Hello, I am a sports specialty student. For the problem you mentioned, first of all, I think the effect of tying sandbags is not very effective. Generally, when you take it off, you will feel a lot relaxed all over. You should stick to it for a long time. I used to tie sandbags almost every day until I went to bed. Besides, I was tied with 5KG. I suggest you do more leapfrog. Squat jumping, leg press, tiptoe and other sports are very effective for leg explosiveness ... No matter what you do, you should stick to it. Don't rest for a few days. It's no use. If you do too much for the first time, your muscles will ache. Don't stop training. Reduce the amount of training appropriately. Finally, I wish you success.