Ch. 2 Flashcards
Mechanical Advantage
Muscle Arm / Resistance Arm
Open Chain Exercise
Combination of successfully arranged joints in which the terminal segments move freely
Closed Chain Exercise
Movements where the distal aspect of the extremity is fixed to an object that is stationary
Isotonic
Constant tension as muscles changes length (cable machine)
Isokinetic
Constant speed (biodex machine)
Equation & Units of Force
Force = Mass x Acceleration
Unit: Newton
Equation & Units of Work
Work = Force x Displacement
Unit: Joule (Newtons x Meters)
Equation & Units of Power
Power = Work / Time
Unit: Watts
Angle of Pennation
the difference between the angle of the muscle fibers and the line between muscle origin and insertion
more pennation = more force, less velocity
Strength
Contractile force is proportional to muscle cross sectional area
(smaller athletes are stronger pound for pound than larger athletes)
3 types of exercises via inertia
Resistance - agonist muscles have to overcome large resistance early, resistance decreases throughout range of motion
Accommodating resistance - bands/chains - increases resistance as the weight is lifted
Explosive - high resistance early, less resistance toward end of range of motion
Overspeed vs Underspeed
Decrease BW up to 10%, allows acceleration at higher speed to train neuromuscular system
Increase BW up to 10%, develops greater force during acceleration
Friction
Friction = K x Normal Force
Resistance
Resistance = K (constant of the elastic component) * X (distance stretched beyond resting)
Valsalva
Expiring against a closed glottis, causes the muscles of the abdomen and rib cage contract creating a rigid compartment of liquid in the lower torso and air in the upper torso
