Echauffement et blessures : page 3.8

Corrélation entre un niveau bas de sélénium et l’arthrose

08/06/2016 | Echauffement et blessures et Etudes Compléments alimentaires et Etudes Anti-âge


The Association Between Serum Selenium Levels with Rheumatoid Arthritis
Na Yu, Fang Han         Biological Trace Element Research July 2016, Volume 172, Issue 1, pp 46-52

There are conflicting reports on the correlation between serum selenium (Se) levels with rheumatoid arthritis (RA). Through a meta-analysis approach, the aim of the present study is to clarify the relationship between serum Se levels with RA. We searched literatures that met our predefined criteria in PubMed, ScienceDirect, and OVID published as of September 2015. Ten eligible articles with 14 case–control studies involving 716 subjects were identified.

Overall, pooled analysis indicated that subjects with RA had lower serum levels of Se than the healthy controls (standardized mean difference (SMD) = −1.347, 95 % confidence interval (CI) = [−1.872, −0.823], p < 0.001). Further subgroup analysis indicated that subjects with RA had lower serum Se levels than healthy controls in Europe (SMD = −1.063, 95 % CI = [−1.571, −0.556], p < 0.001) and Asia (SMD = −3.254, 95 % CI = [−4.687, −1.821], p < 0.001) but not in USA (SMD = −0.322, 95 % CI = [−0.657, 0.012], p = 0.059). The serum Se levels were lower in RA than healthy controls measured by graphite furnace atom absorption spectrometry (GFAAS) (SMD = −1.026, 95 % CI = [−1.522, −0.530], p < 0.001), electrothermal absorption spectrometry (EAS) (SMD = −1.197, 95 % CI = [−2.373, −0.020], p < 0.05), flame atomic absorption spectrophotometry (FAAS) (SMD = −0.681, 95 % CI = [−1.049, −0.313], p < 0.001), and inductively coupled plasma–mass spectrophotometer (ICP-MS) (SMD = −11.707, 95 % CI = [−15.189, −8.224], p < 0.001) but not by neutron activation analysis (NAA) (SMD = −0.674, 95 % CI = [−1.350, 0.003], p = 0.051).

In conclusion, this meta-analysis supports a significant association between low serum Se concentration with RA. However, this finding needs further confirmation by a trans-regional multicenter study to obtain better understanding of causal relationship between serum Se with RA of different human races or regions.

Comment le sport endommage t’il le coeur sur le long terme?

19/05/2016 | Etudes cardio et Echauffement et blessures et Etudes Anti-âge


Long-term leucine supplementation aggravates prolonged strenuous exercise-induced cardiovascular changes in trained rats
Gustavo Barbosa dos Santos             Experimental Physiology 2016

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 hour of exercise, 5 d.wk−1 for 6 wk. Three days after the training period rats were submitted to swimming exercises until exhaustion and cardiac parameters were assessed.

Exercising until exhaustion significantly increased cardiac biomarker levels and cytokines, glycogen content and inhibited protein synthesis signaling also led to cardiac electrical disturbances. When combined with exercise, leucine supplementation led to further increases in the aforementioned parameters and also significant increase in blood pressure and protein degradation signaling. We report, for the first time, that leucine supplementation not only does not 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 cardiac myocyte damage.

Effets de l’effort physique sur le spleen

17/02/2016 | Etudes cardio et Echauffement et blessures


Responses of the human spleen to exercise
Journal of Sports Sciences 2016 Volume 34, Issue 10,  pages 929-936     Roy J. Shepharda

The human spleen shows a decrease in volume of around 40% early during vigorous exercise and in response to other stressful stimuli such as maximal apnoea and the breathing of hypoxic gas mixtures. Contraction seems an active response, mediated by alpha-adrenergic fibres in the splenic nerve. Given the relatively small size of the human spleen, the effect upon physical performance is likely to be small; the augmentation of total blood volume is <2%, and even taking account of other causes of haemoconcentration during vigorous exercise, the increase of haematocrit is <10%. However, one of two studies suggested that the haemoconcentration may be sufficient to cause errors in the traditional method for calculating exercise-induced changes of plasma volume. The spleen also contributes leucocytes and platelets to the general circulation as part of the “fight or flight” reaction to stressors. The mobilisation of leucocytes proceeds more slowly than that of the red cells; it depends not only upon an active contraction of the spleen, but also a modulation of leucocyte adhesion molecules. Splenectomy impairs exercise performance in horses, but human performance data are lacking; overall health effects seem minimal, and many patients live many years after removal of their spleens.

