The Most Misunderstood Fitness Myth EVER!

The myofibrils housed within skeletal muscle fibers are the primary contractile units, comprising sarcomeres that generate force upon neural activation. Meanwhile, the mitochondrial reticulum facilitates energy production, and the sarcoplasmic reticulum serves as the reservoir for calcium, essential for muscle contraction.

These components, as research suggests, constitute the major portion of muscle fibers, with myofibrils occupying approximately 85% of the intracellular space. Beyond these structures, muscle fibers harbor various organelles, metabolic enzymes, and ions crucial for physiological functions. Additionally, stored substrates like glycogen and triglycerides provide energy. Muscle fiber size, notably its cross-sectional area, predominantly increases through myofibrillar protein synthesis (MPS) and myofibril accretion induced by resistance training (RT) over weeks to months.

This conventional hypertrophy involves enlarging individual myofibrils or splitting them to create new ones, leading to muscle fiber growth. Another phenomenon, sarcoplasmic hypertrophy, involves an increase in sarcoplasm volume relative to myofibril growth, albeit to a lesser extent. It may occur alongside myofibrillar hypertrophy, possibly facilitating it by priming the cell spatially and energetically.

However, its role remains less defined, especially in response to different RT protocols. Future studies are needed to elucidate the nuances of muscle growth in various training contexts, as hypertrophic responses vary among individuals. Despite this variability, the scientific consensus affirms muscle hypertrophy in response to RT across diverse populations, indicating its efficacy as a training modality.

Source:
https://doi.org/10.3390/cells9071658

https://doi.org/10.3389%2Ffphys.2020....

https://journal.iusca.org/index.php/J...