Eccentric Exercise Activates Novel Transcriptional Regulation of Hypertrophic Signaling Pathways Not Affected by Hormone Changes

Unaccustomed eccentric exercise damages skeletal muscle tissue, activating mechanisms of recovery and remodeling that may be influenced by the female sex hormone 17β-estradiol (E2). Using high density oligonucleotide based microarrays, we screened for differences in mRNA expression caused by E2 and eccentric exercise. After random assignment to 8 days of either placebo (CON) or E2 (EXP), eighteen men performed 150 single-leg eccentric contractions. Muscle biopsies were collected at baseline (BL), following supplementation (PS), +3 hours (3H) and +48 hours (48H) after exercise. Serum E2 concentrations increased significantly with supplementation (P<0.001) but did not affect microarray results. Exercise led to early transcriptional changes in striated muscle activator of Rho signaling (STARS), Rho family GTPase 3 (RND3), mitogen activated protein kinase (MAPK) regulation and the downstream transcription factor FOS. Targeted RT-PCR analysis identified concurrent induction of negative regulators of calcineurin signaling RCAN (P<0.001) and HMOX1 (P = 0.009). Protein contents were elevated for RND3 at 3H (P = 0.02) and FOS at 48H (P<0.05). These findings indicate that early RhoA and NFAT signaling and regulation are altered following exercise for muscle remodeling and repair, but are not affected by E2

(Mal) adaptações metabólicas ao treinamento contínuo: concepções não consensuais de terminologia e diagnóstico

Altos desempenhos esportivos demandam treinamentos pesados necessários ao estímulo adaptativo específico a cada esporte. A elevada carga de treino é geralmente acompanhada de discreta fadiga e reduções agudas no desempenho, mas caso acompanhada de períodos apropriados de recuperação, resulta em supercompensação metabólica ao treinamento, refletida como aumento na capacidade aeróbica e/ou força muscular. Visto como contínuo, os processos de intensificação do treinamento e o estresse relacionado à supercompensação, o aumento da sobrecarga ou do estresse poderá, em algum momento, acarretar a quebra da homeostase e a queda temporária da função (supra-alcance - OR ou supra-alcance funcional - FOR). Quando a sobrecarga excessiva de treinamento é combinada com recuperação inadequada há instalação do estado de supratreinamento (OT) ou supra-alcance não funcional (NFOR). O OT excede o OR, cujo pico é também o limiar do OT resultando em desadaptações fisiológicas e queda crônica do desempenho físico. A forma crônica de desadaptação fisiológica ao treinamento físico é chamada de síndrome do supertreinamento (OTS). A própria expressão da síndrome denota a etiologia multifatorial do estado e reconhece que o exercício não é necessariamente seu único fator causal. O diagnóstico de OTS é baseado na recuperação ou não do desempenho. Não há biomarcador objetivo para OTS. A distinção entre OTS e NFOR (supratreinamento extremo) é dependente de desfecho clínico e exclusão diagnóstica de doenças orgânicas, mais comuns na OTS. Também a diferença entre OR e OT é sutil e nenhum de seus marcadores bioquímicos pode ser universalizado. Não há evidências confirmatórias que OR evolui para OT ou que os sintomas de OT são piores dos que os de OR. Apenas pela fadiga aguda e queda de rendimento experimentada em sessões isoladas de treinamento, não é possível diferenciar presentemente os estados de OR e OT. Isto é devido, parcialmente, à variabilidade das respostas individuais ao treinamento e à falta de ambos instrumentos diagnósticos e estudos bem controlados.Sports top-level performance requires heavy training loads that provide a stimulus to sport-specific adaptation. Competitive training involving high workload is generally accompanied by minor fatigue and acute performance reduction, but when followed by appropriate recovery periods results in training-metabolic supercompensation reflected as increase in aerobic capacity and muscular strength. When the intensified training process leading to supercompensation and related-stress is seen as a continuum, the increased stress or overload might result in disruption of homeostasis and temporary decrease in function (overreaching - OR or functional overreaching - FOR). When excessive overload is combined with inadequate recovery, a state of overtraining (OT) or non-functional overreaching (NFOR) is installed. OT exceeds OR and the OR peak is also the OT threshold, resulting in stark physiological maladaptations and chronically reduced exercise performance. The chronic form of physiological maladaptation to training is called overtraining syndrome (OTS). The expression of the syndrome emphasizes the multifactorial etiology of the state and acknowledges that exercise (training) is not necessarily the sole causative factor. There is no objective biomarker for OTS besides the diagnosis based on performance recovery. Other distinctions between NFOR (extreme OT) and OTS depend on clinical outcome and exclusion diagnosis of organic diseases more common in OTS. Additionally, the difference between OR and OT is subtle and none of their biochemical markers should be considered universal. There is no evidence to confirm that OR will develop into OT or that OT symptoms are worse than those of OR. It is presently not possible to differentiate OR and OT states from the acute fatigue and decreased performance experienced from isolated training sessions. This situation is partially due to the variability of individual responses to training and to a lack of both diagnostic tools and well controlled studies

