It can take 12 weeks for the body to change at a cellular level. Factors that might affect an athlete’s ability to change their body include their initial fitness level, their diet, their work schedule, their support network, how they manage their time, their ability to cope with stress, their personal finances, their mental or physical strengths & weaknesses, even their attitude or willingness to commit to a goal on a regular basis.
Technique changes depend on many things too – even things outside of the athlete’s control such as the environment or equipment they have available to them. Even their coach (or whatever they are using to get feedback about what changes need to be made). When I was working on changing my technique, my coaches told me that I should feel “weird” or “out of my comfort zone” because anything less wasn’t pushing me enough to really change. The rule of thumb was that I had to feel like I was over-correcting to know I was doing it right. Eventually, the different feeling became the new normal, but it took time… and usually more time than I thought it should.
Be patient with yourself. Accept that change takes time. Give yourself time to change before giving up or feeling disappointed in yourself. One of the best things about sports is that we all start on different playing fields. We all face different obstacles. We all have a different story and different motivations. Things will be more difficult for some people than others. Some people make it look easy and some people visibly struggle. In this day and age it is easy to forget that change is uncomfortable for us all. Remember, real change takes time.