Gettin prolific…
When I was training at Bath, Malcom Arnold had a Repetition Prediction Chart posted which his athletes adhered to religiously. Experienced lifters however accept that the link between load and repetitions is highly specific to the individual and that gradient is both none linear and variable over time. It is influenced by the volume of endurance work and skewed by the prevailing training repetition number. For example when I use predominantly doubles my 2RM lays considerably closer to my 1RM than when I train with singles or 5’s. To confuse matters further the gradient is also specific to the exercise being performed. I have, for example, an extremely shallow gradient for military press and a much steeper one for squats. Often it is the stabilising muscles rather than the prime movers that fatigue first and limit performance in higher rep sets. I guess core stability has some benefit after all! Certain physiologists estimate the percentage of fast twitch fibre through the gradient of the rep:load curve. The gradient of an athlete’s pyramid may be useful to determine an optimum repetition number. Those with steep pyramids would be advised to use lower reps and achieve volume through sets. In contrast those with shallower pyramids are likely to adapt better with higher rep numbers.