grade 12 kin exam

types of bones

• long bones

• short bones

• flat bones

• irregular bones

• seasmoid bones

long bones

are found in the arms and legs (e.g., the femur).

Short bones

are most common in the wrists (e.g., the carpal bone, the ankles).

Flat bones

are flat and thin and are found in the roof of the skull.

Irregular bones

include odd-looking bones such as the sphenoid bone or vertebrae.

Sesamoid bones

are unusual, small, flat bones wrapped within tendons that move over bony surfaces (e.g., the patella or knee bone).

Classification of Joints

Joints are classified according to their structure (what they are made of) or their function (the type and extent of movement they permit).

• The structural classification recognizes three main types of joints:

  • Fibrous joints, Cartilaginous joints, and Synovial joints

The Characteristics of Synovial Joints

Synovial joints permit movement between bones and are distinguished by the following:

• Articular cartilage: is located on the ends of bones that come in contact with one another.

• Joint capsule: consists of the synovial membrane and fibrous capsule.

• Joint cavity: is filled with synovial fluid, which acts as a lubricant for the joint.

• Bursae: are the small fluid sacs found at the friction points (“bursa” is the singular).

• Intrinsic: ligaments are thick bands of fibrous connective tissue that help thicken and reinforce the joint capsule.

Extrinsic: ligaments separate from the joint capsule and help to reinforce the joint.

Ball-and-socket (spheroidal) joints

The “ball” at one bone fits into the “socket” of another, allowing movement around three axes (e.g., the humerus rests in the glenoid cavity).

Gliding (or plane or arthrodial) joints

This type connects flat or slightly curved bone surfaces that glide against one another (e.g., between the tarsals and among the carpals).

Hinge (ginglymus) Joints

A convex portion of one bone fits into a concave portion of another (movement in one plane). The joint between the ulna and the humerus is an example.

Pivot (or trochoid) Joints

A rounded point of one bone fits into a groove of another (e.g., the joint between the first two vertebrae in the neck, which allows the rotation of the head).

Saddle joints

allow movement in two planes (but not rotation like a ball-and-socket joint). A key saddle joint is found at the carpo- metacarpal articulation of the thumb.

Elipsoid joints

This type of synovial joint also allows movement in two planes. The wrist is an example of an ellipsoid joint.

Skeletal Muscle

• Are the type of muscles that are attached to the bones (by tendons and other tissues)

• Are most prevalent muscle type in the human body (30 to 40% of human body weight) 

• Are voluntary-humans have conscious control over their skeletal muscles 

• Referred to as striated or striped because of its appearance under a microscope as a series of alternating light and dark stripes. 

Components of Skeletal Muscle

• Sarcolemma

• Sarcoplasm

• Sarcomeres

• Sarcoplasmic Reticulum 

• Motor Unit

Sarcolemma

A plasma membrane that lies beneath the endomysium, a sheath of connective tissue that surrounds a muscle fibre.

Sarcoplasm

The muscle cell’s cytoplasm which is contained by the sarcolemma. 

Sarcomeres

The units of skeletal muscle containing the cellular proteins myosin and actin.

Sarcoplasmic Reticulum

A network of channels in each muscle fibre that transport the electrochemical substances involved in muscle activation. 

Motor Unit

The motor neuron, its axon (pathway) and the muscle fibres it stimulates.

Types of Contractions

• Concentric contraction (shortening) 

• Eccentric contraction (lengthening)

•  Isometric contraction (static)

Bone Injuries and Bone Disease

• Fractures

• Stress fractures

• Shin splints

• Osteoporosis

Fractures

bone “breaks,” normally divided into three types: simple, compound, and comminuted

Stress fractures

tiny cracks caused by a rapid increase in activity or when an athlete switches training surfaces or wears footwear with improper cushioning.

Shin splints

a painful condition occurring on the medial or lateral side of the tibia (shin bone) are another common sports injury.

Osteoporosis

a degenerative disease characterized by low bone mass and bone deterioration, can be prevented by a balanced diet rich in calcium and vitamin D; weight-bearing exercise; avoidance of smoking and excessive alcohol; and bone density testing and medication when appropriate.

Joint-Related Injuries and Disease

• Dislocations

• Separations

• Osteoarthritis

Dislocations

A dislocation occurs when a bone is displaced from its joint. Dislocations are often caused by collisions or falls, and are common in finger and shoulder joints.

