Clustering technical approaches of elite and world-class pole vaulters based on 10 years of measurement during competitions.

Recently, a variety of technical approaches in world-class pole-vaulters' behaviour have been observed. The aim of this study was to investigate the presence of subgroups using different technical approaches and to compare biomechanical performance differences. Biomechanical analysis of performances over 5.

Success to Clear the Bar in Elite Pole Vaulters is Affected by Step Frequency Perturbation.

The purpose of the study was to identify the interaction of step characteristics, along with the direction and magnitude of their asymmetry of elite male and female pole vaulters between successful and failed attempts. It was hypothesized that step characteristics and the magnitude of asymmetry between the two legs would interact with the outcome of the attempt. The approach runs of 12 pole vaulters (7 males, 5 females) were recorded during an indoor international competition.

Lower Muscle and Blood Lactate Accumulation in Sickle Cell Trait Carriers in Response to Short High-Intensity Exercise.

It remains unclear whether sickle cell trait (SCT) should be considered a risk factor during intense physical activity. By triggering the polymerization-sickling-vaso-occlusion cascade, lactate accumulation-associated acidosis in response to high-intensity exercise is believed to be one of the causes of complications. However, our understanding of lactate metabolism in response to high-intensity exercise in SCT carriers is incomplete.

Effect of simplifying the body model to compute the energy parameters in pole vaulting.

This study compared changes in the energy-time profiles in pole vaulting using several body models. Two-dimensional kinematics were collected from 20 successful vaults (5.20-6.

Endurance Is Improved in Female Rats After Living High-Training High Despite Alterations in Skeletal Muscle.

Altitude camps are used during the preparation of endurance athletes to improve performance based on the stimulation of erythropoiesis by living at high altitude. In addition to such whole-body adaptations, studies have suggested that high-altitude training increases mitochondrial mass, but this has been challenged by later studies. Here, we hypothesized that living and training at high altitude (LHTH) improves mitochondrial efficiency and/or substrate utilization.

Biomechanical Pole Vault Patterns Were Associated With a Higher Proportion of Injuries.

Pole vault is a highly demanding sport where many physical and technical requirements are engaged in performance process. Considering level of energy transferred from athlete's horizontal speed to the pole during pole bending, we can imagine that associated musculoskeletal tensions, in addition to trials accumulation, can increase the risk of (specific) injuries. Given the multiple morphological, physical and technical characteristics of vaulters and ways of pole vaulting, we can hypothesis that some patterns of pole vaults can lead to higher injury risk than others.

The Elevated Track in Pole Vault: An Advantage During Run-Up?

Background: Approach speed is a major determinant of pole-vault performance. Athletic jump events such as long jump, triple jump, and pole vault can utilize an elevated track for the runway. Feedback from athletes indicates a benefit of using an elevated track on their results.

Maternal exercise modifies body composition and energy substrates handling in male offspring fed a high-fat/high-sucrose diet.

Key Points: Maternal training during gestation enhances offspring body composition and energy substrates handling in early adulthood. Offspring nutrition also plays a role as some beneficial effects of maternal training during gestation disappear after consumption of a high-fat diet.

Abstract: Maternal exercise during gestation has been reported to modify offspring metabolism and health.

Alterations to mitochondrial fatty-acid use in skeletal muscle after chronic exposure to hypoxia depend on metabolic phenotype.

We investigated the effects of chronic hypoxia on the maximal use of and sensitivity of mitochondria to different substrates in rat slow-oxidative (soleus, SOL) and fast-glycolytic (extensor digitorum longus, EDL) muscles. We studied mitochondrial respiration in situ in permeabilized myofibers, using pyruvate, octanoate, palmitoyl-carnitine (PC), or palmitoyl-coenzyme A (PCoA). The hypophagia induced by hypoxia may also alter metabolism.

High-intensity training reduces intermittent hypoxia-induced ER stress and myocardial infarct size.

Chronic intermittent hypoxia (IH) is described as the major detrimental factor leading to cardiovascular morbimortality in obstructive sleep apnea (OSA) patients. OSA patients exhibit increased infarct size after a myocardial event, and previous animal studies have shown that chronic IH could be the main mechanism. Endoplasmic reticulum (ER) stress plays a major role in the pathophysiology of cardiovascular disease.

