Gender-, age-, body composition- and training workload-dependent differences of GH response to a discipline-specific training session in elite athletes: a study on the field.

Ninety-nine Italian elite athletes (61 M, 38 F, mean age +/- SE: 24.1 +/- 0.6 yr, age range: 17-47 yr) of different disciplines volunteered to participate in this investigation. Basal GH concentrations were significantly higher (p<0.0001) in females (6.2 +/- 1.1 ng/ml) vs males (1.9 +/- 0.5 ng/ml). Basal GH values were negatively correlated with age and body mass index (BMI); no significant correlation was found between GH and IGF-I levels. Among female athletes, 8/38 had basal GH values higher than 10 ng/ml [2/8 athletes were taking oral contraceptives (OC)], while among males 6/61 had values higher than 5 ng/ml. In females, training sessions significantly increased (p<0.0001) basal GH concentrations (peak GH: 18.5 +/- 1.9 ng/ml), while in males GH responses were lower than in females (11.8 +/- 1.4 ng/ml, vs F: p<0.005). Six out of 38 female and 6/61 male athletes were considered GH hypo-responders (i.e. negative difference between peak GH and basal GH values), the large majority of them being subjects with elevated basal GH concentrations. In responsive athletes, peak GH values occurred immediately at the end of the training session both in males and in females; GH concentrations rapidly declined during recovery. No significant correlations were found between peak GH and age, body weight and BMI in either gender. GH responses were directly related (p<0.001) to the intensity of the workload during the sessions. In conclusion, the present study demonstrates that: 1) some elite athletes had increased GH concentrations before training, which were however associated with normal IGF-I levels; 2) GH peaks after a discipline-specific training session were significantly higher in females than in males performing the same discipline, gender-related differences disappearing when post-exercise total GH outputs (area under the curve) were compared; 3) peak GH values were directly correlated with training workload; 4) GH concentrations rapidly declined during recovery, values at the end of the post-training GH sampling being generally lower than those found in basal condition.

Short-term changes of fatigability and muscle performance in severe obese patients after an integrated body mass reduction program.

The effects of a short-term (3-week) integrated body weight reduction (BWR) program on fatigue perception and on lower limb anaerobic power output were evaluated in 200 severely obese in-patients (40 males and 160 females, age: 18-83 yr, BMI: 35.0-65.3 kg/m2). Fatigue was assessed by a 7-point Likert-type scale questionnaire (Fatigue Severity Scale, FSS), while average lower limb power output (W) during a maximal effort was determined with a modification of the Margaria test for stair climbing. In both genders, total FSS score was influenced by both age and obesity level, resulting significantly (p < 0.001) lower in younger subjects (< 45 yr) than in older (> 45 yr) and in patients with lower BMI (< 40 kg/m2) than in those with a higher one (> 40 kg/m2). An opposite trend was observed in W. The 3-week BWR integrated program with moderate aerobic exercise and free standing and ground gymnastic routines induced a significant reduction in body weight (p < 0.001), in total FSS score (p < 0.001) and a significant increase in W, both in absolute terms (p < 0.05) and relative to body mass (p < 0.001). Total FSS score and absolute or relative power output were positively correlated both before and after the BWR program (p < 0.001, Wilcoxon rank test). It is concluded that: a) subjective fatigue perception, assessed by a FSS questionnaire, can be considered an indirect indicator of effective lower limb power output in severely obese patients and, b) in spite of a relatively small, although significant, decline of BMI, the full-time participation in a hospital-based, integrated BWR program with moderate exercise activity is associated with significant short-term improvements of both fatigue sensation and power output. Dia

Thyroid function is more strongly associated with body impedance than anthropometry in healthy subjects.

