Why Can’t I Open the Jar Anymore?
Body · The Reading Room, Vol. 28 · 7 min read · Why strength falls faster than muscle does, what the mirror cannot tell you, and the one task worth taking back this week
Based on the published research of Matthew J. Delmonico, PhD, MPH — Associate Professor, Department of Kinesiology, University of Rhode Island. Faculty profile
Losing strength after 50 does not track the size of your muscles. In one long study, strength fell two to five times faster than muscle did, and gaining weight protected nobody.
A jar of passata, at ten past seven, with people arriving at eight.
You run it under the hot tap. You use the tea towel. You do the thing with the back of a spoon that your mother did. And then you carry it into the next room and hand it to somebody without saying anything about it, and you go back to the onions.
It is a small moment and you have had a version of it about six times this year. The suitcase into the overhead locker. The second bag of shopping. The window at the back that has always been stiff and now is not worth the argument.
None of it is dramatic enough to mention to anyone. Which is precisely why nobody mentions it to you either.
The short answer: losing strength after 50 is a real and measured change, and the thing that makes it confusing is that it does not track muscle size. In a study following 1,678 adults, strength fell two to five times faster than muscle area did.¹ The people who gained weight over the follow-up still lost strength, despite a small increase in muscle.¹ So the mirror cannot see this, the scale cannot see it, and the first honest signal most women get is a jar.
The skim version
- In 1,678 adults followed over several years, annual loss of strength was two to five times greater than annual loss of muscle area.¹
- Weight gain did not prevent strength loss. Participants who gained weight, and gained a little muscle with it, still lost strength each year.¹
- That cohort was aged 70 to 79 at baseline, which is two decades older than most women reading this. The direction is well established. The size of it at 52 is not what this study measured.¹
- Separately, lean mass in women shifts from rising slightly to falling slightly at the start of the menopause transition, at about 0.2 per cent a year.²
- Both findings point the same way: strength is a separate quantity from size, and it needs its own signal.
Why losing strength after 50 does not show up in the mirror
Because strength and muscle size come apart, and they come apart in a direction nobody warns you about.
The Health ABC study followed 1,678 older adults and measured both things repeatedly: the force their legs could produce, and the cross-sectional area of the muscle producing it. Both declined. What was striking was the ratio. Strength losses ran two to five times greater than the loss of muscle each year.¹
Read that as an instrument problem and it becomes useful. Anything you can see, in a mirror or a photograph or a dress that used to fit differently, is reporting on size. Size is the slower-moving of the two quantities. The faster-moving one is invisible until the day it meets a jar.
The second finding in that paper is the one that dismantles the most common assumption. Participants who gained weight over the follow-up, and gained a small amount of muscle along with it, still lost strength annually.¹ More muscle did not buy strength. Whatever is changing is about the quality of the tissue and the signal reaching it, not the quantity of it.
What the research found
Delmonico and colleagues, publishing in the American Journal of Clinical Nutrition in 2009, tracked 1,678 men and women and reported annual declines in knee extensor strength of roughly 3 to 4 per cent against muscle-area declines of roughly 0.5 to 1.9 per cent. Weight gain did not prevent the strength loss, and the participants who gained weight still lost around 2 to 3 per cent of their strength a year.¹
The limitation, and it is a big one: those participants were 70 to 79 years old at baseline. A woman of 52 is not in that population, and applying their annual percentages to her is an extrapolation, not a finding. What survives the gap is the structural point, that strength and size decline at different rates and the visible one is the slower one. The specific numbers belong to people twenty years further along.
If the reason the jar goes into the next room is less about your grip than about not wanting to be seen struggling, that is a different mechanism and it costs more. The Quiet Audit is a private ten-minute pass through what you are currently managing to look fine about. Start here.
What the menopause transition adds to this
A second, smaller change, running underneath the first and starting earlier than most women expect.
The body-composition work from the Study of Women’s Health Across the Nation found lean mass reversed direction at the start of the transition. Before it, lean mass was drifting upward by about 0.2 per cent a year. During it, the same measure drifted down by roughly the same amount, and that continued until about a year and a half after the final period, when the rate flattened.²
That is not a large number and it is not meant to alarm anybody. It matters because of the timing. It means a woman in her late forties is losing lean mass and gaining fat at the same time, on a scale that barely moves, in a period where she is also being told to worry about her weight. The composition side of that has its own piece, and this is the strength side of the same window.
What the jar is actually reporting
| What you are watching | What is actually moving | |
|---|---|---|
| The instrument | Mirror, scale, the way clothes fit | Whether a specific task still works |
| What it measures | Size, which changes slowly | Force, which changes two to five times faster |
| How you find out | Daily, and it tells you nothing | Once, at ten past seven, holding a jar |
| What you usually do | Change what you eat | Hand the task to somebody else |
The last row is the one that compounds. Handing over the jar solves the evening and removes the only load that task was still supplying, and there are usually six or seven of these substitutions running before anyone notices there is a pattern.
What to change first, and why it is not a gym
Take one task back.