Oxidative capacities of cardiac and skeletal muscles of heart transplant recipients: mitochondrial effects of cyclosporin-A and its vehicle Cremophor-EL.

Chronic immunosuppressive treatment was suspected to alter maximal muscle oxidative capacity (Vmax ) of heart transplant recipients, leading to a limitation of their exercise tolerance. It remains undefined whether the mitochondrial respiratory chain (MRC) of right ventricle (RV) and vastus lateralis (VL) muscles were altered by immunosuppressants and/or their vehicles. Vmax was measured polarographically in saponin-skinned fibres of RV and VL biopsies of patients and compared with Vmax of healthy VL and myocardium.

Effects of regular physical activity on skeletal muscle structural, energetic, and microvascular properties in carriers of sickle cell trait.

To assess the effects of regular physical activity on muscle functional characteristics of carriers of sickle cell trait (SCT), 39 untrained (U) and trained (T) hemoglobin (Hb)AA (CON) and SCT subjects (U-CON, n = 12; U-SCT, n = 8; T-CON, n = 10; and T-SCT, n = 9) performed a graded exercise and a time to exhaustion (T(ex)) test, and were subjected to a muscle biopsy. Maximal power, total work performed during T(ex), citrate synthase and cytochrome c oxidase (COX) activities, respiratory chain complexes I and IV content, and capillary density (CD), diameter (COD), and surface area (CSA) were upregulated by the same proportion in T-CON and T-SCT compared with their untrained counterparts. These proportionally similar differences imply that the observed discrepancies between U-SCT and U-CON remained in the trained subjects.

Interleukin-6 contributes to hepcidin mRNA increase in response to exercise.

The iron regulatory peptide hormone hepcidin has been proposed to participate in training-induced iron deficiency. Plasma and urinary hepcidin increase in response to one bout of prolonged exercise, a condition also known to increase plasma interleukin-6 (Il-6). Because Il-6 activates hepcidin transcription and expression during inflammation, our aim was to study the role of this cytokine in hepatic hepcidin mRNA expression during exercise and recovery.

Basal peroxisome proliferator activated receptor gamma coactivator 1α expression is independent of calcineurin in skeletal muscle.

Both calcineurin-A and peroxisome proliferator activated receptor gamma coactivator 1α (PGC-1α) are key players in the acquisition and maintenance of slow-oxidative skeletal muscle phenotype. Whether calcineurin can control PGC-1α expression has been proposed but is still controversial. Our aim was to examine the relationship between calcineurin activation and PGC-1α expression in nonexercising skeletal muscles of rats.

Muscle inactivation of mTOR causes metabolic and dystrophin defects leading to severe myopathy.

Mammalian target of rapamycin (mTOR) is a key regulator of cell growth that associates with raptor and rictor to form the mTOR complex 1 (mTORC1) and mTORC2, respectively. Raptor is required for oxidative muscle integrity, whereas rictor is dispensable. In this study, we show that muscle-specific inactivation of mTOR leads to severe myopathy, resulting in premature death.

Control of gluconeogenic genes during intense/prolonged exercise: hormone-independent effect of muscle-derived IL-6 on hepatic tissue and PEPCK mRNA.

Prolonged intense exercise is challenging for the liver to maintain plasma glucose levels. Hormonal changes cannot fully account for exercise-induced hepatic glucose production (HGP). Contracting skeletal muscles release interleukin-6 (IL-6), a cytokine able to increase endogenous glucose production during exercise.

Decreased muscle ACE activity enhances functional response to endurance training in rats, without change in muscle oxidative capacity or contractile phenotype.

In the present study, we tested the hypothesis that chronic ANG I-converting enzyme (ACE) inhibition could improve the training-induced improvement in endurance exercise performance and that this could be related to enhanced skeletal muscle metabolic efficiency. Female Wistar rats were assigned to four groups comprising animals either maintained sedentary or endurance trained (Sed and Tr, respectively), and treated or not for 10 wk with an ACE inhibitor, perindopril (2 mg.kg(-1).

[Thyroid hormones and muscle phenotype: involvement of new signaling pathways].

