Students will explore how skeletal muscle contraction during exercise, identify major muscle groups, and reflect on their function through guided slides, journaling, and a quick quiz.
This lesson builds foundational understanding of muscle mechanics, empowering students to make informed choices about physical activity and body awareness, and boosting engagement through self-paced exploration and reflection.
Audience
8th Grade Students
Time
20 minutes
Approach
Self-paced slides, guided journaling, and formative quiz.
Student completes a matching exercise pairing muscle names with their functions or images.
Monitor pacing and offer clarifications as needed.
Collect quiz for immediate review.
Step 5
Closure & Reflection
2 minutes
Review one or two quiz responses together, correcting misconceptions.
Ask: "What surprised you most about muscle mechanics today?"
Encourage the student to set one personal fitness goal based on what they learned.
Slide Deck
Inside Your Muscles
• Understand how muscles contract
• Identify major muscle groups
• Explore tendon connections
• Reflect on muscle function during activity
Welcome the student and introduce the lesson: “Today we’ll go Inside Your Muscles to see how they work when you move.” Read the objectives aloud and prompt the student: “What do you already know about how your muscles help you move?”
Explain that muscles contract at the microscopic level through a process called the cross-bridge cycle. Play the animation and ask the student to watch how actin and myosin filaments slide past each other. Pause at key moments to point out sarcomere shortening.
Major Muscle Groups
Image: Illustration with labeled muscles
• Biceps (front of upper arm)
• Triceps (back of upper arm)
• Quadriceps (front of thigh)
• Hamstrings (back of thigh)
• Gluteals (buttocks)
• Deltoids (shoulder)
Display the labeled muscle diagram. Point to each group and have the student name it. Ask: “When you do a bicep curl, which muscle are you using? What about when you stand up from a chair—what muscle in your legs is powering you?”
Tendon & Muscle Connection
• Tendons are strong, fibrous tissues
• They attach muscle to bone
• They transmit the force generated by muscle contraction
Introduce tendons as the connectors between muscle and bone. Emphasize how tendons transmit force so the bone can move. You might have the student gently pull on a thick rubber band to simulate tendon tension.
Summary & Reflection
Key Takeaways:
• Muscle fibers contract via cross-bridge cycling
• Major muscle groups power different movements
• Tendons transmit force to bones
Reflection Question:
What surprised you most about how your muscles work, and why?
Review the four main points verbally: contraction, muscle groups, tendons, and force transmission. Then display the reflection question. Encourage the student to speak or jot down their answer before moving on to journaling.
Journal
My Muscle Map
Use the blank muscle diagram (provided) to complete the parts below. Feel free to sketch, color-code, or annotate your map as you work!
Part 1: Label Your Muscles
List and label the following major muscle groups on your diagram:
Biceps
Triceps
Quadriceps
Hamstrings
Gluteals
Deltoids
Part 2: Reflect & Sketch
Which muscle engages most during your favorite activity, and why?
Describe how tendons and muscles work together to create movement. You may include a small, labeled sketch below or on your diagram.
Optional: On a new or the same diagram, highlight and color the muscle group you find most interesting. Add a brief note explaining your choice.
Part 3: Personal Goal
Based on what you’ve learned today, set one personal fitness goal that involves applying your new understanding of muscle mechanics.
