Do you often feel like you are just guessing at your workouts?
You are at home or at the gym doing squats or lunges, doing about 10 reps every time, repeating that 3 or 4 times... and you do that every... single...workout.
Should you be doing more reps? More sets? How do you know?
Regardless of your goals, the number of reps you do is not as important as whether or not those reps are performed to failure, or to muscular fatigue.
Fatigue is when your muscles are not capable of performing one more rep. If your goal is to improve definition, and while you are performing your set you feel as if you could keep going, you have NOT hit failure. You have NOT fatigued all of the type 2 muscle fibers responsible for creating definition.
If your goal is to get stronger, you’ll want to use heavy weights that cause fatigue after no more than 6 reps.
If your goal is toning and definition, this can be achieved a couple of different ways. The number of reps here isn’t as important as the length of time the muscle stays under tension.
“Definition” comes from a muscle maintaining a state of semi-contraction, which is achieved by keeping a muscle under tension for a longer period of time. Higher reps performed at a slower speed can facilitate the tension needed to increase definition.
No matter how many reps you do, to see definition you must hit failure.
Runners, cyclists, swimmers and other endurance athletes need to activate type 1 muscle fibers, and this requires 20-30 reps. This style of exercise will help you develop aerobic efficiency, no need to work until failure here.
So, a quick frame of reference to how many reps you need according to what your goals are:
Endurance: 20-30 reps
Definition: 10-15 reps
Strength: 4-6 reps
Your last rep should be almost impossible. If you can keep going, you need to up the weight!
When it comes to sets, doing 3 sets as a beginner is sufficient, and then up it to 4 sets as you get stronger.
I did a Facebook/periscope LIVE chat on this subject recently, and I go into more detail and explain it a little bit more in the video (below) Keep in mind this was a live video chat, so you'll hear me answering people's questions :)