Peut-on prévenir les blessure d’usure grâce au rythme cardiaque?

29/01/2016 | Echauffement et blessures


Musculoskeletal overuse injuries and heart rate variability: Is there a link?
Medical Hypotheses Volume 87, February 2016, Pages 1–7           Angela Spontelli Gisselman

Accurate detection and prevention of overuse musculoskeletal injuries is limited by the nature of somatic tissue injury. In the pathogenesis of overuse injuries, it is well recognized that an abnormal inflammatory response occurs within somatic tissue before pain is perceived which can disrupt the normal remodeling process and lead to subsequent degeneration. Current overuse injury prevention methods focused on biomechanical faults or performance standards lack the sensitivity needed to identify the status of tissue injury or repair.

Recent evidence has revealed an apparent increase in the prevalence and impact of overuse musculoskeletal injuries in athletics. When compared to acute injuries, overuse injuries have a potentially greater negative impact on athletes’ overall health burden. Further, return to sport rehabilitation following overuse injury is complicated by the fact that the absence of pain does not equate to complete physiological healing of the injured tissue. Together, this highlights the need for exercise monitoring and injury prevention methods which incorporate assessment of somatic tissue response to loading.

One system primarily involved in the activation of pathways and neuromediators responsible for somatic tissue repair is the autonomic nervous system (ANS). Although not completely understood, emerging research supports the critical importance of peripheral ANS activity in the health and repair of somatic tissue injury. Due to its significant contributions to cardiac function, ANS activity can be measured indirectly with heart rate monitoring. Heart rate variability (HRV) is one index of ANS activity that has been used to investigate the relationship between athletes’ physiological response to accumulating training load.

Research findings indicated that HRV may provide a reflection of ANS homeostasis, or the body’s stress-recovery status. This noninvasive marker of the body’s primary driver of recovery has the potential to incorporate important and as yet unmonitored physiological mechanisms involved in overuse injury development.

We hypothesize that abnormal somatic tissue response to accumulating microtrauma may modulate ANS activity at the level of HRV. Exploring the link between HRV modulation and somatic tissue injury has the potential to reveal the putative role of ANS homeostasis on overuse musculoskeletal injury development.

Connectivité intermusculaire

19/01/2016 | Echauffement et blessures et Etudes Musculation


Altered mechanical interaction between rat plantar flexors due to changes in intermuscular connectivity
M. Bernabei               Scandinavian Journal of Medicine & Science in Sports   2016   Early View (Online Version of Record published before inclusion in an issue)

Connective tissue formation following muscle injury and remedial surgery may involve changes in the stiffness and configuration of the connective tissues linking adjacent muscles. We investigated changes in mechanical interaction of muscles by implanting either a tissue-integrating mesh (n = 8) or an adhesion barrier (n = 8) to respectively increase or decrease the intermuscular connectivity between soleus muscle (SO) and the lateral gastrocnemius and plantaris complex (LG+PL) of the rat. As a measure of mechanical interaction, changes in SO tendon forces and proximal–distal LG+PL force differences in response to lengthening LG+PL proximally were assessed 1 and 2 weeks post-surgery. The extent of mechanical interaction was doubled 1 week post-implantation of the tissue-integrating mesh compared to an unaffected compartment (n = 8), and was more than four times higher 2 weeks post-surgery. This was found only for maximally activated muscles, but not when passive. Implanting the adhesion barrier did not result in a reduction of the mechanical interaction between these muscles.

Our findings indicate that the ratio of force transmitted via myofascial, rather than myotendinous pathways, can increase substantially when the connectivity between muscles is enhanced. This improves our understanding of the consequences of connective tissue formation at the muscle boundary on skeletal muscle function.

Efficacité des injections de prolothérapie contre les tendinites?

