If it were as simple as 'Lift X weight Y amount of times' then we would all be 300lbs. However, it seems as though muscle is a bit more complex than that. I remember the first time i learned the actual science behind a muscle contraction. I was amazed at the complexity and what was essentially instantaneous reaction of so many different parts(I recommend looking into it if you have not already). Learning this complex action/reaction series shed a new light on muscles. The difference was night and day. The point of this story is that this is the same reaction i got when i was literally shoved into the world of some different Bodybuilding Techniques.
Last week, i had the privilege of training Legs with a man who had several different pro cards under his belt. A Man's whose intensity was a whole other world. The workout really broke me down, and i loved/hated every minute of it (As Between sets, i spent a majority of my time laying on the ground, gasping for air). We used an arsenal of different techniques-
Pre Exhaustion- A method in which a muscle group is isolated prior to a multijoint exercise. It works to fatigue the primary muscle group via isolation so that it may be further fatigued on the compound exercise that follows. Of course this can compromise strength on the second exercise, but some use it specifically for that point.
Supersets- Performing two or more exercises, one after the other. Normally, the point in Supersets is to pair antagonizing muscle groups IE Bis/Tris, Quads/Hams, etc. An interesting tidbit here is that research shows that a muscle will be stronger if preceeded immediately by a contraction of it's antagonist. Supposedly(taking Chest for example), the back muscles inhibit the contraction of your pecs to a certain extent. In this instance, performing a set of rows shortly before benching would lessen the inhibitory effect, allowing the pecs to achieve a more forceful contraction.
Forced Reps- Forced reps allow one to get more reps out of a set by having a spotter help you finish past your point of failure. This allows you to push your body to its limits and beyond, important for forcing muscle growth. Studies have shown an increased level of GH in athletes that performed forced reps by up to 3x that shown in standard work.
Negative Reps- Much like forced reps in that a set is performed to failure. After you can no longer complete any more positive reps, you can still squeeze out of a couple negative reps, as muscles can be stronger on the negative portion of the exercise. Do whatever reps you can, then with the aid of a spotter helping you get the weight back to starting position, concentrate on lowering the weight slowly.
Partials- focusing on a specific area of a muscle. partials can be very devastating. The name basically says it all, you perform part of the movement, and leave out another part. Take front squats for example. Throw some weight on, get down ATG, and dont come up beyond half way. It keeps that constant stress on your quads (particularly at the insertions).
Dropset training- The immediate reduction of a weight, and the continuation of the set. This is another technique that basically allows you to lift beyond your limits. Forcing the muscles to continue contracting with lighter weight will cause an elevated response of GH and IGF-1. You just have to keep time between sets no more than 10secs. It helps to have a spotter here, to be able to strip weight, so that as soon as its done you can continue working. An example of this could be DB curls. You just finish 15reps with 55lbs, now drop down to 40lbs and perform another 15, now drop to 30 and try another 15. Lol we all know you wont be getting 15reps for either of those last sets, but you need to set that bar high. It helps to have the spotter here help you perform some of these as forced reps too.
Angle Training- Performing basically a giant set of an exercise, but adjusting the angle of which you perform it slightly. Example: Doing leg press with a wide stance, narrow stance, angled in feet, angled out feet, etc.
Utilizing and grouping techniques such as these made my workout the most gut wrenching experience i have ever encountered. But it also shed a new light on things, and has changed the way i train. Now there are plenty of others that i did not mention, so feel free to chime in with styles that you use.