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Body Strength

Author(s): Nancy Moreno, PhD, Barbara Tharp, MS, and Sonia Rahmati Clayton, PhD.
Body Strength

© Ilia Shcherbakov.

  • Grades:
  • 3-5
  • Length: 60 Minutes

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Students learn that muscles need exercise to stay strong, repetition of exercises builds strength and endurance, and that different activities improve cardiovascular health, strength, flexibility and balance. Students also track their heart rates, measure strength, and examine performance levels.

As part of this activity, students visit the PowerPlay exhibit at the Children's Museum of Houston. This lesson is best conducted before going to the Museum. Also, prior to the visit read "Teacher Tips," to plan the visit, and to learn about alternative options for conducting the activity without a Museum visit (see PDF).

This activity is from the PowerPlay Teacher's Guide. Although it is most appropriate for use with students in grades 3-7, the lessons are easily adaptable for other grade levels.

The PowerPlay project is a partnership between Baylor College of Medicine and the Children's Museum of Houston.

Teacher Background

The Children’s Museum of Houston’s PowerPlay exhibit is designed to help young people discover new ways to be physically active and reinforce healthy behaviors. Students will have opportunities to track their heart rates, measure strength, and examine performance levels.

Students should complete this activity before visiting the Museum. It will help them to focus on ways to 1) measure their performance on different physical activities, and 2) chart their improvement over time.

Exercise includes any activity that requires physical effort, such as walking, running, riding a bike or jumping rope. Our bodies need regular physical activity to be healthy.

Exercise can improve muscle strength and/or stamina (the length of time one can perform an activity without becoming tired). Low-intensity, long-duration activities, such as running and swimming, increase muscle stamina. High intensity, short-duration exercises, like weight lifting, increase muscle strength.

Objectives and Standards

Texas Essential Knowledge and Skills (TEKS) Objectives


3.2.A-F; 4.2.A-F; 5.2.A-F

  • Student uses scientific inquiry methods during laboratory and outdoor investigations.

3.4.A-B; 4.4.A-B; 5.4.A-B

  • Students know how to use a variety of tools, materials, equipment, and models to conduct science inquiry.


3.1.A; 4.1.F; 5.1.E

  • Students will recognize and explain ways to enhance and maintain health and recognize and perform behaviors that reduce health risks throughout their lifespan.

Materials and Setup

Materials per Class

  • Clock with a second hand or timer

Materials per Student

  • Notebook

  • Spring-hinged clothespin

  • Student sheet

Procedure and Extensions


  • 50 minutes on the first day

  • 5 minutes every other day for two weeks

  • 50 minutes on the last day


Write the word “strength” on the board. Ask students to create an acrostic for “strength” in their notebooks, using words related to fitness and exercise (see “Acrostics,” below). Have students share their acrostics during a class discussion.

Acrostics. An acrostic is a paragraph, poem or other text in which the first letter, syllable or word of each line spells out a word or message. For example, an acrostic for the directions of the compass is given below.  



  1. Explain to students that they will learn about one way to improve hand strength. Mention that even in the hands and arms, there are small muscles responsible for movement.

  2. Tell students that they will test the strength and stamina of their hand muscles by squeezing a clothespin with their non-dominant hand (left or right) for one minute.

  3. Have students predict the number of times they can squeeze the clothespin in one minute.

  4. Instruct students to create a table on which to record their predictions and actual results (see example, PDF).

  5. Time students for one minute as they squeeze and count silently. They should count only the times they are able to squeeze the clothespin completely (so that the ends are touching). Have them record the results.

  6. Tell students to rest for a few minutes and then repeat the clothespin “squeeze.” Repeat the test at least two more times, and have students record each count on their data tables.

  7. Instruct students to examine their data. Ask, How did your hand feel after all three trials? What happened after each trial? How did the number of squeezes change over the three trials?

  8. For the next two weeks, have students repeat the exercise at least every other day. During this “conditioning period,” students’ hand muscles should strengthen, enabling students to squeeze the clothespin more times during each trial. Students should record their results each day.


  1. Ask students if the number of squeezes per minute changed during the two-week period. Ask, Why do you think this happened?

  2. Discuss how exercise increases muscle strength and performance over time. 


  1. To promote deeper understanding of how their strength and endurance increased, have students graph their results to produce a visual representation of changes that occurred in the trials over the course of two weeks and analyze the results.

  2. They should create separate graphs for each one-minute period and record how the number of clothespin clicks changed over time. This will help students understand how their strength and endurance increased.


  1. Explain to students that different physical activities can benefit the body in different ways. Go to the Children’s Museum of Houston’s PowerPlay page ( and show students the symbols on the site for a) Cardiovascular, b) Lower Body Strength, c) Flexibility, d) Upper Body Strength, and e) Balance (see symbols, PDF).

  2. Divide students into groups, and have each group create a daily exercise plan focusing on one of the four areas high-lighted on the PowerPlay page. For example, a group might choose to focus on improving upper body strength. That group should be sure to mention the part of the body they are working to improve and how often/how long a person should exercise to achieve the desired improvement.

  3. Have each group explain its plan to the class. Then, lead all students in a class effort to develop an exercise plan that benefits the entire body.

  4. Finally, have each student create a new acrostic for the word, “strength,” using the same criteria as before. Have students compare their “before” and “after” acrostics, and discuss whether students incorporated more information about fitness and exercise into their “after” acrostics.

Funded by the following grant(s)

Science Education Partnership Award, NIH

Science Education Partnership Award, NIH

Grant Number: R25RR022697