NSCA CSCS - Chapter 2 Flashcards
Acceleration
The change in velocity per unit of time.
Agonist
The muscle most directly involved in bringing about a movement. Also known as a prime mover.
Anatomical position
The anatomical position is a reference position of the human body that defines the planes of motion. The anatomical position views the body from an erect, upright position with the arms at the sides and the palms facing inwards.
Angle of pennation
The angle between the muscle fibers and an imaginary line between the muscle origin and insertion.
Angular displacement
The angle through which an object rotates, measured in radians (rad).
Angular velocity
An object’s rotational speed measured in radians per second.
Antagonist
The muscle that can slow down or stop a movement. Antagonists assist in joint stabilization and braking the limb towards the end of a fast movement.
Biomechanics
The mechanism through which the musculoskeletal components interact to create movement.
Bracketing technique
A form of acceleration training where an athlete performs a movement with less than normal and greater than normal resistance.
Cartilaginous joint
Joints in the body that allow some movement, such as the vertebrae.
Classic formula
A formula used to compare the relative strength of athletes taking into account differences in body weight. In the classic formula, the load lifted is divided by the athlete’s body weight to the two-thirds power.
Concentric Muscle Action
Action that occurs when a muscle produces contractile force greater than the resistive force, resulting in shortening of the muscle. The lifting phase of a resistance movement is a classic example of concentric muscle action.
Distal
Further from the midline in reference to limb muscle attachments. The distal attachment is also known as the insertion.
Dorsal
The posterior portion of the vertebral disks.
Eccentric muscle action
Action that occurs when a muscle produces force less than the resistive force, resulting in a lengthening of a muscle. The lowering phase of resistance training exercises is a well-known example of eccentric muscle action.
Fibrous attachments
Attachments from muscle to bone, such as tendons, that are contiguous with the muscle and have connective tissue surrounding the bone, making a very strong union.
First-class lever
A lever for which the muscle force and resistive force act on opposite sides of the fulcrum.
Fleshy attachments
Muscle-to-bone attachments where the muscle fibers are directly attached to the bone, usually over a wide area. Most often found at the proximal attachment.
Fluid resistance
The resistive force encountered by an object moving through a fluid or by a fluid moving past or around an object or through an opening. Fluid resistance is significant in sports such as swimming and sprinting, and is also used in resistance training in hydraulic and pneumatic machines.
Form drag
The resistance from a fluid pressing against the front or rear of an object.
Friction
The resistive force encountered when attempting to move an object that is pressed against another object.
Frontal plane
An imaginary plane that slices the body into front and back pieces when viewed in the anatomical position. The frontal plane is used to describe motions performed by the human body. The lateral dumbbell raise is an example of a frontal plane movement.
Fulcrum
The pivot point of a lever.
Inertial force
Additional force exerted by a barbell or weight stack when it is accelerated. Inertial force can act in any direction.
Insertion
The distal attachment point of a muscle.
Isometric muscle action
Muscle action that occurs when the contractile force is equal to the resistive force, resulting in muscle force with no change in muscle length. Maintaining a neutral spine during the plank exercise is an example of isometric muscle action.
Kyphotic
The natural rounding in the thoracic spine.
Lever
A rigid or semi-rigid body that when subjected to a force whose line of action does not pass through its pivot point, exerts a force on any object impeding its tendency to rotate.
Lordotic
The natural curve in the lumbar spine.
Mechanical advantage
The ratio of the moment arm through which an applied force acts to that through which a resistive force acts. The produce of the applied force and the moment arm must equal the product of the resistive force and the moment arm. Therefore, a mechanical advantage, represented by a ratio greater than 1.0, allows the applied muscle force to be less than the resistive force to produce an equal amount of torque.
Moment arm
The perpendicular distance from the line of action of the force to the fulcrum.
Muscle force
Force generated by biomechanical activity or the stretching of non-contractile tissue that tends to draw the opposite ends of a muscle toward each other.
Origin
The proximal attachment of a muscle to bone.
Pennate muscle
A muscle with fibers that align obliquely with the tendon.
Power
The time rate of doing work. Power is a function of force and velocity and reflects the ability to exert force at a given velocity.
Proximal
Closer to the midline in reference to limb muscle attachments. Proximal muscle attachments are also referred to as the origin.
Rate coding
The rate at which motor units are fired.
Recruitment
The firing of a motor unit
Resistive force
Force generated by a source external to the body that acts contrary to muscle force.
Rotational power
Rotational work divided by the time.
Rotational work
Work measured in joules, calculated by multiplying the torque by the angular displacement.
Sagittal plane
An imaginary plane that slices the body into left and right pieces when viewed from the anatomical position. The sagittal plane is used to describe movements in the human body. Standing bicep curls are an example of a sagittal plane motion.
Second-class lever
A lever for which the muscle force and resistive force act on the same side of the fulcrum, with the muscle force acting through a moment arm longer than that through which the resistive force acts. Second-class levers allow a smaller muscle force to lift a greater resistance through mechanical advantage.
Strength
The ability to exert force.
Surface drag
The friction of a fluid passing along the surface of an object.
Synergist
Muscles that assist indirectly in a movement. Synergists are required to control body motions when the agonist crosses two different joints.
Tendons
Fibrous attachments that are continuous with both the muscle sheaths and connective tissue surrounding the bone. Tendons create a very strong union between muscle and bone.
Third-class lever
A lever for which the muscle force and resistive force act on the same side of the fulcrum, with the muscle force acting through a moment arm shorter than that through which the resistive force acts. The mechanical advantage in a third class lever is less than 1.0, meaning that the muscle force must be greater than the resistance to produce equivalent torque.
Torque
The degree to which a force tends to rotate an object around a specified fulcrum. It is defined quantitatively as the magnitude of a force times the length of the moment arm.
Transverse plane
An imaginary plane that slices the body into upper and lower halves when viewed in the anatomical position. The transverse plane is used to describe human movement. Dumbbell flies are an example of a transverse plane movement.
Valsalva maneuver
A method of generating intra-abdominal pressure by closing the glottis and keeping air from escaping the lungs while contracting the abdomen and rib cage. The Valsalva maneuver creates a compressive force on the heart which can make it more difficult for blood to return to the heart. It is possible to create intra-abdominal pressure by contracting the core and diaphragm without a closed glottis, which is a safer method for most resistance training exercises.
Ventral
The anterior edges of vertebral bodies.
Vertebral column
The vertebral bones of the spine stacked on one another and separated by rubbery disks.
Weight
The mass of an object multiplied by the local acceleration from gravity in meters per second.
Work
The product of the force exerted on an object and the distance the object moves in the direction of the force.
