Marco Bonifazi

Hormonal responses to whole-body vibration in men

Abstract The aim of this study was to evaluate the acute responses of blood hormone concentrations and neuromuscular performance following whole-body vibration (WBV) treatment. Fourteen male subjects [mean (SD) age 25 (4.6) years] were exposed to vertical sinusoidal WBV, 10 times for 60 s, with 60 s rest between the vibration sets (a rest period lasting 6 min was allowed after 5 vibration sets). Neuromuscular performance tests consisting of counter-movement jumps and maximal dynamic leg presses on a slide machine, performed with an extra load of 160% of the subjects body mass, and with both legs were administered before and immediately after the WBV treatment. The average velocity, acceleration, average force, and power were calculated and the root mean square electromyogram (EMGrms) were recorded from the vastus lateralis and rectus femoris muscles simultaneously during the leg-press measurement. Blood samples were also collected, and plasma concentrations of testosterone (T), growth hormone (GH) and cortisol (C) were measured. The results showed a significant increase in the plasma concentration of T and GH, whereas C levels decreased. An increase in the mechanical power output of the leg extensor muscles was observed together with a reduction in EMGrms activity. Neuromuscular efficiency improved, as indicated by the decrease in the ratio between EMGrms and power. Jumping performance, which was measured using the counter-movement jump test, was also enhanced. Thus, it can be argued that the biological mechanism produced by vibration is similar to the effect produced by explosive power training (jumping and bouncing). The enhancement of explosive power could have been induced by an increase in the synchronisation activity of the motor units, and/or improved co-ordination of the synergistic muscles and increased inhibition of the antagonists. These results suggest that WBV treatment leads to acute responses of hormonal profile and neuromuscular performance. It is therefore likely that the effect of WBV treatment elicited a biological adaptation that is connected to a neural potentiation effect, similar to those reported to occur following resistance and explosive power training. In conclusion, it is suggested that WBV influences proprioceptive feedback mechanisms and specific neural components, leading to an improvement of neuromuscular performance. Moreover, since the hormonal responses, characterised by an increase in T and GH concentration and a decrease in C concentration, and the increase in neuromuscular effectiveness were simultaneous but independent, it is speculated that the two phenomena might have common underlying mechanisms.

Sex hormones, central nervous system and pain

The aim of the present review, which highlights some relationships between sex hormones, the CNS and pain, is to provide reference points for discussion on one of the most intriguing aspects of pain pathophysiology: the presence of sex differences in the response threshold to phasic painful stimuli and in the incidence of chronic pain syndromes. The first part of the review deals with sex steroids and their mechanisms of action. In the second part, the connections between sex steroids, the CNS and pain are illustrated to introduce possible areas of discussion in the study of sex differences in experimental and clinical pain.

Changes in the exercise-induced hormone response to branched chain amino acid administration

SummaryIt was the aim of the present experiment to detect possible effects of branched-chain amino acids (BCAA) on the endocrine response to 1 h of continuous running. Blood samples were collected from 14 long-distance runners (age 24–42 years) in two different trials performed at 1-week intervals. In both trials (E and P) blood samples were collected at the following times: 9 a.m. (basal values sample), 10.30 a.m. (sample 90), 11.30 a.m. (sample 150), 12.30 p.m. (sample 210); the athletes performed 1 h of running at a constant predetermined speed between samples 90 and 150. Following the basal sample a mixture containing BCAA (E trial), or not containing BCAA (P trial) was ingested. In both trials no hormone basal concentrations, except insulin, were changed before exercise. In P trial, following exercise (sample 150), human growth hormone (HGH), prolactin (PRL), adrenocorticotropic hormone (ACTH) and cortisol (C) increased, while testosterone (T) decreased. In sample 210, after 1 h of rest, while ACTH, PRL and HGH had recovered to basal concentrations, C remained elevated and T displayed a further decrease. In the E trial a similar pattern of change was observed in sample 150 for HGH, PRL, ACTH and C; in sample 210 HGH and PRL displayed significantly lower values than in the corresponding P trial samples. The T was not modified by the running exercise and increased during the recovery period. It is, therefore, suggested that BCAA administration before exercise affects the response of some anabolic hormones, mainly HGH and T.

