Fibers and Flexes

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Lumps and bumps:

At the first glimpse all that you would see in a body builder is his flexed muscles- formed of muscle fibers or skeletal muscles, also referred to as lumps and bumps in lay terms.  To flex those biceps and muscles would mean a lot of physiology behind it – to get those lumps and bumps to look attractive, big in size and of various shapes and sizes.

Muscle fibers:

Each muscle is made up of muscle fibers bundled together.  But what are these muscle fibers made up of? Well, their composition is myofibrils – which are made up of a number of myofilaments.  What makes up these myofilaments? – Proteins called actin and myosin.


Proteins (Actin and Myosin) – – Myofilaments – – Myofibrils – – Muscle fiber bundles – – Muscle 

It is the interaction between these proteins that causes a muscle to contract.  When an interaction occurs between these proteins, actin gets activated and myosin crosses the bridges within the sarcomere, thereby causing a contraction.  A sarcomere is the smallest functional unit of the muscle.  If you read where I review Adonis Golden Ratio, the system takes advantage of this interaction.

Muscle Structure:

Muscle fibers are of different types.  The difference in these muscle fibers is because of myosin.

Skeletal muscles have the following four types of muscle fibres:

  • Type I
  • Type II A
  • Type II D
  • Type II B

Myosin determines the differentiation on the basis of speed, size, endurance of muscle fibers,  contraction of muscles and concentration of fibers.

  • Type I fibersare also known as Slow fibers or Slow-twitch fibers.  Out of all the other fibers, they are the smallest and slowest, but have the highest endurance level.  They contract slowly due to slow Myosin ATPase activity.  These fibers have a high myoglobin content, low glycogen levels and use aerobic glycolysis for Adenosine Triphosphate (ATP) synthesis.  They are considered to be the best for endurance as they have a low rate of fatigue.
  • Type II A fibers are also known as Fast Oxidative Fibers.  They too have high Myoglobin content, many capillaries and mitochondria.  They are fatigue-resistant, but moderately, as their glycogen content is moderate.  Their contractile speed is fast.
  • Type II B fibers are also known as Fast-twitch or White fibers.  Out of all the other fibers, they are the largest and fastest, but have the lowest endurance level.  They, however, do not rely on oxygen for fuel.  Their myoglobin content is low.  They have a few capillaries and mitochondria.

Every muscle contraction recruits the Type I Fiber first slowly, followed by the Type IIA, IID and IIB muscle fibers as the speed of contraction is increased.  They rely on glycogen for fuel and are very good for intense and powerful training, movements, resistance training etc; but tend to fatigue quickly.

Energy production:

The human body utilizes two types of energy systems, which produce ATP or Adenosine Triphosphate.  The ATP is used by the muscles for contraction.  Based on the energy production, the systems are classified as follows:

  • Aerobic
  • Anaerobic

The details of the systems are:

Aerobic system: This system utilizes proteins, fats or carbohydrates for supplying ATP, as long as oxygen is present.  The power it provides is moderate.

Energy production: is medium to very long, which accounts to less than 85 percent of the maximum output

  • By-products of this system: water, carbon-dioxide, heat

Anaerobic system: This system utilizes only carbohydrates for the production of ATP.

Oxygen is not utilized.

  • Energy production: short duration (just 45-70 seconds), but with high power
  • By-products of this system: heat, lactic acid.  These by-products cause muscle soreness soon after an exercise; whereas muscle soreness a day or two after work-outs and exercises is caused due to torn muscle fibers.  Stretching exercises, warm-up sessions and cooling down adequately can help to reduce the soreness.

Body types:

Depending on the musculature and built, body-types help an individual to determine what exercises work best for them for muscle building.  Some of the common classifications of body-types are:

The Ectomorph:

  • Delicate Built Body
  • Flat Chested
  • Fragile, Lean
  • Lightly Muscled
  • Small Shouldered
  • Takes Longer to Gain Muscle
  • Thin

The Mesomorph:

  • Athletic
  • Hard Body
  • Hourglass Shaped (Female)
  • Rectangular Shaped (Male)
  • Mature Muscle Mass
  • Muscular Body
  • Excellent Posture
  • Gains Muscle Easily
  • Gains Fat More Easily Than Ectomorphs
  • Thick Skin

The Endomorph:

  • Soft Body
  • Underdeveloped Muscles
  • Round Physique
  • Weight Loss is Difficult
  • Gains Muscle Easily Like the Mesomorph.

Sometimes people fall into mixed categories, with a combination of one or more body-types; such as ecto mesomorphs, or endo mesomorphs.  People could have soft bodies wit around physique and thick skin; while others could have a hard body with small shoulders and the likes.

Physiology of muscle growth:

Muscle growth is also known as ‘muscle hypertrophy’.  It is a type of muscular adaptation and change.  Muscles adapt and change as and when they are used.  The extent to which a hypertrophy occurs is largely determined by the age and weight of the individual, besides other individualistic factors.

Resistance training is the best possible way to induce muscular hypertrophy.  It leads to neural adaptations, owing to which there are changes in the strength, size and endurance of muscles.  Muscle hypertrophy also occurs during high intensity resistance activities like weight-lifting.  The number of muscle fibers remains the same; while the cross-sectional area of all the muscle fibers increases.

Muscles and bodybuilding:

Training our muscles regularly helps to gain maximum muscle size.  A combination of bodybuilding power-lifting and bodybuilding prove to be the best.  Bodybuilding stresses the Type I and II A fibers, while power-lifting stimulates the II B fibers.  Using a combination and variation of two or more sets of exercises and training can result in long-term bodybuilding and the related regimes.

The body gets used to a certain set of exercises and a pattern forms.  This routine results in diminished effects.  Thus, one has to keep alternating the routines and training sessions, especially in terms of training volume, intensity and techniques.   Knowing your body-type and teaming it up with the right set of exercises is vital to healthy muscle building.

Category: Bodybuilding

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