What’s best for muscle gain – heavier weights or consistency?
Researchers looked into the 'age old debate' finding repetitions are more important than weight for muscle size: review

Lifting weights regularly builds strength and muscle — but being consistent is more important than whether the weights are heavy or light, a study finds.
All forms of resistance training are beneficial, including body-weight exercises such as planks, lunges and push-ups, according to kinesiologists at McMaster University in Ontario, Canada, who looked at weight, frequency and consistency.