Echauffement et blessures

Chaleur ou froid pour optimiser l’anabolisme?

22/11/2017 | Echauffement et blessures et Etudes Musculation

 

Plus d’anabolisme, moins de catabolisme avec…

Impact of local heating and cooling on skeletal muscle transcriptional response related to myogenesis and proteolysis
Roksana B. Zak European Journal of Applied Physiology October 2017

Purpose

To determine the impact of local muscle heating and cooling on myogenic and proteolytic gene responses following resistance exercise.

Methods

Recreationally trained males (n = 12), age 25.3 ± 1.5, % body fat 13.6 ± 1.92, completed four sets of 8–12 repetitions of unilateral leg press and leg extension while heating one leg, and cooling the other. Muscle biopsies were taken from the vastus lateralis of each leg pre and 4 h post exercise.

Results

MyoD, FOXO1, and MuRF1 mRNA increased with exercise regardless of temperature (p < 0.05). Myostatin, MYF5, and atrogin-1 mRNA decreased with exercise regardless of temperature (p < 0.05). Myogenin, MRF4, and CASP3 mRNA were higher in the hot condition, compared to the cold (p < 0.05). PAX7 mRNA was lower in the hot compared to cold condition (p = 0.041). FOXO3 mRNA was higher in the cold compared to hot condition (p = 0.037). AKT1 and AKT2 were unaffected by either exercise or temperature. Femoral artery blood flow volume was higher in the hot (375.2 ± 41.2 ml min− 1), compared to the cold condition (263.5 ± 23.9 ml min− 1), p = 0.01. Tissue oxygen saturation was higher in the hot (71.7 ± 4.8%) than cold condition (55.3 ± 5.0%).

Conclusion

These results suggest an impaired muscle growth response with local cold application compared to local heat application.

Une blessure peut avoir des conséquences psychologiques graves

08/12/2016 | Echauffement et blessures

 

Are severe musculoskeletal injuries associated with symptoms of common mental disorders among male European professional footballers?
Knee Surgery, Sports Traumatology, Arthroscopy December 2016, Volume 24, Issue 12, pp 3934–3942   Vincent Gouttebarge

Purpose

To explore the associations of severe musculoskeletal injuries (joint and muscles) and surgeries with symptoms of common mental disorders (distress, anxiety/depression, sleeping disturbance, adverse alcohol behaviour , smoking, adverse nutrition behaviour) among male European professional footballers.

Methods

Cross-sectional analyses were conducted on electronic questionnaires completed by professional footballers recruited from the national players’ unions of Finland, France, Norway, Spain or Sweden. The number of severe (time loss of more than 28 days) musculoskeletal injuries (total, joint, muscle) and surgeries during a professional football career was examined through four questions, while symptoms of common mental disorders were evaluated through validated scales.

Results

A total of 540 professional footballers (mean age of 27 years; 54 % playing in the highest leagues) participated in the study. Sixty-eight per cent of the participants had already incurred one or more severe joint injuries and 60 % one or more severe muscle injuries. Prevalence of symptoms of common mental disorders ranged from 3 % for smoking to 37 % for anxiety/depression and 58 % for adverse nutrition behaviour. The number of severe musculoskeletal injuries during a football career was positively correlated with distress, anxiety and sleeping disturbance, while the number of surgeries was correlated with adverse alcohol behaviour and smoking. Professional footballers who had sustained one or more severe musculoskeletal injuries during their career were two to nearly four times more likely to report symptoms of common mental disorders than professional footballers who had not suffered from severe musculoskeletal injuries.

Conclusion

It can be concluded that the number of severe musculoskeletal injuries and surgeries during a career is positively correlated and associated with symptoms of common mental disorders among male European professional footballers. This study emphasises the importance of applying a multidisciplinary approach to the clinical care and support of professional footballers, especially when a player faces lengthy periods without training and competition as a consequence of recurrent severe joint or muscle injuries.

De nouvelles cellules souches découvertes dans les muscles

30/09/2016 | Echauffement et blessures et Etudes Musculation

 

The first characterization of a novel (non-satellite cell) stem cell population in human skeletal muscle
J.P. Nederveen     Appl. Physiol. Nutr. Metab. Vol. 41, 2016 S376

