depends on how much they weighed and if it wasnt over the weight that the spring are supposed to withstand then that means your springs have become weak and lost some of the tension but since you changed the whole strut assembly already i doubt thats the problem even though it is possible to get a brand new pair of bad springs. to tell if the springs are weak you have to remove all the extra weight out of the car( meaning everything that didnt come from the factory and make sure your tank is full. then you find a level spot to park. after that you have a tape measure and measure from the ground to a predetermined spot on the vehicle which the manufacturer supplies. you can find this info. in your owners manual, and what the specs. are supposed to be. if within specs you should be good if not then you should replace them