Question

The patient you are treating does not have a strong science background; explain to them (using complete sentences) how stimulation of skeletal muscle can result in different strength contractions using language which they can understand.

Answer 1

• skeletal muscles are the voluntary muscles or the muscles that are under our conscious control of the body. These muscles are usually found in the limbs and aid in the movement of the body and perform many physical activities.
• The skeletal muscles work by contracting or reducing in size which imparts a force on the object at hand.
• The force produced or that is applied by each muscle directly depends on the stimulus or the signal perceived by brain cells i.e. neurons and sent back to the muscles.
• For example, if a person has missed a step and was about to fall down he will grab the nearby stable surface which involves the muscles in the hands and legs to steady himself and this activity requires a certain amount of muscle force which is decided by the brain and sends the information to the muscle cells. In another case where a person is being chased by a dog, he needs more work to be done by his muscles to escape the threat which too is analyzed by the brain cells and sends the relatively stronger signal to the muscle units.  
• If you closely observe, to extract more work from the muscle the brain's signals will be stronger what we call it as stronger stimulus.
• When the stimulus is intense (maximum) the strength of the contraction of a muscle is more as the signal activates many muscle fibers/threads thus recruiting more of them and this reaches a peak.
• Thus with each varying stimulation/signal, the intensity or extent of muscle contraction and thereby the force applied by the muscle varies aiding in the coordinated movement for various tasks.