Biomechanics Notes
Levers:
1st class:
• Muscle force and resistance on opposite sides of
the fulcrum
• Triceps
2nd class:
• Moment arm of the muscle force Longer than the
moment arm of the resistance
• Mechanical Advantage
• Calf Raise
3rd Class:
• Moment arm of the muscle Shorter than moment arm of the resistance.
• Mechanical Disadvantage for the muscle
• Bicep curl, leg extension, most muscles
Muscle force: Internally generated force
Resistive force: Externally generated force (ex: dumbbell, barbell, bodyweight, etc.)
Muscle Levers Video: https://www.youtube.com/watch?v=wcKgXeYlEkc
Running mechanics:
Work: Force X Displacement
• Newtons X Meters= J
o Ex: Pushing (force) on a barbell to get it to move a certain distance
o Ex: lifting a 100kg barbell 1 meter. 100kg * 9.8 m/s2 * 1m= 980 J of work
(constant speed no acceleration)
Power: Work/ Time
• J/ seconds= Watt
o Ex: Margaria Kalamen stair test
o Ex: Lifting a barbell with 980 J of work in 2 seconds= 980/2= 490 W
Takeaway: It is important to be able to produce force at the velocity required for a given sport.
• Bracketing technique: ~10% more or less resistance than sport movement
Impulse:
• Change in momentum