Skeletal muscle stem cells (satellite cells; SC) represent the primary
cell population responsible for muscle regeneration/repair. SC content
and activation has been show to increase in response to muscle
damaging exercise. However, non-satellite cell progenitors, under experimental
conditions in animals, have been identified to form skeletal
muscle
when the SC population is compromised. PW1+ interstitial
cells (PIC) have also been shown, experimentally, to contribute to
muscle repair in animals. This cell population, however, has never
been identified in humans. We sought to examine the changes in both
PIC and SC content following a single bout of eccentric exercise. Ten
sedentary males (24±3 years of age; mean±SEM) were recruited. Percutaneous
muscle biopsies from the vastus lateralis muscle were taken
prior to a bout of eccentric exercise (Pre), and 6h, 24h, and 72 h
post-exercise. Muscle fiber size, SC and PIC content were determined
via immunofluorescent microscopy. mRNA expression was assessed
by RT-PCR. The number of SC increased from Pre (10.3±0.8 Pax7+cells/
100 fibers) to 72h post-exercise (12.3±2.0 Pax7+cells/100 fibers, p<0.05).
Similarly, PW1+ cells increased from Pre (2.1±0.6 PW1+ cells/100 fibers)
to 72h post-exercise (6.8±2.5 PW1+ cells/100 fibers, p<0.05). PW1 mRNA
expression was significantly (p<0.05) increased 1.9-fold from Pre to
72h post-exercise. Here, for the first time in humans, we identify a
population of cells which are located in the interstitium that respond
to eccentrically-induced muscle damage in a similar fashion to SC.

 

Comment la santé des reins affecte la masse musculaire?

28/09/2016 | Echauffement et blessures et Etudes Anti-âge

 

Low glomerular filtration rate as an associated risk factor for sarcopenic muscle strength: is creatinine or cystatin C-based estimation more relevant?
Asli Tufan       The Aging Male     Pages 1-5 | Received 04 Jul 2016,  Published online: 20 Sep 2016

Introduction: We aimed to evaluate the association of a decreased glomerular-filtration-rate (GFR <60 ml/min/1.73 m2), estimated using Modification of Diet in Renal Disease (MDRD), creatinine- and cystatin C-based (CKDEPI-CR and CKDEPI-CC) Chronic Kidney Disease Epidemiology Collaboration equations with handgrip strength (HGS).

Methods: Community-dwelling males aged ≥60 years admitted to outpatient clinic were included. We used MDRD, CKDEPI-CR, and CKDEPI-CC formulas for GFR estimation and corrected these for body surface area. Muscle strength was assessed by HGS.

Results: 209 men (mean age 67.8 ± 6.4) were enrolled. Sixty-two patients (29.7%) had sarcopenic HGS. Subjects with sarcopenic HGS were older, had higher rate of a GFR < 60 ml/min/1.73 m2, had lower mid-upper arm circumference; tended to have lower creatine kinase, albumin, CKDEPI-CC-GFR levels; and higher BUN/creatinine ratio and cystatin C. Multivariate logistic regression analysis revealed a CKDEPI-CC lower than 60 ml/min/1.73 m2 as the only independent factor underlying sarcopenic HGS. Higher age tended to have an independent association. Only higher age was independently associated with low HGS when other estimations were used (p = 0.013 and p = 0.021 when MDRD and CKDEPI-CR were used, respectively).

Conclusions: There is a strong association of a GFR level of <60 ml/min/1.73 m2 with sarcopenic HGS, when CKDEPI-CC formula is used.

L’ibuprofène contre la fatigue?

28/09/2016 | Etudes cardio et Etudes sur les hormones et Echauffement et blessures

 

Ibuprofen intake increases exercise time to exhaustion: A possible role for preventing exercise-induced fatigue
F. D. Lima     Scandinavian Journal of Medicine & Science in Sports   volume 26, Issue 10 October 2016
Pages 1160–1170

Although the intake of nonsteroidal anti-inflammatory drugs (NSAIDs) intake by athletes prevents soreness, little is known concerning their role in exercise performance. This study assessed the effects of ibuprofen intake on an exhaustive protocol test after 6 weeks of swimming training in rats. Animals were divided into sedentary and training groups. After training, animals were subdivided into two subsets: saline or ibuprofen. Afterwards, three repeated swimming bouts were performed by the groups. Ibuprofen (15 mg/kg) was administered once a day. Pain measurements were performed and inflammatory and oxidative stress parameters were assayed in cerebral cortex and gastrocnemius muscle. Training, ibuprofen administration, or both combined (P 

< 0.05; 211 ± 18s, 200 ± 31s, and 279 ± 23s) increased exercise time to exhaustion.

Training decreased the acetylcholinesterase (AChE) activity (P 

< 0.05; 149 ± 11) in cerebral cortex.

Ibuprofen intake decreased the AChE activity after exhaustive protocol test in trained and sedentary rats (P < 0.05; 270 ± 60; 171 ± 38; and 273 ± 29). It also prevented neuronal tumor necrosis factor-α (TNF-α) and interleukin (IL 1β) increase. Fatigue elicited by this exhaustive protocol may involve disturbances of the central nervous system. Additive anti-inflammatory effects of exercise and ibuprofen intake support the hypothesis that this combination may constitute a more effective approach. In addition, ergogenic aids may be a useful means to prevent exercise-induced fatigue.

