I forgot to add two other useful sources of "wisdom". We all - well, some of us - know Al Henderson's little book. Brilliant! His reframing of various archers' laments to give a positive perspective. "I shot too many nine's" becomes "Well, you shot 70% tens".
Then there's a surprising review article in a book that very few of you will know from, of all places, FITA. Unfortunately the English language in the book is, in many cases, impenetrable. It is called "Sports Medicine and Science in Archery". The article (Chapter) is entitled "Psychological Preparation in Archery" written by two Turkish sports scientists.
The article mentions that "many elite sportsmen (sic) use these techniques [mental training] and a similar number of athletes emphasize that because of time limitations and lack of opportunities they can not use mental training before competition". The article goes on to point out that "beginning" athletes should concentrate on "basic movements".
They outline several techniques, including Visualization (Mental rehearsal), centring, PMR (progressive muscle relaxation) and a long section on Autogenic Training (therapy).
