We have been discussing the skill-related components of Fitness namely – agility, reaction time, balance, co-ordination etc.
The other important components of fitness, particularly health related are – body composition, cardio-vascular fitness, muscular strength and endurance and flexibility. Body Composition, basically represents the different aspects that constitute the total body weight of a person. These aspects include the metabolically active lean body tissues - muscle, bone and metabolically inactive tissues – adipose (fat) tissue.
Typically depending on the body type and the genetic composition of the person, his total body weight as shown by the weighing scale, is a summation of the lean and adipose tissue mass. The lean body mass is metabolically active, in that it uses up the energy stores (creatine, glucose, fat) available to sustain itself, and thus does not lead to accumulation of the energy stores. Adipose tissue mass is metabolically inactive, in that it hardly needs any energy to sustain itself and hence it has a tendency to accumulate.
The percentages of lean mass and fat mass define the over all health and fitness of an individual, and hence are important parameters, which need to be determined. Two people with the same weight and height can have completely different body compositions, which inturn will define the risk factors especially with regard to lifestyle related problems. The lean body mass is more dense and weighs more, while the fat mass is less dense (hence they say that fat people float easily when swimming!).
Body composition is also genetically and demographically affected, e.g. Indians have a tendency to have lower lean body mass percentages as compared to the west, where lean, athletic bodies are more common. Also Indians have a tendency to accumulate fat on the central regions of the body, which has a direct negative effect on cardiovascular fitness and increases the chances of lifestyle disorders like obesity, diabetes etc.
These aspects are these days commonly measured using the Fat monitors, skinfold callipers etc. in many health clubs.