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The purpose of the present study was to evaluate the effects of a 4-week low-carbohydrate (CHO) diet regimen on body weight, exercise performance and hormonal response to running in master athletes. Six endurance master athletes performed three 30-min time trials, before (TT1), after 15 days (TT2) and after 30 days (TT3) on a low CHO diet. Blood samples were collected for hormonal and lactate measurements. After 15 days body weight had decreased (TT1 72.3 ± 2.4 kg, TT2 70.0 ± 2.7 kg; P = 0.006) and then remained stable. No differences were observed in performance (TT1 7,015 ± 273 m, TT2 6,920 ± 286 m, TT3 7,202 ± 315 m) and in the insulin/glucagon ratio. After 2 and 4 weeks, adrenocorticotropic hormone decreased significantly both at rest (baseline: TT1 42.5 ± 7.8 pg·ml, TT3 21.6 ± 3.2 pg·ml) and during exercise (end of exercise: TT1 120 ± 20 pg·ml, TT2 80 ± 16 pg·ml, TT3 31 ± 2 pg·ml). Baseline cortisol concentrations had increased significantly after as little as 15 days on the low CHO diet. The results of the present study demonstrate no changes in time trial performance in master endurance athletes after 4 weeks on a low CHO diet. However, an effect on the hypothalamic pituitary adrenal axis emerged. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to evaluate metabolic and mechanical parameters of Spinning® and to verify if the intensities remain within the American College of Sports Medicine recommendations. Fifteen participants (8 males: 39.0±2.0 years; 70.0±2.0 kg; 177.0±2.0 cm, 58.0±3.0 ml/kg/min; and 7 females: 33.6±5.5 years; 56.6±4.4 kg; 165.0±4.6 cm; 48.8±5.5 ml/kg/min) performing an interval Spinning® session had their heart rate (HR), oxygen consumption (VO2) and power output (W) measured. At the beginning and during the Spinning® session, a blood sample was taken for lactate measurements. Statistical difference between phases was performed with ANOVA repeated measure design and a Chi-square test to calculate the frequency of distribution of HRs. The energy cost of the activity was 3367±159 kJ/h (804±38 kcal/h). Participants worked on average at 54% Wmax, 79% VO2max and 86% HRmax. Participants spent 80% of the session above the HR suggested by the instructor. Peak lactate measured was 5.3±0.69 mmol/l. The registered intensity was higher than the guidelines for healthy activities. Therefore Spinning® should be considered a “very intense” activity and particular attention should be paid to novel or unfit participants because no feedback is provided during the session to control the intensity participants are working at. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to evaluate the accuracy of a novel approach for predicting the one-repetition maximum (1RM). The prediction is based on the force-velocity and load-velocity relationships determined from measured force and velocity data collected during resistance-training exercises with incremental submaximal loads. 1RM was determined as the load corresponding to the intersection of these two curves, where the gravitational force exceeds the force that the subject can exert.Methods: The proposed force-velocity-based method (FVM) was tested on 37 participants (23.9 ± 3.1 year; BMI 23.44 ± 2.45) with no specific resistance-training experience, and the predicted 1RM was compared to that achieved using a direct method (DM) in chest-press (CP) and leg-press (LP) exercises.Results: The mean 1RM in CP was 99.5 kg (±27.0) for DM and 100.8 kg (±27.2) for FVM (SEE = 1.2 kg), whereas the mean 1RM in LP was 249.3 kg (±60.2) for DM and 251.1 kg (±60.3) for FVM (SEE = 2.1 kg). A high correlation was found between the two methods for both CP and LP exercises (0.999, p < 0.001). Good agreement between the two methods emerged from the Bland and Altman plot analysis.Conclusion: These findings suggest the use of the proposed methodology as a valid alternative to other indirect approaches for 1RM prediction. The mathematical construct is simply based on the definition of the 1RM, and it is fed with subject's muscle strength capacities measured during a specific exercise. Its reliability is, thus, expected to be not affected by those factors that typically jeopardize regression-based approaches. [ABSTRACT FROM AUTHOR]

Unlabelled: The combination of acute dopamine/noradrenaline reuptake inhibition (bupropion; BUP) and heat stress (30 degrees C) significantly improves performance (9%). Furthermore the maintenance of a higher power output resulted in the attainment of significantly higher heart rates and rectal temperatures--above 40 degrees C--in the BUP trial compared to the placebo trial. Since BUP is an aid to cease smoking that is taken for longer periods, question remains if similar performance and thermoregulatory effects are found following administration of BUP over several days (10 days). The purpose of the present study was to examine the effects of chronic BUP on exercise performance, thermoregulation and hormonal variables in the heat. Eight trained male cyclists participated in the study. Subjects completed two trials consisting of 60 min fixed intensity exercise (55% W (max)) followed by a time trial (TT) in a double-blind randomized crossover design. Exercise was performed in 30 degrees C. Subjects took either placebo (PLAC) or BUP (Zyban) for 3 days (150 mg), followed by 300 mg for 7 days. Chronic BUP did not influence TT performance (BUP 40'42'' +/- 4'18''; PLAC 41'36'' +/- 5'12''), but significantly increased core temperature (P = 0.030). BUP significantly increased circulating growth hormone levels (PLAC: 9.8 +/- 5.8 ng L(-1); BUP: 13 +/- 6.8 ng L(-1); P < 0.008).Discussion/conclusion: Chronic BUP did not influence TT performance in 30 degrees C and subjects did not reach core temperature values as high as observed during the acute BUP study. It seems that chronic administration results in an adaptation of central neurotransmitter homeostasis, resulting in a different response to the drug. [ABSTRACT FROM AUTHOR]

