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@split_the_week_wes ·

If body-part splits are supposedly worse than training each muscle twice a week, why is nearly everyone big in my gym doing them?

Every article I read says training a muscle twice a week beats once, and that the classic one-body-part-per-day split is outdated. Then I go to the gym and the biggest, most obviously advanced people there are all doing chest day, back day, arm day.

I do not think they are all wrong, and I do not think the research is fabricated. So the two things must be compatible in a way I am not seeing.

What I would like:

  1. Is the twice-a-week finding real, and how big is the difference actually?
  2. What explains the gap between that and what advanced lifters visibly do?
  3. For someone two years in, training four days a week, which way should that push me?
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  • @idle_hours_ike · 2d ago · 2 replies
    @idle_hours_ike ·

    Both things are true and the reconciliation is that frequency is not the variable that matters — total weekly volume is. Frequency only matters because of how it lets you distribute that volume.

    When the studies find twice a week beats once, the comparison is usually at equated weekly sets. Same total work, split into two sessions rather than one. The advantage is real and it is modest — meaningful over a year, not the difference between growing and not.

    Why it exists: there is a limit to how many hard sets one muscle benefits from in a single session. Somewhere past roughly ten working sets the later ones contribute much less, because you are fatigued and the quality drops. Splitting the same twenty sets into two sessions of ten means more of them are done fresh.

    So the rule is not "twice a week is better". It is "do not cram more sets into one session than you can do well".

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    • @split_the_week_wes · yesterday
      @split_the_week_wes OP ·

      That is the part every article leaves out. "Equated volume" is doing all the work in that sentence and nobody says it out loud.

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  • @tapped_thread_tal · 8h ago
    @tapped_thread_tal ·

    On question 2, there are three separate things and they get blurred together:

    Survivorship. The people you are looking at are the ones who stuck with a programme for years. That is the strongest predictor of how they look, far stronger than the split. A worse programme done for six years beats a better one abandoned twice a year, and it is not close.

    They train more than you think. Somebody with an "arm day" is usually also hitting arms indirectly on chest day and back day. Direct volume once a week; actual stimulus more often. The split's label describes the emphasis, not the frequency.

    Advanced lifters have earned the volume. Twenty hard sets for chest in one session is a genuinely reasonable thing for someone with a decade of training and no job that requires standing up. For most people it is a session that ruins the next three days.

    None of that makes body-part splits optimal. It makes them workable for people who have solved the harder problems.

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