10/01/2016 | Echauffement et blessures


Dextrose Prolotherapy Versus Control Injections in Painful Rotator Cuff Tendinopathy  
Archives of Physical Medicine and Rehabilitation Volume 97, Issue 1, January 2016, Pages 17–25   Helene Bertrand

To compare the effect of dextrose prolotherapy on pain levels and degenerative changes in painful rotator cuff tendinopathy against 2 potentially active control injection procedures.


Randomized controlled trial, blinded to participants and evaluators.


Outpatient pain medicine practice.


Persons (N=73) with chronic shoulder pain, examination findings of rotator cuff tendinopathy, and ultrasound-confirmed supraspinatus tendinosis/tear.


Three monthly injections either (1) onto painful entheses with dextrose (Enthesis-Dextrose), (2) onto entheses with saline (Enthesis-Saline), or (3) above entheses with saline (Superficial-Saline). All solutions included 0.1% lidocaine. All participants received concurrent programmed physical therapy.

Main Outcome Measures

Primary: participants achieving an improvement in maximal current shoulder pain ≥2.8 (twice the minimal clinically important difference for visual analog scale pain) or not. Secondary: improvement in the Ultrasound Shoulder Pathology Rating Scale (USPRS) and a 0-to-10 satisfaction score (10, completely satisfied).


The 73 participants had moderate to severe shoulder pain (7.0±2.0) for 7.6±9.6 years. There were no baseline differences between groups. Blinding was effective. At 9-month follow-up, 59% of Enthesis-Dextrose participants maintained ≥2.8 improvement in pain compared with Enthesis-Saline (37%; P=.088) and Superficial-Saline (27%; P=.017). Enthesis-Dextrose participants’ satisfaction was 6.7±3.2 compared with Enthesis-Saline (4.7±4.1; P=.079) and Superficial-Saline (3.9±3.1; P=.003). USPRS findings were not different between groups (P=.734).


In participants with painful rotator cuff tendinopathy who receive physical therapy, injection of hypertonic dextrose on painful entheses resulted in superior long-term pain improvement and patient satisfaction compared with blinded saline injection over painful entheses, with intermediate results for entheses injection with saline. These differences could not be attributed to a regenerative effect. Dextrose prolotherapy may improve on the standard care of painful rotator cuff tendinopathy for certain patients.

Le 5-HTP contre les douleurs articualires?

09/01/2016 | Echauffement et blessures et Etudes Compléments alimentaires et Etudes Anti-âge


Supplement of 5-hydroxytryptophan before induction suppresses inflammation and collagen-induced arthritis
Tao-Hsiang Yang         Arthritis Research & Therapy 2015, 17:364

Evidence is accumulating that a preclinical phase is present before the onset of clinical signs and symptoms of rheumatoid arthritis (RA). This phase represents an important therapeutic window within which interventions can dramatically modulate outcomes. An agent able to prevent RA for high risk individuals in this phase is therefore desired. In this study, we investigated whether tryptophan metabolite, 5-hydroxytryptophan (5-HTP) or 5-methoxytryptophan (5-MTP), can act as such an agent for primary prevention of collagen-induced arthritis (CIA).

Mouse splenocytes were pretreated with 5-HTP or 5-MTP and activated by anti-CD3 plus anti-CD28 antibodies in vitro. The percentages of interferon-γ (IFNγ) + CD4 + T cells and interleukin-17 (IL-17) + CD4 + T cells were measured by flow cytometry. The production of pro-inflammatory cytokines, serotonin and kynurenine was measured by enzyme-linked immunosorbent assay. A CIA model was used to investigate the in vivo effects of 5-HTP on the prevention of arthritis.

5-HTP decreased the percentages of IFNγ + CD4 + T cells and IL-17 + CD4 + T cells and suppressed the production of IL-2, IL-4, IL-6, IL-17, tumor necrosis factor-α (TNFα) and IFNγ in activated splenocytes. 5-HTP administered before induction decreased the disease activities in CIA mice and suppressed the production of TNFα, IL-6 and cyclooxygenase-2 in arthritic joints. 5-HTP also increased serotonin, but decreased kynurenine in the CIA mice.

5-HTP suppresses inflammation and arthritis through decreasing the production of pro-inflammatory mediators. 5-HTP supplement before induction ameliorates arthritis in a CIA model.

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