Trop de leucine: néfaste pour le cœur des sportifs?

04/07/2016 | Etudes cardio et Echauffement et blessures et Etudes Compléments alimentaires et Etudes Anti-âge

 

Long-term leucine supplementation aggravates prolonged strenuous exercise-induced cardiovascular changes in trained rats
Gustavo Barbosa dos Santos 14 June 2016       Exp Physiol 2016 Volume 101, Issue 7 1 July   Pages 811–820

New Findings    

What is the central question of this study?

Can long-term leucine supplementation prevent prolonged strenuous endurance exercise induced cardiac injury?

What is the main finding and its importance?

Prolonged endurance exercise does not seem to exceed cardiac energetic capacity, hence it does not represent an energy threat to this organ, at least in trained subjects. However, it may induce, in susceptible individuals, a state of cardiac electrical instability, which has been associated with ventricular arrhythmias and sudden cardiac death. This situation might be worsened when combined with leucine supplementation, which leads to increased blood pressure and cardiac injury. Leucine supplementation failed to prevent cardiac fatigue symptoms and may aggravate prolonged strenuous exercise-induced cardiovascular disturbances in trained rats.

Observational studies have raised concerns that prolonged strenuous exercise training may be associated with increased risk of cardiac arrhythmia and even primary cardiac arrest or sudden death. It has been demonstrated that leucine can reduce prolonged exercise-induced muscle damage and accelerate the recovery process. The aim of this study was to investigate the effects of prolonged strenuous endurance exercise on cardiovascular parameters and biomarkers of cardiac injury in trained adult male rats and assess the use of leucine as an auxiliary substance to prevent the likely cardiac adverse effects caused by strenuous exercise. Twenty-four male Wistar rats were randomly allocated to receive a balanced control diet (18% protein) or a leucine-rich diet (15% protein plus 3% leucine) for 6 weeks. The rats were submitted to 1 h of exercise, 5 days per week for 6 weeks. Three days after the training period, the rats were submitted to swimming exercise until exhaustion, and cardiac parameters were assessed. Exercising until exhaustion significantly increased cardiac biomarker levels, cytokines and glycogen content inhibited protein synthesis signalling and led to cardiac electrical disturbances. When combined with exercise, leucine supplementation led to greater increases in the aforementioned parameters and also a significant increase in blood pressure and protein degradation signalling. We report, for the first time, that leucine supplementation not only fails to prevent cardiac fatigue symptoms, but may also aggravate prolonged strenuous exercise-induced cardiovascular disturbances in trained rats. Furthermore, we find that exercising until exhaustion can cause cardiac electrical disturbances and damage cardiac myocytes.

Le sport élève ton niveau d’albumine…

30/06/2016 | Etudes cardio et Echauffement et blessures et Etudes Musculation et Etudes Anti-âge

 

Le sport élève ton niveau d’albumine…

Exercise-induced albuminuria is related to metabolic syndrome
Sharon Greenberg                 American Journal of Physiology - Renal Physiology Published 1 June 2016 Vol. 310 no. 11, F1192-F1196

Microalbuminuria (MA) is a known marker for endothelial dysfunction and future cardiovascular events. Exercise-induced albuminuria (EiA) may precede the appearance of MA. Associations between EiA and metabolic syndrome (MS) have not been assessed so far. Our aim was to investigate this association in a large sample of apparently healthy individuals with no baseline albuminuria. This was a cross-sectional study of 2,027 adults with no overt cardiovascular diseases who took part in a health survey program and had no baseline MA. Diagnosis of MS was based on harmonized criteria. All patients underwent an exercise test (Bruce protocol), and urinary albumin was measured before and after the examination. Urinary albumin-to-creatinine ratio (ACR) values before and after exercise were 0.40 (0.21–0.89) and 1.06 (0.43–2.69) mg/g for median (interquartile range) respectively. A total of 394 (20%) subjects had EiA; ACR rose from normal rest values (0.79 mg/g) to 52.28 mg/g after exercise (P < 0.001); this effect was not shown for the rest of the study population. EiA was related to higher prevalence of MS (13.8% vs. 27.1%, P < 0.001), higher metabolic equivalents (P < 0.001), higher baseline blood pressure (P < 0.001), and higher levels of fasting plasma glucose, triglycerides, and body mass index (P < 0.001). Multivariate binary logistic regression model showed that subjects with MS were 98% more likely to have EiA (95% confidence interval: 1.13–3.46, P = 0.016).

In conclusion, EiA in the absence of baseline MA is independently related to MS.

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