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SYLLABUS CONTENT
How do the systems of the body influence and respond to movement?
Explain the interrelationship between the skeletal and muscular systems and movement
Including:
structure and function
major bones and synovial joints
joint actions
major muscles
characteristics and functions of muscle fibres
types of muscle contractions
muscle relationship
THE MUSCULAR SYSTEM:
STRUCTURE AND FUNCTION
The muscular system is composed of over 600 muscles. It includes skeletal muscles for voluntary actions, smooth muscles (involuntary) for organ function, and cardiac muscle (involuntary) for heart contractions.
It has six main functions:
Movement
Posture and Stability
Heat Production
Circulation
Respiration
Digestion
ACTIVITY: Muscle Match-Up
In this activity, you will explore the three types of muscles (smooth, cardiac and skeletal) by actively participating in a matching game.
Instructions:
As I call out clues about muscle functions or locations, quickly move to one of the three designated areas in the room that represent each muscle type. You have 10 seconds to decide and stand by the correct muscle type — whether it’s skeletal muscle that moves bones, cardiac muscle that pumps blood, or smooth muscle that controls organ functions. After each round, we will discuss why the chosen muscle type is correct.
ACTIVITY - MAJOR MUSCLES
Use the post it notes to write down all the muscles listed in the photo. When you are finished, place the labels where you believe the muscles are on your own body. A prize will be on offer for the student who gets the most correct!
ACTIVITY - MAJOR MUSCLES
As a class we will go through the muscles on the image carousel. As we explore them, add them correctly to the labelling sheet.
As a visual tool, colour in the label and the muscle's location on the body to create a pair.
Anterior view
Posterior view
Completed diagram
Completed diagram
Using the completed diagram, fill in any gaps and correct any errors.
Now Practice!
Using the links, learn the names of the major bones through games and repetition.
ORIGIN AND INSERTION
Skeletal muscle is striated (appearing as stripes), which reflects its structure and function. Most skeletal muscles have two points of attachment via tendons, known as the muscle origin and muscle insertion. Muscles can only contract and pull along the direction of the muscle fibers, moving the insertion point towards the origin.
Muscle Origin - The attachment site that connects the muscle to a bone. This point is typically proximal to the body and does not move during contraction.
Muscle Insertion - The attachment site that connects the muscle to a bone. This point is typically distal to the body and moves during contraction.
In the image, the origin of the biceps brachii is the scapula, with the insertion on the radius in the forearm. Therefore, this muscle primarily produces elbow flexion when it contracts, as seen in a bicep curl.
ACTIVITY- Muscles in Motion
Watch the following video to further explore the concept of Origin and Insertion.
ACTIVITY - Muscles in Motion
Create a table like the one modelled. Choose 5 major muscles involved in movement and research their origin, insertion and joint action produced.
BUILD YOUR KNOWLEDGE
Watch the following video and read through pages 182-183 of the Cambridge textbook to further your understanding of muscle fibres, the sliding filament theory and muscular contractions.
Now Practice!
Using the links, learn the key anatomical parts of a muscle, through games and repetition.
Fast and Slow Twitch Fibres
Now that we understand the structure of muscles, we can explore the different types of muscle fibres that make up muscle tissue. These fibres are classified into two main types: fast-twitch and slow-twitch. Every athlete has a genetic predisposition toward a particular ratio of these fibres, which influences their physical abilities, such as whether they are naturally better suited for speed or endurance activities.
There are three types of muscle fibres:
Slow Twitch Fibres (Type 1) - These fibers are designed for endurance activities. They contract slowly but are highly resistant to fatigue. Using oxygen efficiently, they rely on aerobic energy systems, making them ideal for sustained, low-intensity activities like long-distance running or cycling. Although they produce less force, they have greater endurance. Their red color is due to a high capillary network, abundant mitochondria, and a high myoglobin content, all of which support efficient oxygen delivery and energy production. Each fiber contains multiple nuclei, aiding in their endurance capabilities and ability to maintain prolonged activity.
Fast Twitch Oxidative Fibres (Type 2A) - These fibers are designed for both speed and endurance. They contract quickly and generate more force than slow-twitch fibers but are more fatigue-resistant than pure fast-twitch fibers. Type IIa fibers rely on both aerobic and anaerobic energy systems, making them ideal for activities like middle-distance running or swimming. Their pink color results from a moderate capillary network, mitochondria, and myoglobin content, which helps them use oxygen efficiently. Each fiber typically contains multiple nuclei, supporting their ability to adapt to different types of training and generate power.
Fast Twitch Glycolytic Fibres (Type 2B) - These fibres are built for explosive power and speed. They contract very quickly and generate the most force but fatigue rapidly. These fibers rely on anaerobic energy systems, using glycogen as their main fuel source, and have low myoglobin content, giving them a pale, white color. With fewer capillaries, mitochondria, and a single nucleus per fiber, they have limited endurance, making them ideal for short, high-intensity activities like sprinting or weightlifting.
DEPTH STUDY ONE: Muscle Fibres and Energy Systems
We will be exploring these concepts in greater depth through our first group depth study. Click on the button below, which will take you to the landing page.
MUSCLE CONTRACTIONS
There are two major types of muscle contractions that produce force: one that involves movement and one that is stationary. These are known as isotonic and isometric contractions.
Isotonic contractions
Isotonic contractions occur when the muscle length changes as it contracts, producing movement. The load or resistance remains the same (e.g., a 10 kg bicep curl). There are two phases in an isotonic contraction: concentric (when the muscle shortens) and eccentric (when the muscle lengthens).
Concentric
Concentric
When the muscle exerts a force and shortens in length. An example of this is when the biceps contracts causing flexion to occur at the elbow.
Eccentric
Eccentric
When the muscle produces a force but increases in its length. For example, the down phase of a bench press, the pectoralis major lengthens.
Isometric contractions
Isometric contractions occur when the muscle length does not change, but the muscle is still contracted and under tension. These stationary movements are used to build endurance, improve postural strength, and target specific 'weak points' of a movement, such as the bottom of a squat. Examples include a plank, wall sit, dead hang, or holding a bicep curl at a 90° angle.
MUSCLE ACTIONS
Muscle relationships refer to how muscles work together to create movement. A skeletal muscle attaches to one bone, extends across a joint, and attaches to another bone. The muscle involved in producing movement can play three key roles. Most movements require several muscles working together in unison, and most skeletal muscles are therefore arranged in opposing pairs.
Agonist (Prime Mover) - The muscle that is primarily responsible for producing a specific movement. It contracts to create the desired action. Example: During a bicep curl, the biceps brachii acts as the agonist.
Antagonist - The muscle that opposes the action of the agonist. It lengthens and relaxes as the agonist contracts. Example: In a bicep curl, the triceps brachii is the antagonist, as it lengthens while the biceps contract.
Stabiliser (Fixator) - Muscles that contract to hold a joint or body part in place, ensuring stability during movement. They support the agonist by preventing unwanted movement. Example: When performing a bicep curl, the muscles around the shoulder joint act as stabilizers to keep the arm steady.
WRITING TASK - RESPONSE WRITING
WRITING TASK - RESPONSE WRITING
CUBE the following question. Then, use your verb sheet and ALARM matrix to formulate a response:
Explain the interrelationship between the skeletal and muscular systems when producing movement. 5 marks
WRITING TASK - GLUE
WRITING TASK - GLUE
Assess your response by applying the GLUE method. Highlight the following:
Green - Specific verb requirements/language
Pink - Links to the question
Orange - Syllabus-specific content
Yellow - Examples
Award yourself a mark out of 5.
Annotate what you did well and areas for improvement.
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