muscle

Movement, we all do it. Whether it is typing on our phones, walking across our homes, or playing our favorite sport our bodies movement is made possible by our muscles, without them we would be stuck. It is interesting to look at how muscles are formed, what they are made up of, and how they grow larger.

Muscle development begins in the womb! Through a four step process known as Myogenesis.
1. Formation is where the primary layer, the mesoderm, is formed.
2. Separation occurs and the mesoderms separate into blocks called somites
3. Proliferation myogenic cells, which are the muscle forming cells begin increasing.
4. Differentiation the cell then fuse into myotubes before eventually maturing into myofibers.

Inside our muscles are composed of many pieces all working together.
Sarcomere: the basic unit of muscle.
Somites: A group of sarcomere
Myofibril: Rod like units that contain sarcomere.
Myofilaments: found within the myofibril, there are two kinds myosin which is a thick filament, and actin which is a thin filament.
Myocyte: A cell made up of myofibrils.
Myoblasts: Early cells in the mesoderm
Mesoderm: primary layer in the embryo

Knowing a bit about our muscles anatomy, how then do our muscles grow bigger?  The simple answer is exercise. Muscles work by contracting, lifting a load upward for a concentric contraction, lowering a load would be an eccentric contraction, and holding a load steady would be a isometric contraction.

Three ways to promote muscle growth through exercise are:

-Creating tension with our exercise intensity stimulates growth.

-Muscle damage through eccentric exercises creates an inflammatory response triggering growth.

-Metabolic stress that is associated with resistance training, stimulates a hormonal growth  response.

Strength training, when it is beneficial? Training for stronger muscles can be extremely beneficial not only for athletes, but for everyday life. But how should strength training change with age? At what age is it safe to begin a strength training regime? Lets break it down into what is recommended at different ages.

Younger children, less than 5 years old, should not do any strength training. At this young age they are simply not coordinated enough to safely perform strengthening exercises. At this stage muscles are still uncoordinated, and lack flowing movement patterns. Furthermore strength training at this age has not been shown to reduce injuries, or enhance sports performance.

Older children, 6-13, can begin a strength training program as early as 7 years old. By that age children are more coordinated, have better balance, and body control. As long as the exercises are performed with proper form, and instruction strength training can enhance athletic performance.

Older adults, fast forward to about 30 years old, and our muscles begin to age. Due to changes at the cellular level as we age our muscles take longer to repair, and recover after exercising. As we age we have a loss of muscle mass, creating not only a loss of physical strength, but also a loss of protein stores. Protein stored in our muscles gives us our energy reserves, when those are lessened we have a decline in energy, and a decline in reserves needed in case of illness. Sarcopenia is the term for age related muscle mass, which results in decreased size and quality of muscle. Resistance training is an important tool in preventing sarcopenia. Older adults should perform 1-2 sets of 6-8 repetitions with the last repetition leading to failure, 2-3 times a week.