Separations

is more serious than a dislocation. In a shoulder separation, the ligaments attaching the collarbone (clavicle) and shoulder blade (scapula) are disrupted.

Osteoarthritis

is a condition involving loss of cartilage at joints. Osteoarthritis (a joint disease) is often confused with osteoporosis

Rotator Cuff Tears

• Rotator cuff tears usually involve one or all four muscles that make up the rotator cuff at the shoulder joint: supraspinatus, infraspinatus, teres minor, and subscapularis.

• These muscles share a common tendinous insertion on the greater tubercle of the humerus. Thus, when a part of the tendon is torn, all three muscles around the joint are affected.

• The severity of a rotator cuff tear must be diagnosed by a doctor.

Anatomical Planes

• Frontal plane: The frontal (coronal) plane is vertical and extends from one side of the body to the other.

• Transverse plane: The transverse (horizontal) plane is horizontal and divides the body into upper and lower segments.

• Sagittal plane: The sagittal (median) plane is vertical and extends from the front of the body to the back.

Anatomical Axes

• Horizontal axis

• Longitudinal axis

• Antero-posterior axis

Horizontal axis

The horizontal axis extends from one side of the body to the other.

Longitudinal axis

The longitudinal axis (also known as the polar axis) is vertical, running from head to toe.

Antero-posterior axis

The antero-posterior axis extends from the front of the body to the back.

Smooth Muscle:

Surrounding the body’s internal organs, including the blood vessels, hair follicles and the urinary genital and the digestive tract are smooth muscles. Contracts more slowly than skeletal muscles, but can remain contracted for longer periods of time. They are involuntary.

Cardiac Muscle:

Found in the heart, are responsible for creating the action that pumps blood from heart to rest of body. Are involuntary, not controlled consciously, instead directed to act by the autonomic nervous system.

The Anatomical Position

• is the standard position (standing straight, looking forward, arms at your side, and hands facing forward) used to describe the locations and relationships of anatomical parts on your body.

• It is used in a similar way to how the markings on a compass are used to describe locations in geography.

Characteristics of the Anatomical Position

• The person is in an upright, standing position with his or her head, eyes, and toes pointing forward.

• The feet are together and the arms are slightly out to the side.

• The forearms are fully supinated; in other words, the palms of the hands are facing forward.

Sliding Filament Theory

Explains how muscles contract by describing the interaction between actin (thin filaments) and myosin (thick filaments). Instead of the muscle physically shortening, the filaments slide past each other in a ratchet-like motion, causing the sarcomere (the basic unit of a muscle) to shorten, leading to muscle contraction.

Myocardium

Specialized muscle tissue (cardiac muscle) that forms the heart. The heart is considered a “double pump” that is divided into right and left sides.

Pulmonary Circulation

The main function of the right side of the heart is to pump deoxygenated blood, which has just returned from the body, to the lungs.

Systemic Circulation

The role of the left side of the heart is to pump oxygenated blood, which has just returned from the lungs, to the rest of the body.

Arteries

blood vessels that carry blood away from the heart

Arteries in Systemic Circulation

carry oxygenated blood from the left side of the heart towards body tissues.

Arteries in Pulmonary Circulation

Carry deoxygenated blood from the right side of the heart towards the lungs.

Veins

blood vessels that carry blood towards the heart.

Veins in Systemic Circulation

Carry deoxygenated blood towards the right side of the heart from body tissues.

Veins in Pulmonary Circulation

carry oxygenated blood towards the left side of the heart.

Arterioles

Are vessels in the blood circulation system that branch out from arteries and lead to capillaries, where gas exchange eventually occurs. Surrounded by smooth muscle. Are the primary site of vascular resistance

Capillaries

The smallest of the blood vessels. Help to enable the exchange of water, oxygen, carbon dioxide, and other nutrients and waste. Substances between blood and the tissues of the body.

Atria

Upper chambers of the heart, Singular: atrium

Ventricles

lower chambers

VO2 Max:

is the maximum volume (V) of oxygen (O2) in millilitres that the human body can use in one minute, per kilogram of body weight, while breathing air at sea level.

Cardiovascular System Diseases

• Coronary Heart Disease: This refers to the narrowing of the coronary arteries due to atherosclerosis, where plaque (cholesterol deposits) accumulates, restricting blood flow to the heart muscle.This can lead to angina (chest pain) or myocardial infarction(heart attack)​.

