So you're ready to start strength training. You've identified your goal, you know what gym you're going to or you've got some equipment at home, maybe you even have a list of exercises to start with. But, you have no idea what rep range you should focus on...
Well to give you a short answer, if your goal is to gain strength and also build muscle, doing both will probably be just fine for you and give you the progress you're looking for.
But let's dive into the benefits of each and when it's appropriate to use one or the other.
LOW REPS
Typically heavy weight with lower reps (anything 8 reps or less) is used to build strength. You'll most likely see an increase in muscle mass as well utilizing this rep range. I wouldn't recommend this approach to ever exercise. Compound movements such as squat, bench press etc are perfect for pushing heavy weight. Exercises such as lateral raises or leg extensions would not be my recommendation for this rep range.
It's a good idea to lift heavier with lower reps if you have hit a plateau for your goals or if you struggle with elevated cortisol (stress hormone). Read more here if you're unsure what your cortisol levels are like. Lifting heavier with less reps tends to keep cortisol lower allowing testosterone to be elevated.
HIGH REPS
A rep count of 15+ is generally considered high. Doing lighter weight and higher reps helps increase endurance. If your primary goal is fat loss, I would recommend using this rep range at least part of the time. Keep in mind building strength and muscle with increase your metabolic rate helping you burn calories. So don't think that you HAVE to do higher reps for fat loss. However, building your endurance can help you lift heavier for longer.
MODERATE REP RANGE
This is going to be a rep range of about 8-15. I would recommend this rep range for most beginners. If you're new to lifting, chances are you don't have the endurance for 15+ reps, but you're also not ready to be pushing heavy weight. Working in this rep range for a while allows your body to adapt to exercise (strengthening connective tissue, improving lactic acid threshold, etc)
I like to utilize this rep range when mostly focusing on growth of the muscle and volume of the workout. But if you only work in this rep range, you can expect a plateau of strength and endurance at some point.
I hope this helps give you some guidance and clarity for your workouts. If you need more assistance, you know where to find me!