Physiology In Sport

Original Editor - Alberto Bertaggia.

Top Contributors - Wanda van Niekerk, Naomi O'Reilly, Alberto Bertaggia, Lucinda hampton, Kim Jackson, 127.0.0.1, Evan Thomas, WikiSysop, Nikhil Benhur Abburi, Tony Lowe and Jess Bell  

Introduction

Biology is a branch of science that deals with living organisms and vital processes, both in animals and plants.

Physiology and anatomy are two closely related branches of biology.

While anatomy is the science that investigates the structure of the body, physiology is the scientific discipline that deals with the processes or functions of living things. Physiology derives from Ancient Greek φύσις (physis), meaning "nature, origin", and -λογία (-logia), meaning "study of".

The major goals of physiology are:

• to understand and predict the body’s responses to stimuli;
• to understand how the body maintains conditions within a narrow range of values in the presence of a continually changing environment.
  

Exercise Physiology is the specialist branch of physiology which studies the acute responses and chronic adaptations to a wide range of exercise and sport conditions.

Exercise Physiology

Studies in exercise physiology help athletes achieve greatness. For example, it is now known that olympic weightlifting and plyometric training are two methods to increase vertical jump height (Hackett D, Davies T, Soomro N, Halaki M. Olympic weightlifting training improves vertical jump height in sportspeople: a systematic review with meta-analysis. Br J Sports Med. 2015 Nov 30)

Exercise is one of the most common stimulii which perturbates human homeostasis.

Usually people think of exercise as a sport-related activity to increment performance and train athletes (such as basketball, football, volleyball, hockey players, weightlifters, runners, etc.). But physical exercise is also present during job-related physical activity (lifting loads, moving objects, walking and standing for 8 hours, etc.), activities of daily living (doing laundry, mowing the lawn, cleaning house, cooking dinner, etc.), and rehabilitation of patients, such as following a stroke or heart attack. In all of these non-sport-related activities, exercise is involved. Therefore, exercise physiology matters in all of these contexts.

The physiological response to exercise is dependent on the intensity, duration and frequency of the exercise as well as the environmental conditions.

During physical exercise, requirements for oxygen and substrate in skeletal muscle are increased, as are the removal of metabolites and carbon dioxide. Chemical, mechanical and thermal stimuli affect alterations in metabolic, cardiovascular and ventilatory function in order to meet these increased demands.

Musculoskeletal System

If you need a recap on muscle physiology these videos will be very useful.

The musculoskeletal system is fundamental in exercise physiology because to exercise, there is the need of muscle functional contraction, of course. The strength of a muscle depend mostly by its cross sectional area, therefore size matter.

Mechanical work performed by a muscle is the amount of force applied by the muscle multiplied by the distance over which the force is applied.

Muscle strength is the maximal amount of tension or force that a muscle or a muscle group can volountarily exert on a maximal effort when type of muscle contraction, segment velocity and joint angle are specified.

The power of muscle contraction is different from muscle strength because power is a measure of the total amount of work that the muscle performs in a unit period of time and is generally measured in kilogram meters (kg-m) per minute.

Another important concept is endurance, defined as the ability to perform repeated contractions against a resistance or maintain a contraction for a period of time.

Types of Muscle Contraction

There are several types of muscle contraction, as follows:

• Isometric; it occures when tension is developed in the muscle without movement, therefore muscle origin and insertion do not move and there is not changes in muscle lenght.
• Concentric; it occures when tension is developed in the muscle with origin and insertion moving closer, therefore the muscle shortens.
• Eccentric; it occures when tension is developed in the muscle with origin and insertion moving apart, therefore the muscle lengthens.

Metabolic Systems

Adenosine triphosphate (ATP) is the common chemical intermediate that provides energy essential for muscle contraction.

The bonds attaching the last two phosphate radicals to the molecule are high-energy phosphate bonds. Each of these bonds stores about 7300 calories of energy per mole of ATP. Removal of the first phosphate converts the ATP into adenosine diphosphate (ADP), and removal of the second converts this ADP into adenosine monophosphate (AMP).

However, at the onset of exercise there is an immediate requirement for increased supply of energy and there is only enough ATP stored for
1–2 seconds of work and therefore rapid ways to resynthesize ATP are required.

Phosphocreatine-Creatine System

Phosphocreatine is another chemical compound that has a high-energy phosphate bond that can be hydrolysed to provide energy and resynthesize ATP. This occurs within a small fraction of a second. Therefore, all the energy stored in the muscle phosphocreatine
is almost instantaneously available for muscle contraction, just as is the energy stored in ATP.

Thus, the energy from the phosphagen system (ATP and Phosphocreatine stored in the muscle) is used for maximal short bursts of muscle power.