In the last century coaches, athletic trainers, anthropologists and sports doctors have been interested in determining the "anthropometric" characteristics that allow maximum performance.
Thus for years researchers have examined the physiological profile of high-level athletes, especially Olympians.
Body composition analysis reveals that athletes have physical characteristics that correlate to the physical activity they practice; for example, athletes who compete in athletic launches have a high lean mass but also a relatively high percentage of fat mass; the bottom run athletes have little fat mass and little lean mass.
In particular, low amounts of fat are required in endurance sports, jumps and speed, while a large muscle mass characterizes strength and power athletes.
Athletes are generally leaner than sedentary subjects and their amount of fat depends on the type of sport and the level of intensity practiced.
In addition to establishing the physiological profile of the athlete, information on body composition can be used to estimate the athlete's optimal body weight. For males, scholars agree that the minimum amount of fat should not be less than 3-5% (to ensure normal physiological and metabolic functions).
Not well established the female one, Lohman 1992 suggests values between 12-16% for most athletes.
At levels below 16% some women become amenorrheic (<3 cycles per year) with a substantial loss of bone minerals and with an increased risk of fractures and premature osteoporosis. Although physical activity is positively associated with bone mineral content, amenorrhea athletes tend to have a lower bone mineral content than eumenorroic athletes and sedentary women.
In the sports population the prevalence of amenorrhea is higher (from 3.4% to 66%) than in the general population (2% -5%). This phenomenon is related not only to weight and body fat but also to factors such as delayed menarche, eating disorders, training intensity and psychological stress.
Ballerinas usually very thin compared to control subjects of the same age have a higher frequency of menstrual irregularities, alterations of the diet and delay of the menarche.
The reproductive function is in fact suppressed when the conditions of psycho-physical stress do not allow the evolution of a motherhood (increase in cortisol values, decrease in estrogens).
Some athletes can feel the pressure of having to lose weight and can develop eating disorders in the unrealistic attempt to reach the ideal weight. This pressure can lead the female athlete to the so-called triad, a pathological picture characterized by: eating disorders, amenorrhea and early osteoporosis.
There are optimal values of weight and BODY COMPOSITION to maximize performance in a given sport, but these values may vary among athletes.
Wilmore 1983: the consequences of physical activity on the BODY COMPOSITION are:
- moderate weight loss
- moderate to large loss of body fat
- recently to moderate increase in GREAT MASS
these effects depend on the frequency, intensity and duration of the training.
Cross-sectional studies indicate that physically active individuals and athletes have:
OR
greater content of bone minerals
increased bone density
greater musculoskeletal mass
therefore it is likely that the density of GREAT MASS is higher than in sedentary subjects. Using standard body density, the fat percentage is underestimated by 3% in female bodybuilders with high bone mineral content.
It is advisable to use equations based on a multi-compartment model even if almost all the equations developed for athletes are based on the 2 compartment model. In these cases it is recommended to use the generalized Jackson and Pollock equations (sum of 7 pliche and sum of 4 pliche).
Once the athlete's COMPOSITION is determined, the minimum or competitive weight can be calculated.
MINIMUM BODY MASS
Minimum weight of an athlete = lowest weight that the athlete can maintain without negative effects on health and performance.
Males = the minimum body mass includes 5% of primary fat
Women = the minimum body mass includes about 12% of primary fat
MINIMA body mass for the standard woman is 48.5 kg.
(concept developed by BEHNKE based on experimental observations related to the measurement of bone diameters).
Low values of body fat were found in marathon champions 1-8% as a result of adaptation to the heavy workload borne by athletes. In fact in these cases a reduced body mass reduces the energy cost and favors the thermal dispersion.
Among the athletes there is a great variability for lean mass: from a minimum of 48.1 kg for jockeys to over 100 kg in American football athletes, pitchers and sumo wrestlers.
Desirable body mass
Excessive fat mass does not correlate with good physical condition but, on the contrary; represents a strong health risk.
But what is the optimal fat mass for each subject?
For physically active young adults the% of fat mass = 15% and 25% for women
The MCD (desirable body mass) can be calculated with the formula:
| MCD = | Lean mass |
| 1-% Fsuggerito |
Example:
subject of 91 kg and 20% of fat mass
We want to know how much fat mass must be reduced to bring it to 10% of body mass.
Fat mass = (91 x20) / 100 = 19.2 kg
Lean mass = 91-18.2 = 72.8kg
MCD = 72.8 / (1-0.10) = 72.8 / 0.9 = 80.9 kg
Desirable fat mass = 91 - 80.9 = 10.1 kg
Fat mass to be lost = 19.2 - 10.1 = 8.1 kg
(The calculations assume that the lean mass remains constant)