Preparatory versus main competitions: differences in performances, lactate responses and pre-competition plasma cortisol concentrations in elite male swimmers.

Abstract Two groups of elite male swimmers were studied using a similar protocol during the winter training seasons of two consecutive years. In the first season (September 1997–January 1998), eight male swimmers (age 19–25 years) of the Italian National Team participated, after 12 weeks of increased training volume, in a preparatory national competition (PWC) and then, after a further 6 weeks of specific training, in the World Championships (WC, both competitions in a 50-m pool), which represented the main competition at the end of the 18-week-long winter season. In the second season (September 1998–December 1998), a group of ten high-level male swimmers (18–22 years) participated, after 8 weeks of increased training volume, in a preparatory national competition (PIC) and then, after a further 6 weeks of specific training, in the Italian Championships (IC, both competitions in a 25-m pool), the main competition at the end of the 14-week-long winter season. A tapering period lasting 1–3 weeks was observed before the main competition in both seasons. All swimmers were competing at distances of up to 400 m; two of them participated in the study in both seasons. The swimming velocities and post-competition blood lactate concentrations were higher in the main competitions than in the preparatory competitions in both seasons. Pre-competition plasma cortisol (CORT) concentrations were higher than the initial values at the beginning of the season, reaching maximal values at the preparatory competitions and then decreasing before the main competitions in both seasons. The percentage increase in individual swimming velocity from the preparatory to the main competition was positively correlated with the corresponding increase in post-competition blood lactate (r=0.63, P=0.046) in the 1997 season (WC), and negatively correlated with the corresponding decrease in pre-competition CORT concentration (r=−0.66, P=0.019) in the 1998 season (IC). Our results indicate that a decrease in pre-competition CORT could be a prerequisite for an improvement in swimming performance.

Effects of gonadal steroids on the input-output relationship of the corticospinal pathway in humans

Most of our knowledge about gonadal steroid effects on the nervous system come from studies of limbic structures, while virtually nothing is known about the action of these hormones on the motor system. We carried out experiments on six healthy volunteer males to determine the threshold and gain of the input-output relationship (i.e. stimulus intensity vs. response size) of the corticospinal motoneurones in relation to the transient increase of gonadal steroids induced by a single intramuscular injection of human chorionic gonadotropin (hCG). The motor cortex was excited by focal transcranial magnetic stimuli and the evoked responses from the first dorsal interosseous (FDI) were recorded with surface electromyographic electrodes. In some experiments, the threshold and recruitment curve of the soleus H reflex were determined to assess the gonadal steroid effects on spinal motoneurones. All the subjects showed a significant decrease of cortical motor threshold concomitant with a significant increase of testosterone and oestradiol plasma concentrations. By contrast, there was no significant change of the slope of the curve expressing the relationship between the intensity of magnetic stimulation and the size of the muscle response. Both the threshold and slope of the H reflex were unaffected by the gonadal steroid levels. Latencies of the maximal FDI response to cortical and cervical magnetic stimulation were also unmodified. We conclude that gonadal steroids are involved in regulating the threshold of corticospinal motoneurones in humans. Our observations confirm that the threshold and gain of corticospinal motoneurones are determined by different neural mechanisms.

