Watch this animated lecture by Wendy Riggs, or watch the videos below:

https://www.youtube.com/watch?v=fXsw3h6oi08

Muscle Strength:

https://www.youtube.com/watch?v=12WbSX1r7q4

Muscle Size:

https://www.youtube.com/watch?v=U2pCVtGdd3s

Overstretched Muscles:

https://www.youtube.com/watch?v=NbqntE67JG4

High Heels:

https://www.youtube.com/watch?v=xH2baRdK5f4

Muscle Fibers:

https://www.youtube.com/watch?v=krGYcbTNKhE

Motor Units:

https://www.youtube.com/watch?v=AI66BdE8BwA

Fine Motor Skills:

https://www.youtube.com/watch?v=UjXSNTb5BsA

Muscle Soreness:

https://www.youtube.com/watch?v=krmZBwcL3Bs