Biomedical subjects

G Melchiorri

Publications and source records attributed to G Melchiorri.

9 recordsLinked to original sources

PubMed2004

A method for positioning electrodes during surface EMG recordings in lower limb muscles.

PURPOSE: The aim of this work is to provide information about the degree of inter-subject uniformity of location of innervation zone (IZ) in 13 superficial muscles of the lower limb. The availability of such information will allow researchers to standardize and optimize their electrode positioning procedure and to obtain accurate and repeatable estimates of surface electromyography (sEMG) signal amplitude, spectral variables and muscle fiber conduction velocity. METHODS: Surface EMG signals from gluteus maximus, gluteus medius, tensor faciae latae, biceps femoris, semitendinosus, vastus medialis obliquus, vastus lateralis, rectus femoris, tibialis anterior, peroneus longus, soleus, gastrocnemius medialis and lateralis muscles of ten healthy male subjects aged between 25 and 34 years (average = 29.2 years, S.D. = 2.5 years) were recorded to assess individual IZ location and signal quality. RESULTS: Tensor faciae latae, biceps femoris, semitendinosus, vastus lateralis, gastrocnemius medialis and lateralis showed a high level of both signal quality and IZ location uniformity. In contrast, rectus femoris, gluteus medius and peroneus longus were found to show poor results for both indexes. Gluteus maximus, vastus medialis obliquus and tibialis anterior were found to show high signal quality but low IZ location uniformity. Finally, soleus muscle was found to show low signal quality but high IZ location uniformity. CONCLUSIONS: This study identifies optimal electrode sites for muscles in the lower extremity by providing a standard landmarking technique for the localization of the IZ of each muscle so that surface EMG electrodes can be properly positioned between the IZ and a tendon.

Adult↗

PubMed2004

Multicompartment model to assess body composition in professional water polo players.

AIM: The aim of this study was to compare differences between skinfold thicknesses (SK), bioelectrical impedance analysis (BIA), a 2-compartment model (2C), and 2, 3-compartment models (3C) of percent body fat (%BF) assessment with a 4-compartment model (4C) in professional water polo athletes. METHODS: Ten male subjects, 18 to 29 years of age, participated in this study. Under water weighing, deuterium dilution, and dual-energy X-ray absorptiometry (DXA) were used to provide the required values for the models. The two, 3C models used were established by Withers et al. (3C-W) and by the DXA manufacturers (3C-DXA). 4C was also established by Withers et al. RESULTS: There were no significant differences between 2C, 3C-W, and 3C-DXA when compared with 4C (criterion model). There were no significant differences between 2C and 3C-W. %BF was significantly greater using 2C compared with 3C-DXA. %BF derived from SK and BIA were significantly greater than all other METHODS: 4C was best correlated with 3C-W (R2=0.998), followed by 2C (R2=0.806), 3C-DXA (R2=0.5071), SK (R2=0.2945), and BIA (R2=0.2377). CONCLUSION: We conclude that 2C and 3C-W assess %BF equally as well as 4C; however, SK and BIA significantly over-estimated %BF in water polo athletes.

Absorptiometry, Photon↗

PubMed2003

Effect of different sports on body cell mass in highly trained athletes.

The objective of this study was to verify the impact of various sports on body cell mass (BCM). Ninety-eight male subjects, 17-33 years of age, participated in the study. The sample included athletes from three professional Italian football (soccer) teams, representing three different divisions (A, n=16; B, n=14; and C, n=18), judo athletes (J, n=10), and water polo athletes (W, n=14) who all competed at the national level. Twenty-six age-matched individuals served as the control group (CG). Fat-free mass (FFM), fat mass (FM), percent body fat (%BF), and BCM were assessed using bioimpedance spectroscopy (BIS). There were no significant differences in body weight and FFM among the groups. A and B were significantly taller than J and CG. B had a significantly lower body mass index (BMI; kg/m(2)) than CG, while C had a significantly lower BMI than J and CG. CG had a significantly greater FM and %BF than A, B, and C. C had a significantly lower BCM than Aand B. CG had a significantly lower BCM than A, B, J, and W. In conclusion, differences in BCM exist among athletes of different sports, and among athletes within the same sport who compete at different levels.

