Konstantinos Mandroukas

Physical training in obese women. Effects of muscle morphology, biochemistry and function

SummaryPeripheral adaptations to 3 months of physical endurance training without food restrictions were studied in skeletal muscles of 14, middle-aged, physically untrained, obese women.In comparison to aged-matched controls of normal weight, the obese group showed significantly lower isometric endurance. In the obese group, physical training resulted in a significant increase of maximal isometric and isokinetic strength. Isokinetic but not isometric endurance also increased after training. The isometric strength of obese women showed a positive correlation with the percentage of FTb fibres.The training (50 min/day, 3 days/w) did not result in any change in body weight, body fat, and the number and weight of fat cells. The 20% increase of

The Effects of Marathon Swimming on Serum Leptin and Plasma Neuropeptide Y Levels

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Effects of basketball training on maximal oxygen uptake, muscle strength, and joint mobility in young basketball players.

after training was found to be significantly correlated with the increase in the number of capillaries around muscle fibres. The relative percentage of FTa fibres, the number of capillaries per fibre as well as the activities of citrate synthase, 3-hydroxy-acyl-CoA-dehydrogenase, and hexokinase showed a significant increase after training.The concentrations of glucose during OGTT showed a trend to decrease with a significant decrease at the end glucose curve (120-min value). The concentration of insulin and C peptide and the insulin removal did not change after training. The changes in the concentration of glucose during OGTT was significantly correlated with the increase in muscle capillarization and of dynamic endurance.

Physical training, growth hormone and testosterone levels and blood pressure in prepubertal, pubertal and adolescent boys

Objectives: To compare the effects of proprioceptive neuromuscular facilitation (PNF) and isokinetic training on fibre type distribution and cross sectional area of the vastus lateralis muscle. Methods: Twenty four male university students were divided into two equal groups: PNF training and isokinetic training (ISO). The training regimen for the PNF group consisted of three sets of 30 repetitions against maximal resistance, alternating two patterns of sequential movements of the right lower extremity: (a) toe flexion and ankle plantar flexion and eversion; (b) knee extension and hip extension, abduction, and internal rotation. The ISO group performed three sets of 30 repetitions alternating knee extension and flexion of the right leg at angular velocities of 180 and 90°/s in an isokinetic dynamometer (Cybex). Both groups trained three times a week for a total of eight weeks. Muscle biopsy specimens were obtained from the right vastus lateralis muscle before and after training. Results: The mean percentage area of type IIB fibre was significantly decreased (p<0.01) after eight weeks of PNF training, whereas that of type IIA fibre was significantly (p<0.05) increased. The mean percentage area of ISO trained type IIAB fibres exhibited an augmentative pattern (p<0.01) with a parallel reduction (p<0.05) in type IIA. Percentage fibre type distribution exhibited a similar pattern. Conclusions: Both PNF and ISO training alter fibre type distribution and mean cross sectional area. These changes occur in the type II fibre subgroup.

Atrial natriuretic factor responses to submaximal and maximal exercise.

Abstract It seems likely that the neuropeptide Y (NPY)-leptin axis is involved in the regulation of energy expenditure in man. The purpose of this study was to observe the effect of a model of intense prolonged exercise-mediated energy expenditure (25 km swim race in 6.9–10.5 hours) on leptin and NPY concentrations in male longdistance swimmers. Sixteen long-distance swimmers (mean age 25, range 18–45 years) who took part in a 25 km sea swimming competition (Toroneos golf, Chalkidiki, Greece) participated in the study. Mean competition time was 8.5 hours (range 6.5–10.5). The participants were allowed food and beverage intake ad libitum before and throughout the 25 km race. Venous blood samples were taken prior and immediately after the race for the measurement of serum leptin and plasma NPY. Non-esterified free fatty acids (NEFFA) and glycerol levels were determined as indicators of adipose tissue lipids mobilization. Results showed that leptin levels after marathon swimming were significantly reduced (p<0.001) in all athletes. There was a statistically significant negative correlation (r=−0.812, p<0.01) between the values of leptin and glycerol just after the termination of swimming. Blood serum glycerol and free fatty acid levels were significantly increased (p<0.001) in all swimmers. Plasma NPY levels were also increased (p<0.01) in 81.2% of the swimmers. Linear regression analysis revealed a significant negative correlation between the values of leptin and NPY (r=−0.789, p<0.01). In conclusion, these data support our initial hypothesis that appropriate changes in leptin and NPY take place during marathon swimming to compensate for the negative energy balance produced due to this prolonged effort. This indicates the NPY-leptin axis involvement in the regulation of energy expenditure in man.

