Gossamer Gear posted a good summary of “Fastpacking” which is about as close to what I practice as I’ve seen published.
Here is their definition:
Fastpacking is the love child of trail running and ultralight backpacking. Fastpackers cover long distances on trail and carry only the essentials needed for a quick camp at the end of each day. So, think speed backpacking, or multi-day trail running—or ultramarathon camping.
You may have noticed an uptick in fastest known times (FKTs) for different trails over the past several years. Oftentimes, the adventure athletes setting these records are fastpacking. Carrying an ultralight load—often no greater than 15 pounds, and ideally less than 10 pounds—helps these individuals keep up their momentum without being weighed down by their gear.
Fastpacking will look a little different depending on the individual’s goals and the terrain. Some fastpackers might hike uphills, jog flat stretches, and run downhills. Some fastpackers may choose to go fairly far, while others choose to go really dang far. The experience can be tailored to meet the needs of the adventurer.
Distance runner conversion
For an x-long distance runner (who chose to save knees with different activity), fast-packing is perfect. It took me about 3 years to slowly stop running (20-50 miles / week for 40+ years) and completely move to hiking, biking, yoga and pilates. I am probably as fit as any time since my early thirties, and hold fast-packing or fast-hiking as the key to that achievement in my mid-60s.