While there are numerous methods for evaluating aerobic capacity, in most instances treadmill walking/running is appropriate for the majority of individuals. Normative data correlates time on the treadmill with aerobic fitness. V̇O2 is an index of the body’s efficiency at producing work. It is expressed in milliliters of oxygen consumed per minute, and adjusted for body weight in kilograms: ml/kg/min. There are many factors that can influence V̇O2max, e.g. heredity, training, age, gender, and body composition. Generally, V̇O2max declines with age (about 2% per year after age 30) and males typically have a greater oxygen consumption value than females. Nevertheless, the trend is that a higher V̇O2 max allows one to produce more energy, thereby performing more work. With this in mind, V̇O2 max is the "gold standard" measure of overall fitness. Show
Aerobic fitness is assessed by having the subject perform exercise at increased loads, for 12 to 15 minutes, while breathing into a mouthpiece which collects information on inspired and expired air. A treadmill, personal bike on a Computrainer, or a stationary bicycle are typically used. The test starts with an easy-moderate work load which is maintained for a 1-2 minutes. The load is increased gradually every 1-2 minutes until reaching the maximum level that the subject can tolerate and/or until physiological parameters such as heart rate, oxygen consumption, f... have hit a peak or plateau. This is done by increasing the cycling resistance or the speed and/or grade of the treadmill. The oxygen uptake, heart rate, speed and/or watts are measured at the ventilatory threshold and at maximal load, the latter would be the subject's V̇O2 max. V̇O2 max values cannot be used in every day training, but follow-up V̇O2 tests can be used as a measure of progress. However, since heart rate, speed and/or power is typically measured during a V̇O2 max test, various heart rate, speed and/or power levels can be garnered from testing and then associated to appropriate training zones, which are then applied to everyday training. Other information such as V̇O2 economy (oxygen consumption values at a given heart rate or power output) can also be extracted from the data, compared to subsequent tests and against performance norms. Training results in an increase in the efficiency of oxygen transport within the body. By lowering the resting heart rate (HR), and the HR at sub maximal loads, the heart pumps more blood with every heart beat. This, in addition to other physiological changes, increases the oxygen extraction capability. When an individual is tested before and after training while performing exercise at the same load, a lower HR is shown after training because more blood (thus, oxygen) is delivered in each heart beat. Such HR differences during exercise can be used to predict aerobic fitness. The % of increase in V̇O2 max is dependent on many variables and differs considerably from individual to individual, ranging from 5-30%. In general, individuals who are the least fit see the largest changes and individuals who are highly fit see the smallest changes. Significant amounts of research and public health data indicate that low aerobic fitness levels are correlated with an increased risk of premature death from many causes but in particular from cardiovascular disease. Accordingly, higher aerobic fitness levels are associated with numerous health benefits e.g. longer lifespan, better quality of life, reduced risks for stroke, heart disease, diabetes and cancer, improved mood and self-esteem, and improved sleep patterns. To improve or maintain cardiovascular health an individual must engage in cardiovascular exercise (run, walk, swim, bike, etc...) at least 3 times per week. Currently, however, public health data indicates that only 22-25% of Americans exercise regularly enough to achieve these positive health benefits. V̇O2 max is also a predictor of performance, although its correlation to athletic success in endurance sports is only 30-40%, with other factors such as sustainable lactate threshold, motivation, training, etc... also playing a role. In general, however the higher a V̇O2 max the more potential for a successful performance in an aerobic endurance event. Maintaining a good level of physical fitness is important. However, it can be difficult to determine what fitness entails. Experts define physical fitness as “one’s ability to execute daily activities with optimal performance, endurance, and strength with the management of disease, fatigue, and stress and reduced sedentary behavior.” This description goes beyond being able to run quickly or lift heavy weights. Despite being important, these attributes only address single areas of fitness. This article provides details of the five main components of physical fitness. Being physically fit depends on how well a person fulfills each of the components of being healthy. When it comes to fitness, these components are:
The following sections will look at each of these components individually. Cardiorespiratory endurance indicates how well the body can supply fuel during physical activity via the body’s circulatory and respiratory systems. Activities that help improve cardiorespiratory endurance are those that cause an elevated heart rate for a sustained period of time. These activities include:
People who regularly engage in these activities are more likely to be physically fit in terms of cardiorespiratory endurance. It is important to begin these activities slowly and gradually increase the intensity over time. Exercising increases cardiorespiratory endurance in a number of ways. For example, the heart muscle becomes stronger so that it is able to pump more blood per heartbeat. At the same time, additional small arteries grow within muscle tissue so that they can deliver blood to working muscles more effectively when needed. How does heart health change with exercise?The heart’s efficiency changes and improves after persistent training. However, recent research suggests that different types of activity change the heart in subtly different ways. All types of exercise increase the heart’s overall size, but there are significant differences between endurance athletes such as rowers and strength athletes such as football players. The hearts of endurance athletes show expanded left and right ventricles, whereas those of strength athletes show thickening of the heart wall, particularly the left ventricle. How does lung health change with exercise?Although the heart steadily strengthens over time, the respiratory system does not adjust to the same degree. Lung size does not change, but the lungs do use oxygen more effectively . In general, exercise encourages the body to become more efficient at taking on, distributing, and using oxygen. Over time, this improvement increases endurance and overall health. Health benefits of cardiorespiratory fitnessCardiorespiratory fitness can help reduce the risk of conditions including:
