Reducing the mitochondrial oxidative burden alleviates lipid-induced muscle insulin resistance in humans.

Preclinical models suggest mitochondria-derived oxidative stress as an underlying cause of insulin resistance. However, it remains unknown whether this pathophysiological mechanism is conserved in humans. Here, we used an invasive in vivo mechanistic approach to interrogate muscle insulin action while selectively manipulating the mitochondrial redox state in humans.

Beta-Adrenergic Stimulation Induces Resistance Training-Like Adaptations in Human Skeletal Muscle: Potential Role of KLHL41.

Skeletal muscle mass plays a pivotal role in metabolic function, but conditions such as bed rest or injury often render resistance training impractical. The beta-adrenergic receptor has been highlighted as a potential target to promote muscle hypertrophy and treat atrophic conditions. Here, we investigate the proteomic changes associated with beta-adrenergic-mediated muscle hypertrophy, using resistance training as a hypertrophic comparator.

10-20-30 exercise training improves fitness and health.

Intense interval exercise training has been shown to improve performance and health of untrained and trained people. However, due to the exercise intensity causing high-perceived exertion, the participants often do not wish to continue the training. The 10-20-30 training concept consists of low intensity for 30 s, 20 s at a moderate pace, and then 10 s with high intensity either running or cycling.

Intensified training augments cardiac function, but not blood volume, in male youth elite ice hockey team players.

While it is well-established that a period of interval training performed at near maximal effort, such as speed endurance training (SET), enhances intense exercise performance in well-trained individuals, less is known about its effect on cardiac morphology and function as well as blood volume. To investigate this, we subjected 12 Under-20 Danish national team ice hockey players (age 18 ± 1 years, mean ± SD) to 4 weeks of SET, consisting of 6-10 × 20 s skating bouts at maximal effort interspersed by 2 min of recovery conducted three times weekly. This was followed by 4 weeks of regular training (follow-up).

Active ischemic pre-conditioning does not additively improve short-term high-intensity cycling performance when combined with caffeine ingestion in trained young men.

We investigated the effect of ischemic preconditioning (IPC) with and without caffeine supplementation on mean power output (MPO) during a 4-min cycling time-trial (TT). In a double-blinded, randomized, crossover-design, 11 trained men performed a TT on 4 days separated by ∼1 week. One hour before TT, participants ingested either caffeine (3 mg kg bw) or placebo pills, after which femoral blood-flow was either restricted with occlusion cuffs inflated to ∼180 mmHg (IPC), or sham-restricted (0-10 mmHg; Sham) during 3 × 2-min low-intensity cycling (10% of incremental peak power output).

Exercise training alters skeletal muscle microvascular endothelial cell properties in recent postmenopausal females.

The present study examined and compared the impact of exercise training on redox and molecular properties of human microvascular endothelial cells derived from skeletal muscle biopsies from sedentary recent (RPF, ≤ 5 years as postmenopausal) and late (LPF, ≥ 10 years as postmenopausal) postmenopausal females. Resting skeletal muscle biopsies were obtained before and after 8 weeks of intense aerobic exercise training for isolation of microvascular endothelial cells and determination of skeletal muscle angiogenic proteins and capillarisation. The microvascular endothelial cells were analysed for mitochondrial respiration and production of reactive oxygen species (ROS), glycolysis and proteins related to vascular function, redox balance and oestrogen receptors.

Beta2-agonist Impairs Muscle Insulin Sensitivity in Persons With Insulin Resistance.

Context: Given the promising effects of prolonged treatment with beta2-agonist on insulin sensitivity in animals and nondiabetic individuals, the beta2-adrenergic receptor has been proposed as a target to counter peripheral insulin resistance. On the other hand, rodent studies also reveal that beta2-agonists acutely impair insulin action, posing a potential caveat for their use in treating insulin resistance.

Objective: To assess the impact of beta2-agonist on muscle insulin action and glucose metabolism and identify the underlying mechanism(s) in 10 insulin-resistant subjects.

Low-Volume Speed Endurance Training with Reduced Volume Improves Short-Term Exercise Performance in Highly Trained Cyclists.

Purpose: We investigated the effects of low- and high-volume speed endurance training (SET), with a reduced training volume, on sprint ability, short- and long-term exercise capacity, muscle mitochondrial properties, ion transport proteins, and maximal enzyme activity in highly trained athletes.

