Second is hypertrophy of skeletal tissues. This includes increases in bone density, hypertrophy of tendons, ligaments and muscle. Hard/non-contractile tissues take longer to hypertrophy in part due to their lower blood supply.
There are two types of hypertrophy: sarcoplasmic; and myofibrillar. Sarcoplasmic is common in bodybuilding, and is about increases in muscle cell size. Myofibrillar is common in strength training. Myofibrials are the cylindrical organelles of the muscle cells (muscle fibres of the cells if you will) and hypertrophy of these increases their size. You can also get division of myofibrils such that you end up with more "fibres" per cell, although this is far less common.
So strength is about increased skill of recruitment of muscle fibres using the motor units. To tap into the fast twitch fibres (the ones that are most likely to hypertrophy and also responsible for strength and explosive speed) you need to recruit the higher threshold motor units. This requires heavy loads (>80% of 1RM) or fast/explosive movements. This in turn trains you to use your muscles efficiently and to increase the size and strength of the muscles. For more on how muscles hypertrophy see the links below.
Awesome. yeah, i never really new the science for strength but it was always common knoledge as to how to train for strength. I did strength training instead of bodybuilding for 1 month and i increased my bench by 55lbs, squat by 60 lbs, and deadlift for 40 lbs. but then i stopped coz it was time to go back to bodybuilding instead :)
round and only made any shifts to what you might call bodybuilder training during contest prep. And we all know The Big Nasty can shift big fucking weight like it was peanuts.
I might also add that a shift to strength training does not have to include abandoning bodybuilding principles. Just do the bodybuilding as part of your assistance work.