1. 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 Bellwork What 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 21 Exploring Muscle Fatigue

2. 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

3. 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 5 th 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.

4. 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

5. 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.)

6. 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 fatigueMuscle tone Cramping Carpal Tunnel Syndrome