Transcription

• Speaker #0

  Hi, and welcome to BioPilates Deep Dive. Today, I'm taking you on a precise journey into the heart of the hip twist, a movement that, behind its apparent simplicity, conceals a true laboratory of stability, control, and the connection between the nervous system and the musculature. I set myself up, seated, with the weight slightly back on the ischial tuberosities. the lumbar spine is in a gentle flexion. while the thoracic spine lengthens. The arms are extended behind me, palms on the floor, fingers turned outward. The scapulae are stabilized down and inward, creating space around the neck and shoulders. The legs are extended in the air, parallel and adducted, the hips flexed as much as possible without losing stability. I inhale to fill the space between the pelvis and the sternum. I exhale to engage the center. Subtly roll a bit further back on the ischial tuberosities and begin drawing a circle with both legs in one direction. The legs remain parallel and adducted throughout the movement. I inhale to complete the circle and return to the starting position. I perform three to five repetitions in each direction, alternating, and I always prioritize the quality of the trajectory over the quantity. My aim is not performance but clarity. I seek the minimum necessary force and the maximum internal organization. The transversus abdominis acts like a belt that draws in. The pelvic floor supports and the deep pelvic wall co-activates. The rectus abdominis and the obliques maintain lumbar flexion and prevent any unwanted rotation. The hip flexors work eccentrically as the legs lower and and concentrically as they lift. In the shoulder girdle, the rhomboids, the middle trapezius, the lower trapezius, the latissimus dorsi, and the teres major prevent collapsing into the shoulders, preserving upper body stability. In a hip movement, we often forget the foot muscles, yet the end of the chain directly influences proximal stability. The quadratus plantae originates from the medial and lateral surfaces of the plantar aspect of the calcaneus and inserts into the tendon of the flexor digitorum longus. Its role is to straighten the pull of this tendon and help flex toes two through five. It contributes to maintaining the plantar arch and distributing forces. The lumbricals originate from the tendons of the flexor digitorum longus and insert into the dorsal aponeurosis and the bases of the proximal phalanges of toes 2 through 5. They flex the metatarsophalangeal joints and extend the proximal and distal interphalangeal joints. In the hip twist, I do not push through the toes, but I maintain an active line down to the distal points of contact. The quadratus plantae and the lumbricals work subtly to organize the plantar arch and transmit clear proprioceptive information upward. An organized forefoot becomes a reference point that secures adduction and the trajectory of the legs in the circle. Every movement begins in the motor cortex. The command travels down the corticospinal tracts to the alpha motor neurons. Myelin speeds conduction by allowing the signal to jump from node of Ranvier to node of Ranvier, preserving timing and precision. The motor nerves reach the quadratus plantae and the lumbricals as well as the transversus abdominis, the obliques, the hip flexors and the scapula stabilizers. The entire body is involved. At the neuromuscular junction, the arrival of the action potential opens calcium channels in the nerve terminal. Calcium triggers the exocytosis of acetylcholine. which diffuses across the synaptic cleft and binds to nicotinic receptors. A local depolarization becomes an end plate potential, then a muscle action potential, which travels along the sarcolemma and dives into the transverse tubules. The dihydropyridine receptors activate the ryanodine receptors in the sarcoplasmic reticulum. Calcium is released, binds to troponin C, shifts tropomyosin, and allows actin-myosin cross-bridges to form. Acetylcholinesterase then breaks down the acetylcholine to prepare for the next contraction. In the background, the spinal cord fine-tunes tone through reciprocal inhibition, Renshaw interneurons, muscle spindles, and Golgi tendon organs. This proprioceptive loop is what prevents compensations. I set the breath as an internal metronome. On the inhale, I expand the ribcage, lengthen the thoracic spine, and create space between the ischial tuberosities and the sternum. On the exhale, I set the pelvis, activate the transversus abdominis, and maintain stability as the legs draw the circle. The descent of the legs is done on the exhale. to resist the lever arm. The ascent is done on the inhale to regain the axis without tensing the psoas. If the shoulders grow heavy, I come down to the elbows to reduce the load on the scapular stabilizers. If the hip flexors tire too much, I slightly bend the knees to shorten the lever and allow the transversus abdominis to take back control. I can also reduce the amplitude of the circle and to preserve pelvic stability and movement quality. A pelvis that rolls to help overloads the quadratus lumborum and the facet joints. Shoulders that sink in overuse the levator scapulae and the upper trapezius. Dominant psoas muscles lock the pelvis in anterior tilt. Conversely, a modest controlled circle strengthens lumbopelvic support, synchronizes breathing and motor control, And and transfers these gains to other movements, such as the teaser, twist on apparatus, walking, or running. I follow Henneman's principle. The small motor units are recruited first. Calm, precise, and regular repetition sculpts brain plasticity. Afferent input from the muscle spindles, the Golgi tendon organs, and the skin recalibrates the balance between excitation and inhibition. What once required conscious attention becomes a postural reflex. I finish as I began, with listening. A clean set today is worth more than a long, approximate set tomorrow. I note what my body tells me, where it pulls, where it leaks, where it holds. I carry away one sentence. I draw small, I draw clean, I draw for a long time. Small, to stay where the center wins. clean to let the distal proximal and axial segments converse without noise, long so the nervous system records, and tomorrow the circle almost draws itself. Thank you for diving with me into this deep dive on the hip twist. Remember, each circle is an opportunity to refine your precision, strengthen your stability, and cultivate harmony between anatomy, breathing, and motor control. practice with awareness adjust with intelligence, and let your body engrave the movement into its deep memory. I'll see you very soon for another episode. Until then, take care of your axis, your points of support, and your breath.