My biggest decision for this athlete is to choose what hammer to improve the 6kg hammer. He is throwing 60 metres with the 6kg, 52 with the 7.26kg and 47 with the 8 kg, 42.70 with 9kg. I think the 9kg could be the one.
I know for a fact that in Germany Throwers asked to do it. At least the ones who are in the national team. The Head Coach Jürgen Schult provides everyone with an Excel file which enables the throwers to put in their log entries. Not everyone is doing it but the ones who do will receive an overview. It is a really good training log which enables the coaches to check what their athletes have done and why there are improvements and downfalls in distances.
I coach a young 18 year old hammer thrower in Australia. We log everything much the same way Derek Evely @eveltrak does. We track whet hammers shift performance and keep all sessions short but at high intensity. Keeping record on performance levels enables better coaching decisions to made in the ring and in the weight room