Stretching can increase your range of motion temporarilyThe best reason to stretch before a workout is to prepare yourself for that specific workout. But that’s exactly why it’s good to do these stretches right before your workout. Your pre-workout stretches can contribute to that, although it’s good to also do some stretching and other flexibility work after your workout (or as its own workout) if that’s your goal. Stretching can slightly decrease strength in the short termAll that said, it is possible to stretch too much before a workout. Before a squat workout, someone who struggles with squatting deeply enough should probably do some calf and ankle stretches , and maybe some stretches for the hips.