• The Causes of Coronary Artery Disease: Poor diet, smoking, elevated blood lipids, hypertension, family history, physical inactivity.

• Bradycardia: Is one of the most easily observed adaptations that occurs with training. is characterized by a heart rate of 60 beats per minute or less at rest.

• Tachycardia: is a heart rate of more than 100 beats per minute at rest.

Stroke Volume

The amount of blood pumped out of the heart's left ventricle during each contraction

Cardiac Output

• The total volume of blood pumped by the heart per minute. It is calculated as:

• Cardiac Output=Stroke Volume×Heart Rate

Macronutrients

make up the largest part of the food we eat and supply us with the energy we need for daily life and for physical exercise.

Micronutrients

are found in small amounts in food. They include vitamins and minerals, which help in energy transfer and tissue synthesis.

Bone Landmarks 

A landmark is a ridge, bump, groove, depression, or prominence on the surface of the bone that serves as a guide to the locations of other body structures.

Origin

The point where the muscle attaches to the more stationary of the bones of the axial skeleton

Insertions

the point where the muscle attaches to the bone that is moved most.

Muscle tissue

refers to a collection of cells that shorten during contraction.

Muscular Contraction

the tightening, shortening, or lengthening of muscles when you do some activity

Lactate Threshold:

The point where blood lactate concentrations begin to increase

Ventilation Threshold

A state in which ventilation increases much more rapidly than workload

Onset of Blood Lactate Accumulation

When lactate levels begin to accumulate rapidly in the blood.

ATP

stands for adenosine triphosphate, a molecule that stores and provides energy for cells in all living things. It's often called the "energy currency" of the cell

Energy Systems

1. Anaerobic System

2. Aerobic System

Aerobic System

• A separate but to some extent overlapping energy system, requires oxygen. 

• It involves many enzymes and several complex sub-pathways, and it leads to the complete breakdown of glucose. (Fats and protein also enter the cycle at this stage.)

Anaerobic System

• Occurs without the requirement of oxygen.

• It can occur in two separate metabolic pathways, one not involving the breakdown of glucose and the other involving the partial breakdown of glucose.

Stages of Development

The stages of human development refer to the division of human growth and development into four basic stages, each with its own characteristics and particular relationship to gender:

1. Infancy/Toddler

2. Childhood

3. Puberty/Adolescence

4. Adulthood

Infancy/Toddler

APPROXIMATELY BIRTH TO TWO TO THREE YEARS

• Infancy, the period between birth and one year of age—marks the time of the most significant growth in humans, relative to all the other stages.

• The head and chest grow rapidly, allowing the brain, heart, and lungs to develop quickly. The bones harden considerably during this time.

• During this early period, we also experience considerable muscular development and considerable gains in our ability to perform a huge range of “motor skills” such as crawling, grasping objects, walking, and running.

Childhood

APPROXIMATELY FOUR TO TEN YEARS

• In middle childhood, the body undergoes a stabilizing period that allows the child to begin to establish an important base of motor skills.

• Because the human body is in such a rapid state of growth and development during childhood and because this is often the age at which children are introduced to organized sports or games, those who work with children are challenged by how to accommodate a wide range of sizes, abilities, and developmental levels in the same unified activity.

• Child development experts have identified the important role of unstructured, imaginative play during this formative period, including active movement with no time pressures or expected outcomes, in benefiting children’s overall healthy development.

Puberty/Adolescence

APPROXIMATELY ELEVEN TO EIGHTEEN YEARS

• Puberty usually takes place between the ages of ten and fifteen in both sexes but, in general, occurs slightly earlier in females.

• During puberty, a whole range of physiological changes take place, as both genders begin to grow into sexual maturity. Hormones from the pituitary gland cause the sex organs to grow and develop, making them capable of reproduction.

• It is a time of considerable psychological adjustment, as many changes brought on by puberty take on a social and behavioural context.

• In addition, new social relationships with peer groups are being formed that can positively or negatively influence a person’s sense of self, values, and choice of activities.

Adulthood

APPROXIMATELY EIGHTEEN YEARS OF AGE AND OLDER

• Although most of the body’s growth has taken place by adulthood, adults do go through a wide range of physical changes as they grow older:

• Relatively large gains in weight;

• A reduced capacity to take in and utilize oxygen;

• An increase in blood pressure and resting heart rate;

• A weakening of stress-bearing joints, such as the knees and hips.

