Final answer:
For untrained, beginning weightlifters, a minimum of one set is required to gain strength, although more sets may be needed as they become more experienced.
Step-by-step explanation:
The minimum number of sets required for strength gains in untrained, beginning weightlifters is one set.
This is based on research that shows significant strength improvements can be achieved with a minimal amount of exercise for those just starting out.
However, as individuals become more trained, the number of sets may need to increase to continue seeing strength gains.