This is a very interesting question. One that I too have wondered about. After taking a hiatus from practising, as in anything, it’s important to ease in wisely. For yoga you might consider starting with some free form dance to loosen up, reduce any tension and warm up the joints and tissues. Vigorous, free form movement can be much less hard on the muscles than jumping into a somewhat “linear” practise. When you are in the asanas, you might consider a longer slower time in them with deep and steady breathing.
Be sure to have a 10 minute minimum relaxation at the end of your practise no matter what length it is as recovery and rest are very important.