If you have ever felt “randomly” strong one week and flat the next, you are not imagining things. Hormone levels change across the menstrual cycle, and those changes can influence pain, motivation, fluid balance, and neuromuscular function. The real coaching question is practical: do these shifts meaningfully change maximal strength performance, and should you adjust your strength training or testing?
Below is a single, evidence-first breakdown of one recent systematic review with meta-analysis that pulled together the available studies on menstrual cycle phase and maximal strength.
The Influence of Menstrual Cycle Phases on Maximal Strength Performance in Healthy Female Adults: A Systematic Review with Meta-Analysis (Niering et al., 2024)
Does maximal strength performance differ across menstrual cycle phases in healthy, naturally cycling adult women?
Methods
The authors searched major databases from 1960 to September 2023 and included within-subject studies where women were tested in the early follicular phase (used as the “baseline” because bleeding is easy to identify) and at least one other phase. They grouped strength outcomes into three categories: isometric (force without movement), isokinetic (constant-velocity dynamometer tests), and dynamic (1-rep max style lifts). They then meta-analyzed differences between early follicular and other phases using standardized mean differences (SMD).
Key results
- Overall dataset: 22 studies, 433 women, with wide variation in training status (sedentary to athletes) and in how cycle phase was verified.
- Isometric maximal strength: Early follicular was generally the weakest point. The biggest improvement versus early follicular showed up in the late follicular phase (medium effect), with ovulation also higher (small effect). Luteal-phase results were smaller and mixed.
- Isokinetic maximal strength: The ovulatory phase showed a small improvement versus early follicular. Late follicular and mid-luteal differences were small.
- Dynamic maximal strength (1RM-type): Differences were small. Late follicular was slightly higher than early follicular, and mid-luteal was roughly similar.
- Quality and consistency: Most studies were rated low or very low quality, and results, especially for isometric strength, were highly heterogeneous (meaning effects varied a lot between studies).
Authors’ conclusions (1–2 sentences): Early follicular appears unfavorable for maximal strength across isometric, isokinetic, and dynamic categories. Peak performance was most consistently seen in late follicular for isometric and dynamic strength, and around ovulation for isokinetic strength, but overall confidence is limited by study quality and inconsistent cycle-phase verification.
What the findings mean
Not all “strength” responds the same way
This review is helpful because it separates strength into three buckets:
- Isometric strength (like a maximal mid-thigh pull or fixed-position leg press) showed the clearest cycle signal. The late follicular phase (roughly the week after bleeding ends, before ovulation) tended to outperform early follicular by a moderate amount on average.
- Isokinetic strength (lab-based dynamometer testing) peaked most around ovulation, with small average differences.
- Dynamic strength (1RM-style lifting) moved the least. The average changes were small, which matters for real training. Small effects can still matter for elite performance or testing day, but they are unlikely to justify major program overhauls for most lifters.
Why early follicular might feel harder
Early follicular is typically characterized by low estrogen and progesterone. The review discusses plausible mechanisms: estrogen may support neuromuscular excitability and force production, while progesterone may have opposing effects on cortical excitability. But the practical takeaway is simpler: early follicular is often a time when soreness, cramps, sleep disruption, and perceived exertion can be higher for some athletes, which can reduce top-end output even if the “muscle” itself is not dramatically different.
The big caveat: the evidence is noisy
A key coaching point is that the average effect is not the same as your effect. Many included studies did not verify cycle phases with gold-standard methods (blood hormone confirmation), sample sizes were often small, and protocols varied (rest times, familiarization, encouragement, exercise selection). The review itself labels the overall confidence as low. So treat this as a pattern worth testing in your own training log, not a rigid rulebook.
Synthesis
Where the evidence agrees (within this review)
- Early follicular tends to be a weaker point for maximal strength testing, especially for isometric outcomes.
- Late follicular often looks best for isometric strength, with small benefits for dynamic strength.
- Ovulation often looks best for isokinetic strength, though the effect is small.
Where the evidence differs or is uncertain
- The size of the effect varies widely across studies, especially for isometric strength.
- Dynamic strength changes are small and may not be practically meaningful for many lifters.
- Study quality and cycle-phase identification methods limit confidence.
Evidence-based conclusions (supported by this review)
- 1.If you only adjust one thing, adjust expectations in early follicular, because it is the most consistently “unfavorable” phase for maximal strength across categories.
- 2.Isometric max testing is most likely to look best in late follicular on average.
- 3.Isokinetic max performance trends highest around ovulation, but the average change is small.
- 4.1RM-style strength appears relatively stable across the cycle, with only small average phase effects.
- 5.Because evidence quality is low and individual responses vary, the best strategy is individualized tracking rather than strict cycle-based programming.
What this means for your training
- Plan max testing with intent (if it matters). If you are scheduling a true max test or a high-stakes isometric assessment, late follicular is a reasonable “best bet” based on the average pattern in this review.
- Use early follicular for high-quality work that is not purely maximal. Technique practice, moderate-heavy volume, and controlled hypertrophy work often fit well here. This supports consistency without forcing maximal days when output may be lower.
- Keep your program stable unless you have clear personal data. Because dynamic strength effects were small, most athletes should not dramatically change their strength training split across phases. Instead, adjust with small levers: exercise selection, top-set intensity, or extra warm-up time.
- Autoregulate hard sets with symptoms and performance markers. If cramps, poor sleep, or unusually high RPE show up in early follicular, consider lowering intensity 2–5% or reducing one top set. When you feel great in late follicular, that is a smart time to push heavy singles or low-rep work.
- Track what matters for you. Log cycle day or phase, sleep, symptoms, and 1–2 performance anchors (like top single load, bar speed, or isometric peak). After 2–3 cycles, you will know whether the “average” pattern applies to your body.