Chapter 2 - Biomechanics of Resistance Exercise

Question 1

Acceleration

Answer 1

The change in velocity per unit of time.

Question 2

Agonist

Answer 2

The muscle most directly involved in bringing about a movement. Also known as a prime mover.

Question 3

Anatomical position

Answer 3

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.

Question 4

Angle of pennation

Answer 4

The angle between the muscle fibers and an imaginary line between the muscle origin and insertion.

Question 5

Angular displacement

Answer 5

The angle through which an object rotates, measured in radians (rad).

Question 6

Angular velocity

Answer 6

An object’s rotational speed measured in radians per second.

Question 7

Antagonist

Answer 7

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.

Question 8

Biomechanics

Answer 8

The mechanism through which the musculoskeletal components interact to create movement.

Question 9

Bracketing technique

Answer 9

A form of acceleration training where an athlete performs a movement with less than normal and greater than normal resistance.

Question 10

Cartilaginous joint

Answer 10

Joints in the body that allow some movement, such as the vertebrae.

Question 11

Classic formula

Answer 11

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.

Question 12

Concentric Muscle Action

Answer 12

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.

Question 13

Distal

Answer 13

Further from the midline in reference to limb muscle attachments. The distal attachment is also known as the insertion.

Question 14

Dorsal

Answer 14

The posterior portion of the vertebral disks.

Question 15

Eccentric muscle action

Answer 15

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.

Question 16

Fibrous attachments

Answer 16

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.

Question 17

First-class lever

Answer 17

A lever for which the muscle force and resistive force act on opposite sides of the fulcrum.

Question 18

Fleshy attachments

Answer 18

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.

Question 19

Fluid resistance

Answer 19

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.

Question 20

Form drag

Answer 20

The resistance from a fluid pressing against the front or rear of an object.

Question 21

Friction

Answer 21

The resistive force encountered when attempting to move an object that is pressed against another object.

Question 22

Frontal plane

Answer 22

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.

Question 23

Fulcrum

Answer 23

The pivot point of a lever.

Question 24

Inertial force

Answer 24

Additional force exerted by a barbell or weight stack when it is accelerated. Inertial force can act in any direction.

Question 25

Insertion

Answer 25

The distal attachment point of a muscle.

Question 26

Isometric muscle action

Answer 26

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.

Question 27

Kyphotic

Answer 27

The natural rounding in the thoracic spine.

Question 28

Lever

Answer 28

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.

Question 29

Lordotic

Answer 29

The natural curve in the lumbar spine.

Question 30

Mechanical advantage

Answer 30

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.

Question 31

Moment arm

Answer 31

The perpendicular distance from the line of action of the force to the fulcrum.

Question 32

Muscle force

Answer 32

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.

Question 33

Origin

Answer 33

The proximal attachment of a muscle to bone.

Question 34

Pennate muscle

Answer 34

A muscle with fibers that align obliquely with the tendon.

Question 35

Power

Answer 35

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.

Question 36

Proximal

Answer 36

Closer to the midline in reference to limb muscle attachments. Proximal muscle attachments are also referred to as the origin.

Question 37

Rate coding

Answer 37

The rate at which motor units are fired.

Question 38

Recruitment

Answer 38

The firing of a motor unit

Question 39

Resistive force

Answer 39

Force generated by a source external to the body that acts contrary to muscle force.

Question 40

Rotational power

Answer 40

Rotational work divided by the time.

Question 41

Rotational work

Answer 41

Work measured in joules, calculated by multiplying the torque by the angular displacement.

Question 42

Sagittal plane

Answer 42

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.

Question 43

Second-class lever

Answer 43

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.

Question 44

Strength

Answer 44

The ability to exert force.

Question 45

Surface drag

Answer 45

The friction of a fluid passing along the surface of an object.

Question 46

Synergist

Answer 46

Muscles that assist indirectly in a movement. Synergists are required to control body motions when the agonist crosses two different joints.

Question 47

Tendons

Answer 47

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.

Question 48

Third-class lever

Answer 48

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.

Question 49

Torque

Answer 49

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.

Question 50

Transverse plane

Answer 50

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.

Question 51

Valsalva maneuver

Answer 51

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.

Question 52

Ventral

Answer 52

The anterior edges of vertebral bodies.

Question 53

Vertebral column

Answer 53

The vertebral bones of the spine stacked on one another and separated by rubbery disks.

Question 54

Weight

Answer 54

The mass of an object multiplied by the local acceleration from gravity in meters per second.

Question 55

Work

Answer 55

The product of the force exerted on an object and the distance the object moves in the direction of the force.