This study aimed to describe and compare ballet dancers' cardiorespiratory responses, muscle damage and oxidative stress levels during a ballet class (practice of isolated ballet exercises performed with barre/hand-rail support and across-the-floor movements to improve technical skills) and rehearsal (practice of ballet choreography involving technical-artistic skills to improve dancers' performance for shows). The 12 advanced female ballet dancers undertook three exercise sessions: maximum effort test, class and rehearsal. Heart rate (HR) and oxygen consumption (VO2) were continuously measured. Lactate was determined before 15 min and after class and rehearsal. Blood was sampled pre, post and 48 h after class and rehearsal for creatine kinase (CK), lipid peroxides (LPO) and glutathione analysis (GSSG/GSH). Class was of lower intensity than rehearsal as shown by VO2, HR and lactate values: VO2 (mL.kg(-1).min(-1)): 14.5±2.1 vs. 19.1±1.7 (p < 0.001); HR (bpm.min(-1)): 145.7±17.9 vs. 174.5±13.8 (p < 0.001); lactate (mmol.L(-1)): 4.2±1.1 vs. 5.5±2.7 (p = 0.049). CK (IU) increased following class and rehearsal, remaining high 48 h after: class (pre = 109.3±48.5; post = 144±60; 48 h = 117.2±64.6); rehearsal (pre = 78.6±52.1; post = 122±70.7; 48 h = 104.9±89.5). LPO (µM) increased from pre-class (1.27±0.19) to post-class (1.41±0.19) and went down after 48 h (1.20±0.22). No LPO time-course changes followed the rehearsal. GSSG/GSH decreased 48 h after class and rehearsal. Greater increases in LPO post-class suggest it promotes CK release by an oxidative membrane-damage mechanism. Physiological increases of LPO and CK in class indicate it prepares the dancers for exercise-induced oxidative stress and muscle damage during rehearsals. Ballet dancers' muscle damage and oxidative stress responses seem not to be dependent on exercise intensity based on VO2 responses.

The purpose of this study was to examine the influence of the intrasession sequencing of concurrent strength and aerobic training on the acute testosterone (TT) and cortisol (COR) responses. Ten recreationally strength-trained young men (23.5 ± 0.9 years) performed 2 exercise interventions: aerobic-strength (AS) and strength-aerobic (SA), which consisted of 30 minutes of aerobic exercise on a cycle ergometer at 75% of maximal heart rate and 3 sets of 8 repetitions at 75% of 1 repetition maximum (1RM) in 4 strength exercises. Maximal heart rate was determined using a maximal incremental test on a cycle ergometer. Blood samples were collected before, between exercise modalities, and immediately after the concurrent training sessions to determine basal and acute total TT and COR concentrations. There were significant increases in TT after the first modality in both exercise orders (p < 0.05). However, the TT level remained significantly higher than the resting levels after the second exercise modality only in the AS (p < 0.05) which resulted in a significant higher relative total change after the complete concurrent training session compared with SA (p < 0.05). Regarding COR, there were significant increases after the first modality in both AS and SA orders (p < 0.05), but the COR returned to resting levels after the second modality in both AS and SA interventions. During AS and SA, the change observed after the first modality performance was greater than that after the second in both hormones. The present results suggest that the TT response is optimized after the AS order, whereas both AS and SA produced similar hormonal levels at all time points. However, it is important to state that the present results should be applied only when short duration and moderate intensity aerobic training is performed.

The objective of this study was to investigate the effect of running versus cycling exercises upon serum S100B levels and typical markers of skeletal muscle damage such as creatine kinase (CK), aspartate aminotransferase (AST) and myoglobin (Mb). Although recent work demonstrates that S100B is highly expressed and exerts functional properties in skeletal muscle, there is no previous study that tries to establish a relationship between muscle damage and serum S100B levels after exercise. We conducted a cross-sectional study on 13 male triathletes. They completed 2 submaximal exercise protocols at anaerobic threshold intensity. Running was performed on a treadmill with no inclination (RUN) and cycling (CYC) using a cycle-simulator. Three blood samples were taken before (PRE), immediately after (POST) and 1 h after exercise for CK, AST, Mb and S100B assessments. We found a significant increase in serum S100B levels and muscle damage markers in RUN POST compared with RUN PRE. Comparing groups, POST S100B, CK, AST and Mb serum levels were higher in RUN than CYC. Only in RUN, the area under the curve (AUC) of serum S100B is positively correlated with AUC of CK and Mb. Therefore, immediately after an intense exercise such as running, but not cycling, serum levels of S100B protein increase in parallel with levels of CK, AST and Mb. Additionally, the positive correlation between S100B and CK and Mb points to S100B as an acute biomarker of muscle damage after running exercise.

The present study investigated the effect of an aerobic exercise bout associated with a high-carbohydrate (CHO) meal on plasma levels of acylated ghrelin and hunger sensation. Eight healthy males performed an exercise (ET) and a control (CT) trial. In ET, participants performed a 60-min cycling exercise (∼70% of maximal oxygen uptake) after consuming a high-CHO meal. In the CT, participants remained at rest throughout the whole period after consuming the high-CHO meal. Hunger sensation was assessed and blood samples were taken to determine the levels of acylated ghrelin, glucose, insulin, total cholesterol (TC), and triglycerides (TG). There was suppression of hunger after consuming the meal in ET and CT (p = 0.028 and p = 0.011, respectively). Hunger increased in CT in the period correspondent to the exercise session (p = 0.017) and remained suppressed in the ET. The area under the curve for acylated ghrelin showed that its levels were lower in the ET compared with CT in the period of the exercise plus the immediate period (1 h) postexercise (60.7 vs. 96.75 pg·mL(-1)·2 h(-1), respectively; p = 0.04). Inverse correlations between acylated ghrelin levels and insulin, TC, and TG levels at different time points were observed. In conclusion, these findings suggest that 1 bout of aerobic exercise maintains the meal-induced suppression of hunger. The mechanism underlying this effect may involve the exercise-induced suppression of acylated ghrelin. These results implicate that the combination of a high-CHO meal and aerobic exercise may effectively improve appetite control and body weight management.

This study compared rectal temperature (Tre), heat sensation and sweating between obese and non-obese boys during cycling in the heat. Participants (aged 12-15 years) were 17 obese and 16 non-obese (BMI=29.4±4.3 and 16.8±1.7 kg · m⁻², respectively) boys. They cycled for 30-min (50-55% VO(2peak)) in a climatic chamber (35°C, 45% RH) and Tre, heat sensation and sweat volume were monitored. From the start to the end of cycling, Tre was similar between the obese (37.4±0.3-37.8±0.3°C) and non-obese (37.3±0.2-37.9±0.2°C) groups. Heat sensation was higher in the obese group from the start (3.6±2.7 vs. 1.3±1.4 cm; P=0.008) to the end (7.6±2 vs. 5.2±2.2 cm; P=0.003) of cycling. Sweat volume corrected by body surface area was similar between the obese (200±123 mL · m⁻²) and non-obese (212±80 mL · m⁻²) groups. Initial and final HR were similar in both groups, and RPE was higher in the obese group at 25th (P=0.040) and 30th (P=0.019) min. In conclusion, the obese pubescent participants presented similar Tre and sweating volume, but higher heat sensation while cycling in the heat.