Kemmler checked if Brzycki's formula could accurately predict 1 rep maxes for older adult lifters using their data. It could.
https://wikimedia.org/api/rest_v1/media/math/render/svg/70bf397a1e59a65ce6578b067362d5fd4d9edda9
The Kemmler et al. 1RM formula is an equation proposed in a 2006 research study published in the Journal of Strength and Conditioning Research.
The formula is:
Predicted 1RM = Weight / (1.0278 - (0.0278 x Reps))
This equation may look very familiar, as it is essentially the same as the Brzycki 1RM formula discussed earlier.
However, the key difference is in how Kemmler and his colleagues derived and validated this equation compared to Brzycki's original work.
In their study, Kemmler et al. analyzed strength training data from 155 older adults (60-88 years old) who performed 1RM and submaximal repetition tests for multiple exercises.
They used this dataset to evaluate the accuracy of several existing 1RM prediction equations, including Brzycki's, across this older adult population.
Their analysis found that the Brzycki formula provided the most accurate 1RM predictions compared to other equations when applied to their data from older participants.
Based on this validation using experimental data from a specific population sample, Kemmler et al. proposed adopting the Brzycki equation as a accurate method for predicting 1RMs in older adults.
So while the equation itself is identical to Brzycki's, the key contribution of Kemmler et al. was validating and recommending this formula's use for the older adult population based on their empirical analysis across a range of ages and exercises.
This highlights how even pre-existing 1RM prediction equations can be re-evaluated and validated for specific populations through additional experimental research studies.