Since fat-free tissues are responsible for 95% of basal energy expenditure, fat-free mass is expected to be a better determinant of thyroid size and function than anthropometry. We tested the hypothesis that fat-free tissues as qualitatively determined by body resistance (R) at 50 kHz are more strongly associated with TSH than anthropometric indicators in healthy subjects. A number of 78 euthyroid adults of both sexes were consecutively studied. R was the best single predictor of TSH (R2(adj)=0.65, p<0.0001). It explained 36% more variance than bw (R2(adj)=0.29, p<0.0001), the most accurate anthropometric predictor. Sex had no effect on the relationship between TSH, bioelectrical impedance analysis and anthropometry. After the contribution of R to TSH was taken into account, anthropometric indicators were not able to explain any additional part of TSH variance. We conclude that in healthy subjects, bioelectrical resistance is a better indicator of thyroid function than anthropometry, probably because of its more direct relationship with fat-free tissues. Further studies are needed to test whether this relationship holds in under- and over-weight subjects.

The impact of gender, body dimension and body composition on hand-grip strength in healthy children.

Maximum hand-grip (HG) strength, body composition and main anthropometric variables were evaluated in 278 children with normal weight and growth, aged 5-15 yr divided into 3 age groups: group 1, age+/-SD: 7.6+/-0.9 yr 7.6+/-0.9 SD (Tanner stage 1); group 2, age: 10.8+/-0.7 yr (Tanner stage: 2-3); group 3, age: 13.2+/-0.9 yr (Tanner stage: 4-5). Weight, height, body surface area (BSA), BMI, percent body fat (BF) and fat free mass (FFM) increased progressively and significantly from the younger to the older age group. A significant difference between genders was detected only for BF and FFM, females having a higher fat mass and a lower FFM compared to males. Most children were right-handed (91%). In either genders, a curvilinear relation was detected between HG strength and age, with best fit for the dominant (d) hand given by the equations: dHG=5.891 *10(0.051) age, r2=0.986, p<0.001 in males and dHG=6.163 *10(0.045) age r2=0.973, p<0.001 in females. The increase in HG strength after 11 yr appears to be steeper in males as compared with that found in females. In both d and non-dominant (nd) hand, a significant difference in HG strength was detected between males and females, the average difference being about 10% at all ages. For both genders, nd hand was significantly weaker than d hand in the older age groups (2 and 3), but not in the younger group 1. Age and gender-dependent differences in HG strength (but not differences between d and nd hand) disappear if HG strength is normalized for FFM. Thus, in general, dHG strength normalized for FFM resulted on average to be 0.67+/-0.11 kg/kg. A multiple linear regression analysis indicated that HG was positively correlated with BMI, BSA, stature, stature2 and FFM (p<0.001 for all correlations) without differences between genders, while a negative correlation was found between HG strength and %BF. The most significant correlation was found between HG strength and FFM, without any significant difference between genders, so that the overall equation describing the line for the d hand was: dHG strength= 2.32+0.63 FFM, r2=0.72, p<0.001. In conclusion, the present study indicates that the age-dependent increase of HG strength as well as the between-gender differences are strongly related to changes of FFM values occurring during childhood. Moreover, the study provides a standard normative value of maximal HG strength for the healthy children population in Northern Italy.

Retrospective analysis of long-term hemorheologic effects of pentoxifylline in diabetic patients with angiopathic complications.

Blood rheology alterations have often been reported in diabetic patients and may be associated with an increased risk for diabetic vascular disease. In this light a hemorheologic approach with pentoxifylline has been suggested in diabetic patients with hemorheological changes in order to improve the hemorheology approach and to evaluate the long-term effects of this treatment on the other clinical and metabolic variables. The study concerned a 10-year retrospective analysis of diabetic patients with hemorheologic alterations and angiopathic complications. Pentoxifylline (Trental 400) significantly reduced blood and plasma viscosity (at high and low shear-rates), fibrinogen and erythrocyte aggregation, and increased erythrocyte filterability throughout the study. The improvement of the hemorheologic pattern was obtained independently of the variation in glycometabolic control and body weight changes, whereas concomitant reductions of arterial blood pressure levels and of urinary excretion of albumin and total proteins was observed during the treatment. Pentoxifylline might therefore be successfully employed for long-term periods in the treatment of hemorheologic disorders in diabetic patients without effects on the metabolic pattern.