RESUMO
A three-compartment body composition analysis of 42 professional football (soccer) players and 33 age- and body mass index-matched control subjects was determined by dual X-ray absorptiometry (DXA). The equipment provided a direct measurement of fat, lean, and bone mass. Fat mass was significantly higher in the controls subjects whereas lean mass and bone mass were markedly higher in the players. The percentage of body weight fat varied from 6.1 to 19.5% in the football players and from 9.1 to 29.9% in the control subjects. The respective averages were 12.0 +/- 3.1 and 19.2 +/- 5.6% (p < 0.001). The midfielders had a significantly higher percentage of fat (13.6 +/- 3.3%) than backs or forwards (11.1 +/- 2.8 and 11.0 +/- 2.3%, p < 0.05 and p < 0.06, respectively). In the football players, the correlation between age and fat mass was significant (r = 0.53, p < 0.001), whereas there was no correlation between fat and age in the control subjects (r = 0.13 p > 0.1). This article provides, for the first time, DXA analysis of body composition of football players in relation to their age and function. The results should be of interest to coaches because they will help improve athletes' performance.
Assuntos
Composição Corporal , Futebol/fisiologia , Absorciometria de Fóton , Adulto , Humanos , MasculinoRESUMO
The total skeletal bone mineral content (BMC), bone mineral density (BMD), bone size, and body composition were measured by dual-energy x-ray absorptiometry (DXA) in all professional male football players of a 1st division team (n = 24) and age- and BMI-matched (n = 22) controls (less than 3 hours of recreational sport activities per week). Average (+/- 1 SD) age of the athletes was 22.6 +/- 2.5 years. Intensive training is conducted during 48 weeks a year for 20-22 hours/week. The length of the registered playing career before the study was 8.2 +/- 2.7 years. Total skeleton BMC was 18.0% (P < 0.001) greater in the football players. The difference resulted from the sum of 5.2% (P < 0.02) increment of bone size and 12.3% (P < 0.001) increment of BMD. The analysis of skeletal subareas revealed that the difference of the BMC and BMD was greater at the level of the pelvis and legs compared with the arms or trunk. The BMC and BMD of the head was equal for both groups. Also, the bone size of the legs and pelvis was significantly greater for the players compared with controls; there was no difference at the level of the arms or head. Within the group of football players the increment of total skeleton BMD was similar in the young players, with less than 7 years of practice (age 20.6 +/- 0.9 years) compared with relative older players (age 24.6 +/- 1.9) with more than 7 years of practice. Lean body mass was significantly greater in the players (63.3 +/- 4.0 kg) compared with the controls (56.7 +/- 3.6, P < 0.001) whereas fat mass was markedly lower (9.4 +/- 2.9 kg versus 14.9 +/- 6.3 kg), P < 0.002). The BMD of the controls was significantly correlated to total weight, height, and lean mass whereas the BMD of the players was only correlated to muscle mass. The calcium intake from dairy products was similar in both groups. The range of calcium intake was wide among the players (184-2519 mg/day) but it was not significantly correlated to BMD (r = 0.03). In conclusion, male professional football players develop a significant increment of BMC as a result of increased bone size and density. This is already present at the end of the second decade and maintained at least to the end of the third decade in active players. As in other high impact loading sports, the effect on area is specific involving mainly the pelvis and legs. The increment was totally unrelated to the calcium intake from dairy products. The fate of the increased BMC after intensive training is discontinued should be assessed. However, if the findings of the present cross-sectional study are supported by detailed longitudinal investigations, the presently reported observations might be important for the prevention of future osteoporotic fractures.