But if they're not used right, they can strain muscles and even cause back pain.
Montgomery strained a muscle running before the first full practice.
"We can participate in sports with no concern about straining a muscle."
"With the light gravity it's hard to imagine anyone straining a muscle."
He strained a muscle in his left side Friday and was placed on the disabled list yesterday.
You can strain a muscle with an unexpected pull or twist.
He strained a muscle on his left side in the first inning, and pitching through the pain did not help.
He thought he had strained a muscle, but it didn't go away.
He also strained a muscle in his lower leg.
Running out a ground ball to end the second inning, he strained a muscle in his upper thigh.
The risk of pulling a muscle in that temperature is too high.
"This isn't like I pulled a muscle or had a bad day," he said.
I pulled a muscle in my leg playing football yesterday.
He pulled a muscle during the initial reaction, but otherwise he's feeling fine.
He wouldn't risk pulling a muscle or getting any injury this close to the competition.
This other time, I was scrubbing the kitchen floor and pulled a muscle in my side.
Just when you're primed for the biggest race of your life, you pull a muscle.
It hit a side window and I pulled a muscle in my neck wrenching around to see what was about to eat me.
"Let me get settled first; you'll pull a muscle in your neck doing it that way."
At the 1988 games she pulled a muscle midway through the final and limped over the line in 8th place.