“Light” has a meaning with respect to resistance as does “moderate” and “heavy”. Repetitions should correlate to resistance in pursuit of a distinct muscular response.
Qualifying Light Versus Heavy Weight
Light resistance is qualified as 50 to 70 % of your one-repetition maximum (1 RM). For this amount of resistance, you ought to be able to perform, successfully and individually, a relatively high number of repetitions (reps), from 24 (at 50 % 1 RM) to 12 (at 70% 1 RM).
Moderate resistance is 70 to 85 % of your 1 RM. With moderate resistance, you ought to be able to perform a moderate number of reps, from 12 (at 70 %) to 6 (at 85 %). The resistance no longer qualifies as moderate, however, if you can’t do at least 6 reps with a given weight or you can actually exceed 12 with your best effort.
Heavy resistance is 85 to 100 % of your 1 RM. With heavy resistance, you should only be able – on account of the difficulty – to perform a 1ow number of reps, from 6 (at 85 %) to 1 (100 %).
Muscle fiber engagement and muscle growth-type varies each resistance-repetition level.
Moderate resistance allows fewer reps; the effect is to generally promote an increase in size and, to a lesser extent, strength
Resistance that’s light enough to train for high reps provokes a significant increase in muscular endurance with a much less substantive improvement in size and virtually no improvement in absolute strength.
Moderate resistance allows fewer reps; the effect is to generally promote an increase in size and, to a lesser extent, strength. This is the go-to range for bodybuilders seeking a great deal of muscle mass and volume.
Going heavy expectedly constrains the lifter to low reps. Heavy weight best develops absolute strength (i.e., the largest amount of weight you can handle) with a lesser effect on size and endurance.
Determining Your Objective
There is an optimum rep range when taking into consideration body type and muscular-development goals.
Training heavy isn’t better or worse than light or moderate; each has benefits. In fact, an advanced lifter creating a sophisticated routine might choose to do higher reps for some exercises and in certain sets and do lower reps on others.
The resistance-rep levels are typically correct for the average person. Nevertheless, experimentation over time will help to optimize training.
Evaluating Your Resistance-Rep Level
When your goal is clear, use enough weight to limit yourself to the target rep range for the desired muscular effect.
If your intent is to pack on muscle and get big, showy, sleeve-splitting muscles, you’ll want to go moderate. Size comes readily from weights that are not so heavy as to preclude at least 6 reps, but heavy enough that you couldn’t do more than 12 reps if you tried. If you can’t do 6 or more, decrease resistance; if you can do more than 12, add resistance.
You must train to failure within range if you want to capitalize on the stimulus response for the resistance-rep level. If your goal is size, performing 10 reps when you could conceivably do 14 reps with supposedly moderate weight will undercut your efforts. Unfortunately, many people won’t train to near or actual failure; stopping instead when boredom or a little muscle burn hits.
Push your sets to failure and always strive for more reps at the same resistance. When weights become too easy and allow you to break past your intended rep range, it’s time to increase resistance. Such a progression is a fundamental weight-training principle.