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Featured GraphicBackpacks = Backaches for Some Kids


A recent study by doctors at Johns Hopkins University provides a valuable lesson for students. Let kids do the math for themselves!

Backpacks are a weighty problem for some students, according to a recent report by doctors at Johns Hopkins University in Baltimore, Maryland.

Students often overpack their backpacks; they often carry their backpacks slung over one shoulder too. Those habits can result in muscle spasms, shoulder or lower back pain, tingling hands, or posture problems, university doctors say.

Kids should stay away from cheap, lightweight backpacks that have unpadded nylon straps, says Dr. Jane Benson. The university's doctors have a few other recommendations:

  • Use a knapsack with well-padded straps and use both straps when carrying the knapsack.
  • Buy a knapsack with several compartments to better distribute the weight being lugged around.
  • Pack heavier items near the top of the pack. That way, the legs are carrying most of the weight. Heavy items packed at the bottom of the pack put more stress on the back.
  • Never carry a backpack that weighs more than 20 percent of your body weight.

Follow Up Math Activities

  • Graphing - Invite students to weigh their individual knapsacks. Create a bar graph to show how much the knapsacks weigh.

  • Word Problems - Following are some sample math word problems for your students. Create additional problems for students to solve.

A Few Examples for Younger Students

  1. Marty's knapsack weighs 4 pounds. Angel's knapsack weighs 5 pounds. How much do the two knapsacks weigh all together? (4 + 5 = 9 pounds)

  2. How much heavier is Marty's knapsack than Angel's is? (5 - 4 = 1 pound)

  3. Sandy's knapsack weighs 6 pounds. Stan's knapsack weighs 4 pounds. Sasha's knapsack weighs 5 pounds. How much do the three knapsacks weigh all together? (6 + 4 + 5 = 15 pounds)

A Few Examples for Older Students

  1. The students in Mr. Howland's class weighed their knapsacks. Kerry's knapsack weighed 11 pounds. Stan's knapsack weighed 6 pounds. Steve's knapsack weighed 7 pounds. Emma's knapsack weighed 8 pounds. What was the average weight of those four knapsacks? (11 + 6 + 7 + 8 = 32; and 32 divided by 4 = 8 pounds average)

  2. Doctors say students shouldn't carry knapsacks that weigh more than 20 percent of their body weight. If Cody weighs 80 pounds, what is the heaviest load he should carry in his knapsack? (80 X .20 = 16 pounds)

  3. Some experts say a simple rhyme---Take your weight and divide by eight---should be used as a guideline for figuring out the ideal knapsack weight. Use that guideline rhyme to figure out the ideal weight for Cody's knapsack. (80 divided by 8 = 10 pounds)

Gary Hopkins
Education World® Editor-in-Chief
Copyright © 1997 Education World