Question, Puunui, since you know/converse with some of the pioneers. How many still practice daily? Do any of them still teach on a regular basis?
A lot of them have passed away. This includes GM LEE Won Kuk, GM YOON Byung In, GM CHUN Sang Sup, GM HWANG Kee, GM YOON Kwe Byung, General CHOI Hong Hi, GM LEE YONG Woo (Jung Do Kwan founder), GM HONG Chong Soo, GM LEE Byung Ro (inventor of steps and step drills) and most recently GM LEE Kum Hong.
Some are still alive. The ones that work out daily in current Jidokwan President LEE Seung Wan, GM PARK Hae Man and GM PARK Chull Hee. GM PARK Hae Man is still pretty active teaching and I know GM PARK Chull Hee really enjoys working out and teaching still. I would say the ones who would give GM Jhoon Rhee a run for his money are GM LEE Seung Wan and GM PARK Hae Man.
A lot of the USTU pioneers also work out daily. During trips you can see President Sang Lee running or doing the trendmill every morning. I remember I caught the red eye once for a USTU Annual Meeting, got in at around 6 am, and saw President Lee holding a coffee cup ready to do his morning run. People like GM LEE Hee Sup still work out, and can still do the splits, as can other USTU types. These gentlemen lived Taekwondo their whole life and work out because they love it.