Effects of a 25-km trial on psychological, physiological and stroke characteristics of short- and mid-distance swimmers.

AIM: The aim of this paper was to evaluate the effects of a very long distance swimming task on psychological, biomechanical and physiological responses. Eight swimmers (age 21.0 ± 1.2 years; stature 1.80 ± 0.07 m; body mass 76.7 ± 11.0 kg; means ± SD) participated in a 25-km trial in a swimming pool. METHODS: Before and immediately after the trial, swimmers underwent a 50-m sprint test, during which we assessed velocity, stroke rate (SR), stroke length (SL) and psychological condition (rate of perceived exertion [RPE] and profile of mood state [POMS] questionnaire). During the 25-km trial we determined also elbow angle, heart rate (HR) and lactate concentration ([La]). RESULTS: Velocity, SR and SL during the sprint test after the trial decreased compared to before from 1.91 ± 0.01 m·s⁻¹, 0.94 ± 0.01 cycles·s⁻¹ and 1.99 ± 0.02 m·cycle⁻¹ to 1.45 ± 0.01 m·s⁻¹, 0.78 ± 0.01 cycles·s⁻¹ and 1.84 ± 0.03 m·cycle⁻¹, respectively (P<0.05). During the 25-km trial, velocity and SL decreased significantly, while SR and elbow angle did not change. Velocity and SR during the sprint test after the trial were significantly higher than those during the trial. RPE and fatigue (POMS subscale) increased significantly, while the other negative POMS subscales and vigor decreased significantly. HR decreased significantly at 20 km, then increasing significantly at 25 km, while [La] did not change. CONCLUSION: These results suggest that, despite the occurrence of fatigue, as evidenced by the drop in velocity and changes in psychological profile, swimmers were able to complete the 25-km trial by adopting a conservative pacing, unveiling also a reserve in maximum performance.

Metabolic and hormonal responses to a single session of kumite (free non-contact fight) and kata (highly ritualized fight) in karate athletes.

BACKGROUND: Several studies report martial arts as a good model for investigating neuroendocrine responses to competitive fighting. However, little is known on the metabolic responses elicited by elite athletes during fighting. In particular, the metabolic picture in elite athletes of martial arts is little known. AIM: In the present study, our aim was to investigate the acute effects of a session of karate practice on the glucose-insulin system. SUBJECTS AND METHODS: Ten healthy individuals (6M/4F; BMI: 22.1 ± 0.7 kg/m(2); 21.9 ± 1.1 years, mean ± SE) who practice karate in national or international competitions were enrolled. All participants completed two experimental trials in a randomised-crossover fashion. A basal blood sample was collected from each athlete to assess plasma glucose, insulin, cortisol, testosterone and catecholamines, before karate training session. In two separate days, another blood sample was collected from each participants after 3 min of real fighting (kumite) and 3 min of ritualized simulation of combat (kata). RESULTS: In both trials, plasma glucose resulted to be higher at the end the of performance compared to the basal (p < 0.001 after kumite and p < 0.02 after kata). In contrast, insulin was similar in the basal and after physical activity in the two trials. Catecholamines were higher after kata and kumite sessions with respect to the basal values (p < 0.04) and, in particular, epinephrine post-kumite values were much greater than those measured after kata. CONCLUSIONS: Our results indicate that unlike performances of karate (kumite and kata) elicit different plasma glucose increases. In particular, we found that glucose and epinephrine concentrations increased more after kumite than after kata.

Effect of L-acetylcarnitine on body composition in HIV-related lipodystrophy.

This study examined the impact of L-acetylcarnitine treatment on metabolic parameters and body composition in patients with lipodystrophy syndrome secondary to antiretroviral treatment in human immunodeficiency virus (HIV) infection. A total of 9 HIV-1 infected patients with lipodystrophy syndrome (4F/5M, age 41+/-5 years, HIV duration 8+/-2 years, BMI 23.7+/-3.4 kg/m(2), on protease inhibitors and nucleoside analogue Reverse Transcriptase inhibitors) were evaluated before and after 8 months of therapy with L-acetylcarnitine (2 g/die) and 9 matched healthy subjects served as control subjects. In all patients fasting plasma glucose, insulin concentrations (for evaluation of surrogate indexes of insulin sensitivity), lipid profile, lipid oxidation (by indirect calorimetry), body composition (by DEXA), and intramyocellular triglyceride (IMCL) content of the calf muscles (by (1)H NMR spectroscopy) were assessed. After this therapy, in HIV-1 patients, the IMCL content of the soleus had significantly decreased (p=0.03). Plasma FFAs (0.79+/-0.31 to 0.64+/-0.25; p<0.05) and Respiratory Quotient (0.83+/-0.18 to 0.72+/-0.16; p<0.03) also decreased. Insulin sensitivity was significantly lower prior (HOMA-IS 0.56+/-0.30) and nonstatistically different than controls after therapy (0.72+/-0.49 vs. 0.78+/-0.42) whilst the percentage of fat in the legs increased (p=0.05). Eight months of L-acetylcarnitine treatment increased lipid oxidation, decreased intramyocellular triglyceride content, and induced a more physiological distribution of fat deposits.

Left ventricular function and energy metabolism in middle-aged men undergoing long-lasting sustained aerobic oxidative training.

OBJECTIVE: Ageing of the human heart is characterised by morphological, functional and metabolic changes. Short-term interventions and cross-sectional studies in older individuals questioned the possibility that physical exercise may reverse these alterations. In this study we aimed to assess whether in middle-aged men involved in regular and long lasting physical activity these alterations were attenuated. DESIGN: Left ventricular (LV) magnetic resonance imaging (MRI) and three-dimensional image selected in-vivo spectroscopy (3D-ISIS) (31)P magnetic resonance spectroscopy (MRS) were performed using a 1.5T scanner in 20 healthy, young and 25 healthy middle-aged non-obese men with a sedentary lifestyle (11 young and 14 middle-aged) or undergoing regular aerobic oxidative training (9 young and 11 middle-aged). Insulin sensitivity was estimated by the homeostatic model assessment 2 (HOMA-2) model. RESULTS: Sedentary young and middle-aged men were not different with respect to LV morphological parameters and systolic function. The phosphocreatine/ATP (PCr/ATP) ratio (marker of high energy phosphates metabolism) and the LV E-peak filling rate/A-peak filling rate ratio (E/A ratio) were lower in sedentary middle-aged than physically active subjects. Parameters of LV systolic function and the PCr/ATP ratio were not different in the middle-aged compared with the young trained men; the E/A peak flow ratio was higher in the middle-aged trained men than in the middle-aged sedentary men. Within the entire population, the PCr/ATP ratio and the E/A peak flow ratio were associated with insulin sensitivity. CONCLUSIONS: Trained middle-aged subjects showed a better pattern of LV energy metabolism and of diastolic function than their sedentary counterparts. At this age the exercise-related cardiac benefits were detectable when physical exercise was performed regularly and for a long period of time.