to an extend [MENTION=66316]1engineer[/MENTION] is right. While understanding your body type is extremely important, mesomorphic, endomorphic, or ectomorphic... everyone has the potential to grow. Granted it'll take time, the tall lanky kid in the corner, standing at 6'2 has an incredible opportunity to pack on some serious mass while retaining a lean look. It's just going to take a while, and a lot of calories to do so. The simple science behind it is more calories taken in than burned off = weight gain. more calories burned than consumed = weight loss. Period.
[MENTION=66316]1engineer[/MENTION] is correct though in saying the goofy guy in the corner could be stronger than you, even if he's lifting less weight.
To throw it out there... everyone should know that work(W) = force(F) multiplied by distance(d). W=FxD
The importance of understanding this formula pertains to increasing your resting metabolic rate which directly correlates with creating an anabolic environment within the body, promoting fat loss and muscle building.
To understand the importance of this formula, take an example of someone who is doing a 5 exercise routine. We'll use 1 exercise for an example in 2 scenarios so i'm not going on longer than I already am.
Lets say he is performing calf raises at 305lbs for 4 sets of 12 reps, and the distance the weight is travelling is approximately 3 inches or 0.25ft. And for S&G's lets say it takes him 5 minutes. When applying these numbers to our formula we can see that...
work = 305 x 4 x 12 x 0.25 = 3,660 lbs per ft
Now lets say that instead, he performs a barbell clean and press at 105lbs for 4 sets of 12 reps with the weight travelling about 8 feet (the bar is travelling from the ground to overhead). We'll say this also takes 5 minutes
work = 105 x 4 x 12 x 8 = 40,320 lbs per ft
So essentially, even though someone is lifting less weight, it doesn't mean they aren't performing more work. More work means more muscle use, more muscle use means more muscle fatigue, and more muscle fatigue means more muscle breakdown.
This is why crossfit is so successful. The multi-joint movements result in more work done in a shorter period of time, or maybe the same amount of time as a standard routine. And with full body exercises, you get well rounded benefits. You engage your core for stability during these movements, which is passively training your abs and lower back, you're using secondary or accessory muscles more to facilitate the movement, and you're generating more work, resulting in better bang for your buck time wise.
Touching on resting metabolic rate really quick... performing a multi-joint movement, such as a barbell clean and press, and throwing in a few other multi-joint movements, like burpees, snatches, deadlights, bench press, etc... increases your resting metabolic rate for approximately 2 days. This means that your body is more receptive to burning fat and producing hormones that promote muscle growth. This exercise can be performed in roughly 30 minutes, at a moderate to high intensity.
A cardio routine, say riding a bike or jogging on a treadmill, will increase your resting metabolic rate for roughly 2 hours.
Just some food for thought.
