Muscle action analysis
Open your materials, follow the steps, then turn in your work.
Analyze agonist and antagonist muscle pairs and revise your model labels.
1. Open your materials
Use the materials named in the first step below. Open lesson resources.
2. Start the work
Read the notes on agonist, antagonist, and synergist roles in movement.
Show all 5 required steps
- Read the notes on agonist, antagonist, and synergist roles in movement.
- Choose one joint movement and identify the agonist and antagonist muscles.
- Complete the PLTW online task on muscle pairing.
- Revise your Maniken labels to mark each muscle's role in one movement.
- Submit your agonist-antagonist analysis and revised labels.
Lost your place? Pick up where you left off: read the notes on agonist, antagonist, and synergist (step 1), choose one joint movement and name its agonist and antagonist (step 2), do the PLTW pairing task (step 3), revise your Maniken labels, then submit your analysis.
Check your work before submitting
- You can identify agonist and antagonist muscles for a movement.
- You can revise model labels to show muscle roles.
3. Turn in your work
DueCheck Schoology- Hand in
- Agonist-antagonist-synergist analysis for one chosen movement, plus a revised Maniken label card showing each muscle's role.
How to submit and name your file
Submit your analysis and revised label card as a single document or photo.
In Schoology, open your course and the assignment for this lesson. Attach your file, select Submit, and check that it appears in the submission.
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Check the section number beside Human Anatomy and Physiology in Schoology.
Assignment: Wk6 Lab notebook: Muscle action analysis
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How this lesson connects
Keep using what you learned last class: A muscle can only pull its insertion toward its origin, so the placement of those two points determines which bone moves and in which direction. Today: Because a muscle can only pull, controlled movement needs an agonist that contracts and an antagonist that relaxes, so the same pair swaps roles when the movement reverses.
Unit 1 guide: what to keep and use nextOptional: listen or watch a unit review▸
Need help? Warm-up, timing, and directions▸
💡 Big idea: Because a muscle can only pull, controlled movement needs an agonist that contracts and an antagonist that relaxes, so the same pair swaps roles when the movement reverses.
- 0-8Intro: agonist, antagonist, synergist definitions with elbow example
- 8-25Notes: muscle pairing logic and three roles
- 25-45PLTW online task: muscle pairing
- 45-62Choose one movement; identify agonist, antagonist, and synergist
- 62-75Revise Maniken label card to mark roles; submit revised photo or diagram
- 75-80Class share: which movements produced the most disagreement?
- • Yesterday you placed muscles. Today you explain how they cooperate. No muscle works alone.
- • For every movement, one muscle is the prime mover, another resists, and one or more stabilize the . Those roles have names.
- • You will pick one movement from your Maniken build and label every muscle involved by its role. Then you revise the Maniken labels to match.
- • This analysis is the kind of thinking physical therapists and athletic trainers use every day.
- • Agonist: the prime mover contracting to produce a specific movement. Antagonist: the muscle on the opposing side that relaxes and resists. Synergist: stabilizes the during the movement.
- • Classic pair: biceps brachii (agonist, elbow ) and triceps brachii (antagonist). Reversed for elbow extension.
- • Muscle imbalance between agonist and antagonist pairs is a common cause of overuse injury and movement dysfunction.
PLTW connection and today's work
Complete the agonist-and-antagonist analysis task in Activity 1.2.2 Makeup of a Muscle (Lesson 1.2 Muscles and Motion) on myPLTW; use it to check your model labels during the analysis window.
Today's stopping point: Maniken task is done; today the analysis task should show complete and your revised labels should be submitted.
PLTW activity titles identify the course connection. If your account will not open, use the posted materials for today and tell Mr. Mendoza. Do not mark an online activity complete unless you completed it.
Course connection
- Activity 1.2.2 Makeup of a Muscle
Use the turn-in directions at the top of this page. Do not create a second submission unless your teacher asks for one.
Show another explanation or a smaller first step
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Lesson resources: reading, slides, and vocabulary▸
The deck carries the prior idea forward, lets you inspect an analogy, maps the rule to biology, and ends with the same evidence decision and exit ticket used on this page.
Generated from this lesson's canonical data with a red-team citation check.
A muscle can only pull its toward its origin, so the placement of those two points determines which bone moves and in which direction.
Because a muscle can only pull, controlled movement needs an agonist that contracts and an antagonist that relaxes, so the same pair swaps roles when the movement reverses.
A research team lays out its question, variables, controls, sampling plan, measurement record, and analysis before deciding what the data support.
