If you can complete more than 20 repetitions over three sets with your current weight, you should
a.
increase the weight until no more than 20 repetitions and three sets are possible
b.
decrease the weight and increase the number of sets to 8 to 10
c.
increase the weight until you can do no more than 2 to 4 repetitions in three sets
d.
keep the weight the same and increase the number of repetitions and sets until you are tired

If someone can complete 3 sets with 20 repetitions then he should increase the weight until the person will not be able to do 20 repetition and 3 sets. Option A is correct.

Progressive Overload:

It is concept in which muscles are challenged to adapt for more load or increasing intensity progressively.

If muscle tissue can adapt to the more load if someone bear it daily. If progressively load will increase, muscle tissue will force to bear it.

Therefore, if someone can complete 3 sets with 20 repetitions then he should increase the weight until the person will not be able to do 20 repetition and 3 sets.  20 repetition and 3 sets are possible.

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