Estimated 1-Rep Max (1RM)

A safe strength progression heuristic that estimates maximum capabilities from submaximal resistance training sets.

What this system does

  • Estimates maximum lift capacity (1RM) using the Epley equation.
  • Restricts calculations to sets at or under 10 repetitions to preserve model accuracy.
  • Provides a secure, on-device tracking model with local storage by default.
  • Enables consistent monitoring of strength progress without testing failure.

What it does NOT do

  • It does not measure actual physical or absolute failure thresholds.
  • It cannot predict injury or validate structural joint safety limits.
  • It is not a substitute for clinical diagnostics or athletic training supervision.

The Science of Estimated 1-Rep Max (1RM)

Instead of testing true maximal capacity—which places substantial physical stress and injury risks on connective tissues—Train Libre computes estimated strength limits using the Epley equation.

The Epley equation approximates 1RM using the submaximal weight lifted and completed repetitions: $1\text{RM} \approx w \cdot \left(1 + \frac{r}{30}\right)$, which computes as $w \cdot \frac{36}{37 - r}$.

Peer-reviewed sports science research (e.g. Wood et al., 2002) compares linear and non-linear predictions, confirming that linear submaximal models are highly correlated with true 1RM for lower repetition sets (1–10 reps), keeping strength progression measurements safe and accessible.

Why it is a guide, not a measurement

Subjectivity: Muscular performance fluctuates daily based on sleep quality, nutritional states, and nervous system fatigue. Treat estimations as directional guides.
Accuracy Decay: Estimates are disabled for sets exceeding 10 repetitions, as endurance and fatigue dynamics become non-linear beyond this range.

Evidence & further reading