• The importance of regular exercise and paying attention to diet may be overlooked.

• With regular exercise, a healthy diet, and a positive outlook on life, most adults can enjoy the benefits of physical activity and healthy living well into old age.

Coaching Styles

• The coach’s role is to help manage various constraints, individual, environmental, and task, in order to benefit the athlete and optimize his or her performance.

• A coach must not only have a grasp of the context in which the athlete is performing, but also know the athlete as an individual as well as that person’s capabilities at any given time.

• Coaching style refers to the overall approach that a coach takes in training an athlete and the training methods he or she prefers.

• For example, a coach may be described as: “Authoritarian”, “Business-like”, “Nice Guy/Gal”,  “Intense,” or “Easy-Going”

Skeletal Age

Age as indicated by the physical maturity of the skeleton.

The Law of Inertia

“A body in motion tends to stay in motion and a body at rest tends to stay at rest unless acted upon by an external force.”

Law of Acceleration

“A force applied to an object causes an acceleration of that object of a magnitude proportional to the force and in the direction of the force, but inversely proportional to the object’s mass.” In other words, F = ma

The Law of Action-Reaction

“For every action, there is an equal and opposite reaction”

Newton's Laws

1. The Law of Inertia

2. Law of Acceleration

3. The Law of Action-Reaction:

Coaching Styles

• The coach’s role is to help manage various constraints, individual, environmental, and task, in order to benefit the athlete and optimize his or her performance.

• A coach must not only have a grasp of the context in which the athlete is performing, but also know the athlete as an individual as well as that person’s capabilities at any given time.

• Coaching style refers to the overall approach that a coach takes in training an athlete and the training methods he or she prefers.

• For example, a coach may be described as: “Authoritarian”, “Business-like”, “Nice Guy/Gal”,  “Intense,” or “Easy-Going”

Ergogenic Acids

• Are the various substances and techniques by means of which athletes attempt to improve their performance and recovery.

• Ergogenic aids fall into the following categories:

  • Nutritional aids and dietary supplements, e.g., vitamin and mineral supplements, energy drinks, protein supplements, caffeine

  • Pharmacological aids, e.g., anabolic steroids

  • Physiological aids, e.g., blood doping

  • Technological aids, e.g., performance-enhancing fabrics, materials, clothing, and equipment

Factors affecting physical growth and development

• Glandular and hormonal activity

• Heredity

• Nutrition and diet

• Physical activity

• Sociocultural factors

Jean Piaget Motor Learning Theory

• Piaget’s theory of cognitive development describes the ways in which children interpret and assimilate new experiences.

• Piaget’s theory laid out four stages of cognitive development in a progressive model. The four stages are:

  • The sensorimotor stage

  • The pre-operational stage

  • The concrete operational stage

  • The formal operational stage

The Sensorimotor Stage

• INFANCY (APPROXIMATELY BIRTH TO 2 YEARS OF AGE)

• This stage of cognitive development is characterized by an infant’s demonstration of intelligence by means of motor activity without the use of symbols.

• The later part of this sensorimotor stage is also characterized by the development of early language abilities.

Biomechanical Principle 1

• Stability

• “The greater the mass, the lower the centre of mass to the base of support, the larger the base

  of support, and the closer the centre of mass is positioned to the base of support, the more stability increases.”

Biomechanical Principle 2

THE PRODUCTION OF MAXIMUM FORCE

• “The production of maximum force requires the use of all possible joint movements that contribute to the task’s objective.” When people lift heavy objects, or perform other such tasks, they must make slow, controlled, and simultaneous high-intensity movements.

• These movements are best produced by sequenced joint rotations.

• If the full joint range of motion (ROM) is restricted at any one of the joints involved in the movement, perhaps due to injury or disease (e.g., arthritis), fewer muscles are able to contribute to the movement and therefore less force is produced.

Example of Principle 2 in Action

When we attempt to run as fast as we can, we are demonstrating biomechanical principle 2.

• When we run, we necessarily rely on joint rotation at the ankle, knee, and hip joints.

• Full rotation at each joint is achieved through the contraction of multiple muscles.

• These movements begin at the ankles and are followed by similar sequenced joint rotations at

 the knees and hips.

