There are approximately 320 pairs of muscles (in total approximately 640) in a human body. They are amazing protein filaments which form a tissue called muscle in our body. Muscles surround the bones and when they contract and release, they massage us from inside: their contractions assist in blood circulation and make even our organs slightly shift location or change shape. Take the diaphragm for example – its contraction and release make the organs below the diaphragm move up and down respectively. In order for muscles stay tuned, we need exercise them actively throughout our lives.
Every movement we do is like a complex coreography of bones, joints, connective tissue, nerves, blood vessels and muscles. Our heart is also a muscle although the muscle there is called cardiac muscle and it works somewhat differently from the skeletal muscles which this text will primarily focus on. Skeletal muscles can be consciously controlled whereas cardiac muscle is governed autonomously
Muscle cells or fiber, also known as myocytes are long, tubular cells which contain protein filaments of actin and myosin that slide past one another, producing a contraction. Both the length and the shape of the cell changes during the contraction. Each muscle fiber is surrounded by a layer of connective tissue and every muscle is surrounded by it, too. This connective tissue is called fascia.
There are two basic types of exercise or energy expenditure in the body also related to the potential and oxygen intake of the resporatory cavity – aerobic and anaerobic.
- Aerobic means “with oxygen” because your muscles use oxygen and carbohydrates to fuel aerobic exercise
- Anaerobic means “without oxygen” as the muscles rely on carbohydrates.
Drawing: “Skeletal muscle”.
Licensed under CC BY-SA 3.0 via Wikimedia Commons
Aerobic capacity is the amount of oxygen consumed by the body during exercising. In aerobic respiration, oxygen helps enzymes metabolize energy through the glycolysis process. In anaerobic respiration, the cells have to use fermentation to keep the metabolism going and fermentation creates a waste byproduct called lactic acid.
Training the body to handle heightened levels of lactic acid can lead to greater performance in short duration. Training body to handle the anaerobic mode is used in exposive sports such as short distance running (Usain Bolt is good at it). However, activities lasting longer than about two minutes have a large aerobic metabolic component.
When lactic acid is released, this also heightenes stress levels in the body. Lactic acid in blood plasma is significantly elevated during stress situations or during anaerobic exercising. This is why according to a recent study I happened to read heavy exercising can sometimes augment stress, not to give a releaf to it. There is also a connexion between adrenaline and lactic acid – when the body starts to produce the hormone adrenaline in a flight or fight situation, adrenaline directly increases lactate release.
The intensity of exercise which causes that muscles can keep functioning in the aerobic mode, is different in different people. It depends also on age and physical fitness. The end of aerobic and the beginning of anaerobic is usually measured by heart rate per minute. The heart rate for a 30 year old can be 150 per minute in order to get to the anaerobic level. The more people age, the lower the rate per minute is. For example, for a 50 year old it only takes 135 beats per minute to come to the anaerobic level. At rest the heart beats ca 70-80 times per minute.
Yoga is a practice which is intended to be running primarily on aerobic level although there are different kinds of yoga which can also take the practitioners to the anaerobic mode. Why is the aerobic mode preferred and predominant in yoga?
Although some muscles may sometmes be running in the anaerobic mode, the idea is to relieve tensions and by controlled slow and deep breathing make sure that there is enough oxygen supply to keep the heart from racing and the body producing high amounts of lactic acid. When exercising in an anaerobic mode, there is no stillness of mind. Think of throwing a stone into a big ant nest. It get’s busy and agitated, right. Same with a heavily exercising body – it just has too much stimuli to process.
There is no muscle in the body that works alone. Based on whether we run, sit, carry something heavy or dance, different muscles in the body are either married, divorced or indifferent to each other. Mucles are amazingly efficient – they can calibrate how much effort they have to put into a movement and use the minimum amount required (unless their owner pushes them consciously to behave differently).
It is important to remember that people are different and not in every body does the same muscle the same amount of work in the same position. In yoga practice, the idea that each human body works somewhat differently and there are variations in muscular movement, can help to keep an open mind in asana practice. This being said, this does not mean that you can do whatever you like. If you keep holding the weight of your body either on the outer or inner side of your feet, this is bound to create imbalances and strain some leg and thigh and even back muscles too much and some too little. Same if you keep rounding your shoulders forward and bowing the head while working behind the computer, it is bound to shorten your anterior neck muscles, pectoralis minor (connects the bones of the chest to the shoulder) and the anterior deltoid muscle (the muscle on top of the shoulder and upper arm) among other things. At first it gets uncomfortable and after a while it can cause pain.
It is also important to remember that muscles and fascia are interconnected. The connective tissue facia, which surronds muscles like a thin coating or separates organs, has up to 10 times more sensory receptors than the muscle. One could say that nothing in the muscles takes place wihtout the supervision of the fascia. It is like the muscle’s personal trainer which tells how much it needs to contract or release. A damn good personal trainer though and well informed about the exact conditions and capabilities at the very moment.
As a yoga practitioner it is good to be aware what limits you want to test with your yoga practice. Regardless of what your muscles do, there is the anatomy of your body, too. Yoga comes from a country where people in general have a much greater range of movement in the hip joint. Watch any Bollywood film featuring a scene with dancers, and you notice that these hip openings are much more challenging to a regular dancer in the Western world. As a yoga teacher, it is good to know how to work with a less flexible hip joint when using asanas developed for a more flexible range. And then there’s the ego. My modern dance teacher once told me (she is teaching dance at a university) that she never met a student who understood the limits without having injured him or herself first. Next time I will write about the consequences of listening to the ego. 18+ years of yoga practice has included quite many trials and errors. I guess my modern dance teacher was right…
More reading:
The top 5 ways facsia matters to athletes
Yoga anatomy. 2012. Leslie Kaminoff, Amy Matthews
http://en.wikipedia.org/wiki/Muscle
http://www.livestrong.com/article/158315-what-is-anaerobic-respiration-in-humans/
http://en.wikipedia.org/wiki/Aerobic_exercise
http://www.innerbody.com/image/musc08.html