Discuss the effect of change orientated feedback on sports performance.

I have a dissertation proposal which I need to have slyly altered in terms of the topic and some extra results , I’m looking to conduct a meta analysis dissertation looking into ” the effects of change orientated feedback on sports performance ” firstly I need to know if there is a specific variable that that is common in all topics relating to this question, this will allow the writer of this dissertation to to compare a specific variable , secondly I need to know if there is a substantial amount of results and information which can be used as results for my dissertation ( between 20-30) , I am ready to pay for a full dissertation , I just need to know whether you can find these topics as I have already presented it to my lecturer. Please let me know where it will be possible to conduct this dissertation with this topic (please remember that it is a meta analyze)