Guess what they found out in February? - or - Estimation of a one rep bench press max using the 225 lb repetition test.                                                                                                                                              

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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.

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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.

 

michigan

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.

   

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                      Pendulum Power Racks at The University of Michigan 

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