Lever mechanisms Department of Biology, WCU

Introduction Lever, fulcrum, force Bone, joint, muscle Load is object or structure Function move load for effort force fulcrum load lever

Lever types 1. Power levers Characteristics e.g. standing on toes Load close to fulcrum Effort far from fulcrum e.g. standing on toes

Lever types 2. Speed levers Characteristics e.g. pitching a baseball Load far from fulcrum Effort near fulcrum e.g. pitching a baseball

Lever classes Characteristics First class levers position of effort, fulcrum and load First class levers load, fulcrum, force

First class levers 1. power levers 2. speed levers mechanical advantage e.g. head extension 2. speed levers mechanical disadvantage e.g. tricep extension of forearm

Second class levers Characteristics fulcrum, load, force uncommon all power levers e.g. stand on toes

Third class levers Characteristics fulcrum, force, load all speed levers most common e.g. flexion of forearm

Conclusions Speed have little power, power have slow speed Difference among lever classes fulcrum, force, load Affect speed of contraction range of movement weight lifted