CBSE Class 12 Physical Education Physiology and Injuries in Sports Notes Set 02

Physiology and Injuries in Sports

Physiological Factors Determining Components of Physical Fitness

In physiology, we study how our organs, systems, tissues, cells and molecules within cells work and how their functions are put together to maintain our internal environment. "Physiology is the study of how the human body functions." Physiology is very essential to understand how to attain physical fitness in order to enhance the performance in sports.

To understand the physiological factors, the components of physical fitness have to be understood.

The components of physical fitness are as follows

• (i) Muscular Strength One of the basic requirements for success in all movements is muscular strength. It may be defined as the maximum force or tension a muscle or a muscle group can exert against a resistance. The development of strength is specific to the muscle or muscles involved in a particular activity.
• (ii) Power Power is the ability of the body to release maximum muscle contraction in the shortest possible time.
• (iii) Speed It is the rapidity with which one repeats successive movements of the same pattern. It may also be defined as the ability of a person to move quickly through a short distance.
• (iv) Muscular Endurance It may be defined as the ability of a muscle or muscle group to perform repeated contractions against a resistance / load or to sustain contraction for an extended period of time with less discomfort and more rapid recovery.
• (v) Agility It is the ability of the person to change direction while moving at or near full speed. More specifically, agility is the ability of a person to change direction or body position quickly (as fast as he can) and regain body control to proceed with another movement.
• (vi) Flexibility In general, flexibility is that quality of the muscles, ligaments and tendons that enables the joints of the body to move easily through a complete range of movement.
• (vii) Size of the Muscle The size of the muscle determines the strength possessed by an individual. Males have bigger and larger muscles due to which they have more strength than females.
• (viii) Body Weight There is a positive correlation between body weight and strength among international weightlifters. So people who weigh heavier are stronger and have more strength than people who are lighter.
• (ix) Muscle Composition Muscles consist of two types of fibres i.e. fast twitch fibres (white fibres) and slow twitch fibres (red fibres).
• (x) Intensity of the Nerve Impulse A muscle consists of many motor units. The number of contracting motor units determines the total force.
• (xi) Metabolic Power The metabolic power depends upon the energy supplied through certain enzymes.
• (xii) Aerobic Capacity The ability of a person to maintain adequate supply of oxygen to the working muscles influences the endurance.
• (xiii) Joint Structure The joint structure of a person determines the range of motions and hence level the flexibility of an individual.
• (xiv) Age and Gender The age of a person as well as the gender determines the level of flexibility. Flexibility decreases with advancement of age and females are more flexible than males.

Effects of Exercise on Cardio-Respiratory System

It has been observed that physical exercises affect the various parameters of the cardio-respiratory system in many ways, which includes both the cardiovascular and respiratory systems.

Effects of exercise on the cardiovascular system are

• (i) Cardiac Output It is the amount of blood pumped by the heart in one minute. In other words, it is the product of stroke volume and heart rate.
  Cardiac output increases with the intensity of the exercises. At rest it is 4 to 6 L/min and during exercises it is 20 to 40 L/min.
  \[ \text{Cardiac output} = \text{heart rate} \times \text{stroke volume} = \frac{\text{mL blood}}{\text{min}} \text{ or } \frac{\text{Litres}}{\text{min}} \]
• (ii) Heart Rate The number of cardiac contractions in one minute is called heart rate. Generally normal adult heart rate is 72 beats/min. During exercises the heart rate goes up.
• (iii) Stroke Volume The amount of blood pumped into the aorta with every heartbeat is known as the stroke volume. In an untrained male, it is 70 - 90 mL/beat. In a trained male athlete, it may be 100 - 120 mL/beat. The stroke volume increases in response to the intensity of the exercises.
• (iv) Blood Flow Exercise increases the blood volume caused by a 12% increase in the plasma volume and a slight increase in the red blood cells volume.
  With increasing intensities of exercise, a greater accumulation of lactic acid and the production of other metabolic end products (potassium, phosphate) occurs.
  This increases blood flow in the cardiac output, while it decreases in the kidneys and abdomen.

Many parameters of respiratory system get affected due to exercises. Effects of exercise on respiratory system are

• (i) Lung Volume With endurance training, lung volume and lung capacity increase. Vital capacity, which is maximal volume of air forcefully expelled is increased after endurance training.
• (ii) Breathing Frequency Breathing frequency is the number of breaths per minute. After training, breathing frequency or respiratory rate is decreased.
• (iii) Maximum Minute Ventilation Minute ventilation is the amount of air which is inspired or expired in one minute. After training, maximum, as well as minute ventilation is increased.
• (iv) Tidal Volume Tidal volume, which is the amount of air inspired or expired per breath, is also increased as a result of endurance training.
• (v) Ventilatory Efficiency With physical exercises, particularly endurance training, our ventilatory efficiency increases.
• (vi) Pulmonary Diffusion Pulmonary diffusion is the exchange of gases taking place in the alveoli (small air sacs in our lungs).

Effects of Exercise on the Muscular System

The effects of exercise on the muscular system are as follows

• (i) Increase in Blood Flow The volume of blood flow to muscle tissues increases during exercise. It can increase by upto 25 times during specially demanding exercise.
• (ii) Respiration During exercise, muscles repeatedly contract and relax, using and requiring energy to do so. The energy comes from the chemical ATP that is broken down during exercise into another chemical called ADP. When there is plenty of oxygen available in the muscle tissues, the energy for muscle action is produced aerobically so muscles get more oxygen.
• (iii) Muscle Size Although muscle size (and other physical characteristics such as height) is largely determined by a person's genes but muscle size also gets affected by the intensity of exercises.
• (iv) Blood Supply (to and through muscles) As a result of frequent exercise over a sustained period of time, both the quantity of blood vessels and the extent of the capillary beds increases.
• (v) Muscle Coordination Frequent exercise and specially use of specific muscles for the same or similar skilled tasks.
• (vi) Muscle Biochemistry Many beneficial biochemical changes take place in muscle tissues as a result of regular long-term exercise such as increase in the size and quantity of mitochondria in the cells, increase in the activity of enzymes.