Dual career (i.e., the combination of elite sport and higher education) is a strategic issue in Europe, and student-athletes' motivations toward sport and academic achievements are deemed crucial. Thus, this study aimed to validate the Italian version of the Student Athletes' Motivation toward Sport and Academics Questionnaire (SAMSAQ-IT). Three-hundred and twenty-eight Italian student-athletes (females 26 %, males 74 %) participated in the study. Exploratory factor analysis, Cronbach's alpha, and confirmatory factor analysis were applied to test the three-factor structure (i.e., SAM, student athletic motivation; AM, academic motivation; CAM, career athletic motivation) of the instrument, to assess the internal consistency of each subscale, and to verify the fit of the Italian model, respectively. Differences ( p ≤ 0.05) in SAM-IT, AM-IT and CAM-IT scores were calculated in relation to gender and competition level. The three-factor structure was confirmed for the Italian model with an internal consistency ranging from good (SAM-IT: α = 0.84) to acceptable (CAM-IT: α = 0.71; AM-IT: α = 0.70), and an overall acceptable fit emerged. Independent of gender and competition level, Italian student-athletes showed highest CAM-IT and lowest SAM-IT values. Considering that in Europe distinct education and sport career paths exist, findings indicate that the assessment of student-athletes' dual-career motivations requires an adapted, valid and reliable psychometric tool. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare in amateur swimmers the critical swimming velocity (CV) with the swimming velocity corresponding to a blood lactate concentration of 4 mmol l ( V). Ten amateur swimmers volunteered for this study (six men, age 22.3 ± 2 years; four women, age 21.3 ± 1 years) and performed a 7 × 200-m swimming test (at 70%, 75%, 80%, 85%, 90%, 95% and 100% of their 200-m best time) with 5 min rest between each repetition. Blood lactate concentration was determined after each repetition. V was determined from the speed-lactate curve. In order to calculate CV, the best front-crawl swimming results over 50, 100, 200 and 400 m were used. CV was expressed as the slope of the linear relationship between time and distance. Swimming velocities obtained with the two tests (CV 1.086 ± 0.151 m s; V 1.087 ± 0.128 m s) were positively and significantly correlated ( r = 0.93, p < 0.05) and no significant differences were found. A Bland-Altman plot showed a good agreement between the two measurement methods. These results confirm that the CV seems to be a valid and noninvasive method for also determining training intensities and monitor endurance capacity in less-experienced athletes. [ABSTRACT FROM AUTHOR]

Thrombosis of the portal system is a potentially life-threatening complication after splenectomy. The reported incidence is low (≅1%), however may be underestimated due to difficult in making the diagnosis. The factors associated with its development and the clinical outcome are poorly characterized. The aim of this study was to assess the incidence, risk factors, treatment, and outcome in series of consecutive cases. All patients who had undergone a splenectomy (both open and laparoscopic) between January 1997 and December 2004 at the Department of Surgery of University of Milan Bicocca were retrospectively reviewed. Twelve cases of thrombosis (7.6%) among 158 splenectomies were identified. No significant differences were noted in age, gender, and surgical approach between patients who developed thrombosis and those who did not. Indication for splenectomy in patients with thrombosis were myeloproliferative disorders ( n=5), hemolytic disease ( n=4), and lymphoproliferative disorder ( n=3). All patients had splenomegaly (mean 1.380 kg, range 0.400–3.120 kg). Among patients with myeloproliferative disorders, five (33%) developed the complication, compared with 4 of 35 (11.5%) with hemolytic disease. Patients with both splenic weight >2.500 kg and myeloproliferative disorders had 80% incidence of portal thrombosis. Preoperative prophylactic anticoagulant therapy with low molecular weight heparin was administered in each case. All these patients had fever, abdominal pain, or leukocytosis. All diagnoses were made by contrast-enhanced computed tomography (CT) scan and ecocolordoppler ultrasonography, and anticoagulation therapy was initiated immediately. Treatment within 15 days after splenectomy was successful in all patients, while delayed treatment was ineffective. Portal thrombosis should be suspected in patients with fever or abdominal pain after splenectomy. Patients with myeloproliferative disorders and hemolitic diseases are at higher risk, as well as patients with marked splenomegaly. A high index of suspicion, early diagnosis, and prompt anticoagulation therapy are the keys to a successful outcome. [ABSTRACT FROM AUTHOR]

The original central fatigue hypothesis suggested that an exercise-induced increase in extracellular serotonin concentrations in several brain regions contributed to the development of fatigue during prolonged exercise. Serotonin has been linked to fatigue because of its well known effects on sleep, lethargy and drowsiness and loss of motivation. Several nutritional and pharmacologicalstudies have attempted to manipulate central serotonergic activity during exercise,but this work has yet to provide robust evidence for a significant role of serotonin in the fatigue process. However, it is important to note that brain function is not determined by a single neurotransmitter system and the interaction between brain serotonin and dopamine during prolonged exercise has also been explored as having a regulative role in the development of fatigue. This revised central fatigue hypothesis suggests that an increase in central ratio of serotonin to dopamine is associated with feelings of tiredness and lethargy, accelerating the onset of fatigue, whereas a low ratio favours improved performance through the maintenance of motivation and arousal. Convincing evidence for a role of dopamine in the development of fatigue comes from work investigating the physiologicalresponses to amphetamine use, but other strategies to manipulate central catecholamines have yet to influence exercise capacity during exercise in temperate conditions. Recent findings have, however, provided support for a significant role of dopamine and noradrenaline (norepinephrine) in performance during exercise in the heat. As serotonergic and catecholaminergic projections innervate areas of the hypothalamus, the thermoregulatory centre, a change in the activity of these neurons may be expected to contribute to the control of body temperature whilst at rest and during exercise. Fatigue during prolonged exercise clearly is influenced by a complex interaction between peripheral and central factors. [ABSTRACT FROM AUTHOR]