The 5 out of 10 rule, and judge a drive by timeEmerging evidence
During the exercise, pain up to about 5 out of 10 is acceptable. It should settle within an hour or so, and your hip should be no worse that night or the next morning. If it is, do less next time (fewer repetitions, a smaller range, a lighter load), not nothing.
Pain can go up a little when you start a new exercise programme; guidelines for arthritis say so and still recommend keeping going. If pain climbs week after week, or a warning sign appears, stop and get it checked.
For sitting (our suggestion, built on an NHS occupational therapy leaflet's pacing and the HSE's advice on breaks): sit until just before the ache starts to build, then get up. The ache should settle within about an hour of moving, and your hip should be no worse that night or the next morning. If it is, shorten the next spell rather than avoiding sitting.
For the car (our suggestion, built on the same rule): use the way in and out that keeps it within 0 to 3 out of 10, with the hip no worse that night, and bring back a lower seat, a quicker exit or a long drive one at a time. After a hip replacement, your team's precautions come before any pain rule. Sudden sharp pain with the leg giving way, a leg that looks shorter, or numbness around your bottom aren't pain-rule questions: see the warning signs.
For the drive itself (our suggestion, built on the sitting paragraph above and an NHS pain clinic's pacing): drive until just before the ache starts to build, stop and walk for a few minutes, and check that your hip is no worse that night or the next morning. When a length of drive has passed that check 3 or 4 times, add 15 to 30 minutes. With a groin pinch, the pinch is the limit: change the seat before you add time. After a hip replacement, your team's advice comes before any pain rule.
Sources 19, 12