It's an interesting concept, looking at ages and peaks. It is something I can relate to personally. From my mid twenties (I started late) I was opening the bowling in the top side, albeit at a Club level. By my mid thirties I was fluctuating between the 1st and 2nd XIs and in my late 30s it was decided I'd best serve the Club captaining the young 3rd XI. After a couple of seasons I was required in the 2nd XI and, in my early 40s, I worked my way back into the top side for a couple of full seasons. The cycle then repeated. Captained the 2nd XI and then the 3rd XI before going into semi-retirement at 50. Did my bowling change dramatically over those years? My initial decline was probably due to losing pace and my resurrection due to adding more guile and variation. Perhaps a factor would also be the fluctuations in the Club's bowling stocks.
Similarly, at a Test level, players might have highs and lows but their selection at that level might also depend on the depth of top class talent. Those highs, particularly for pace bowlers, would have to coincide with peak fitness levels and, when remaining injury free, those levels can be maintained for longer periods. As aerobic fitness declines it may or may not be replaced by the skills that come with experience. In the case of Test batsmen I think that trying to balance the demands of Test cricket with other forms of International cricket would add mental stress to the physical demands. Hence we are seeing batsmen retiring at an earlier stage than they may have done in the past.
Like subshakerz, I would be interested to see any research on this topic as well as reading of other members' thoughts and experiences.
