Time to Re-Classify Ultra Running?

When is a run, no longer a run? I believe that ultra running truly brings this point into question.

Now, before I start, this is not a blog about what is the 'better' distance or which discipline is truly ultra or tougher but it's to ask the question: at what point does the race in itself become a different sport altogether and in itself comparable to adventure racing, triathlons and the like?

Personally, when it comes to ultra running I am a multi-tasker, I love to run the 100k roads as well as the mountains. 

Each event holds its own challenges:

the 100k, 24hr, 50k being more prescriptive and comparable to track style running. Road ultras require constant pounding of the tarmac or track which adds to the toughness of the run with the repetitive running cycle, harshness on the joints (with little give) and usually ran at a faster pace. Personally, I have found that nutrition and hydration is tougher at these events as you are running that much faster with little time to stop and recoup.

Trail and mountains offer a truly unique experience and in most cases (for me) offer a more 'enjoyable' run with a truly unique experience each time you put the trainers on and hit the trail. Of course, the obvious challenges for mountain and trail running being the terrain, harsh ascents and descents and the frequently changeable and unpredictable weather (saying that the past few 100k World Champs have been bloody hot). That said, I don't think anyone can put a plausible argument across as to whether road or mountain running is the tougher sport. They each have their own challenges.

With that point in mind, I'd like to pose the question when is a run no longer a run? Presumably when its a walk. Right? Or a scramble, climb,  abseil or whatever? But we are actively encouraged to walk ultras in places and taught that it forms part of the race. So surely walking is fundamental to ultra running?

Sure, I think this is a simply concept to grasp. Anyone who has run a tough ultra (whether on road or mountain) will have spent some time walking or standing at an aid station. 

However, (posing an extreme example) what if the majority of competitors in a competition walked, scrambled, or hiked say 90% of the race course - would this still be an ultra run? Presumably not. It would most likely be deemed as a pedestrianism event. So on this basis there must be a stage where the run no longer qualifies as a run. So are we talking stats here to re-classify an event? If so, are we talking about distance walked and percentage of those walking that distance?

Let's take an example,

if over 50% of competitors walk, hike or scramble over (let's say) 30% of the course, can it still be defined as an ultra run? or should it be re-classed as an ultra race? Does it matter? Will it matter in the future when ultra running becomes more mainstream?

let's take another example that may not be unimaginable, 95% of competitors walk, hike or scramble over 20% of the course. Should this race still be deemed as a run or something else? Again, does it really matter?

I think we can drop the term "ultra marathon" as to me a marathon is a determined distance and ultra marathon simply doesn't make sense. So what should we call it? Perhaps there should be several disciplines:

ultra mountain race
ultra mountain running (but how much should be ran)
ultra run (where the event is run by over 95%?)
ultra road running
ultra race (other races not an ultra run)

I dunno, just chewing the cud. What are your thoughts?

Dan