This study was done to measure the age-related decrements in cycling and running performance.
Its in PDf so I am having a heck of time uploading it.
(( recently it has been suggested that high-intensity and endurance running may damage the neuromuscular system, Mechanical disruption of muscle fibres caused by eccentric muscle activity has been proposed as a cause of exercised-associated muscle damage.
The importance finding of this study was that age-related decrements in performance began at an earlier age in runners compared to cyclists. Cyclist in general maintained performance levels until age 55 years.))
I will try and post a link if I can find it again.
review the study in PDF format its very interesting, I am not surprised as a previous runner most of my adult life til about age 55, I ad to stop due to nerve problems in my legs. Running may actually cause muscle damage to increase in aging. Where cyclist may not see changes in ability much later in life.