The starting point, also called the fixed point, is relatively fixed when moving.
The dead point is also called the moving point, and the relative displacement is large when moving.
Referring to other fields (fitness), the fixed point and moving point in fitness field seem to have different names. Perhaps it is to make it easier for people without corresponding knowledge to understand, and to use imprecise language such as "near-definite, far-definite".
According to the principle of muscle action, the so-called near-retention and far-retention are actually anatomical "translocation of starting point and ending point"
Among the quadriceps femoris, the rectus femoris originates from the hip joint, and the other muscle heads directly originate from the femur, and the distal end ends at the patella (finally connected with the tibia through the patellar ligament).
When all muscle fibers of quadriceps femoris contract, their main function is to "stretch the knee". When the rectus femoris contracts alone, it can bend the hip and extend the knee.
This is described as "under normal circumstances, anatomy stipulates that the attachment point of muscles starts from the proximal side".
Therefore, when the hip joint is fixed, it is equivalent to what you call "near fixation"-the proximal end (hip bone) is fixed, and the distal contraction pulls the calf bone to move, so that the knee joint is "stretched". At the same time, the contraction of rectus femoris pulls the hip bone (hip joint) to move, resulting in hip joint flexion, and the result of joint stress is to do "straight leg lifting" movement.
It can be understood that the attachment point on quadriceps femoris is defined as "starting point" (fixed point). The trunk is motionless, the muscles contract and the legs "pull".
When the knee joint is fixed, it is equivalent to what you call "far fixation"-the distal end (tibia, knee joint) is fixed, and the rectus femoris pulls the hip bone (hip joint) when contracting, and the trunk bends forward! ! It is impossible to "keep the human body upright"! ! ! ! ! But at this time the thighs and calves are relatively fixed and straight.
It can be understood that the lower attachment point of quadriceps femoris is the starting point (fixed point), and the leg itself does not move. But "pulled" the body.