I had a total hip replace­ment four months ago. My recov­ery has been great and my con­sult­ant has given me per­mis­sion to start cyc­ling and swim­ming. But it would be more con­veni­ent if for the time being I could use my exer­cise ball to tone up at home. What would you advise?

It’s good that you are tak­ing ser­i­ously the need to get back to full fit­ness after your oper­a­tion. As I’m sure your con­sult­ant explained, to get the best out of your new hip, it is cru­cial to do your physio­ther­apy and then get your­self into a lifelong exer­cise habit.

As a gen­eral rule, by three to four months post-​op a new hip should be able to bear your weight safely, allow­ing you to return to reg­u­lar exer­cise. It is, how­ever, essen­tial that your con­sult­ant or GP gives you offi­cial clear­ance, as many people have com­plic­at­ing cir­cum­stances or con­di­tions that may affect their recov­ery times­cales.

Your con­sult­ant has sug­ges­ted swim­ming and cyc­ling for good reas­ons. Both activ­it­ies are low-​risk for your new hip, as they don’t involve heavy impact (unlike, eg, jog­ging or a step­per). They will there­fore allow you to build leg and hip muscle strength safely. The only cau­tion I would add is that if you are swim­ming, be wary of doing breast-​stroke leg kick, as this puts quite a strain on your hips. The free­style (front crawl) kick or back­stroke are bet­ter. Alternatively try deep water jog­ging or water aer­obics.

The other great bene­fit of swim­ming or cyc­ling is that both can be excel­lent ways to get your heart and lungs work­ing. For many people, a new hip is the cul­min­a­tion of sev­eral years of increas­ing pain and loss of mobil­ity, par­tic­u­larly if your joint was arth­ritic. And the sad fact is that when you slow down and stop mov­ing around, you start to put on weight. That in turn puts more strain on your heart, which like any other muscle, becomes weak and inef­fi­cient if you don’t give it reg­u­lar exer­cise.

So while your first pri­or­ity is to strengthen your hip and leg muscles, this is closely fol­lowed by the need to get your car­di­ovas­cu­lar sys­tem fight­ing fit. Do these two things and you will feel as though your life has been trans­formed within just a few months.

As you may have guessed, that leaves the exer­cise ball a bit lower down the list of pri­or­it­ies. If you are already exper­i­enced at using it, you can start doing so again, but in addi­tion to, not instead of cyc­ling or swim­ming. The exer­cise ball is really a tool for con­di­tion­ing your stom­ach and back muscles, not your legs and hips, and cer­tainly not your heart and lungs. There is a small risk, too, that if you are sit­ting or lying on the ball, you might roll awk­wardly, put­ting a bad stress on your new joint. Anyway if you’ve done no abdom­inal or back exer­cises for four months or more, doing your core exer­cises on a mat will be quite hard enough — you simply don’t need to use the ball for a while yet.