Depending on the source[0], average walking speed in older adults is about 0.8-1 m/s. The world record is 100m /9.63 s = 10.4 m/s, so it would not be at all su

Depending on the source[0], average walking speed in older adults is about 0.8-1 m/s. The world record is 100m /9.63 s = 10.4 m/s, so it would not be at all surprising if your grandad were just about 10x slower. Since the "10x engineer" is defined relative to other engineers, the right comparison is probably more like "other runners" than all people, which of course narrows that gap even more. [0] https://jamanetwork.com/journals/jama/fullarticle/644554 https://jamanetwork.com/journals/jama/fullarticle/644554 summarizes some studies in Table 1.