Pick the specific thing you have quietly started handing over. The jar, the top shelf, the case into the boot, the walk up rather than the lift with the shopping. One of them, chosen because it happens weekly anyway, and do it yourself this week even though it is slower and mildly annoying.
The reasoning is not motivational. Load is the input that maintains the tissue, and task substitution removes load without ever announcing itself as a decision. You did not decide to stop lifting things. You decided, six separate times, that this particular evening was not the moment. The aggregate of those six decisions is a training programme running in reverse.
Resistance work has a serious evidence base in this age group and it is the right next conversation, with someone who knows your joints and your history. It is also a bigger ask than most women in the middle of a full year will actually start. Taking one task back costs nothing, needs no equipment, and reverses the mechanism that is quietly doing the damage. If pain rather than force is what stops you, that is a different problem and worth separating out first.
The source for this piece
Matthew J. Delmonico, PhD, MPH
Associate Professor in the Department of Kinesiology at the University of Rhode Island, whose research tracks how strength, muscle quality and fat infiltration change across ageing populations.
What we read: Delmonico, M. J., et al., The American Journal of Clinical Nutrition (2009), the Health ABC longitudinal analysis.¹
Where to follow his work: Faculty profile
Who else has measured this
The strength-versus-size gap is not one study’s idiosyncrasy. It is built into the history of the word used to describe it.
Irwin H. Rosenberg, MD (faculty profile · The Conversation), of Tufts University, coined the term sarcopenia in 1988 specifically because he judged muscle mass alone an inadequate measure of what ageing takes from the body — the same distinction the Health ABC data would later quantify.²
Two vantage points, four decades apart: the researcher who named the gap in 1988, and the cohort study that measured it directly. Both point at the same instrument error.
The mirror cannot see this. The scale cannot see it. The first honest signal most women get is a jar.
Questions worth having an answer to
Is this the same thing as sarcopenia?
Related, and the words have drifted apart usefully. Loss of muscle mass is one quantity. Loss of strength is another, and the research above found the second moves faster than the first. Clinicians increasingly measure both, which is a reasonable thing to ask about.
Would gaining weight help?
The data says no. Participants who gained weight, and a little muscle with it, still lost strength every year.¹ That finding is worth holding onto, because it removes a whole category of advice that sounds sensible and is not supported.
How would I know if this is worth raising medically?
A gradual change across several tasks over a couple of years is the ordinary pattern. Weakness that arrives quickly, affects one side, comes with numbness or pain, or interferes with walking or grip in a way you can date to a particular month, is not that pattern and belongs with your clinician promptly.
Is it too late to change anything?
The literature on resistance training in older adults is one of the more encouraging bodies of evidence in this whole field, and it includes people considerably older than you. This is not the part of the transition where the window closes.
The one move
Name the one task you have started handing over. Write it down in five words. Then do it yourself the next time it comes round, even though it is slower and you will be aware of doing it.
If handing it over was never really about the jar, the Quiet Audit is a private pass through what you have been managing to look fine about. Start here.
On the researcher. Matthew Delmonico is an exercise physiologist, not a physician: his Health ABC analysis is longitudinal cohort research in adults 70 to 79, and applying its annual rates to a woman of 52 is an extrapolation the paper itself does not make.
Sourcing, disclosure and disclaimers
This is not medical advice. Blue Leaf Journal publishes general information for a general readership. Nothing here is a diagnosis, a treatment recommendation, or a substitute for care from a clinician who knows your history.
We are not clinicians. Blue Leaf Journal is an independent publication. We read published research and translate it. The findings belong to the researchers and institutions named and linked above; the plain-English rendering is ours, and so is any error in it.
No affiliation and no endorsement. Blue Leaf Journal is not affiliated with Matthew J. Delmonico, Irwin H. Rosenberg, the University of Rhode Island or Tufts University. None of them has reviewed, approved or endorsed this article, and none of them is responsible for it. They are cited because their published work is the evidence for what it says.
No commercial relationship. Nobody named above paid for or was paid for this coverage. There are no affiliate links, no sponsored placements and no gifted products in this article.
How this was checked. Every figure above is drawn from the primary papers, each linked in the references, and can be verified there. Sources were checked on 6 September 2026. If you find something we have got wrong, write to norawhitfield@blueleafjournal.com and we will correct it and say that we did.
References
1. Delmonico, M. J., Harris, T. B., Visser, M., et al. (2009). Longitudinal study of muscle strength, quality, and adipose tissue infiltration. The American Journal of Clinical Nutrition, 90(6), 1579-1585. Read the study
2. Greendale, G. A., Sternfeld, B., Huang, M., et al. (2019). Changes in body composition and weight during the menopause transition. JCI Insight, 4(5), e124865. Read the study
Nora Whitfield writes the Body desk at Blue Leaf Journal, where the working rule is that a mechanism you can name is easier to live with than one you cannot. She reads the limitations section before the conclusion, and passes on what she finds there.
Written by Nora Whitfield for Blue Leaf Journal. Updated: 30 August 2026.