The effect of different exercise-testing protocols on atrial natriuretic peptide.

The purpose of this study was to assess differences in isokinetic muscle torque in the knee among mentally retarded individuals with Down syndrome, mentally retarded individuals without Down syndrome, and sedentary subjects without mental retardation (ns of 7, 8, and 12, respectively). Subjects performed strength tests to knee extension and flexion on a Cybex II isokinetic dynamometer. The measure was peak torque at angular velocities of 60, 120, and 300 degrees/sec. For the Mentally Retarded subjects with and without Down syndrome, the test was performed on two separate days 24 hr. apart. For Sedentary subjects, testing was performed on one day. Their scores indicated significantly higher values of torque than the two other groups. Also, subjects with Down syndrome had inferior muscle torque of lower extremities than peers in the Mentally Retarded Group.

Isokinetic Strength and Joint Mobility Asymmetries in Oarside Experienced Oarsmen

The purpose of this study was to examine the effects of prolonged basketball skills training on maximal aerobic power, isokinetic strength, joint mobility, and body fat percentage, in young basketball players, and controls of the same age. Twenty basketball players and 18 control boys participated in the study. Basketball players participated both in their schools physical education program and in a childrens basketball team training program. Controls participated only in their schools physical education program. All subjects were tested every 6 months (18 months total, 111/2, 12, 121/2, 13 years old) for &OV0312;O2max, peak torque values of the quadriceps and ham- strings at 180 and 300°·s-1 and range of motion of the knee and hip joints. Body fat percentage was assessed at the beginning and the end of the experimental period. Results showed that the basketball group had lower heart rate values in all ages and higher &OV0312;O2 values in the initial test compared with the control in submaximal intensity. The &OV0312;O2max was altered in both groups on the final test, when compared to the initial test. However, the basketball group had a higher &OV0312;O2max on each of the 6-month follow-up measurements, compared to the control group (p > 0.001). At the end of the 18-month follow-up period no significant differences were observed in isokinetic strength and joint mobility of the lower limbs between the 2 groups. On the contrary, the boys of the trained group had significantly lower percentage body fat values, compared to controls. In conclusion, regular basketball training increased aerobic power and decreased body fat percentage of prepubescent boys, while it did not affect muscle strength and joint mobility of the lower limbs. The major implication suggested by the findings of the present study is that, in order to improve the basic physical components, specific training procedures should be incorporated during the basketball training sessions. It is recommended that all children should be involved in some type of cardiovascular and resistance training program.

Morphology of the deltoid muscles in elite tennis players

The purpose of this study was to determine the resting values of growth hormone (GH) and testosterone (T) within prepubertal, pubertal and adolescence ages and to compare the effects of physical training in each age, in 2 groups. The exercise group (A) consisted of 10 ten‐year‐old boys, 10 thirteen‐year‐old boys and 9 sixteen‐year‐old boys. The control group (B) consisted of approximately the same number of subjects of the same ages. Group A, in addition to the school activity, trained with intervals (3 months, 50 mid/day, 3 days/week). at high intensity (80–85% of max) and at light intensity (30–40% of max). Group B participated only in the school physical education program 2–3 times/week. Venous blood samples were taken at rest by intravenous catheter before and after training. Levels of GH and T in blood serum was determined by radioimmunoassay. Before training, the levels of T differed between the 3 ages, but there were no significant differences in GH (group A and B). After training, the levels of GH and T in group A were significantly higher in the 13‐year‐old boys and in the 16‐year‐old boys, but were unchanged in the 10‐year‐old boys. In group B the levels of GH and T were unchanged in all 3 ages. The conclusion is that neither high nor mild intensity training can change the levels of GH and T in prepubertal boys. However, high intensity training can be a stimulus for increasing GH and T levels in puberty and adolescence