Answer to Question 1
Muscle soreness and stiffness are common in individuals who (a) begin an exercise program or participate after a long layoff from exercise, (b) exercise beyond their customary intensity and duration, and (c) perform eccentric training. The acute soreness that sets in during the first few hours after exercise is related to general fatigue caused by chemical waste products that build up in the exercised muscles. The delayed-onset muscle soreness (DOMS) that appears several hours after exercise (usually 12 hours or so later) and lasts two to four days may be related to microtears in muscle tissue, muscle spasms that increase fluid retention and thereby stimulate the pain nerve endings, and overstretching or tearing of connective tissue in and around muscles and joints.
Answer to Question 2
c
anatomy of leg muscle
biceps muscle
Recruitment of Muscle Fiber Type
Types of muscle tissue.
Cardiac muscle
Smooth muscle