Objectives•Measure the rate at which muscles tire during exercise

•Plot and analyze data about muscle fatigue on a graph

•Identify the parts of a neuron and the functions of the nervous system

BellworkWhat is muscle fatigue? What causes muscles to become fatigued?

(demonstrate muscle fatigue by having students hold arms in T position with books in hands)

Lesson 21Exploring Muscle Fatigue

Problem

What happens to muscles when they are used continuously for a period of time?

Hypothesis

If I squeeze a test tube clamp repeatedly for 150 seconds, then ________because_______

Materials

Test tube clamps, colored pencils, stopwatch

Procedure

Inquiry 21.1 (Teacher reviews steps 3A – 3E (squeezing must be vigorous, not easy)

1. Using your dominant hand, squeeze a clamp with your thumb and first 2 fingers. (monitor technique)

2. Squeeze for a total of 150 continuous seconds and record the number of squeezes you could do each 30 second.

3. Each 30 sec is a trial. Continue until you complete the 5th trial for a total of 150 sec.

4. Your partner will time you and record the number of squeezes each 30 sec.

5. Repeat procedure with your partner.

Design a data collection table •Must have room for all 5 trials for both partners•Label all headings and use proper units•Use a ruler

Graph results (SS 21.1 p 251 TM or graph paper. This is great for homework)

1. Answer the original question using data to support your conclusion. Restate your hypothesis.

2. Answer the 3 questions in step 7

Complete as a class with teacher input.

Readings

“Repetitive Stress Injury” p 177 SG

***“Command Central” p 179 SG (This will provide an opportunity to introduce and/or extend information about the brain and nervous system, which is not covered elsewhere in the module. See p 246 TM in the background for this lesson.)

Extension 1 – repeat lab with weak hand and compare

Extension 2 – Research cardiac muscle and why it doesn’t fatigue

Preparation for lesson 22- Crushed/cubed ice p 250 TM

Distribute Study guide for assessment in lesson 23

Muscle fatigue Muscle toneCrampingCarpal Tunnel Syndrome