Guess what they found out in February? - or - Estimation of a one rep bench press max using the 225 lb repetition test.
A population of people found to have a max of 295 pounds on the bench press are further tested at 75% (225 Pounds) of their maximum. The average result is 10 repetitions for the test. The value of each rep is therefore 0.03 or 7 pounds a rep.
From this you may assume that you could then predict an athlete's max bench press based upon the results. The # of reps x 7 + 225 = Estimated Max. You would then simply derive the following chart:
# of Reps Estimated Max # of Reps Estimated Max
1 232 21 372
2 239 22 379
3 246 23 386
4 253 24 393
5 260 25 400
6 267 26 407
7 274 27 414
8 281 28 421
9 288 29 428
10 295 30 435
11 302 31 442
12 309 32 449
13 316 33 456
14 323 34 463
15 330 35 470
16 337 36 477
17 344 37 484
18 351 38 491
19 358 39 498
20 365 40 500
Looks good and many athletes who may use the chart will find it dead on. The problem is that the error can be as much as +/- 100 pounds or even more. In other words there will be athletes that can bench 225 x 35 reps and their max is roughly 400 and others whose max is closer to 500. Then there are those who will struggle to bench press 350 pounds and you may even find an athlete well over 550. The disparity is enormous and actually so are the number of formulas that have been made in attempt to excogitate a person's strength without actually testing it.
The reasons are complex and numerous that the strength of athletes to date cannot be predicated accurately from charts and formulas. To get some insight into the issues lets first look at it physiologically relative to the alpha motor neuron and motor unit.
Alpha motor neurons are large nerve cells that initiate skeletal muscle contraction. A motor unit is an alpha motor neuron and all the corresponding muscle fibers it innervates. When we activate our motor units through effort all the fibers connected to that unit contract. One way to describe the size of a motor unit is according to its innervation ratio: the number of muscle fibers innervated by a given motor neuron.
The innervation ratio of the motor unit is a major factor governing force output. The number of muscle fibers connected to a motor neuron varies widely between different muscles and different humans. Some people have more fibers per nerve cell than others. Based upon how we are naturally hooked up has a lot to do with the percentage of our tissue we used during effort. It is our neurological efficiency and is one factor that accounts for variation of strength between individuals.
There is much more than motor neurons and motor units involved in the complexity of strength. Connective tissue (i.e. tendon, ligament, aponeurosis), tissue composition, motivation are just a few of the reasons predictive equations are inaccurate. Perhaps one of the most interesting reasons people vary in strength was written about in February's Journal of Applied Physiology.
The researchers studied the protein kinase-2 (PTK2) gene involved in lateral transmission forces. The results of the study clearly demonstrated for the first time how there is a clear genetic variation on the way force is transmitted from the muscle fibers to the tendon between individuals. The researcher's conclusion, which has been alluded to forever by humanity, was that some people are just stronger than others.
Pendulum Power Racks at The University of Michigan