Training around your cycle: what the evidence says

You have been told to train hard in one phase and back off in another. Seventy-eight studies were pooled to test that idea. The effect came out trivial, and the quality of the evidence was rated low.

That opens a better subject, because the cycle matters enormously to a fighter, for a different reason from the one it is being sold on.

What was actually found

A systematic review and meta-analysis published in Sports Medicine gathered 78 studies. Fifty-one had data usable in the pairwise analysis, 73 in the network analysis.

Performance might be trivially reduced in the early follicular phase. The authors then state their own conclusion plainly: because the effect is trivial, the variation between studies is large and many of the included studies were poor quality, general guidelines on performance across the cycle cannot be formed.

Their recommendation was a personalised approach based on the individual's own response.

The other reviews say the same

A separate meta-analysis of 21 papers and 232 participants looked specifically at strength. Trivial effects on maximal voluntary contraction, isokinetic peak torque and explosive strength, all below a Hedges g of 0.2.

The conclusion was that cycle phase does not affect strength-related outcomes.

An umbrella review published in 2023 went further and examined every available meta-analysis on the question. It found scant, low-quality and largely inconsistent evidence of marked differences between phases in strength, performance or hypertrophy.

Why the popular version got so far ahead

Because it is a good story, it sells apps and programmes, and it contains something true.

The true part is that many women feel different across the cycle, and that experience is real. Bloating, sleep, mood, motivation and perceived effort are real, and they affect how a session goes.

What the research says is that when you measure output rather than sensation, and average across many women, the differences mostly disappear. Those two things can both be true, because a trivial average effect can sit on top of large individual variation in both directions.

So the honest position: the cycle may well do something, nobody can tell you in advance what it does to you, and a programme sold on phase-based rules is claiming knowledge that does not exist.

What the cycle is genuinely useful for

The reframe is the part that belongs to a nutritionist rather than to a strength coach.

Menstrual function responds to energy availability. It is one of the earliest visible signals that a body is not getting enough, and it costs nothing to observe: no blood test, no scan, no equipment.

Which makes it the most accessible measurement any athlete in this sport has, and it is being wasted on training calendars.

Sustained low energy availability has been associated in female physiology with reduced estradiol and with functional hypothalamic amenorrhoea. Guidance for female athletes states plainly that missing cycles is not normal for an athlete, and that irregularities warrant clinical evaluation.

Reviews also note something worth saying out loud: menstrual irregularities are often ignored or dismissed in the athletic environment, by coaches, by support staff and by healthcare professionals.

What this means in a camp

Do not plan sparring around a calendar. The evidence does not support phase-based scheduling, and building a camp on it means moving hard sessions for a reason that may not exist.

Do track what happens to your own cycle across camps, to see whether it changes when the work goes up. That change is information about the camp.

Treat a cycle that becomes late or absent during a camp as a stop sign. It is the clearest signal available that the job was too big, and the weight cut is usually part of that picture.

Take your own record to a doctor. Three months of cycle history alongside training load gives a physician something to work with. "My cycles have been a bit odd" does not.

The one place a cycle effect is not in doubt

The scale.

Fluid retention shifts across the cycle, which moves body mass without any change in fat or muscle. For a woman making weight, that shows up as a number on a scale on a specific morning, and it needs to be in the plan rather than treated as a surprise.

That is a hydration question rather than a performance one, and it is covered in the article on the weight cut.

Where I have landed on this

I am not comfortable telling a fighter to train differently on a schedule the evidence does not support.

Seventy-eight studies producing a trivial effect at low quality is not a foundation to build a camp on.

I am entirely comfortable telling her to watch her cycle, because that has a documented relationship with something that genuinely ends careers.

The industry is selling the weak version and ignoring the strong one. If you take one thing from this page, make it that the cycle is a warning light rather than a timetable.