Originally Posted by Trevor Lane
I get that, but is an 8-20 rep approach really more effective for size and 1-5 for strength???
For a beginner it really doesn't make much difference. If you're not a beginner, ignore the rest of this. I just make this comment because 99% of readers are
beginners, and anyway this is the beginner's forum.
Strength is built in the gym, size at the dinner table. It doesn't matter what your rep range is if you eat only a bowl of rice a day, you won't grow. And whatever your rep range, if you eat four whole chickens a day you'll grow muscle. Beginners should lift progressively and eat lots if they want to gain muscle and strength.
I say you are a beginner until you can manage lifts like overhead pressing 75% your bodyweight for 3+ reps, benching and rowing 100%, squatting 150% and deadlifting 175%. Or if you want it put in weight terms, a small-framed person should manage to overhead press, bench and row an Olympic barbell with a single 45lb plate on each side, squat 2 and deadlift 3. A large-framed person an extra plate on each of those. That's a rough guide for you anyway.
As a beginner, you will grow muscle and increase strength whatever rep range you use. Lower reps are recommended because fatigue will degrade form in 10+ reps, and when a beginner your form isn't brilliant to begin with. We want to minimise the chances of injury and maximise the effect of the exercise, so form is important for beginners.
The important thing is not rep range, but progression. In every workout, do more than you did before. More weight, or more reps, or more sets. So if you lifted 100lbs 5x5 today, you need to lift 105lbs 5x5 tomorrow, or 100lbs 5x6, or 100lbs 6x5 - any of those would be progress. More, more or more. If in every session you lift more weight or more the same weight more times, and you combine that with good food, then you will get bigger.