velocity

Examples of velocity in the following topics:

• Velocity and Duration of Muscle Contraction

  • The shortening velocity affects the amount of force generated by a muscle.
  • The force-velocity relationship in muscle relates the speed at which a muscle changes length to the force of this contraction and the resultant power output (force x velocity = power).
  • Though they have high velocity, they begin resting before reaching peak force.
  • As velocity increases force and power produced is reduced.
  • Maximum power is generated at one-third of maximum shortening velocity.

• Force of Muscle Contraction

  • The force a muscle generates is dependent on its length and shortening velocity.
  • The force-velocity relationship in muscle relates the speed at which a muscle changes length with the force of this contraction and the resultant power output (force x velocity = power).
  • As velocity increases force and therefore power produced is reduced.
  • Although force increases due to stretching with no velocity, zero power is produced.
  • Maximum power is generated at one-third of maximum shortening velocity.

• Velocity of Blood Flow

  • It's important to understand the different between velocity and flow.
  • Velocity refers to the distance an object moves over time; for example, in blood this measurement is often given as cm/sec.
  • Where F = flow, v = velocity and a = cross-sectional area.
  • While the above example is a simple calculation, in reality there are numerous factors that influence velocity and flow.
  • As resistance increases the difference in pressure which influences velocity decreases, which in turn reduces flow.

• Classification of Nerves

  • Peripheral nerve fibers are grouped based on the diameter, signal conduction velocity, and myelination state of the axons.
  • Fibers of the A group have a large diameter, high conduction velocity, and are myelinated.
  • Fibers of the B group are myelinated with a small diameter and have a low conduction velocity.
  • Fibers of the C group are unmyelinated, have a small diameter, and low conduction velocity.
  • The lack of myelination in the C group is the primary cause of their slow conduction velocity.

• Local Regulation of Blood Flow

  • The greatest change in blood pressure and velocity of blood flow occurs at the transition of arterioles to capillaries.
  • This reduces the pressure and velocity of flow for gas and nutrient exchange to occur within the capillaries.

• Arterioles

  • This reduces the pressure and velocity of blood flow to enable gas and nutrient exchange to occur within the capillaries.

• Agonists, Antagonists, and Drugs

  • However, in this tissue, these changes are manifested as a reduction in impulse conduction velocity through the AV node.
  • By doing so, they increase heart rate and conduction velocity.

• Aging and the Nervous System

  • In addition the voluntary motor movements slow down, reflex time increases, and conduction velocity decreases.

• Pulse

  • Pulse rate or velocity is usually measured either at the wrist from the radial artery and is recorded as beats per minute (bpm).

• Injuries to Nerves Emerging from the Brachial Plexus

  • Traumatic brachial plexus injuries may arise from several causes, including sports, and high-velocity motor vehicle accidents, especially in motorcyclists, but also in all-terrain-vehicle (ATV) accidents.