Muscle Movement Mechanics

Overview

This is Lesson 2 of 4 in the unit Muscle Mechanics Unleashed for Year 7 students (age 11-12). Building on students’ prior understanding of muscle types and basic functions, this lesson explores how muscles contract and relax to create movement, with a focus on antagonistic muscle pairs. The lesson provides hands-on activities that help pupils internalise these concepts through models and movement investigations.

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National Curriculum Links (England)

• Programme of Study: Key Stage 3 – Science
  Biology – Human Nutrition and Movement
  Pupils should be taught to:

  • Describe the skeletal and muscular systems as essential for movement (KS3 Biology QCA Unit B3)
  • Explain how muscles work in antagonistic pairs to create movement (KS3 Biology B3)
  • Understand the mechanical action of muscles contracting and relaxing (QCA Unit B3)

• Working Scientifically
  • Plan and carry out simple practical enquiries, recognising and controlling variables where necessary
  • Interpret observations and data, including identifying patterns and causal relationships

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Learning Objectives

By the end of this 60-minute lesson, all students will be able to:

• Describe how muscles contract and relax to produce movement.
• Identify examples of antagonistic muscle pairs in the human body.
• Model muscle action using hands-on materials (rubber bands and cardboard).
• Explain how antagonistic muscles work together to control movement.

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Resources Needed

• Printed diagrams of upper limb muscles (biceps and triceps)
• Rubber bands (various sizes) – 1 per student group
• Cardboard strips or rulers
• Scissors, sticky tape
• Whiteboard and markers
• Student exercise books
• Stopwatch or timer

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Lesson Structure

1. Starter (5 minutes)

Engage with Movement: “What Moves Your Arm?”

• Ask students to hold their arm out straight and then bend their elbow.
• Prompt: “Which muscles do you think are working to make your arm bend?”
• Show a labelled diagram of the upper arm muscles (biceps and triceps).
• Recap from Lesson 1 about voluntary muscles used in movement.

2. Introduction: Muscle Mechanics (10 minutes)

Teacher Explanation with Diagram

• Briefly explain the concepts of muscle contraction and relaxation in simple terms:
  Muscles can only pull, never push.
• Introduce antagonistic pairs — one muscle contracts while its pair relaxes to move a joint.
• Use the diagram to demonstrate how the biceps contract to bend the elbow, while triceps relax, then vice versa.

Scientific Vocabulary: contraction, relaxation, antagonistic pairs, joint

3. Activity 1: Rubber Band Muscle Models (20 minutes)

Objective: Model muscle contraction and antagonistic muscle action.

Instructions:

• In groups of 3-4, students use two rubber bands to represent antagonistic muscles attached to cardboard “bones” (strips or rulers).
• One rubber band represents ‘biceps’, the other ‘triceps’.
• When one rubber band is stretched (contracts), the other loosens (relaxes).
• Groups experiment by ‘moving’ their model joint back and forth and observe the opposing actions.
• Students draw and annotate a labelled diagram of their model in their exercise books, describing how the model demonstrates antagonistic action.

Teacher notes: Circulate to check understanding, prompt with questions: What happens to one rubber band when the other is pulled? How does this relate to real muscles?

4. Activity 2: Investigating Antagonistic Pairs in the Body (10 minutes)

• In pairs, students perform simple exercises to feel muscles working antagonistically (e.g., bending and straightening the elbow).
• They use their hands to feel their biceps and triceps contracting and relaxing.
• Students then list other antagonistic pairs in the body (e.g., quadriceps and hamstrings).
• Quick discussion as a class to share findings.

5. Plenary: Recap and Reflect (10 minutes)

• Students complete a short quiz on mini whiteboards or in books answering:
  • What does it mean that muscles work in antagonistic pairs?
  • Why can muscles only pull, not push?
  • Describe what happens when you bend your elbow in terms of muscle action.
• Teacher-led discussion summarising key learning points and addressing misconceptions.

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Assessment and Feedback

• Formative: Observation during activities (do students understand antagonistic muscle action?).
• Written: Annotated diagrams from Activity 1.
• Quiz Responses: Used in plenary for instant feedback.
• Teacher questioning throughout to probe understanding and extend learning where applicable.

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Differentiation

• Support: Provide simplified diagrams and step-by-step instructions for model building; pair with supportive peers.
• Challenge: Extend learning by asking how muscle diseases might affect movement or what other joints have antagonistic muscles; introduce terminology like 'flexors' and 'extensors'.

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Cross-curricular Links and SMSC

• Physical Education: Understanding the science behind muscle movement complements practical sports activities.
• Personal Development: Awareness of how the body works encourages healthy lifestyle choices and body positivity.
• Cultural Studies: Discussion of how different activities use different muscle groups.

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Teacher Reflection

After the lesson, consider how well students engaged with the model building and whether the hands-on approach helped clarify the concept of antagonistic muscle action. Adjust for next lessons by incorporating more interactive simulations or digital animations if needed.

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This lesson actively engages students in constructing knowledge through kinaesthetic and visual learning, reinforcing scientific concepts consistent with the National Curriculum for England.