Muscle fatigue and EMG basics
Explain muscle fatigue and how EMG measures electrical muscle activity.
Labeled prediction sketch of an EMG trace across repeated trials showing fatigue onset, plus a written fatigue-mechanism summary.
- 1Do thisExplain muscle fatigue and how EMG measures electrical muscle activity.
- 2Use this resource
- 3Submit thisPre-lab: Labeled prediction sketch of an EMG trace across repeated trials showing fatigue onset, plus a written fatigue-mechanism summary.
- 4Submit it here
- 1CMSD website. Go to clevelandmetroschools.org and click the Clever button.
- 2Clever. Clever opens. Sign in if it asks.
- 3Microsoft (district) login. Use your district Microsoft account (the one for school).
- 4Schoology. Open Schoology, then your class, then Assignments, and find the file named below.
The file to submit is named: Human Anatomy & Physiology (Human Body Systems) › Unit 1.2 Motion Data: Muscle strength, fatigue, physiology sensors, range of motion, joint testing, kinesiology taping. › Pre-labOpen Schoology
- 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 — you open it through Schoology.
Minute-by-minute · 80-minute block
💡 Big idea: EMG records the electrical activity of motor units during contraction; fatigue appears as a change in signal amplitude and frequency over repeated contractions.
- 0-8Intro: what EMG actually measures and its units
- 8-25Notes: muscle fatigue mechanisms and EMG signal interpretation
- 25-45PLTW online task: EMG and fatigue
- 45-62Draw and label predicted EMG trace for a fatiguing muscle
- 62-75Write fatigue-mechanism summary (3-4 sentences)
- 75-80Submit prediction trace and summary; preview Wednesday lab
- • Tomorrow you put sensors on your body and collect real EMG data. Today we learn what the signal means so you can interpret what you collect.
- • EMG stands for electromyography. It records the electrical storm that happens inside a muscle every time a motor neuron fires.
- • Fatigue is not just weakness. It is a specific physiological process. By the end of class you will be able to predict what a fatiguing EMG trace looks like before you ever see one.
- • Your prediction sketch is an artifact. Make it labeled and specific.
- 1Read the notes on muscle fatigue and the causes of declining force over time.
- 2Learn what an electromyography (EMG) signal represents and its units.
- 3Complete the PLTW online task on EMG and fatigue.
- 4Predict how an EMG trace should change as a muscle tires.
- 5Submit your fatigue summary and labeled prediction of an EMG trace.
- • You can explain what causes muscle fatigue.
- • You can describe what an EMG signal measures.
- • Electromyography (EMG) measures the electrical potentials generated by muscle fibers when a motor neuron fires. Signal is measured in millivolts (mV).
- • Muscle fatigue results from depletion of ATP and phosphocreatine, lactic acid accumulation, and failure of neuromuscular transmission with repeated contractions.
- • A fatiguing EMG trace typically shows increased amplitude and decreased frequency as the nervous system recruits more motor units to maintain force.
Your PLTW work today
Unit 1.2 Motion Data: Muscle strength, fatigue, physiology sensors, range of motion, joint testing, kinesiology taping. · Muscle fatigue and EMG basics
Day 2 of this lesson. Open this exact section in myPLTW (reached through Schoology), then do the work below.
Do this: Complete the muscle-fatigue and EMG basics task in Lesson 1.2 Muscles and Motion on myPLTW; work through all screens on electrical muscle activity.
Mark the EMG task complete after submitting your fatigue explanation and labeled EMG diagram.
Introductory task is done; today the EMG task should show complete.
myPLTW completion status plus your submitted notebook entry.
All PLTW activities are completed inside the PLTW course environment — this page only gives direction. Submit producibles on Schoology.
Today's PLTW tracker
Check things off as you work, then submit. This tells Mr. Mendoza how you're doing so he can help the class. It does not replace turning in your producible on Schoology.
Use the code Mr. Mendoza gave you, not your name. Saved on this device.
Unit 1.2 Motion Data: Muscle strength, fatigue, physiology sensors, range of motion, joint testing, kinesiology taping. · Muscle fatigue and EMG basics
Complete the muscle-fatigue and EMG basics task in Lesson 1.2 Muscles and Motion on myPLTW; work through all screens on electrical muscle activity.
Introductory task is done; today the EMG task should show complete.
This is how Mr. Mendoza sees the class keeping pace with PLTW. Be honest, it only helps if it is accurate.
🎯 Explain muscle fatigue and how EMG measures electrical muscle activity.
- Read the notes on muscle fatigue and the causes of declining force over time.
- Learn what an electromyography (EMG) signal represents and its units.
- Complete the PLTW online task on EMG and fatigue.
- Predict how an EMG trace should change as a muscle tires.
- Submit your fatigue summary and labeled prediction of an EMG trace.
Pre-lab: Labeled prediction sketch of an EMG trace across repeated trials showing fatigue onset, plus a written fatigue-mechanism summary.
Submit on SchoologyUpload by 11:29 PM for full credit.
| Task | Who |
|---|---|
| Read the notes on muscle fatigue and the causes of declining force over time. | _______ |
| Learn what an electromyography (EMG) signal represents and its units. | _______ |
| Complete the PLTW online task on EMG and fatigue. | _______ |
| Predict how an EMG trace should change as a muscle tires. | _______ |
| Submit your fatigue summary and labeled prediction of an EMG trace. | _______ |
Working solo? Put your own name in "Who" for every row.
- You can explain what causes muscle fatigue.
- You can describe what an EMG signal measures.
Resources & readings
Vetted 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.
Lab & supplies
This unit's vocabulary
Tap the speaker to hear a term. Weekly vocabulary task: add two of these terms to your notebook glossary with a definition and an example in your own words.
WebXam practice
Cumulative WebXam review
A quick mixed-review pulling questions from earlier units plus today, so the WebXam material stays fresh.
Where this leads — careers
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.
What to do if you were absent
Today is individual PLTW work, so do exactly what we did in class, from home: complete the same PLTW target above, then submit your Pre-lab.
Open Schoology (CMSD) and keep goingHow to get there: open the CMSD website, click Clever, sign in with your Microsoft (district) account, then open Schoology from Clever.
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: Joints and Movement- 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.
- SubmittedTurned in the right way (Schoology for routine work) and confirmed.
Drop your Wed, Sep 23, 2026 · Muscle fatigue and EMG basics here. Use a clear file name (your initials + project). Routine work still goes to Schoology (via the CMSD portal).
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