Twice the muscle from the same twelve weeks, and no stronger for it

Every physiotherapist who works with women in their fifties has noticed the same thing, and most of them have stopped mentioning it because it sounds like an excuse.

The programme is right. The loading is right. The person turns up and does the work. And the response is smaller and slower than the same programme produces in the same woman ten years earlier, or in her husband next to her.

There is now a trial that goes some way towards explaining why, and it is worth reading carefully, because the headline result and the useful result are not the same result.

The trial

A Danish group ran a double-blind randomised controlled trial in early postmenopausal women. Thirty-one of them, healthy and untrained, average age in the early fifties, all within five years of their final period and all confirmed postmenopausal on bloods.

Everybody trained. Twelve weeks, three supervised resistance sessions a week, thirty six sessions in total. The only difference between the groups was a patch: transdermal estradiol at 100 micrograms per 24 hours, or an identical placebo. Neither the women nor the researchers knew which.

The primary outcome was not a questionnaire or a gym number. It was the cross-sectional area of the quadriceps, measured on MRI.

Read the last sentence of that box again, because it is the one that matters in a clinic.

More muscle, and no stronger. That is not a contradiction, it is a warning

Nearly double the growth in the muscle that lifts you out of a chair, and no measurable difference in what that muscle could actually do. Not in maximal force, not in a five rep max, not in jumping.

Anyone who has read the falls literature will recognise the shape of this immediately. Size and function are related, but they are not the same quantity, and the one that predicts whether somebody can get off the floor is function. A programme that grows tissue without improving what the tissue does has not finished the job.

The hormone appears to build the material. It does not appear to teach the nervous system what to do with it. Those are two different problems and only one of them comes on a patch.

The honest reading is that twelve weeks is a short trial in an untrained group, that thirty one people is a small sample, and that strength gains early in a programme are mostly neural anyway. It is entirely possible that the strength difference appears later, once the extra tissue has something to say. It is also possible that it does not. Nobody has run the longer trial.

What the biggest trial found, and the part that gets left out

The Women's Health Initiative randomised 10,739 postmenopausal women who had had a hysterectomy to daily conjugated equine estrogens or placebo, and asked them about their joints.

Joint pain was less common on estrogen. At one year, 76.3 percent against 79.2 percent, and the difference held out to year three.

Three percentage points. From a trial with nearly eleven thousand women in it, which is large enough to find almost anything. Real, reproducible, and much smaller than the way this finding usually gets described.

And there is a second result that rarely travels with the first. Joint swelling was more common on estrogen, 42.1 percent against 39.7 percent. Less pain, slightly more swelling, in the same trial, in the same women.

The pooled answer on strength

A meta-analysis gathered 23 studies comparing muscle strength in postmenopausal women on estrogen-based hormone therapy against those not on it.

The overall effect size was 0.23 (p=0.003), which the authors translate as roughly 5 percent greater strength.

Five percent is not nothing. Across a population it is meaningful. Across one person in a treatment room it is smaller than the difference a good month of training makes, and far smaller than the difference between training and not training.

Why any of this might work

The mechanism people reach for is collagen, and there is a study behind it. Postmenopausal women on oral estrogen were compared with non-users, at rest and after one-legged resistance exercise, with tendon collagen synthesis measured directly using stable isotope incorporation.

After exercise, the tendon collagen synthesis rate was 86 percent higher in the estrogen users.

That is a striking number and it should be held loosely. This was ten women against ten women, and they were habitual users compared with non-users, not randomised. Women who choose hormone therapy differ from women who do not in ways that are difficult to fully account for. It tells us the tissue is listening to estrogen. It does not tell us how much difference that makes to a tendon that is actually injured.

How to hold that honestly

One more boundary, and it is the important one. Nothing here is an argument for or against taking hormone therapy. That decision rests on a much wider balance sheet than muscle, it is different for every woman, and it belongs in a consultation with a doctor who knows her history. Muscle and tendon are one column in that ledger and a fairly small one.

What we take from it in practice

The response really is different, and saying so is not making excuses. A woman in her early fifties putting identical work into an identical programme may build less tissue than she would have ten years earlier. Naming that honestly is better than letting her conclude she is doing it wrong.

Do not let the patch be the plan. The estrogen group in that trial did thirty six supervised sessions. Every woman in it trained. Hormone therapy changed how much muscle the training produced. It did not produce muscle on its own, and nothing in this literature suggests it would.

Train function separately, because the tissue will not do it for you. Twice the muscle and no measurable strength gain is the clearest possible argument for keeping the heavy, specific, deliberately practised movements in the programme rather than assuming that a bigger quadriceps will look after itself.

Ask the question, and pass it to somebody who can answer it. Whether a woman is on hormone therapy is worth knowing, in the same way her thyroid and her blood sugar are worth knowing. It is not a physiotherapist's decision and never should be. It is context, and it is context that changes what a reasonable twelve week expectation looks like.

Be honest about the size of the effect. Five percent on strength, three points on joint pain, roughly double the muscle gain in one small trial. Those are real findings and they are modest findings, and the internet reports them as though they were transformative. Nothing here beats showing up three times a week, and the trial that appears to prove the hormone's value is also a trial in which everybody trained.