Research

Mixed

Mechanical loading induces skeletal muscle growth primarily through myofiber hypertrophy (increase in cross-sectional area) and fascicle architectural changes (increased length and pennation angle), rather than hyperplasia (increase in fiber number).

To maximize muscle growth, focus on resistance training that creates significant mechanical load. Expect your muscle fibers to get thicker (hypertrophy) and your muscle architecture to adapt (changes in fiber length and pennation angle). Do not rely on the idea that you are creating entirely new muscle fibers (hyperplasia), as evidence for this is weak and controversial.

GoodSupportsHIGH confidence
Myofiber hypertrophy is, by far, the longest-standing and most widely acknowledged contributor to the mechanical load-induced growth of skeletal muscle... The magnitude of change in myofiber CSA observed in the above examples is similar to the 10–35% that is typically observed in humans after 8-16 weeks of resistance exercise... mechanical loading can lead to both longitudinal and radial growth of fascicles... the notion that extreme forms of mechanical loading can induce hyperplasia remains controversial.
Kent W. Jorgenson et al. · Cells · 2020

Why this rating

High volume of human and animal studies cited for hypertrophy; hyperplasia evidence is conflicting.

Source

Identifying the Structural Adaptations that Drive the Mechanical Load-Induced Growth of Skeletal Muscle: A Scoping Review

Kent W. Jorgenson et al. · Cells · 2020

DOI 10.3390/cells9071658

narrative_reviewCited 154×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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