I've been reading through the forum and saw that those who wanted to get bigger needed to go through a bulking process. How much muscle can a person put on without going through this process? I run track so going through the bulking process will slow me down. I have to stay as lean as possible at all times. Is it even possible to put on muscle without going through the bulking process?
The amount one can gain in muscle can depend on the individual person because there are
far too many variables in the equation to to "blanket everyone the same". The sitting general among those factors are how you train, how hard you train (intensity/volume/rest), your diet circumference, and your unique genetic potential, IMO.
Additionally, muscle "tends" to be easily put on when one first begins a weight training program (or new to weight training gains), and then it "can" get progressively more difficult as the body adapts and over comes training stimulation. It seems it becomes more "biologically expensive" as one matures in training.
However, those who follow a solid weight trainin program, those who diet and train for muscle mass, and "understand and correctly apply proven mass gain bodybuilding techniques" (education is a must) can accomplish amazing things in short periods of time.
One can underestimate the extreme efficiency of our "bodily adapting mechanic" we all possess.
For example: A typical person that is a several pounds over weight (and never weight trained before), deficit diets (within their personal approximations) for about 3 weeks, and become disheartened because the scale didnt "go down" as much as they want.
Well, "some" may not be looking at their self with "educated eyes": It is possible being so new to weight training that the body built some muscle in this example 3 week period, and fat loss did in fact occur.......but, the muscle gain offset some of the loss (or they gained good weight and lost fat at-the-same-time). This is one reason "scales" can be bad, and looking in the mirror is better, for example. The body "can be" extraordinarily efficient at the beginning, and one has to remember what the stimulant in the gym can bring to the table (other than just simply burning calories).
Think of it this way: If you are running along an even surface (ones prior history of eating what ever and when ever they want and no weight training), and then suddenly jump off a mountain (watching diet, training 3 to 4 times per week, etc), the body "tends" to hit the ground hard. It's response tends to be rather strong.
However, what most dont realize, is that one ends "back up on level ground" again (the body's attempt at homeostasis-or staying the same, or striking a balance) and one MUST because of "continual adaption" (fall off the cliff again), to solicite additional muscle improvement. This is why "progression and intensity" (volume, rest) are so important, not to mention knowing your caloric intake (and making adjustments as your weight changes).
Remember the training provides the stimulation, but the DIET can ruin potential growth as well as cause it. Like abs are made in the kitchen.....so are muscles, IMO. And, some miss this important point.
Another example: If you want a plant to grow, you must constantly keep it in what I will term as the "right habitat" to prosper.
You have to have the right size pot to allow the roots to grow, and you have to water it.
If you keep its soil rich with quality fertilizer day after day. What do you expect?
A healthy, strong, and thriving plant.
It is from this soil of high-quality fertilizer, where the plant gets the nutrients, and make it grow. The higher the quality, the better growth and health you can expect from the plant. The more "consistently" you have that fertilizer available to the plant, the better the results.
Much to learn. Must open eyes. Nutrition...ROCKS.
Oh......another note 
: If you train for an hour (for example), it is what you do within the other 23 hours that can affect the quality of one's muscle growth. The training provides the stimulation, the other 23 provide the growth, and what you do or don't do in that period determines.......the outcome......THINK ABOUT IT.
One more....damn I can't shut the heck up! :
When you lift with the goal of muscle gain, you know (or should know) that it is absolutely imperative that you exhaust the muscles. To do this you go to "fatigue or failure", you don't leave anything in the tank at the end of a set. Maximum intensity!!!!!! OH! This is my opinion, thanks!
It is through this type of lifting that you signal to the body that you need more muscle. The body interprets this as a threat to its survival "and when provided the opportunity", it responds by increasing strength levels and muscle mass. In turn, you respond by increasing resistance, always pushing for more (progressive overload).
Educate yourself. Apply this education to yourself. Train hard and progressivley, and adapt to the feed back your body gives you (correctly), and the muscle will come.
Best wishes,
Chillen
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