Mine is very gentle, not a grab and twist fellow. My wife started 9 yrs ago due to many years of back issues such as 2 degenerating disks. Went from missing about 2 wks of work a year to 3 days in 9 yrs. She doesn't even go unless it acts up.
A few yrs back I had a pinched nerve in my neck and just raising my arm was too painful..6 or so visits with him and good as new.