Effect of a 12-week aerobic training program on perceptual and affective responses in obese women

[Purpose] The aim of this study was to observe the effect of self-selected intensity or imposed intensity during aerobic training on perceptual and affective responses in obese women. [Subjects] The study included 26 obese women aged 30–60 years. [Methods] The subjects were randomly divided into two groups, with 13 subjects in each group: self-selected intensity and imposed intensity (10% above ventilatory threshold) groups. All subjects completed an intervention program that lasted 12 weeks, with three exercise sessions a week. The rating of perceived exertion and affective responses (Feeling Scale and Felt Arousal Scale) were monitored in the first, sixth, and twelfth weeks. [Results] Significant differences were observed between groups in heart rate and rating of perceived exertion. The affective responses during exercise were more negative in the imposed intensity group. [Conclusion] Use of a self-selected exercise intensity can promote smaller negative affective responses during exercise and provide a sufficient stimulus for improvement in cardiorespiratory fitness.Key words: Self-selected exercise, Rating of perceived exertion, Affective responses     

Endothelial Glycocalyx Damage Is Associated with Leptospirosis Acute Kidney Injury

Leptospirosis is a common disease in tropical countries, and the kidney is one of the main target organs. Membrane proteins of Leptospira are capable of causing endothelial damage in vitro, but there have been no studies in humans evaluating endothelial glycocalyx damage and its correlation with acute kidney injury (AKI). We performed a cohort study in an outbreak of leptospirosis among military personnel. AKI was diagnosed in 14 of 46 (30.4%) patients. Leptospirosis was associated with higher levels of intercellular adhesion molecule-1 (ICAM-1; 483.1 ± 31.7 versus 234.9 ± 24.4 mg/L, P < 0.001) and syndecan-1 (73.7 ± 15.9 versus 21.2 ± 7.9 ng/mL, P < 0.001) compared with exposed controls. Patients with leptospirosis-associated AKI had increased level of syndecan-1 (112.1 ± 45.4 versus 41.5 ± 11.7 ng/mL, P = 0.021) and ICAM-1 (576.9 ± 70.4 versus 434.9 ± 35.3, P = 0.034) compared with leptospirosis patients with no AKI. Association was verified between syndecan-1 and ICAM-1 with serum creatinine elevation and neutrophil gelatinase-associated lipocalin (NGAL) levels. This association remained even after multivariate analysis including other AKI-associated characteristics. Endothelial injury biomarkers are associated with leptospirosis-associated renal damage.     

SCF increases in utero–labeled stem cells migration and improves wound healing

Diabetic skin wounds lack the ability to heal properly and constitute a major and significant complication of diabetes. Nontraumatic lower extremity amputations are the number one complication of diabetic skin wounds. The complexity of their pathophysiology requires an intervention at many levels to enhance healing and wound closure. Stem cells are a promising treatment for diabetic skin wounds as they have the ability to correct abnormal healing. Stem cell factor (SCF), a chemokine expressed in the skin, can induce stem cells migration, however the role of SCF in diabetic skin wound healing is still unknown. We hypothesize that SCF would correct the impairment and promote the healing of diabetic skin wounds. Our results show that SCF improved wound closure in diabetic mice and increased HIF‐1α and vascular endothelial growth factor (VEGF) expression levels in these wounds. SCF treatment also enhanced the migration of red fluorescent protein (RFP)‐labeled skin stem cells via in utero intra‐amniotic injection of lenti‐RFP at E8. Interestingly these RFP+ cells are present in the epidermis, stain negative for K15, and appear to be distinct from the already known hair follicle stem cells. These results demonstrate that SCF improves diabetic wound healing in part by increasing the recruitment of a unique stem cell population present in the skin.     

Seasonal Strength Performance and Its Relationship with Training Load on Elite Runners

The aim of this study was to analyze the time-course of force production of elite middle and long-distance runners throughout an entire season and at the end of the off-season, as well as its relationships with training load and hormonal responses. Training load was recorded daily throughout an entire season by measuring and evaluating the session distance (km), training zone and session-RPE in a group of 15 elite middle and long-distance runners (12 men, 3 women; age = 26.3 ± 5.1yrs, BMI = 19.7 ± 1.1). Also, basal salivary-free cortisol levels were measured weekly, and 50-metre sprints, mean propulsive velocity (MPV), mean propulsive power (MPP), repetition maximum (RM) and peak rate of force development (RFD) of half-squats were measured 4 times during the season, and once more after the off-season break. There were no significant variations in force production during the season or after the off-season break, except for the RFD (-30.2%, p = 0.005) values, which changed significantly from the beginning to the end of the season. Significant correlations were found between session-RPE and MPV (r = -0.650, p = 0.004), MPP (r = -0.602, p = 0.009), RM (r = -0.650, p = 0.004), and the 50-metre sprint (r = 0.560, p = 0.015). Meanwhile, salivary-free cortisol correlated significantly with the 50-metre sprint (r = 0.737, p < 0.001) and the RM ( r = -0.514, p = 0.025). Finally, the training zone correlated with the 50-metre sprint (r = -0.463, p = 0.041). Session-RPE, training zone and salivary-free cortisol levels are related to force production in elite middle and long-distance runners. Monitoring these variables could be a useful tool in controlling the training programs of elite athletes.

Key points

• Session-RPE, training zone and salivary free cortisol levels correlate significantly with strength-related variables in middle and long-distance elite runners.
• A month of active rest during the off-season break is enough to prevent decreases in force production of such athletes.
• Monitoring training loads through session-RPE is a suitable and simple method for controlling the training process in elite middle and long-distance runners.

Key words: Endurance, exercise, testing, physiology