Home of Sports Medicine and Exercise Physiology

Little moves like parking in the farthest spot really do help you lose more weight, even if you work out regularly. When 34 women followed the same fitness plan for 8 weeks, some lost up to 7 pounds of body fat, while others gained as many as 5, found one study. The reason for this 12-pound difference: The “biggest losers” were active all day long—walking, climbing stairs, even fidgeting—while the “gainers” decreased their movements. By Prevention Magazine

Basketball prodigy: This 5th grader can run a mile in 4 minutes and 50 seconds, which is faster than any 11 year old kid. Later on, doctors figured out why this machine runs so efficiently; His VO2 max(a measure of how much oxygen the lungs can take in) was tested, and was found to be off the charts. doctors claimed they have never seen anything like it!

Theory of VO2 max:

The capability of the human body to deliver energy for intense exercises lasting more than 30 seconds depends on the consumption and expenditure of oxygen (O2). Most intense physical activities in daily life, in athletics, and in physical medicine take more than 90 seconds. Thus, intake of 02 provides the energetic foundation of our existence and survival. Normally, the adult human body requires about 88 pounds of oxygen daily. However, the rate of intake of a given volume of O2 (abbreviated V(O2).) increases as activities progress from rest to easy, to difficult, and finally to maximal workloads. The maximum rate at which an individual can consume oxygen (V(O2) max) is an important determinant of the peak power output and the maximal sustained power output, or physical work capacity, of which an individual is capable. Moreover, an adequate good capacity to consume and utilize oxygen is essential for recovery from sprint (or burst) activity, as recovery is mainly an aerobic process.
As will be shown in upcoming posts, the capacity for V(O2) max depends on the capacity of the cardiovascular system. This realization that physical work capacity,Vo2 max, and cardiovascular fitness are interrelated has resulted in a convergence of physical education (athletic performance) and medical (clinical) definitions of fitness. From the physical education —sports science perspective, cardiovascular function determines V(O2) max, which in turn influences physical work capacity, or fitness. From the medicoclinical perspective, fitness involves, minimally, freedom from disease. Because cardiovascular disease is the greatest threat to the health of individuals in contemporary Western society, medical fitness is largely cardiovascular fitness. One of the major ways of determining cardiovascular fitness is measuring V(O2) max. Therefore,Vo2 is not only an important parameter of metabolism but also a good measure of fitness for life in contemporary society. In fact, Vo2 max is so important from both the physical education—sports science and medicoclinical perspectives, it has emerged as the single most important criterion of physical fitness.

Relationship between oxygen consumption (V02) and external work rate (power output)

Source: McGraw Hill, Brooks, Fahey, Baldwin – Exercise Physiology, Human Bioenergetics and Its applications – Fourth Ed(book)

Human Heart

In a complex biological machine such as an exercising human, many physiological processes occur simultaneously. For example, when a person runs a mile, the heart’s contraction and beating frequency increase, hormones are secreted, the metabolic rate increases, and body temperature is elevated. Despite the vast number of events occurring simultaneously, usually only a few control and limit the overall performance of the activity. Many scientists approach the understanding of physiological systems by studying the rate-limiting processes. First, scientists seek to define the metabolic or signaling pathway by identifying the components and sequences, then efforts focus on identifying the controlling factors. Imagine an assembly line that manufactures a commodity such as an automobile. Although there are many steps in the manufacturing process, assume that one step, installing the engine, is the slowest. If we want to increase production. it will do us little good to increase the speed of the other steps, such as assembling the chassis. Rather, we should focus our attention on speeding up the process of installing the engine. We might hire extra people to do the task, or use more machinery, or remove some impediment to the process so that workers can perform more rapidly. As we shall see, the body is controlled by and adjusts to exercise in a similar fashion.

In athletics, successful coaches are those who can identify the rate-limiting factor, sometimes called a weakness, and improve the individual’s capacity to perform that process. Let us assume, for instance, we are coaching a novice wrestler who has been a successful competitive weight lifter. It makes no sense to emphasize strength training. Rather, we should emphasize technique development and other aspects of fitness, such as endurance. We would strive to maintain strength while concentrating on the performance-limiting factors. Similarly, we would be ill advised to have a 400-m runner do 100 miles of road running a week, because this type of fitness is of minimal use to this athlete and may even interfere with the enzymatic apparatus that facilitates the high rates of power output used in 400-m runs.

Source: McGraw Hill, Brooks, Fahey, Baldwin – Exercise Physiology, Human Bioenergetics and Its applications – Fourth Ed(book)