| A | B |
|---|
| voluntary | muscles you can control |
| involuntary | muscles you cannot control |
| relax | not working returns to regular size |
| contract | working and gets shorter |
| tendon | strong tissues that connect muscle to bone |
| skeletal muscles | move bones |
| smooth muscles | found in blood vessels and organs |
| cardiac muscles | found only in the heart |
| energy | what muscles need to work |
| lactic acid | waste produced when muscles work |
| heat | produced when muscles work |
| food | source of energy for muscles |
| muscle strenght | how much weight a muscle can fit |
| muscle stamina | how long a muscle can work without getting tired |
| flexibility | ability to bend and stretch |
| posture | how you hold your body |
| strained muscle | pulled muscle |