Methods: Highly trained male cyclists (maximal oxygen consumption (V̇O 2max ): 68.3 ± 5.

No additive effect of creatine, caffeine, and sodium bicarbonate on intense exercise performance in endurance-trained individuals.

Background: Athletes commonly use creatine, caffeine, and sodium bicarbonate for performance enhancement. While their isolated effects are well-described, less is known about their potential additive effects.

Methods: Following a baseline trial, we randomized 12 endurance-trained males (age: 25 ± 5 years, VO: 56.

Inhaled salbutamol induces leanness in well-trained healthy females but not males during a period of endurance training: a randomised controlled trial.

Introduction: Many athletes use short-acting inhaled β-agonists multiple times weekly during training sessions to prevent exercise-induced bronchoconstriction, but it is unclear if treatment impairs training outcomes. Herein, we investigated performance adaptations in well-trained females and males training with prior inhalation of salbutamol.

Methods: 19 females and 21 males with maximal oxygen uptake (') of 50.

Inhaled beta -agonist, formoterol, enhances intense exercise performance, and sprint ability in elite cyclists.

Purpose: Many athletes use long-acting beta -agonist formoterol in treatment of asthma. However, studies in non-athlete cohorts demonstrate that inhaled formoterol can enhance sprint performance calling into question whether its use in competitive sports should be restricted. We investigated whether formoterol at upper recommended inhaled doses (54 μg) would enhance sprint ability and intense exercise performance in elite cyclists.

Similar improvements in 5-km performance and maximal oxygen uptake with submaximal and maximal 10-20-30 training in runners, but increase in muscle oxidative phosphorylation occur only with maximal effort training.

Objective: The aim of the present study was to examine whether 10-20-30 training (consecutive 1-min intervals consisting of 30 s at low-speed, 20 s at moderate-speed, and 10 s at high-speed), performed with submaximal effort during the 10-s high-speed runs, would lead to improved performance as well as increased maximum oxygen uptake (VO -max) and muscle oxidative phosphorylation (OXPHOS). In addition, to examine to what extent the effects would compare to 10-20-30 running conducted with maximal effort.

Design: Nineteen males were randomly assigned to 10-20-30 running performed with either submaximal (SUBMAX; n = 11) or maximal (MAX; n = 8) effort, which was conducted three times/week for 6 weeks (intervention; INT).

Exercise training induces thrombogenic benefits in recent but not late postmenopausal females.

Although regular physical activity is known to improve cardiovascular health in men, evidence for its beneficial effects in postmenopausal females is less convincing and it remains unclear whether initiation of exercise training soon after, rather than many years after menopause impacts the magnitude of training-induced adaptations. We evaluated exercise-induced changes in markers of thrombotic risk and conduit artery function in recent compared with late postmenopausal females. Fourteen recent and 13 late healthy postmenopausal females completed 8 wk of regular intensive exercise training, consisting of floorball and cycling.

Inhaled formoterol impairs aerobic exercise capacity in endurance-trained individuals: a randomised controlled trial.

Background: The 2022 Global Initiative for Asthma guidelines emphasise the inhaled long-acting β-agonist formoterol as part of the first treatment step, and therefore formoterol use among athletes will probably increase. However, prolonged supratherapeutic use of inhaled β-agonists impairs training outcomes in moderately trained men. We investigated whether inhaled formoterol, at therapeutic doses, imposes detrimental effects in endurance-trained individuals of both sexes.

Importance of training volume during intensified training in elite cyclists: Maintained vs. reduced volume at moderate intensity.

Introduction: Male elite cyclists (average VO -max: 71 mL/min/kg, n = 18) completed 7 weeks of high-intensity interval training (HIT) (3×/week; 4-min and 30-s intervals) during the competitive part of the season. The influence of a maintained or lowered total training volume combined with HIT was evaluated in a two-group design. Weekly moderate-intensity training was lowered by ~33% (~5 h) (LOW, n = 8) or maintained at normal volume (NOR, n = 10).

High-Intensity Training Represses FXYD5 and Glycosylates Na,K-ATPase in Type II Muscle Fibres, Which Are Linked with Improved Muscle K Handling and Performance.