Morphological and Functional Adaptation of Left and Right Atria Induced by Training in Highly Trained Female Athletes

Background—Exercise is able to induce atrial remodeling in top-level athletes. However, evidence is mainly limited to men and based on cross-sectional studies. The aim of this prospective, longitudinal study was to investigate whether exercise is able to influence left and right atrial morphology and function also in female athletes. Methods and Results—Two-dimensional echocardiography was performed before season and after 16 weeks of intensive training in 24 top-level female athletes. Left and right atrial myocardial deformation was assessed by two-dimensional speckle-tracking echocardiography. Left atrial volume index (24.0±3.6 versus 26.7±6.9 mL/m2; P<0.001) and right atrial volume index (15.66±3.09 versus 20.47±4.82 mL/m2; P<0.001) significantly increased after training in female athletes. Left atrial global peak atrial longitudinal strain and peak atrial contraction strain significantly decreased after training in female athletes (43.9±9.5% versus 39.8±6.5%; P<0.05 and 15.5±4.0% versus 13.9±4.0%; P<0.05, respectively). Right atrial peak atrial longitudinal strain and peak atrial contraction strain showed a similar, although non-significant decrease (42.8±10.6% versus 39.3±8.3%; 15.6±5.6% versus 13.1±6.1%, respectively). Neither biventricular E/e′ ratio nor biatrial stiffness changed after training, suggesting that biatrial remodeling occurs in a model of volume rather than pressure overload. Conclusions—Exercise is able to induce biatrial morphological and functional changes in female athletes. Biatrial enlargement, with normal filling pressures and low atrial stiffness, is a typical feature of the heart of female athletes. These findings should be interpreted as physiological adaptations to exercise and should be considered in the differential diagnosis with cardiomyopathies.

Influence of training on the response of androgen plasma concentrations to exercise in swimmers

In eight top-level male endurance swimmers the aerobic performance and the response to exercise of total testosterone (T), free testosterone (fT), sex hormone binding globulin (SHBG), non-SHBG-bound testosterone (NST) and cortisol (C) were evaluated during a training season. The swimmers participated in three test sessions which occurred 6, 12 and 24 weeks after the beginning of the season. During each session, after a standard warm-up, the swimmers performed a set of 15 × 200-m freestyle, with a 20-s rest between repetitions, at a predetermined individual speed. Three blood samples were collected: before warm-up, at the end of the set, and after 1 h of recovery. A few days before each session, the individual swimming velocity associated with a 4 mmol · l−1 blood lactate concentration (ν4) was assessed as a standard of aerobic performance. The values of ν4 were lower in the second session than in the third one. The concentrations of C, which increased after the exercise, showed the highest values in the second session. The values of T and the T: SHBG ratio increased after the exercise but returned to their initial concentrations during the recovery period. The values of fT and NST increased after the exercise in the first and third sessions. In the initial two sessions, when the aerobic performance was still low, the concentrations of NST decreased to below the initial values after recovery. In session III, when the adaptation to the training workload was complete, NST returned to resting concentrations after recovery. The results would suggest that stressful stimuli produced by an increase in training volume may induce changes in androgen metabolism during exercise. In this respect, NST would appear to be a better index of metabolic response than T, T/SHBG and fT.

Novel echocardiographic techniques for the evaluation of athletes’ heart: A focus on speckle-tracking echocardiography

Background The development and rapid dissemination of two-dimensional echocardiography led to important further advances in our understanding of athletes’ heart that has been the subject of several echocardiographic studies involving many thousands of athletes. The description of ventricular chamber enlargement, myocardial hypertrophy and atrial dilatation has led to a more comprehensive understanding of cardiac adaptation to exercise conditioning. Most recently, advanced echocardiographic techniques have begun to clarify significant functional adaptations of the myocardium that accompany previously reported morphological features of athletes’ heart. In particular, speckle-tracking echocardiography (STE) has recently provided further insights into the characterisation of myocardial properties. Discussion STE is a relatively new, largely angle-independent, non-invasive imaging technique that allows for an objective and quantitative evaluation of global and regional myocardial function. STE has enhanced our understanding of athletes’ heart through a comprehensive characterisation of biventricular and biatrial function, providing novel insights into the investigation of physiological adaptation of the heart to exercise conditioning. These peculiarities can provide further useful data to distinguish between athletes’ heart and cardiomyopathies. Furthermore, STE represents a promising tool to address new concerns on right ventricular function and to increase understanding of the complexity of the non-systemic circulation, especially in the athletic population. Conclusion This review article analyses new data on cardiac function in athletes by novel echocardiographic techniques with a particular attention to the application of STE to characterise biventricular and biatrial function in athletes.

