We've covered bodybuilding, and how it is a style of lifting that highlights hypertrophy (increasing muscle size) and aesthetics (looking good and symmetrical.) When it comes to strength, however, the program is simply focused on increasing the amount of weight you can lift. Of course, this will increase your muscle size, but not to the same effect as a bodybuilder.
The key difference between bodybuilding and strength training is strength trainers ditch most isolation movements and glamour muscle work, in favor of compound, multi-joint movements. Instead of working in the 6-12 rep range, they typically work in the 1-5 rep range. Lifts like bench press, squat, deadlift, press, the snatch and the clean, are preferred over rear-delt cable crosses, leg extensions, lateral raises and the like. Whereas a bodybuilder sometimes burns out and plays with rest time in between sets to keep their heart rate up, a strength trainer takes more time in between sets to rest so (s)he can perform the prescribed reps. Getting the weight up for a specified number of reps is priority #1. Muscle failure, keeping a quick pace, and adding too much accessory work are not conducive to this goal, so they don't generally do it.
Strength trainers care less about keeping lean than they do about being strong. If you are too shredded, it zaps your strength. And while, if you compete, you might want to keep your weight class in mind, it is a general rule that strength trainers eat to fuel their lifts; they don't restrict calories and carbs to look good on stage.
There is a misconception that lifting heavy just yolks you up into a freak beast overnight. Many people make the mistake of staying in higher rep ranges with lighter weight to stay "toned" and avoid getting huge. WRONG. If it was that easy, kids, no one would need steroids. Plus the word "toned" is meaningless. Either you have firm muscle or you don't. No amount of "toning" actually tones. You have to build lean muscle mass to feel solid under your skin, and to do that, you have to step outside of your comfort zone a bit and push a little heavier. You won't get huge unless you try to. And even then, it takes a long time.
One of the single best things you can ever do for your body image and self-esteem is to strength train. When you focus on plates going up instead of the scale going down, it is a much more positive experience. Being proud of what you accomplish is more meaningful on a deeper level than what your body looks like at any given moment. (Because it can look totally different in a span of 24 hours due to diet, lighting, the timing of bodily functions, selfie angle, Instagram filter, etc.)
Being strong is fucking great, obviously, but for those of you who aren't convinced, here's just a few benefits: impress your friends, carry your groceries in one trip, have increased energy and stamina, be a man and do manly shit, be a woman and open your own damn jars, chop wood, strangle a bear, knock out a villain, be admired, feel great, and look awesome naked.
You can also add increasing your bone density, alleviating stress and anxiety, and reducing or preventing age-related diseases and chronic conditions to the list. People who strength train age much better, feel less pain, and experience far less miserable old people bullshit than those who don't bother. Plus, strength training boosts your muscle mass, which, in turn, boosts your metabolism and burns more calories at rest. This helps you maintain a healthy weight for life. Do you want to be the grandma/pa that is getting pushed around the assisted living home in your wheelchair, or do you want to be the grandma/pa that just got back from hiking the alps?
I know my answer.
The Bad & The Ugly
There are few disadvantages to strength training. Just like with bodybuilding, there is a risk of injury. As I said, You may experience a pulled muscle from time to time, or a joint or ligament that gets inflamed. You'll pull out the Advil and Tiger Balm once in awhile. And, you might need to take a short break while something heals up. The risk for more serious injury goes up when you bite off more than you can chew, get impatient with your progress, or don't clear your mind and focus while you are in the gym.
You will need to make an investment in weights, equipment, or a gym membership. You can't strength train without weights, not for real. You may end up needing things like chalk, belts, wrist wraps and the right footwear. The good news is you can avoid contest fees, costumes and tanning fees, so it is definitely cheaper than bodybuilding.
Is Strength Training Right for You?
But seriously, strength training is the foundation of all lifting. Whether it is bodybuilding, Olympic lifting, strongman, or recreational gym rattery, big, strong compound movements should make up the base of your routine. You are strength training when you are increasing the load, in a challenging manner, over time (progressive overload). It is one of the best things you can do for your body. In my opinion, it is more generally beneficial than anything else out there. Even if you don't fall in love with it, you should find a few days a week to work it into your routine. Strength training can benefit other activities, like running, hiking, swimming, sports, dancing, sex, shopping, eating, sleeping, watching Netflix... you name it. Strength training is for men and women at any age and at any starting point.
Here are a few good resources to get you started:
Starting Strength (beginner's super-simple strength training routines)
Jim Wendler (Intermediate and advanced routines, funny and no-nonsense)
Alan Thrall (Great YouTube tutorials and solid information/advice)