MUD Mired in time...

Above are examples of spastic diplegia with medial leg rotation ‘crouch gait’. The reasons for seeing doctors are typically about this wrong angle and that angle… this bent twisted look vs “nice and straight”. You can’t say “straight” without saying “nice and..” – this was not allowed. Detailed histories disclose that these kids can do just about anything. But, they do not want to. They can’t do it quite well enough or to keep doing (whatever it is) long enough to be satisfying. Free tickets to a theme park? Only if carried or wheeled. Too exhausting -for everybody. FATIGUE is the bush they beat around. More energy required than can be sustained. We see two main patterns of movement in what we do. 1. CONCENTRIC – Each muscle does what it’s name implies. Biceps, a flexor, flexes. Quadriceps, an extensor, extends. Move this thing from here to there? OK. Each muscle does its part CONCENTRICALLY (gets shorter when in action). ATP is required to elongate the muscle AFTER the action – like a crossbow. Nerve trigger unlocks the number of muscle fibers needed to release their already predelivered muscle energy. Heat of RELAXATION = resetting by elongating actin/myosin (ATP). Dead = rigor mortis = contracted everywhere. 2. ECCENTRIC – The muscle trigger unlocks the muscle mechanism to a greater external tension which actually further elongates the muscle. The flexors are extended by eccentric ‘activation’. The extensors are flexed. This has BIG energy savings. In human walking, only the psoas is concentric. It is the cue stick that hits the cue ball. Everything else is ricochet. Leg muscles act eccentrically to divert the energy source as a billiard ball bounces off cushions. All the energy was delivered in the pool stick hit. In gait, the energy savings is immense. This is why we have hips at all!! … to allow eccentric control of walking progression. Less energy. Period! So, when we climb steep stairs? There is no ‘MO’. We go CONCENTRIC, just like the kids with spastic crouch gait whose actual abnormality is that pendulum energy is dampened. The killer: ATP delivery is during RELAXATION (elongation of actin/myosin units) which requires blood flow. Sustained contracted states make blood delivery stop. Muscle ‘activation’ is best when brief with relaxed time to follow for replenishment and removal of pre-Krebs anaerobic waste (muscle will get some of it done anaerobically until O2 is again supplied). If not, cramps. Some odd stuff we see is cramp avoidance.