Muscle Contraction and Energy Systems Overview

Fulcrum

The pivot point

Load in a lever system

The object being moved

Isometric contraction

The muscle length stays the same.

Concentric contraction

The muscle shortens.

Isometric

Length stays constant

Concentric

Muscle shortens.

Eccentric

Muscle lengthens.

Origin of a muscle

The end attached to the bone that is relatively fixed.

Insertion of a muscle

The movable attachment.

Steps in the mechanics of movement

1️⃣ Torque developed in muscle

2️⃣ Tendon transfers through joint

3️⃣ Tendon pulls on bone

4️⃣ Bone pulls loaded object

5️⃣ Movement occurs.

Slow twitch muscle fibres

Are anaerobic and fatigue quickly.

Fast twitch muscle fibres

Best suited for short-duration, high-power activities.

Skull

Protects the brain.

Rib cage

Protects vital organs.

Vertebral column

Supports the body.

Sternum

Joins the rib cage.

Appendicular skeleton

Includes the limb bones, pectoral girdle, pelvic girdle, and shoulder.

Medial

Refers to a position closer to the midline of the body.

Abduction

Movement away from midline.

Flexion

Decreasing the angle of a joint.

Extension

Increasing the angle of a joint.

Rotation

Movement around an axis.

Agonist

The muscle primarily responsible for producing force.

All-or-nothing principle

Full contraction or none.

Type 1 muscle fibres

Are recruited before type 2 fibres.

Fixed joint

An immovable joint found in the skull.

Synovial joints

Are freely moveable.

Hinge joint

Example: Elbow.

Pivot joint

Example: Neck.

Ball & Socket joint

Example: Hip.

Saddle joint

Example: Thumb.

Benefits of aerobic exercise

Improves cardiovascular health.

Reduced training

Allows the body to recover from intense periods of exercise.

Creatine

A non-essential nutrient used to improve recovery in high-intensity activities.

Sodium bicarbonate

Improves performance in high-intensity exercise by delaying onset of fatigue.

Criteria for a substance to be prohibited by WADA

1️⃣ Enhances performance

2️⃣ Poses a health risk

3️⃣ Violates the spirit of sport.

Stimulants

Increased heart rate.

Narcotics

Masks pain.

Peptide Hormones

Stimulates hormone production.

Glucocorticoids

Reduces inflammation.

Supplements

Used to enhance athletic performance and promote general health.

Cultural consideration regarding performance-enhancing drugs

Moral or religious beliefs.

Drugs

Chemicals that change the body's functions.

Acute injury

Occurs suddenly without warning.

Chronic injury

Develops over a long period.

Fracture

Break in a bone.

Sprain

Tear of ligaments.

Osteoporosis

Caused by a decrease in bone mineral density.

Steps in a warm-up

1️⃣ Increase heart rate

2️⃣ Increase breathing rate

3️⃣ Increase blood flow

4️⃣ Raise body temperature

5️⃣ Perform dynamic stretches

Benefits of a warm-up for injury prevention

Reduces risk of injury

Cool-down

A cool-down helps the body return to its pre-exercise state

Intrinsic factors in musculoskeletal injuries

False

Poor posture

Increases strain on joints

Joint mobility

Limits range of motion

Muscle weakness

Reduces force production

Overuse in the context of musculoskeletal injuries

Repetitive stress on muscles

Taping

The application of tape to an injured area to provide support

BANIP

Blood flow, Agility, Neuromuscular activation, Injury Prevention, Performance

Musculoskeletal injuries causes

Musculoskeletal injuries can be caused by both intrinsic and extrinsic factors

Intrinsic factors related to musculoskeletal injuries

False

Body composition

Excess body fat

Extrinsic factors related to musculoskeletal injuries

Can be changed or avoided

Factors related to overuse injuries

1️⃣ Poor technique

2️⃣ Intense nature of the activity

3️⃣ Insufficient recovery

4️⃣ Inappropriate training methods

Primary cause of overuse injuries

Repetitive stress

Proprioception

The awareness of body position.

Taping benefits

Taping is used to provide support, stability, or compression

Bracing benefits

Support ↔️ Limits range of motion

Stability ↔️ Allows for earlier return to sport

Compression ↔️ Reduces pain

Common benefit of both taping and bracing

Reduces risk of re-injury

Pulmonary circuit

Pumps blood to the lungs

Heart function

The heart pumps blood to the lungs and then back to the body in a continuous cycle.

Systolic pressure

Pressure when heart contracts

Homeostasis

Maintains the body core temperature within a small range.

Upper limit for body core temperature

38°C

Functions of blood

Transportation ↔️ Carries oxygen and nutrients

Protection ↔️ Fights against pathogens

Regulation ↔️ Maintains pH balance

Primary role of red blood cells (RBCs)

Carry oxygen

Plasma

Contains fibrinogen, which helps blood to stop clotting

Stroke volume

Blood ejected per beat

Cardiac output

Calculated by multiplying stroke volume and heart rate.

Vasodilation

Occurs when blood vessels widen

Arteries

Carry oxygen-rich blood away from the heart, except for the pulmonary artery.

Type of blood veins carry

Carry deoxygenated blood back to the heart.

Inspiration Steps

1️⃣ Diaphragm contracts and moves downwards; 2️⃣ External intercostal muscles contract; 3️⃣ Rib cage moves upwards and outwards; 4️⃣ Volume of chest cavity increases; 5️⃣ Pressure in lungs decreases; 6️⃣ Air flows into the lungs.

Expiration Process

During expiration, the diaphragm relaxes and moves upwards.

Typical Resting Heart Rate

60-80 bpm.

Stroke Volume During Exercise

During exercise, stroke volume increases.

Cardiac Output Calculation

Increased cardiac output during exercise is calculated by multiplying stroke volume and heart rate.

Blood Flow Redirection During Exercise

Working muscles.

Ventilation During Exercise

During exercise, ventilation increases due to an increase in breathing rate and tidal volume.

VO₂ Max Measurement

Oxygen the body can utilise.

Altitude Training Benefit

Altitude training can improve performance by increasing oxygen availability in the muscles.

Prohibited Substances in Sports

Blood doping, steroids.

Genetic Manipulation in Sports

Genetic manipulation, which alters genes to enhance performance, is a prohibited method.

Energy Requirement for Muscle Contraction

Energy.

Digestion Definition

Digestion is the body's way of breaking down food into nutrients.

Sources of Fuel Energy

Carbohydrates, fats, and proteins are the only sources of fuel energy for the body.

Excess Carbohydrate Storage

As glycogen.

Fatty Acids Storage

Fatty acids are stored in the body as triglycerides.

Preferred Fuel During Exercise

Carbohydrates are the body's preferred source of fuel during exercise.

Insulin Function

What hormone regulates blood glucose levels by allowing glucose to enter the muscle? Insulin.

Liver Glycogen Importance

Liver glycogen is important for sustained aerobic activity.