Torsional stress like tennis, swimming, etc. tends to lengthen the arms. The reason for this is likely due to the fact that torsional stress is the most efficient way to drive fluid forces in the bone(think like wringing out a sponge).

Devon Larratt is 47 years old BTW. A 53.6cm to 54.1cm increase over two years is a pretty good growth rate. And that’s not accounting for the humerus. Also imagine if you grew the clavicle and other arm length too. That would be a solid increase in wingspan over two years.

There are many sports that cause torsional force on the arms but the only sport I could find that could really exert torsional force was on the legs and I did find some evidence of leg height increase however there is a high rate of selection bias towards shorter divers.

I am currently testing exercises that could potentially exert spiral/torsional/rotation forces in bone. There are many for the arms(think hammer curls for instance). For legs, I am trying things like split legged woodchop exercises. Something like kicking could potential work. The problem is that the kicks have to be sufficiently weighted and you still have to maintain momentum.