Adipose Tissue↗

PubMed2003

Body composition differences in adolescent female athletes and anorexic patients.

Osteopenia is a frequent complication affecting adolescent girls with anorexia nervosa (AN). Moreover, female athletes suffering from eating disorders can be affected by premature osteoporotic fractures. The aim of this study was to examine bone mineral content (BMC) and bone mineral density (BMD) in three groups of adolescent females. Anthropometric and body composition measurements were performed on 22 adolescent females (age+/-SD=15.6+/-1.4 years) divided into groups: athletes ( n=8), patients with AN ( n=8) and age-height matched control subjects ( n=6). Body weight and body mass index were significantly lower ( p<0.01) in athletes and AN patients compared with healthy controls. BMC and BMD were lower ( p<0.01) for AN patients and athletes compared with healthy controls; AN patients had the lowest BMC value. Athletes had higher lean body mass values compared with AN patients and healthy controls. These results suggest that the effects of eating disorders, specifically BMC loss, could be attenuated by physical activity.

Adipose Tissue↗

PubMed2003

Physical activity energy expenditure measured using a portable telemetric device in comparison with a mass spectrometer.

BACKGROUND: Several studies have evaluated the accuracy of portable metabolic gas analysis systems, which measure physical activity energy expenditure. Since the Cosmed K2 telemetric system, two K4 devices (RQ and b2) have been developed. OBJECTIVE: To compare measurements using the Cosmed K4 RQ with measurements by a traditional method (mass spectrometer) for a sample of healthy subjects performing physical exercise of various intensities. METHODS: Nine healthy male footballers (mean (SD) age 18.3 (2.2) years) performed an incremental exercise running test from 8 km/h to exhaustion, with an increase of 2 km/h for each level of the test protocol. The expired air was collected simultaneously using the Cosmed K4 RQ and Airspec QP9000 mass spectrometer. Oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured at rest and at each exercise intensity. RESULTS: No significant differences were found between VO2 and VCO2 measured by the two instruments, at rest or during exercise. CONCLUSIONS: The application of the Cosmed K4 RQ system for VO2 and VCO2 measurements at rest and during both submaximal and maximal exercise may be of interest to sport physiologists, nutritionists, and doctors.

Adolescent↗

PubMed2002

Bioelectrical impedance measures in different position and vs dual-energy X-ray absorptiometry (DXA).

BACKGROUND: Bioelectrical impedance analysis (BIA) is a safe, low-cost, non-invasive, rapid method for the assessment of body composition. It has therefore a great potential to be employed for epidemiological and clinical studies. However, many devices are available to estimate total body water (TBW), fat-free mass (FFM) and fat mass (FM) by bioelectrical impedance measurements. Moreover, bipedal devices allowing measurements in the only standing position are recently developed. They are easy and practical to use without operator, so a large diffusion can be forecasted in fields as sport and diet programs. Comparison of body composition estimation by a bipedal device with bioimpedance devices currently used, using dual-energy X-ray absorptiometry (DXA) as reference method. METHODS: The study was performed on 18 healthy women volunteers, age 32.0+/-10.7 years divided in two groups at different levels of body fatness. A Xitron 4000 impedance analyser, a BIA-101 RJL System, and the bipedal device Tanita were used for comparison. The measurements were performed in standing and supine position for Xitron and RJL devices. DXA measurements were performed with a total body scanner DPX, Lunar. RESULTS: FM and FFM were not statistically different when measured with Xitron and RJL in comparison with DXA, while these variables were significantly different between Tanita and DXA measurements. No significant difference were found between measurements in the supine and standing position with the Xitron and RJL system. CONCLUSIONS: Our results suggest that FM and FFM evaluated by bipedal device Tanita are significantly different from FM and FFM measured by DXA in both normal and obese population.

Absorptiometry, Photon↗

PubMed1995

[Effects of prolonged administration of branched-chain amino acids on body composition and physical fitness].

