When I first read the premise of this thread, I thought it was all bad. I tried to come up with something positive. First, OP must have a mouse in his pocket since he titles the thread "Plotting our decline. I would change it to "Plotting my decline". He made an observation about his data over years not everyones. What I see in OP's data is a rider who needs motivation or assistance if the goal is to improve. There is nothing wrong with declining performance.

We do not have to plot personal data if we want to see diminishing cycling performance with age. All one has to do is look at state championship time trial times for a 40k time trial by age group to see the older riders are generally slower than the younger riders. This is not surprising or shocking. The same is true for track flying 200 meter times. The best younger track sprinters turn in better times than the older ones.

Now there are some notable exceptions where a few older racers are really good. Ned Overland (53) is an example and routinely beats the elite (under 29) category 1 racers in hill climbs. Ned is a former world champion mountain bike racer. And there are others.

So where is the positive? IMO, most of the decline is in strength which can be managed to an extent. Strength is lost and recovery subdued. What that means to me is that I have to work harder at maintaining strength and recover harder.

I started weight training in 1977 and have been consistent missing very few days in over 35 years. Today, I strength train at least 4 times per week. I focus on those muscles that cycling does not and I pay particulate attention to the back and core. I work very hard on recovery. I am extremely careful what I eat. Getting older and maintaining or improving performance is very hard work.

Since starting track racing in 2007 my times in the 500 meters and 2Km pursuit have improved and I hope to improve them again this year.

Over the weekend, I attended a two day track clinic that focused on standing starts. The standing start is highly technical and very dependent on strength, reaction time and skill. We started the clinic with each of us doing a standing start that was video taped. The coaches played back the videos and we had to comment on what we thought. One older guy said that was the best he could do. Another older guy said he was terrible at the start. The coaches countered with, we will not have any negative thoughts or discussion. With proper technique, practice and feedback, we all improved our start including the guy who thought he could not (he was the best) and the guy who was terrible improved dramatically. Both of those guys are over 60. Never sell yourself short... no negative thoughts.