Na/K ATPase (NKA) comprises several subunits to provide isozyme heterogeneity in a tissue-specific manner. An abundance of NKA α, β, and FXYD1 subunits is well-described in human skeletal muscle, but not much is known about FXYD5 (dysadherin), a regulator of NKA and β1 subunit glycosylation, especially with regard to fibre-type specificity and influence of sex and exercise training. Here, we investigated muscle fibre-type specific adaptations in FXYD5 and glycosylated NKAβ1 to high-intensity interval training (HIIT), as well as sex differences in FXYD5 abundance.

Effect of sample fractionation and normalization when immunoblotting for human muscle Na/K-ATPase subunits and glycogen synthase.

Immunoblotting is widely used in muscle physiology to determine protein regulation and abundance. However, research groups use different protocols, which may result in differential outcomes. Herein, we investigated the effect of various homogenization procedures on determination of protein abundance in human m.

High-Intensity Exercise Training Alters the Effect of -Acetylcysteine on Exercise-Related Muscle Ionic Shifts in Men.

This study investigated whether high-intensity exercise training alters the effect of -acetylcysteine (a precursor of antioxidant glutathione) on exercise-related muscle ionic shifts. We assigned 20 recreationally-active men to 6 weeks of high-intensity exercise training, comprising three weekly sessions of 4-10 × 20-s all-out bouts interspersed by 2 min recovery (SET, n = 10), or habitual lifestyle maintenance (n = 10). Before and after SET, we measured ionic shifts across the working muscle, using leg arteriovenous balance technique, during one-legged knee-extensor exercise to exhaustion with and without -acetylcysteine infusion.

Performance Adaptations to Intensified Training in Top-Level Football.

Because physical demands are surging in football (soccer, USA), clubs are more and more seeking players who have a high capacity to perform repeated intense exercise. High-intensity interval training (HIIT), comprising exercise performed at intensities near or exceeding the capacity of aerobic energy systems, effectively enhances the physical conditioning of players. But given that HIIT imposes high loads, it increases the risk of overload-associated match performance decline and injury.

The effect of 5 years of team sport on elderly males' health and social capital-An interdisciplinary follow-up study.

Background And Aims: Floorball training induces positive effects on health among untrained older adults. However, the effect of long-term participation (>2 years) in floorball training among elderly males has not been investigated. The aim of the present study was to examine the effect of 5 years of floorball training on risk factors for lifestyle diseases, fitness, physical function, and social capital of elderly males and compare to a control group that continued their usual lifestyle.

Four Weeks of Intensified Training Enhances On-Ice Intermittent Exercise Performance and Increases Maximal Oxygen Consumption of Youth National-Team Ice Hockey Players.

Purpose: We investigated whether 4 weeks of intensified training consisting of speed endurance training (SET) enhanced high-intensity exercise performance in youth national-team ice hockey players.

Methods: Utilizing a randomized crossover design, we subjected 17 players to 4 weeks of SET, comprising 6 to 10 × 20 seconds at maximal effort (>95% maximum ice skating speed) with 120-second recovery performed 3 times weekly, or maintenance of regular training (control period). Before and after each period, players completed ice-hockey-specific tests on ice, including a Yo-Yo Intermittent Recovery Level 1 test, a 30-m sprint test, and an agility test.

High-intensity interval training remodels the proteome and acetylome of human skeletal muscle.

Exercise is an effective strategy in the prevention and treatment of metabolic diseases. Alterations in the skeletal muscle proteome, including post-translational modifications, regulate its metabolic adaptations to exercise. Here, we examined the effect of high-intensity interval training (HIIT) on the proteome and acetylome of human skeletal muscle, revealing the response of 3168 proteins and 1263 lysine acetyl-sites on 464 acetylated proteins.

Beta -agonist increases skeletal muscle interleukin 6 production and release in response to resistance exercise in men.

Objective: Several tissues produce and release interleukin-6 (IL-6) in response to beta -adrenergic stimulation with selective agonists (beta -agonists). Moreover, exercise stimulates muscle IL-6 production, but whether beta -agonists regulate skeletal muscle production and release of IL-6 in humans in association with exercise remains to be clarified. Thus, we investigated leg IL-6 release in response to beta -agonist salbutamol in lean young men at rest and in recovery from resistance exercise.