Hard work on the circuits

Observations from the last 2 weeks lead me to believe that the circuit class is hard on the delicate hamstring. Of course, they are supposed to be strengthening sessions and that requires an element of overload. During Monday and Tuesday the irritation eases but then exercises such as single leg squats (using TRX for balance) reactivate it. When you're doing day-to-day activities and exercises there is usually some compensation between legs but in this sort of isolation exercise the weaker one can't be helped out. Hopefully as it strengthens the problem will fade...