- Which variable is changed or compared?
- Which conditions and measurements must stay consistent?
- Which conclusion is inside the study's evidence boundary?
Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
A well-organized classroom study can still be limited by , measurement quality, confounding, and the population represented.
- • Question and variable cards map to the study design.
- • Control and measurement cards map to fair, reproducible data collection.
- • The conclusion card maps to a bounded claim supported by the analysis.
Driving question: When you bend your elbow, your biceps contracts, but what is the triceps doing at that exact moment, and why would a big strength gap between the two lead to overuse injury?
What you already know: A muscle can only pull its toward its origin, so the placement of those two points determines which bone moves and in which direction.
New idea: Because a muscle can only pull, controlled movement needs an agonist that contracts and an antagonist that relaxes, so the same pair swaps roles when the movement reverses.
Visual or model: F1. F1. A lesson illustration or teaching diagram for Muscle action analysis. Use it with E1-E3; it is a model or context image, not experimental or patient data. What to notice: Trace the labeled structure, movement, or system relationship that connects form to function.
- Observe or measure the relevant feature in muscle action analysis.
- Organize the observation with a stable evidence ID.
- Apply this rule: Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
- Choose the option the evidence supports and state the limit of the conclusion.
Real biomedical example: When you bend your elbow, your biceps contracts, but what is the triceps doing at that exact moment, and why would a big strength gap between the two lead to overuse injury?
What the evidence supports: E1-E3 and F1 support the daily take-home when the response meets the stated success criteria.
What it cannot prove: The package does not support claims beyond this lesson's or any real patient diagnosis.
- • : The basic contracting unit of a muscle fiber, made of overlapping and filaments that slide past each other to shorten the muscle.
- • : A that forms thin filaments inside cells and slides past to produce muscle and cell movement.
- • : A motor in muscle whose heads grab and pull on filaments, producing the sliding motion that contracts the muscle.
- • : The shortening of a muscle as its fibers pull together, generating force to move bones, pump blood, or squeeze organs.
- • : A tough band of that anchors a muscle to a bone, transferring the muscle's pull so the bone can move.
- • origin: The fixed, anchoring attachment point of a muscle on a bone, which stays still while the muscle pulls on its other end.
- • : The end of a skeletal muscle attached to the bone that moves when the muscle contracts, as opposed to the more fixed origin end.
- • lever: A rigid bar that pivots at a fixed point to move a load, the simple machine that bones, joints, and muscles form to create movement.
Use it now: Choose one decision option. Cite E1 and E3, then explain how the rule connects the evidence to your choice.
Go further, optional: The source links below are optional enrichment. Every fact required for today's local evidence decision appears in this lesson package.
Musculoskeletal function depends on the interaction of structure, force, joints, neural activation, and loading history, so one model or measurement captures only part of performance.
Limit: A classroom model or movement measure cannot diagnose an injury or prescribe .
Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
Limit: A well-organized classroom study can still be limited by , measurement quality, confounding, and the population represented.
You can identify agonist and antagonist muscles for a movement.
Limit: E3 defines the classroom product or success criterion. It is not independent scientific evidence and cannot justify a clinical or causal claim.
PLTW-HAP-2027-02-24 · Simulated classroom evidence scenario
Your role: anatomy and physiology consultant
Decision: Your team must decide what the evidence from muscle action analysis supports before submitting the notebook record named on today's page.
- • Label the biceps as the agonist and the triceps as the antagonist that relaxes to allow bending.
- • Show both muscles contracting hard at the same time, each pulling against the other during the movement.
- • Check which muscle stabilizes the first, because a synergist can look like the agonist here.
Response: State one choice, cite at least two evidence IDs, explain the rule that connects them, and add one limitation. Submit it as the notebook record.
Claim ceiling: Today's evidence supports a classroom claim about muscle action analysis. It cannot prove causation, diagnose a real patient, or justify action outside this room.
Rate or percent = part / comparison total x 100%. Percent change = (new - comparison) / comparison x 100%.
If 18 of 60 records meet a condition, the frequency is 18 / 60 x 100% = 30%.
Name the comparison total. A percent describes the supplied group and does not automatically predict an individual's outcome.
Use today's supplied counts to calculate one rate, risk, frequency, or percent change. Show the denominator and interpretation.
Students often think Students think the agonist and antagonist both contract hard at the same time, fighting each other during a movement.. The trap: They do not both contract fully. The agonist contracts to make the movement while the antagonist relaxes and lengthens to allow it. If both fully contracted at once, the would lock and no movement would happen. A synergist, separately, stabilizes the joint.