There are a number of ways to measure muscular strength. Generally, lifting a set weight in a prescribed position and comparing the results against any given population is the best way. In general, if a person works their muscles consistently and regularly, they will increase in strength. There are various ways of putting the muscles through rigorous activity, but anything that works a muscle until it is tired will increase muscle strength over time. How does muscle structure change with exercise?Muscles consist of elongated muscle cells. Each muscle cell contains contractile proteins, called actin and myosin, that give the muscle its strength. These fibers contract together, producing the so-called power stroke. The total force depends on the number of these units contracting in unison. To build muscle, an individual must regularly exercise their muscles and take in enough protein. Scientists do not fully understand the exact mechanism of muscle building, but the general principles are well known. Training causes the muscle cells to expand, and there is an increase in actin and myosin production. Also, in untrained muscles, fibers tend to fire in an asynchronous manner. In other words, they do not fire in unison. As a person trains them, however, they learn to fire together as one, thereby increasing maximum power output. Fitness can also include muscular endurance, which is the ability of a muscle to continue exerting force without tiring. As mentioned above, strength training builds bigger muscles. Endurance training, on the other hand, does not necessarily generate muscles of a larger size. This is because the body focuses more on the cardiovascular system, ensuring that the muscles receive the oxygenated blood they need to keep functioning. Another important change in muscles that people specifically train for endurance concerns the different types of muscle tissue: fast twitch and slow twitch fibers. Fast twitch fibers contract quickly but get tired quickly. They use a lot of energy and are useful for sprints. They are whitish, as they do not require blood to function. Slow twitch fibers are best for endurance work, as they can carry out tasks without getting tired. They are present in core muscles. These fibers appear red, as they rely on a good supply of oxygenated blood and contain stores of myoglobin. Different exercises will promote fast twitch fibers, slow twitch fibers, or both. For example, a sprinter will have comparatively more fast twitch fibers, whereas a long distance runner will have more slow twitch fibers. Body composition measures the relative amounts of muscle, bone, water, and fat an individual has. A person can potentially maintain the same weight but radically change the ratio of each of the components that make up their body. For instance, people with a high muscle (lean mass) ratio might weigh more than those with the same height and waist circumference who have less muscle. How is body composition calculated?There are several methods for calculating body composition. For example, a doctor can measure a person’s body fat using tools such as calipers or through bioelectrical impedance analysis to detect fat cells. The above methods are prone to inaccuracies, however. Flexibility refers to the range of movement across a joint. Flexibility is important because it improves the ability to link movements together smoothly and can help prevent injuries. It is specific to each joint and depends on a number of variables, including the tightness of ligaments and tendons. Various activities that stretch the joints, ligaments, and tendons can increase flexibility. There are three common types of stretches that people use to increase flexibility:
There are a number of ways to improve flexibility. Having a daily stretching regimen can be the simplest and most efficient way of achieving whole body flexibility. In general, fitness means different things to different people. The important message is that embarking on any regular exercise will be of benefit to a person’s health. The more exercise they do, the healthier they will look and feel. What is the ability of the body to function at optimal efficiency and still have enough reserve energy to meet the other demands of daily life?Physical fitness refers to the ability of your body systems to work together efficiently to allow you to be healthy and perform activities of daily living. Being efficient means doing daily activities with the least effort possible.
What do we call the ability of the body to function efficiently and effectively?Physical fitness is the body's ability to function efficiently and effectively in work and leisure activities.
What do you call the ability of the body to effectively and efficiently function work without undue fatigue?Physical fitness can be defined as the “ability to carry out daily tasks with vigor and alertness, without undue fatigue, and with ample energy to enjoy leisure-time pursuits and to meet unforeseen emergencies” (Park 1989).
What is required for the body to function at an optimum level of health?Regular physical activity is essential for the optimal function of many vital organs and tissues, and for general function.
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How do you call the ability of the body to function at optimal efficiency and still have enough reserve energy to meet other demands of daily life?
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