Another example of biomechanical principle 2 is the awkward action of a four-year-old T.ball player’s swing of a bat (with that of a professional baseball player).

• A young T-ball player will often stand very upright, with feet planted, and swing the bat using only the arms to make contact with the ball.

• The player has the potential to use more joints during the swing, but may not do so due to lack of experience.

• Over time, with practice and good coaching, the T-baller will become more proficient at this task.

Biomechanical Principle 3

PRODUCTION OF MAXIMUM VELOCITY

“The production of maximum velocity requires the use of joints in order—from largest to smallest.”

Activities requiring the production of maximum velocity (e.g., tennis serve, golfing, or pitching a baseball) are performed most successfully if the larger, slower joints begin the movement, and the smaller joints come into action later.

Example of Principle 3 in Action

When a baseball is thrown, the player’s joint actions are sequenced.

• Joint movement in the legs is followed closely by rotation of the hips.

• Rotation of the hips is followed by rotations of the arms, the elbows, and the wrists.

• By engaging more muscles and joints in a pitching motion, and sequencing them correctly, a professional baseball pitcher is able to generate maximum velocity. 

Sequencing of joint rotation is particularly important when performing activities in which an object is being thrown or being struck by an implement.

• For example, a fly fisher can cast her line more effectively by using sequenced joint rotations.

• She first rotates at the trunk, followed by the shoulder, then the elbow, and finally the wrist.

• If her movements are sequenced correctly, the fly fisher will be able to cast her line with the attached fly a fair distance downstream

Biomechanical Principle 4

THE IMPULSE-MOMENTUM RELATIONSHIP

“The greater the applied impulse, the greater the increase in velocity.” When an object such as a cricket ball, field hockey ball, or tennis ball is in motion, it is said to have momentum. The momentum of the ball or any other object in motion is equal to its mass multiplied by its velocity.

• To get a ball moving, a cricket, field hockey, or tennis player will use a striking implement to apply a pushing force to the ball over a period of time.

• The greater the pushing force, and the greater the amount of time over which it is applied to the ball, the greater the impulse. This is a restatement of biomechanical principle 4.

Example of Principle 4 in Action

Elite athletes and their coaches often rely on biomechanical principle 4 to improve their techniques and performance.

• For example, today’s high jumpers commonly use a technique called the Fosbury Flop.

• As jumpers near the bar, they arch their neck and back and push against the ground to create a powerful impulse force.

• An equal and opposite ground reaction force is generated, which propels the high jumper into the air.

The “jump serve” in volleyball provides another good example of biomechanical principle 4.

• Players begin well back behind the service line, lob the ball forward, and run and jump into tht air in order to “spike” the ball to the opposing team.

• The forward running motion of the server’s body transfers momentum to the ball, making it move through the air at a high velocity.

• This increase in velocity, combined with a high flight path, makes it difficult for the ball to be returned by the opposing team.

Biomechanical Principle 5

THE DIRECTION OF APPLICATION OF THE APPLIED FORCE

“Movement usually occurs in the direction opposite that of the applied force.”

The fifth biomechanical principle is closely related to Newton’s third law of motion, which

states that for every action there is an equal and opposite reaction.

• People at work and at play rely on this principle constantly.

• For example, when a person sitting in an armchair stands up, the individual will place his or her hands on the armrests and push down. A reaction force that is equal in magnitude but opposite in direction will be generated by the chair arms.

Principle 5 and Aquatic Events

Biomechanical principle 5 is evident in many aquatic events.

• When completing a length of a pool, for example, free-style swimmers turn and push against the wall of the pool with their legs.

• The swimmers’ bodies are propelled forward—in the direction opposite that of the applied force.

Example of Principle 5 in Action

Biomechanical principle 5 can be seen in action in many team sports.

• In making a cut, for example, an ultimate player or a soccer player will push his or her foot against the ground to make a change in direction away from an opponent.

• Similarly, an ice hockey player will push off using the edge of the skate blade to make the same type of movement to either avoid a hit or make one.

Biomechanical principle 5 can be seen in action in many team sports.

In making a cut, for example, an ultimate player or a soccer player will push his or her foot against the ground to make a change in direction away from an opponent.

• Similarly, an ice hockey player will push off using the edge of the skate blade to make the same type of movement to either avoid a hit or make one.