CH 5 Biomechanics

Question 1

Define biomechanics

Answer 1

The study of the mechanical laws governing movement of living organisms.

Question 2

Define Kinesiology

Answer 2

study of human movement

The study of the mechanics of human movement.

Question 3

Explain the relationship between kinesiology and biomechanics.

Answer 3

Kinesiology is the study of biomechanics and biomechanics are the laws that the human musculoskeletal system is subject to.

Question 4

Most common movements of the sagittal plane

Answer 4

• Knee flexion and extension
• Trunk flexion and extension
• Shoulder flexion and extension

movement: front to back

exercises: flexion/extension (ex bicep curl, squat, running/walking)

Question 5

Most common movements of the transverse plane

Answer 5

• Torso rotation
• Head and neck rotation
• Scapular retraction
• Scapular protraction

movement: twisting or horizontal ab-adduction

exercises: swinging a bat, push up (as it relates to arm movement), cable chop

Question 6

Most common movements of the frontal plane

Answer 6

• Trunk flexion and extension
• Scapula depression and elevation
• Scapula upward rotation and downward rotation

movement: side to side

exercises: ab and adduction (ie side bend, side lunge, lat raises)

Question 7

Sustained force movement

Answer 7

movement in which there are continuous muscle contractions to keep moving a weight

Question 8

Dynamic balance movement

Answer 8

constant agonist-antagonist muscle contractions occur to maintain a certain position or posture.

Question 9

Ballistic movement

Answer 9

inertial movement exists after an explosive or quick, maximum-force contraction; here is pre-tensing of the muscle in the eccentric contraction so the muscle can contract concentrically with maximum speed and quickness.

Question 10

Guided Movement

Answer 10

movement that occurs when both the agonist and the antagonist contract to control the movement

Question 11

kinesthesis

Answer 11

the system for sensing the position and movement of individual body parts

(Receptors in the joints, muscles, and tendons help you know where your body is in space)

Question 12

Joints typically needing greater mobility

Answer 12

foot/ankle, hip, thoracic spine, shoulder, and wrist

Question 13

Joints typically needing greater stability

Answer 13

knee, lumbar spine, cervical spine, and elbow

Question 14

Explain Newton’s second law of motion in relation to mass and acceleration.

Answer 14

Force is produced by accelerating a mass through a change in velocity

F=M*A

Question 15

Acceleration formula and definition

Answer 15

a = change in v / change in t

the change in the velocity vector in a time interval, divided by the time interval

Question 16

Force formula

Answer 16

Force = mass x acceleration

Question 17

Power formula

Answer 17

P=F*V

power=force x velocity

or…

(force x distance) /time

Question 18

Define “power” and how it is used in a weight training exercise.

Answer 18

Power is the amount of force over a given period of time

Question 19

Explain the principles of biomechanics.

Answer 19

(category) - principle - description

1. (Stability) - stability - the ability to keep control of a joint or a position
2. (Maximum effort) - the production of maximum force - the max amount of force that may be made by a muscle or muscle group
3. (Maximum effort) - the production of max velocity - the max movement velocity or the speed of contraction for a muscle or muscle group.
4. (Linear) force-velocity relationship - the greater the applied force is on one object, the greater the overall velocity.
5. (Linear) - direction of movement - movement occurs within the opposite direction of the force applied.
6. (Linear) - ground reaction forces - the force that is exerted by the ground to the body that is contacting it.
7. (Angular motion) -angular motion - the motion of some object around a fixed point or axis.
8. (Angular motion) - conservation of angular momentum - angular momentum is constant until some external force acts on it.

Question 20

Define “work” and how it is used in an exercise. What is the formula?

Answer 20

Work is defined as the amount of force over a given distance.

Work = Force X Distance (or displacement)

Question 21

Define work and how it is used in an exercise.

Answer 21

Work is defined as the amount of force over a given distance

Question 22

Explain what a lever is as it relates to the body.

Answer 22

A lever is a bone that turns about the rotational axis of a joint

Question 23

what are the categories of biomechanics?

Answer 23

1. stability
2. max effort (force or velocity)
3. linear motion
4. angular motion

Question 24

what is work measured in?

Answer 24

foot-pounds

Question 25

first class lever

Answer 25

fulcrum in the middle

e.g. the head and top of c- spine. Ex: Seesaw

Question 26

second class lever

Answer 26

the load is between the fulcrum and the effort

e.g. rising on one’s forefoot,. Ex: wheelbarrow, nutcracker

Question 27

third class lever

Answer 27

The fulcrum is at one end of the bar and the effort is between the fulcrum and the resistance

E.g. shoulder and forearm.

Question 28

SHERRINGTON’S LAW OF RECIPROCAL INHIBITION

Answer 28

A law that states that for every muscle activation, there is a corresponding inhibition of the opposing muscle.

Question 29

Explain the relationship between agonist and antagonist.

Answer 29

Agonist and antagonist are planar opposite muscles where the agonist contracts concentrically for muscle action and force production while the antagonist contracts eccentrically for stability and control.

Question 30

Define the term “stabilizer muscles” and provide an example of how it is used in an exercise.

Answer 30

The muscles playing the role of stabilizing or minimizing joint movement.

A Stabilizer anchors the bone so that the prime mover has a firm base against which to contract.

Example: the quadriceps and especially the erector spinae of the lower back during an overhead press

Question 31

Explain synergy as it relates to muscles.

Answer 31

• helping synergy: When two muscles contract together to create one movement.
• true synergy: When a muscle contracts to stop the secondary action of another muscle.
• neutralizer: When a muscle contracts to counteract an undesirable action of another muscle.

Question 32

Explain torque as it relates to exercise.

Answer 32

The magnitude of the rotational force of a lever about a fulcrum. E.g. the force generated by muscle contraction about a joint by an extremity.

Question 33

Explain gravity as it relates to exercise.

Answer 33

Force applied per unit of mass. the downward resistance created by free weights.

Question 34

Define “center of gravity” and explain how it relates to movement.

Answer 34

Center of gravity is the point of equal distribution of force due to gravity and is influenced by base of support, mass, height, position and state of motion of the body. Center of gravity influences passive stability.

Question 35

What do muscle spindles do?

Answer 35

prevent muscles from stretching too far or too fast

Question 36

what’s the difference bw muscle spindles and golgi tendons?

Answer 36

spindles=stretch
(golgi) tendons=tension