I am 37 years female & have had 2 THR. The first one 2 yrs ago & the second about 8 months ago. I been doing crossfit for a year & a half. I am also a crossfit coach now. Crossfit has truly strengthen my hip muscles. It made this last replacement a cake walk. I didn’t need rehab & was walking without any assistance 1 week post surgery. In fact 2 weeks after I was back at the box exercising. The only problems I have is when I do too much hip flexion repetitions, I strain my hip flexor muscles. Which result of pain in my inner thigh. So it hurts when I lift my leg. Otherwise I have no problems.