle free carnitine was 30% greater in CARN vs CON at rest and remained 40% elevated prior to the start of bout 2 (P<.05). Following bout 2, free carnitine content, PCr degradation, glycogenolysis, lactate accumulation, and PDC activation were all similar between CON and CARN, albeit markedly lower than before HIIT. VO2max , Wattmax , and work output were similarly increased in CON and CARN, by 9, 15, and 23% (P<.001). In summary, increased reliance on non-mitochondrial ATP resynthesis during a second bout of intense exercise is accompanied by increased carnitine acetylation. Augmenting muscle carnitine during 24weeks of HIIT did not alter this, nor did it enhance muscle metabolic adaptations or performance gains beyond those with HIIT alone.

Quality assessment of shoulder plyometric exercises: Examining the relationship to scapular muscle activity

ObjectivesThe purpose of the study was to evaluate performance quality of shoulder plyometric exercises, and examine the relationship to scapular muscle activation during an intense exercise bout. DesignObservational study. SettingUniversity laboratory. Participants32 healthy university students (male/female: 14/18) volunteers. Main outcome measuresSubjects performed 10 plyometric exercises. Surface EMG of upper (UT), middle (MT) and lower (LT) trapezius and serratus anterior (SA) was registered. A quality assessment questionnaire was administered at the beginning and end of the exercise bout. Muscle activation at the beginning and end was evaluated by t-test. Mixed repeated measures ANOVA was conducted to test the effects of criterion-quality, time, muscles, exercises, and their interactions. ResultsIncreased EMG activation was noted in 34/40 cases, (21/40 significant (p < 0.05) changes). Quality assessment revealed a decline in the ability to maintain initial position (43% of subjects), failure to keep a consistent and symmetrical arc of motion (62% of subjects), and performance with trick movements (48% of subjects). Inability to keep a consistent arc of motion was significant in 4 exercises. ConclusionsThe novel questionnaire may aid quality assessment during plyometric exercises. Ability to keep a consistent arc of motion was the most sensitive marker of decline of performance quality.