Final answer:
The statement comparing the tenderness of the Longissimus dorsi, Trapezius, and Rectus femoris is False since muscle tenderness is influenced by factors such as usage frequency and muscle structure, which vary among these muscles.
Step-by-step explanation:
The statement that the Longissimus dorsi is more tender than the Trapezius, and the Trapezius is more tender than the Rectus femoris, is False. Tenderness of muscle tissue can be influenced by several factors, including the type of muscle fibers present, the amount of connective tissue, and the amount of work the muscle does regularly. Generally, muscles that are used more frequently, like those involved in locomotion or maintaining posture, tend to develop more connective tissue and can be tougher.
The Longissimus dorsi is part of the longissimus group of the erector spinal muscles and is located on the back. It is an axial muscle that helps in extension, lateral flexion, and rotation of the vertebral column. Its counterpart, the Trapezius, is a broad, superficial muscle of the back and neck associated with upper limb and scapular movement as well as providing postural support. Since these muscles are involved in postural maintenance and movement, they may not be as tender as muscles that are used less frequently. The Rectus femoris, on the other hand, is a muscle of the anterior thigh and part of the quadriceps group; it's regularly engaged when we walk or run, implying it might be less tender due to frequent use. However, the comparison of tenderness between these muscles is not typically a subject of direct study, and this statement should not be taken as a fact.