O'Conner 1RM Calculator
Evaluate named O’Conner repetition/load regression on 1–12 observed repetitions; distinct from existing Epley/Brzycki comparison, not measured maximum, load prescription or lifting safety.
Description
O’Conner’s linear repetition correction gives a modeled one-repetition maximum.
O’Conner’s linear repetition correction gives a modeled one-repetition maximum. The named model uses a 2.5% load increment per repetition.1
The returned values include Regression estimated one rep max kg. The How section below explains the calculation, input rules and interpretation.
When to use O'Conner 1RM Calculator
Use O'Conner 1RM Calculator when you need to evaluate the supplied records under the calculation and evidence rules below. No measured maximum, lift prescription or lifting-safety determination is supplied.
Prepare the observed race, match or training records and the stated units. Supply independently verified rule editions, calibration tables and targets where requested.
How to use O'Conner 1RM Calculator and understand its results
- Prepare the observed race, match or training records and the stated units. Supply independently verified rule editions, calibration tables and targets where requested.
- Enter observedLoadKg, observedRepetitions using the field table and calculation rules, then run the tool.
- Read regressionEstimatedOneRepMaxKg. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| observedLoadKg | Observed load kg | number | Required |
| observedRepetitions | Observed repetitions | number | Required |
Enter positive load and integer repetitions 1–12. Return modeled kilograms.
1RM=load×(1+.025reps) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| regressionEstimatedOneRepMaxKg | Regression estimated one rep max kg | number |
{
"input": {
"observedLoadKg": 50,
"observedRepetitions": 5
},
"output": {
"regressionEstimatedOneRepMaxKg": 56.25
}
}Limitations and assumptions
No measured maximum, lift prescription or lifting-safety determination is supplied.
Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Wathan 1RM Calculator: Wathan’s repetition/load regression estimates a one-repetition maximum from an observed set. It is not a measured maximum. For a complementary task, use Lombardi 1RM Calculator: Lombardi’s power-law correction estimates maximum load from an observed repetition count. Its scaling differs from linear models.
References
-
O'Conner 1RM Calculator — tool.io
Similar or alternative tools
- Wathan 1RM Calculator
Wathan’s repetition/load regression estimates a one-repetition maximum from an observed set. It is not a measured maximum.
- Lombardi 1RM Calculator
Lombardi’s power-law correction estimates maximum load from an observed repetition count. Its scaling differs from linear models.