Our flexor muscles—such as the biceps, pectorals, and hip flexors—are predominantly composed of slow-twitch (Type I) fibers. These muscles are built for endurance, can handle continuous load, and play a significant role in supporting the body against gravity. Neurologically, the flexor muscles tend to be activated earlier than their opposing extensors, making them more innervated and neurologically dominant.
While both flexor and extensor muscle groups develop simultaneously during embryonic growth, the fetal position in the womb favors flexion. This curled posture enhances neural development and tone in the flexors, embedding a neurological preference that often carries into postnatal life.
As a result, flexor muscles tend to be overactive, short, and tight—contributing to postural imbalances. In contrast, extensor muscles like the rhomboids, spinal erectors, and glutes are often underutilized and require conscious activation and strengthening to restore balance.
In therapy, we focus on releasing the overactive flexors and activating the underused extensors. For example, engaging the rhomboids helps open the chest, and strengthening the lower back muscles supports spinal extension.
To release the tight hold of flexor muscles, I employ techniques such as Muscle Energy Technique (MET) and joint oscillation. These methods help re-educate the nervous system, providing new proprioceptive input that encourages the muscle to relax and find a new, balanced resting tone.