Sports Injuries

Sports injuries are injuries that occur in athletics activities. They can result from acute trauma, or from overuse of a particular body part.

Classification of Sports Injuries

Sports injuries can be classified in various ways. Classification can be based on the time taken for the tissues to become injured, tissue type affected and the severity of the injury.

Several types of injury are as follows

Soft Tissue Injury (STI)

A Soft Tissue Injury (STI) is the damage of muscles, ligaments and tendons throughout the body.

Soft tissue injuries fall into two basic categories

• (a) Acute Injuries This is one of the most common methods of classifying sports injuries. It is based on the time taken for the tissues to become injured.
• (b) Overuse Injuries Overuse injuries are not so pervasive and represent a greater challenge for the sports therapist in diagnosis and management.

1. Abrasion
It is a shallow wound, typically a wearing away of the top layer of skin (the epidermis) due to an applied friction force against the body. It may be caused by falling on a hard surface.
The scraped-off surface layer of skin from an abrasion can contain particles of dust or dirt, which may lead to an infection or other complications, if not cleaned and attended properly.
Abrasions are distinguished from incised wounds, which are much more serious injuries. While an abrasion is an injury that damages only the superficial layers of skin, incised wound is a deeper cut (typically with a sharp object), that has the potential for serious and severe bleeding.

2. Contusion
Contusion is a muscle injury. It can be caused by a direct hit with any sports equipments. It generally happens when an injured capillary or blood vessel leaks blood into the surrounding area.
The raised area of contusion is due to the accumulation of blood and fluid from the injured blood vessels in the tissue.
Stiffness and swelling are common features of contusion. Soft tissue contusions are much easier to diagnose than bone contusions. While both muscle and skin tissue contusions cause pain, muscle tissue contusions are usually more painful, especially if they affect a muscle that you can't avoid using.

3. Laceration
It is basically tearing of the skin that results in an irregular wound. Lacerations may be caused by injury with a sharp object or by impact injury from a blunt object or force.
They may occur anywhere on the body. In most cases, tissue loss is minimal, and infections are uncommon. Severe lacerations are often accompanied by significant bleeding and pain. Cleaning and preparing a laceration for repair is crucial for preventing infection and reducing the appearance of scarring.

4. Incision
An incision wound is a cut in the skin caused by a sharp object such as a knife, broken glass, scissors, etc. However, occasionally these types of wounds can be very deep, cutting into muscle tissue, tendons or major blood vessels. Damage to major blood vessels can cause life-threatening bleeding.

5. Strain
A strain is defined as an injury to a tendon (tissues that connect your muscles and bones) or muscle. Strains often occur in the lower back and the muscle in the back of the thigh.
Some of the symptoms include pain, swelling, muscle spasms and limited ability to move the muscle. Strain can happen as sudden (acute) strain or develop over days (chronic).

6. Sprain
A sprain is a stretch or tear of a ligament, a strong band of connective tissue that connects the end of one bone with another. Ligaments stabilise and support the body's joints.

Bone and Joint Injuries

The hard tissue injuries take place in bones and cartilages, e.g. a fracture. These injuries are also known as bone and joint injuries. The nature of the damage depends on the direction of the applied force on the bones and the manner in which these bones are attached to other structures.

Bone Injury: Fracture

A hard tissue injury is also called a 'fracture' and is defined as a "loss of continuity in the substance of a bone". In other words, it is a bone injury that breaks the continuity of bone or seperate it into two or more parts.

Fracture is of various types, which are as follows

1. Greenstick Fracture
A greenstick fracture occurs when a bone bends and cracks, instead of breaking completely into separate pieces. In this type of fracture, arm fractures are most common than leg fractures. It can be caused by many things like participation in sports, motor vehicle accidents and falls.

2. Comminuted Fracture
It is a break or splinter of the bone into more than two fragments.
Since considerable force and energy is required to fragment bone, fractures of this kind occurs after high-impact trauma such as vehicular accidents. This type of fracture is usually challenging to treat because the break is so complex.

3. Oblique Fracture
An oblique fracture is characterised by a break that is curved or at a diagonal angle to the bone. A sharp blow that comes from an angle (i.e. above or below) may cause oblique fractures. They are particularly prone to angulation in the plane of the fracture. Trauma, sudden twist of the muscles or bone diseases may cause oblique fracture.

4. Transverse Fracture
It is a fracture where the bone breaks at a right angle to the long axis of the bone.
Transverse fractures most often occur as the result of strong force applied perpendicular to the long axis of a bone.
This may also be caused due to trauma, sudden twisting of the bone due to muscle spasm or indirect loss of leverage or by certain bone diseases.

5. Impacted Fracture
An impacted fracture is one whose ends of cracked bones are driven into each other. This commonly occurs with arm fractures in children and is sometimes known as a buckle fracture.
In other words, it is a fracture caused when bone fragments are driven into each other. Lifting overweight item is one of the main causing factors of this fracture.

6. Dislocation
Joint injuries typically occur in the knees, ankles, wrists, shoulders and elbows. They can range from sprains to fractures and dislocations.
A dislocation is a separation of two bones where they meet at a joint. A dislocated joint is a joint where the bones are no longer in their normal positions.
A dislocated joint may be accompanied by numbness or tingling at the joint or beyond it. It is intensely painful, especially if you try to use joint or put weight on it.