Thyroid hormones (TH) are known to control development, body and muscle growth, as well as to determine muscle phenotype in the adult. TH affect muscle properties through nuclear receptors; they act either by a positive or a negative control on target genes that encode proteins accounting for contractile or metabolic phenotypes. Contractile activity and muscle load also affect muscle phenotype; several intracellular signaling pathways are involved in the transduction of signals related to contractile activity, including the calcineurin/NFAT pathway.

Thyroid hormone is required for the phenotype transitions induced by the pharmacological inhibition of calcineurin in adult soleus muscle of rats.

The present experiment was designed to examine the effects of hypothyroidism and calcineurin inhibition induced by cyclosporin A (CsA) administration on both contractile and metabolic soleus muscle phenotypes, with a novel approach to the signaling pathway controlling mitochondrial biogenesis. Twenty-eight rats were randomly assigned to four groups, normothyroid, hypothyroid, and orally treated with either CsA (25 mg/kg, N-CsA and H-CsA) or vehicle (N-Vh and H-Vh), for 3 wk. Muscle phenotype was estimated by the MHC profile and activities of oxidative and glycolytic enzymes.

Contraction-induced interleukin-6 transcription in rat slow-type muscle is partly dependent on calcineurin activation.

The present work aimed at determining whether interleukin-6 (IL-6) produced by skeletal muscle during exercise is related, at least partly, to calcineurin activity. Rats were treated with two specific calcineurin inhibitors, cyclosporin A (CsA) and FK506, or vehicle (Vhl); they were then subjected to exhaustive treadmill running. Modulatory Calcineurin-Interacting Protein-1 (MCIP-1) mRNA levels, a reliable indicator of calcineurin activity, and IL-6 mRNA levels were measured by real-time RT-PCR in soleus muscles, and IL-6 protein concentration was measured in the plasma.

The responsiveness of regenerated soleus muscle to pharmacological calcineurin inhibition.

The responsiveness of mature regenerated soleus (SOL) muscles to cyclosporin A (CsA) administration was studied in rats. Forty-two days after notexin-induced degeneration of left SOL muscles, rats were treated with CsA (25 mg/kg x day) or vehicle daily for 3 weeks. CsA administration decreased by eightfold the level of transcription of MCIP-1, a well-known calcineurin-induced gene, in intact as well as in regenerated muscles (P < 0.

Fibre-type specificity of interleukin-6 gene transcription during muscle contraction in rat: association with calcineurin activity.

In this study, we quantified the transcription of the interleukin-6 (IL-6) gene in individual fibres and the associated changes in calcineurin activity assessed at the cellular level during prolonged muscle contraction. Individual myofibres were isolated from plantaris and soleus muscles of rats at the end of an exhaustive running exercise test (n = 10), categorized according to their myosin heavy chain isoform content, and compared to those of resting rats (n = 10). Using real-time PCR analysis in individual fibres, a marked rise in IL-6 transcript levels occurred in type I and IIa fibres at the end of exercise (P < 0.

Role of hypoxia-induced anorexia and right ventricular hypertrophy on lactate transport and MCT expression in rat muscle.

To dissect the independent effects of altitude-induced hypoxemia and anorexia on the capacity for cardiac lactate metabolism, we examined the effects of 21 days of chronic hypobaric hypoxia (CHH) and its associated decrease in food intake and right ventricle (RV) hypertrophy on the monocarboxylate transporter 1 and 4 (MCT) expression, the rate of lactate uptake into sarcolemmal vesicles, and the activity of lactate dehydrogenase isoforms in rat muscles. In comparison with control rats (C), 1 mmol/L lactate transport measured on skeletal muscle sarcolemmal vesicles increased by 33% and 58% in hypoxic (CHH, barometric pressure = 495 hPa) and rats pair-fed an equivalent quantity of food to that consumed by hypoxic animals, respectively. The increased lactate transport was higher in PF than in CHH animals ( P < .

Cyclosporin A treatment increases rat soleus muscle oxidative capacities.

Previous studies suggested that administration of cyclosporin A (CsA), an immunosuppressive agent, contributes to the increased fatigability of heart transplant recipients. The aim of this study was to investigate whether CsA itself, without vehicle, affects the function of mitochondria maintained in situ, in rats treated with CsA (25mg/kg/day) dissolved in ethanol and olive oil. Treatment with CsA induced a 16% decrease in slow myosin heavy chain (MHC) associated with a 225% increase in fast MHCIIa.