Biomech Exam 4

ET

effort torque

E

effort

EA

effort arm

effort arm

perpendicular distance between line of muscle force and joint

RT

resistance torque

R

resistance

RA

resistance arm

resistance arm

perpendicular distance between line of resistance and joint

ET>RT

muscle will cause movement of the body

ET=RT

no movement occurs

ET<RT

limb will move in opposite direction of the muscle’s applied force

external torque

clockwise, resistance forces pulling downward

internal torque

counterclockwise, muscle forces pulling upward to overcome external torque

axis (fulcrum)

joint where the movement occurs

resistance

external force that includes body segment weight or load

effort

internal force applied by the muscle to create movement

first-class levers

axis located in the middle, between the effort and resistance

second-class levers

resistance located in the middle, between the axis and effort

third-class levers

effort located in the middle, between the axis and resistance

moment arm

perpendicular to line of force

hip hinge

keep spine neutral

note: holding your breath only reduces compression forces

note: anterior and posterior tilt are both bad for the spine long term

Referring to the components of a lever, which of the following is equivalent to effort?

-gravity

-Joint

-Load

-Muscle

Muscle

Which lever component is situated in the middle of a third-class lever?

-Axis

-Effort

-Resistance

Effort

What are the muscles of the triceps surae?

-Anconeous and Triceps Brachii

-Deltoid Muscle Divisions

-Gastrocnemius and Soleus

-Hamstring Muscles

Gastrocnemius and Soleus

Which type of lever system is considered a mechanical advantage within the body?

-First Class

-Second Class

-Third Class

Second Class

Based on equilibrium and human movement (EA × E = RA × R), what are you able to conclude knowing EA < RA?

-E > R with an effort mechanical advantage

-E > R with a resistance mechanical advantage

-E < R with an effort mechanical advantage

-E < R with a resistance mechanical advantage

E > R with a resistance mechanical advantage

Which of the following is a force?

-Effort

-Resistance

-Resistance Arm

-Effort and Resistance

-Resistance and Resistance Arm

Effort and Resistance

Which of the following is considered an internal torque?

-Effort

-Resistance

Effect

The moment arm is the perpendicular distance from an infinately long line of force to the axis of rotation.

-True

-False

True

The resistance line of action is always directed vertically or parallel with gravity.

-True

-False

False

Based on the resistance moment arm curves, which description best describes an ascending curve?

-The muscle gets stronger through the range of motion.

-The muscle gets weaker through the range of motion.

-The resistance gets easier through the range of motion.

-The resistance gets harder through the range of motion.

The resistance gets harder through the range of motion

Which of the following scenarios highlight a mechanical advantage? Multiple answers may be correct.

-Effort Force greater than Resistance Force

-Effort Moment Arm greater than Resistance Moment Arm

-Resistance Force greater than Effort Force

-Resistance Moment Arm greater than Effort Moment Arm

Effort Moment Arm greater than Resistance Moment Arm

Resistance Force greater than Effort Force

Which of the following external resistance (load) scenarios is easier for the internal effort (muscles)?

-Longer Moment Arm

-Shorter Moment Arm

Shorter Moment Arm

Even though knee extension is still a mechanical disadvantage, the patella provides an improved advantage through the range of motion by increasing quadriceps patellar tendon/ligament effort moment arm distance.

-True

-False

True

Based on the lever system, which of the following exercises utilizes the greatest amount of external body weight resistance?

-Modified Push-Up

-Traditional Push-Up

Traditional Push-Up

What are the main muscle groups used to go up stairs? Select all that apply.

-Hip Extensors

-Hip Flexors

-Knee Extensors

-Knee Flexors

Hip Extensors

Knee Extensors

Based on doing a step up, match the following variables of work with human body characteristics.

1. Step Height relative to Body Height (Joint Angles)

2. Body Weight

-Force

-Distance

1. Distance

2. Force

Which of the following involves variable torque production with a constant joint angular velocity?

-concentric

-isokinetic

-isometric

-isotonic

isokinetic

What type of pulley system reduces the actual load of weight plates on a machine stack?

-compound

-simple

-split

split

Which feature of a selectorized weight-stack machine provides variable resistance by manipulating the moment arm through the range of motion of the exercise?

-bench angle

-cable

-cam

-pulley

cam

Based on the degree of a machine's incline angle, which resistance exercise would you expect to lift the least amount?

-Hack Squat

-Leg Press

-Vertical Leg Press

Vertical Leg Press

What is the appropriate term that describes a constant resistance throughout the range of motion?

-Isometric

-Isotonic

-Isokinetic

Isotonic