Right ventricular remodelling induced by exercise training in competitive athletes

AIMS Conflicting evidence exists concerning right ventricular (RV) morphological and functional remodelling in trained athletes, with a very few longitudinal data prospectively investigating the RV changes. The aim of this study was to assess the morphological and functional RV changes occurring during the competitive season in young athletes engaged in the most popular team sports. METHODS AND RESULTS Twenty-nine top-level athletes (age: 20.9 ± 6.7 years), practicing basketball and volleyball, were evaluated at pre-season, mid-season, and end-season time-points, using tissue Doppler imaging and 2D speckle-tracking echocardiography. RV basal and mid-cavity end-diastolic diameters (EDDs; overall P = 0.011 and P < 0.0001, respectively), and RV diastolic area (overall P < 0.0001) increased during the season. Conversely, RV outflow tract did not vary (overall P = 0.96). During the season, no significant differences were observed in RV diastolic functional indexes and in RV fractional area change (overall P = 0.35). Global RV longitudinal strain did not significantly change (overall P = 0.52), although apical longitudinal strain significantly increased (overall P = 0.017). In association, left ventricular (LV) volume and mass increased during the season (overall P = 0.007). On multivariate analysis, LV mass was the only independent predictor of RVEDD at pre-season (β = 0.69, P < 0.0001) and at end-season (β = 0.82, P < 0.0001). CONCLUSIONS Right ventricular chamber size increases during the competitive season in top-level athletes, with no significant changes in the outflow tract. RV morphological adaptation in top-level athletes practicing team sports is not associated with a reduction in RV function or in myocardial deformation and occurs in close association with changes on the left ventricle, suggesting a physiological remodelling of the right ventricle.

Game activity and blood lactate in men's elite water-polo players.

Melchiorri, G, Castagna, C, Sorge, R, and Bonifazi, M. Game activity and blood lactate in mens elite water-polo players. J Strength Cond Res 24(10): 2647-2651, 2010-The purpose of this study was to examine game demands during highly competitive mens water-polo games after the introduction of the new Federation International Natation Association (FINA) rules. Participants of this study were 77 outfield international level mens water-polo players (age 25.9 ± 4.5 years, height 188 ± 4.5 cm, body mass 93 ± 10.9 kg). Game earlobe blood lactate, speed, and distance covered (semiautomatic image recognition system) were measured during 6 highly competitive matches (FINA International Tournament). In the game, players covered 1,613 ± 150 m (n = 68). This corresponds to a mean coverage rate of 54 ± 5.8 m·min−1 (n = 68). At speeds faster than 1.4 m·s−1 (high-intensity swimming), players covered 44% of the total distance. A significant decrease in coverage rate was detected during the final stage of the game. Mean blood-lactate concentration was 7.7 ± 1.0 mmol·L−1 (range 2.2-14.3). Center Defenders (1,816 ± 496 m) covered significantly (p < 0.05) more distance swimming compared to Field (1,676 ± 348 m) and Center-Forward (1,317 ± 281 m) players. Mean match blood-lactate concentrations for Center Forwards, Center Defenders, and Field Players were 11.2 ± 1.0 (3-14.3), 6.7 ± 0.9 (1.4-8), and 5.3 ± 0.9 mmol·L−1 (2.2-11.9), respectively. This study confirmed the high-intensity nature of male elite level water polo showing remarkable role-dependent game demands. As a result, strength and conditioning interventions should be individualized and mainly address intermittent high-intensity endurance and anaerobic fitness.