Frontside
Front Thighs, Hip Flexors
Psoas Major, Rectus Femoris, Tibialis Anterior
Visualizing Your Muscle Groups
It can be difficult to learn all of the many muscles in the body. An easier way to understand your body is to think of it as having eight zones in the lower body and eight in the upper body corresponding to a total of sixteen major muscle groups. Each zone encompasses a certain area of your thighs/legs and arms and can be thought of as a tube that courses through your body. There are tubes on the front, back, inside, outside, and the four angles in between.
Balancing Muscle Groups
The front muscles of the lower body are a yin muscle group, traversing the anterior aspect of the thighs and legs.
These muscles are balanced by the back muscles of the lower body, a yang muscle group that traverses the posterior aspect of the thighs and legs.
The lengthening capacity of the front muscle group is limited by the back muscle group's ability to shorten. Stretching the balancing muscle group increases its ability to both lengthen and shorten.
The target muscle group will develop more successfully after the balancing muscle group has been stretched and strengthened. If you still are not making optimal flexibility gains in the target muscle group, you will need to develop the counter-balancing muscle groups.
Counter-Balancing Muscle Groups
Counter-balancing muscle groups are located perpendicular to each other and may also be referred to as opposing muscle groups. Optimal flexibility and strength in the counter-balancing muscle group ensures stability in the rotational vector of the target muscle group. If your target muscle group does not increase in flexibility after developing its balancing muscle group, then you'll need to develop the counter-balancing muscle groups.
The front muscles of the lower body are a yin muscle group, traversing the anterior aspect of the thighs and legs.
The front muscles of the lower body are superficially counter-balanced by the outer muscles of the lower body, a yang muscle group that traverses the lateral aspect of the thighs and legs.
The front muscles of the lower body are deeply counter-balanced by the outer muscles of the upper body, a yang muscle group that traverses the lateral aspect of the arms.
Develop the flexibility and strength of the superficial counter-balancing muscle group to troubleshoot the target muscle group. To troubleshoot further, develop the deep counter-balancing muscle group.
Completing Muscle Groups
Completing muscle groups are the 'top' for lower body muscle groups and the 'bottom' for upper body muscle groups.
The front muscles traverse the anterior aspect of the thighs and legs and its completing muscles traverse the anterior aspect of the arms.