This 4-page 5th grade sheet explains why muscles work in pairs. Students look at two arm diagrams, one bent and one straight, and write whether the biceps and triceps contract or relax in each. A fill-in paragraph covers tendons, bones, pull and push. Then they name the muscle pairs that move the knee and the ankle and suggest one more pair in the trunk. The last page is an answer key.
“Explain that muscles can only pull, so skeletal muscles work in pairs.”
Part 2 asks students to complete this idea with pull, push and pairs.
“Describe which muscle of a pair contracts and which relaxes during a movement.”
Items 1 to 4 cover both the bent arm and the straight arm.
“Name muscle pairs in the leg and trunk.”
Items 6 to 8 cover the thigh, the lower leg and one trunk pair.
Diagram A shows the arm bent and Diagram B shows it straight, each with numbered biceps and triceps. Students write contracts or relaxes on four lines, using a two-word bank.
One paragraph with four blanks about tendons, bones and pairs. The bank holds bones, pairs, pull and push, so students must decide which of the last two fits where a muscle can only act on a bone.
A table asks for the muscles that bend and straighten the knee and the muscles that point and lift the toes, chosen from hamstrings, quadriceps, calf muscle and shin muscle. Item 8 asks for one pair in the trunk, with two lines to write on.
The four contract and relax answers, the completed paragraph, the leg pairs with their names and a trunk pair of abdominal muscles and back muscles.
Hands on the arm
Have partners feel the front of the upper arm while one bends and straightens an elbow. The biceps bulges on the bend, and students can use that to answer items 1 and 3.
Page 2 as a short check
The paragraph is quick, so use it after you teach tendons. A student who writes push where the text says a muscle can only pull has missed the main idea.
Leg pairs
Before Part 3, have students sit and straighten one leg, then bend it. The thigh pair is easy to find, and the toes up and toes down pair in the lower leg is the one to model.
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