Source: Weightlifter; Public Domain: http://en.wikipedia.org/wiki/File:EarlyBarbell.gif Runners; Public Domain: http://www.morguefile.com/archive/display/32063
A type of physical activity that gradually conditions slow muscles to work for longer periods of time.
A substance found naturally in muscles or used as a supplement to replenish ATP during muscle workouts allowing muscles to sustain activity for longer periods of time.
A pigment that binds oxygen for the use of ATP production.
A type of physical activity that increases the size of the muscles and has an affect mainly on fast muscle fibers.