Alex typically had 2-4 clients per day he worked with specifically on weeknights and five on Saturdays. If he wasn't personally booked—and he was the most popular trainer at the gym because his reputation preceded him before he was officially hired—he was either helping keep the place clean or sparring with people that needed partners.
The other trainers took his popularity in stride because they had seen him in action and knew how talented he was. He didn't detract from their workload too much because Mark only allowed so many bookings per person per day due to labor laws.
He usually had his breaks the same time a trainer named Dustin did so they became friendly. They worked the same shift and their clients were all the more serious variety. He used to be a combat instructor in the military but preferred a more casual civilian life.