CES Human Anatomy & Biomechanics 3

Question 1

The neutral wrist position is best described as:

Accepted Answer

Straight alignment with the forearm

Answer

Neutral wrist is a straight, aligned position with minimal flexion, extension, or deviation, which minimizes pressure on the carpal tunnel contents.

Question 2

What is the approximate compression force on the L4/L5 disc when lifting 10 kg with a stooped back?

Accepted Answer

Over 3,000 N

Answer

Stooped lifting dramatically increases the moment arm of the load, producing compressive disc forces well above 3,000 N, far exceeding the NIOSH action limit.

Question 3

Which type of muscle contraction generates the most force?

Accepted Answer

Eccentric

Answer

Eccentric contractions (muscle lengthening under load) produce greater force than isometric or concentric contractions, which is why they are a common source of delayed onset muscle soreness.

Question 4

The rotator cuff consists of how many muscles?

Accepted Answer

4

Answer

The rotator cuff is made up of four muscles — supraspinatus, infraspinatus, teres minor, and subscapularis — that stabilize the glenohumeral joint.

Question 5

What biomechanical principle explains why a longer handle on a tool reduces grip force requirements?

Accepted Answer

Leverage (moment arm) principle

Answer

A longer handle increases the moment arm, so the same torque can be achieved with less applied force, reducing grip and pinch force demands.

CES - Certified Ergonomic Specialist Practice Test

CES - Certified Ergonomic Specialist Practice Test

CES Human Anatomy & Biomechanics 3