Chosen movement: bending the elbow (elbow flexion).
- Agonist (prime mover): biceps brachii. It contracts to flex the elbow.
- Antagonist: triceps brachii. It relaxes and lengthens to allow flexion; it would resist or reverse the movement.
- Synergist: brachialis. It assists the biceps and helps stabilize the elbow during flexion.
Reversed movement (elbow extension): the roles flip. The triceps becomes the agonist and the biceps becomes the antagonist.
Revised label card: I marked the biceps on my Maniken as AGONIST for flexion and the triceps as ANTAGONIST, and added a note that the labels swap for extension.
Why it matters: When the agonist and antagonist of a pair are unbalanced, the joint is more prone to overuse injury, which is why physical therapists train both sides of a pair.
This model shows the level of evidence and organization needed to complete: An analysis of one joint movement that names the agonist, antagonist, and synergist, plus a revised model label card showing each muscle's role in that movement.
- Date and label the entry.
- Record the procedure, observation, or design decision clearly.
- End with what the evidence means and the next step.
Keep the structure. Replace the question, facts, measurements, and evidence. Then recheck units, vocabulary, and whether the conclusion goes beyond the evidence.
Also due today: Submit your analysis and revised label card as a single document or photo.
- CER:
- Claim, Evidence, Reasoning: make a claim, back it with evidence, explain your reasoning.
- SOP:
- Standard Operating Procedure, the exact steps to follow (especially in a lab).
- Tracker:
- Your PLTW progress log where you record completed evidence.
- myPLTW:
- The PLTW course site where you do the online activities. Find it in Clever with your Microsoft sign-in, right next to Schoology.
Tap the speaker to hear a term. Add two of these to your notebook glossary with a definition and an example in your own words.
Pick just 2 or 3 words from today and make them yours: write what each one means in your own words, name the context clue or evidence that helped, then give one example from what you actually did in Muscle action analysis. Try your own words first; the glossary is there if you get stuck. This is voluntary and counts as extra credit, so keep it short.
Saved on this device. Show Mr. Mendoza or add these to your notebook glossary to claim the extra credit.
Hand-picked readings, videos, and interactives for this lesson, all free and from authoritative open organizations (NIH, CDC, OpenStax, Khan Academy, PhET, HHMI, and more).
A fillable, Cornell-style notebook for Unit 1: Road to Rehabilitation. Type your notes, cues, and summaries right in the PDF, or print it and write by hand. Each lesson page has a cue column, a notes column, and a summary box, plus dated lab-record pages you can turn in.
HBS Unit 1 notebook: Road to Rehabilitation Fillable PDFCornell notes + lab recordsOpenVetted readings and references for this unit. Use them to prepare, to catch up if you were absent, or to go deeper on today's target.
Practice: try a question, then check your answer▸
Claim ceiling for this check: Today's evidence supports a classroom claim about muscle action analysis. It cannot prove causation, diagnose a real patient, or justify action outside this room.
During elbow flexion (bending the arm), name the agonist and the antagonist, and state what each one is doing.
Write an answer and pick a confidence to unlock the key.
Fast retrieval with instant answers, not the commit-then-reveal check above. Try each from memory first: write what you remember about the earlier units, then check yourself here.
Missed class or ready for more?▸
Run this before you touch the bench. It is built from the real lab procedure, so the decisions you make here are the ones you will make with the equipment in your hands. This lesson has more than one, and they cover different skills.
What today's skills lead to. These are real health-science careers this course builds toward. Tap one to see, on the US Department of Labor's O*NET site, what the job actually involves, what it pays, and how fast it is growing.
Today is individual work you can do from home: complete the same target above, then submit your Notebook check.
Go to Schoology to turn this in. Submit one PDF. Put your first and last name in the document header. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf. If you cannot get in, see Mr. Mendoza. Do not skip the work.
Class still runs. Complete the online activity above (it's self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
Khan Academy: Muscular System- CompleteEvery required part of the artifact is present, nothing left blank.
- AccurateThe science and the data are correct and match the evidence.
- Scientific reasoningYou explain your claim with evidence and reasoning (CER), not just an answer.
- Professional communicationClear, organized, labeled, and written the way a clinician or scientist would.
- SubmittedGo to Schoology to turn this in. Submit one PDF. Put your first and last name in the document header. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf. If you cannot get in, see Mr. Mendoza. Do not skip the work.
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