No conclusive data are reported about the effects of long-term branched-chain amino-acids (BCAA) administration on metabolic and respiratory parameters during the sustained hand-grip test (SHGT). Bedside, few data are reported about the relationship between BCAA administration and body composition. Thus, BCAA (14 g/die; 50% L-Leucine, 25% L-Isoleucine, 25% L-Valine) were administered orally to 10 untrained male healthy subjects for 30 days. Before (T0) and after (T1) BCAA administration, oxygen uptake (VO2) and pulmonary ventilation (VE) were evaluated at rest ("baseline", B) and during SHGT. Body height and body weight, body mass index (BMI), fat mass (FM), fat-free mass (FFM), arm muscle area (AMA) and maximal voluntary contraction of forearm muscler (GS, grip strength) were also evaluated at T0 and T1. At T1 FFM increased significantly (T0: 62.3 +/- 7.6 kg; T1: 63.1 +/- 7.5 kg; mean +/- SD; p < 0.05), as well as GS (T0: 46.8 +/- 7.9; T1: 50.6 +/- 7.8; p < 0.01). At T0, VO2 increased significantly during the test (B: 271 +/- 36 ml/min; SHGT: 332 +/- 71 ml/min; p < 0.01), whereas at T1 no significant increase was observed (B: 271 +/- 50 ml/min; SHGT: 286 +/- 60 ml/min). We conclude that the physical fitness of BCAA treated subjects was improved, because of the decrease of O2 uptake during SHGT. Moreover, in our subjects, BCAA seemed to promote FFM-protein synthesis mostly.

Adult↗

PubMedDate not supplied

[Changes in body composition caused by intense physical training].

PURPOSE: To show the importance of the study of body composition in functional capacity evaluation of athletes who play professional football, during periods of very hard training (before the beginning of the championship), in order to appreciate every kind of adaptation to the training itself more precisely. MATERIALS AND METHODS: 18 semiprofessional football players, ages 18-32 yr., weight 75.2 +/- 8.1 kg, height 180.8 +/- 5.5 cm have been subjected to body composition evaluation, using Biolectrical Impedance Analysis (B.I.A) and antropometrics measurements, the day before the beginning of the trainings and at the end of them (just before the beginning of the championship). RESULTS: The athletes at end the training period (15 day) showed significant loss of weight (1.6 kg; p < 0.001). This reduction was attributed to a loss of the fat mass (2.8 kg; p < 0.001). Fat free mass increased 1.2 kg (p < 0.05); at the same time total body water increased too (1.0 l; p < 0.05) proving that, in spite of hard training, the athletes mateined a good hydratation. CONCLUSIONS: The results suggest that is very important to analyse body composition in the football players, since otherwise we couldn't attained the variation of weight in a quantitative and qualitative way.

Adolescent↗

PubMedDate not supplied

Effect of acute and chronic branched-chain amino acids on energy metabolism and muscle performance.

The aim of this study was to report the effects of acute and chronic branched-chain amino acids (BCAA) administration on energy metabolism and muscle performance. In the acute study which was double-blind, cross-over and placebo-controlled, 12 healthy male volunteers were administered orally on two consecutive days either BCAA (14.4 g/day) or isocaloric placebo; this was followed by measurement of oxygen consumption (VO2) and carbon dioxide production (VCO2) for 180 min by indirect calorimetry. In the chronic study, 10 healthy male volunteers were supplemented with BCAA (14.4 g/day) for 30 days. Before (T0) and after (T1) chronic BCAA administration, VO2, arm muscle area (AMA) and maximal voluntary contraction of forearm muscles (grip strength, GS) were evaluated. Acute study: Both meals increased mean respiratory quotient (RQ) from baseline: in the placebo group, this increase was short-term only (between 15 and 60 min), while this effect on RQ lasted for 120 min in the BCAA group. Moreover, between 30 and 90 min, mean RQ was significantly higher in the BCAA group than in the placebo group. Chronic study: GS increased significantly following chronic BCAA administration without significant changes in the AMA. At T0, VO2 increased significantly during the GS test, whereas at T1 no significant increase was observed. In conclusion, no excess thermogenesis could be detected as compared with placebo following acute BCAA administration, indirectly suggesting a relevant contribution of peripheral catabolic (bypassing liver) pathway to BCAA metabolism; furthermore, chronic BCAA supplementation improved the physical fitness of untrained healthy subjects, as demonstrated by the lack of 02 uptake increase during sustained hand grip test.

Administration, Oral↗