Typically, a heroin abuser may inject up to a day

Depends on the cost . Most of them spend about $200 on heroin daily. They probably inject about 5 times a day .

Abuser may inject up to four times a day

Well if you pick a machine to work on and that's gonna be your exercise if you don't stick to that machine your muscle strength your muscle mass rather will change because you haven't been doing it you change something in your exercise routine which changes your body's form of dealing with things for example you might become weaker or stronger depending on what kind of exercises you do in whether or not the machine you picked actually your muscles grow.