POSTURAL ADJUSTMENT for Nikolas Petteri

Part 1: The pinky toe to use 

Part 2: Relax to contract

Part 3: The big toe to push off

Part 1: The pinky toe to use

The pinky toe is the smallest among others, and what we can do with this little one is highly limited by any means, say, the range of motion and control we can exert over it. But that doesn’t mean it is insignificant – in fact, its role in postural control during locomotion is invaluable yet often misunderstood – or even deliberately ignored and manipulated for some reasons. That being said, there’s a lot more to see. So let’s get to it.

First of all, the role the pinky toe takes is to be understood as a part of a complex functional unit: the foot, the primary base of support for the human body to stand on its feet. In particular, the arches – a half-dome-shaped structure located in the middle portion of the foot – can be described as a defining feature that characterizes how humans stand, walk, run, and jump.

And as suggested by the name, their functional mechanisms are quite similar to how an arch (the architecture) stays balanced with its own weight – that is to say, they do better with the weight placed on them – the pressure exerted downward – throughout their unique shape: a half-dome. The reason we roll our foot – outward and then inward – during walking and running (and even jumping).

The pinky toe finally comes into play when the foot rolls outward – the initial phase of bipedal locomotion – rolling along the base of the arches, ultimately toward the pinky toe. This outward motion of the foot is called supination. Taken together, the pinky toe is meant to be the one that touches the ground first – to initially withstand the impact force – to move forward in ways that are natural to the functional anatomy of the human body. This mechanism is more apparent when it comes to running or jumping – where the impact force is greater than walking – which can be easily examined by doing so barefoot on the floor or ground.

 

Part 2: RELAX TO CONTRACT

In a broad sense, the initial sequence of locomotion – where the pinky toe is to go first – can be understood as the landing phase, which may come naturally with relaxation – during exhalation.

In general, the downward movement starts from the diaphragmatic relaxation that causes exhalation – the process of expelling the air from the lungs – often requiring abdominal muscles to further relax, especially during dynamic movements – eventually leading to postural change – from an upright to a forward-leaning.

Noticeably, the whole body is, to some extent, affected by the respiratory cycle – comprised of one inspiration and one expiration, closely associated with muscle contractions and relaxations, respectively. And all of which come hand in hand – often with the need for coordination.

For example, the body may become upright during inhalation – as the lungs, located above the abdomen, are distended with the help of abdominal muscles – pulling the diaphragm down to the abdominal cavity, narrowing the abdomen, simultaneously expanding the thoracic cavity (around the rips, chest, and the upper back). And especially, this is the case during locomotion or dynamic movements requiring frequent postural changes – meaning the belly may not inflate and deflate laterally while doing so.

In short, muscle contractions and relaxations are to be cyclic, sequential, and complementary. To execute an intended movement as efficiently as possible, muscles are first to be relaxed, to varying degrees, in preparation for contractions – and vice versa. The very way bodily movements are made and controlled.

Taken together, understanding the cyclic nature of bodily movements is crucial because the second phase of locomotion – rolling the foot inward, called pronation – is what may need to come after the initial phase characterized by the downward motion – which comes with the diaphragmatic relaxation and an exhalation. That is to say, it’s time to inhale and rise – move upward. 

 

Part 3: THE BIG TOE TO PUSH OFF

Pronation – rolling the foot inward – can be described as what begins with the pinky toe – which is meant to be small enough to work closely with the ball of the foot to support the entire body, especially during locomotion. So as supposed by its anatomical feature, the pinky toe is to roll inward when supination ends at it – which is to function as a stabilizer and a facilitator for propulsion – to move forward.

The transition from supination to pronation occurs naturally – quite automatically – while walking, running, and jumping – basic locomotor patterns to be done mainly for moving forward. That is, the foot rolls outward and then inward during locomotion – moving toward the big toe where the sequence ends with it pushing off the ground. Particularly, the mechanics of this forward and upward motion is most clear while sprinting – a robust form of running characterized by the projectile motion.  

Notably, at the final moment of pronation, the heel and the pinky toe are likely lifted from the ground. In contrast, the big toe nearly stands alone, holding up the entire body and pushing it forward in concert with other body parts – such as the knee extending upward, the hips rotating internally, the abdomen getting tensed and extending vertically, etc. To reiterate, this sequence is to be performed in a cyclic and reactive manner during locomotion or dynamic movements – yet which is not to be too conscious about. 

To be continued…

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