In studies of myonuclear domain (MND) following resistance exercise (RE), it is widely accepted that domain size changes in response to hypertrophy. However, most of these studies do not control for fiber-type transitions — particularly shifts such as type IIx → IIa — that are commonly induced by RE.

This raises important questions:

• Could observed MND expansion be misattributed to satellite cell-driven nuclear addition, when it might actually reflect altered transcriptional capacity within a newly transitioned fiber type?
• Since different fiber types have different baseline MND sizes and metabolic profiles, doesn’t ignoring fiber-type shifts risk systematically distorting MND interpretation?
• Might this oversight lead to incorrect assumptions about satellite cell involvement, training responsiveness, or even age-related regenerative potential?

In short: Is fiber-type transition acting as a confounding variable in MND analysis — and if so, what are we potentially misinterpreting or missing?

If you know of any studies that have addressed this, or if you have methodological approaches to control for fiber identity in MND assessments, I’d greatly appreciate your input.