Most articles and magazine features won't tell you this golden nugget of information, they will tell you to work within a certain rep range and the amount of sets to do and then go on to tell you how many times a week you should do this for and possibly suggest some weights you should use, a factor which can never be predicted.
Some people will develop superb arms by using relatively light weights, while others need to use much larger amounts of weight to stimulate any change, the reason for this difference is largely down an individual's morphic shape.
Morphic shapes are basically an individual's body type.
They are grouped in to three categories, but it should be stressed that nobody will be rated as one singular body type, instead a little of each one is usually the norm.
The following are the morphic types.
Which one do you most fit in to? ECTOMORPH Ectomorphs are characterised by their tall slender frame, with typically narrow shoulders and thin wirey limbs.
They are usually always busy and blessed with poor fat storage potential.
This type of person tends to store body fat around the abdomen, rarely around the upper body and hardly ever on the legs.
In bodybuilding terms ectomorphs are nearly always hard gainers (they struggle to gain muscle).
Don't worry if you fit in to this category, many a superb physique has been sculpted on such a frame.
MESOMORPH Mesomorphs tend to be the lucky ones with a tendency to having broad shoulders, slim waists and thick limbs.
These guys are usually the ones who seem to have to put in little or no effort to build large muscles and change their shape seemingly overnight.
The down side to this type of morphic shape is that the increase in muscle can be accompanied by an increase in body fat and this tends to be stored around the body as a whole, making the elusive six pack a real rarity.
If you are this shape it is good news in terms of your training, but you will need to be much stricter in the types of foods you consume to avoid looking bulky as opposed to honed.
ENDOMORPHS Endomorphs are the third morphic type and are generally quite rounded in shape, the type of person who readily gains body fat and often has little energy, quickly looking big and bulky when training.
Really this is perhaps the least desirable body type to be because even though muscle is gained much quicker than the ectomorph, body fat is a constant problem, and serious lifetime dietary changes are needed to maintain a great shape.
You should assess your own morphic shape using your teenage years and above, not your current body as this may mask your true shape.
It is vital you understand the type of body shape you are in order to imagine and picture what your ultimate look might be.
If for example you are 18 stone and 5ft 10" and have always been a little on the large side, you fit in to the endomorph category, then it is not going to be a realistic goal to look like a marathon runner.
Instead you should adjust your goals to focus on a more muscular, shapely look which gives more the impression of power as opposed to athleticism.
Likewise if you have always been gangly and skinny like the typical ectomorph, it would be very unrealistic to try to attain Mr Universe proportions.
This isn't to say this can't happen or writing this should in any way dissuade you or dampen your spirits for the journey ahead, because everybody has the potential to change their body in dramatic ways.
Instead you should strive towards a body shape that is attainable for your morphic type and then go out and work towards achieving that look.