The interest of gait markers in the identification of subgroups among fibromyalgia patients

<p>Abstract</p> <p>Background</p> <p>Fibromyalgia (FM) is a heterogeneous syndrome and its classification into subgroups calls for broad-based discussion. FM subgrouping, which aims to adapt treatment according to different subgroups, relies in part, on psychological and cognitive dysfunctions. Since motor control of gait is closely related to cognitive function, we hypothesized that gait markers could be of interest in the identification of FM patients' subgroups. This controlled study aimed at characterizing gait disorders in FM, and subgrouping FM patients according to gait markers such as stride frequency (SF), stride regularity (SR), and cranio-caudal power (CCP) which measures kinesia.</p> <p>Methods</p> <p>A multicentre, observational open trial enrolled patients with primary FM (44.1 ± 8.1 y), and matched controls (44.1 ± 7.3 y). Outcome measurements and gait analyses were available for 52 pairs. A 3-step statistical analysis was carried out. A preliminary single blind analysis using k-means cluster was performed as an initial validation of gait markers. Then in order to quantify FM patients according to psychometric and gait variables an open descriptive analysis comparing patients and controls were made, and correlations between gait variables and main outcomes were calculated. Finally using cluster analysis, we described subgroups for each gait variable and looked for significant differences in self-reported assessments.</p> <p>Results</p> <p>SF was the most discriminating gait variable (73% of patients and controls). SF, SR, and CCP were different between patients and controls. There was a non-significant association between SF, FIQ and physical components from Short-Form 36 (p = 0.06). SR was correlated to FIQ (p = 0.01) and catastrophizing (p = 0.05) while CCP was correlated to pain (p = 0.01). The SF cluster identified 3 subgroups with a particular one characterized by normal SF, low pain, high activity and hyperkinesia. The SR cluster identified 2 distinct subgroups: the one with a reduced SR was distinguished by high FIQ, poor coping and altered affective status.</p> <p>Conclusion</p> <p>Gait analysis may provide additional information in the identification of subgroups among fibromyalgia patients. Gait analysis provided relevant information about physical and cognitive status, and pain behavior. Further studies are needed to better understand gait analysis implications in FM.</p

The amplitude of pulse-synchronous oscillations varies with the level of intramuscular pressure in simulated compartment syndrome

BACKGROUND: Patients with compartment syndromes have elevated intramuscular pressure (IMP) due to increased volume in the affected muscle. However, the accuracy of IMP as a parameter in diagnosing chronic compartment syndrome has been questioned. It has been observed that arterial pulsations create oscillations in the IMP in patients with abnormally elevated IMP. The amplitude of the IMP oscillations appears to be related to a pathogenic mechanism of elevated IMP. Therefore, the purpose of the present study was to investigate the relation between the amplitude of pulse-synchronous IMP oscillations and the absolute level of IMP with a high-end fiber-optic system in a human experimental model of abnormally elevated IMP (simulated compartment syndrome) of the leg. The hypothesis that the amplitude of the IMP oscillations is correlated to the absolute level of IMP was tested. METHODS: IMP was measured at rest in the anterior tibial muscle in 12 legs of 7 healthy subjects (4 females and 3 males) with a mean age of 28 (range 23–38) years. The subject lay supine with his/her heel placed in a footrest. The foot was kept in a neutral position to avoid biased IMP readings. Measurements were performed at baseline and during 10 minutes with a model of abnormally elevated IMP (simulated compartment syndrome) applied. The abnormally elevated IMP was created by venous obstruction induced by a thigh tourniquet (65 mmHg) of a casted leg. Placement of the pressure-recording catheter was verified by sonography. RESULTS: The IMP increased from 4.7 (SD = 1.8) mmHg at baseline to 48.6 (SD = 7.1) mmHg when the model of elevated IMP was applied. The amplitude of the pulse-synchronous oscillations was undetectable at baseline. It increased to 3.9 (SD = 1.4) mmHg with increasing IMP when the model was applied. The amplitude of the oscillations showed a positive correlation (r = 0.59) with the absolute level of IMP. CONCLUSIONS: The amplitude of the pulse-synchronous IMP oscillations is correlated with the absolute level of IMP during abnormally elevated IMP. The oscillations of IMP may therefore be an additional parameter assuring the abnormally elevated IMP in the diagnosis of compartment syndromes

ISSN exercise & sport nutrition review: research & recommendations

Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients