# @mackinprof on Instagram

- **Type:** Image
- **Original URL:** https://www.instagram.com/p/Dd80_zOoPEB
- **Gondola URL:** https://gondola.cc/posts/71016079-mackinprof-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/8f72b5d93e.jpg
- **Posted:** 2026-10-01T11:42:39.000+00:00
- **Account Owner:** Stuart Phillips (@mackinprof) — https://gondola.cc/mackinprof

## Caption

Lift heavy sht if you like it. Just stop telling people they NEED to. Sufficient means it gets the job done; need means nothing else will, and those are two different tests. Heavy passes the first one easily. The second? For most of what people lift for, no.

Take muscle. In our lab, 18 young men trained for 10 weeks and their quads grew 6.8% at 30% of max and 7.2% at 80%. No difference. Three meta-analyses have since landed in the same place, with one catch (and it's a real one): light sets have to be hard. Strength is where heavy earns its keep. Want a bigger max? Lift heavy, because you get good at what you practise.

Bone is messier, and I'd rather say so. It needs load, no argument. Some trials favour heavy, and the spine numbers lean that way. Pool the head-to-head comparisons, though, and most can't find a clear winner. Then there's LIFTMOR, the trial everyone quotes: heavy lifting plus impact, supervised, pushed spine density up 2.9% in 8 months in women with low bone mass. A real result. But the comparison was a light home program, so it can't tell you whether moderate loads, progressed, would do the same. Sufficient, yes. Need, not proven.

What you do need is effort. And if you want to keep improving, progression: more load, more reps or more sets. Pick one and keep going. About 28% of US adults strength train twice a week (2018 data), and I can't see how telling the other 72% it only counts if it's heavy gets anyone started. Love lifting heavy? Fill your boots.

Refs: Mitchell 2012 J Appl Physiol; Schoenfeld 2017 J Strength Cond Res; Lopez 2021 Med Sci Sports Exerc; Refalo 2021 J Sports Sci; Currier 2023 Br J Sports Med; Souza 2020 Exp Gerontol; Kast 2022 Osteoporos Int; Shen 2026 Geriatr Gerontol Int; Watson 2018 J Bone Miner Res; Currier 2026 Med Sci Sports Exerc (ACSM Position Stand); Hyde 2021 J Phys Act Health

#evidencebased

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## Tags

evidencebased

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