Your muscles are imbalanced.
What is muscle imbalance? It is when one muscle group is much stronger than the other one and it weakens the body. This is the reason why you need to be consistent. Some people tend to over train their upper body and leave out their legs. There are also some who have really powerful legs but their arms are too weak. It must be balanced or else, your body will not progress.
You can always go to a physical therapist and ask for advice on how to “fix” this muscle imbalance issue. The PT’s are trained and certified to provide you the proper exercise movements and how to execute it correctly.