Question: How many repetitions and sets of strength training exercises do I need to do to see results?
Answer: The research on how many sets and repetitions of an exercise one needs to improve their strength and get results is pretty varied. There is some research that says that a single set can gain strength in some individuals, whereas multiple sets might be needed to gain strength in other individuals. I think it really comes down to where you're starting at. If you're starting at a pretty low level, a single set could be beneficial for you in gaining strength for a while.
However, as you progress, as your strength improves, you need to have more of an overload. So getting more of an overload can come through more sets, more volume at a higher resistance and that can help you improve your strength. So, in the end the research doesn't really support either way significantly. Many people will say that multiple-set strength training is the most important way to go, others will say single-set.
So, it really is important to figure out where you start and watch what your gains are and watch how you change. If you're not changing, if you hit a quote, unquote "plateau," then maybe we need to do something different with our program, which may be including a multiple-set or a single-set routine.