ME workout typically comes in towards the end of your training cycle when you move to event-specific training. For e.g. I am following the 24-week mountaineering plan and ME (Z3 Weighted Climb) is after I have gone through the Transition and Base period.

I would recommend completing your Base period and then adding ME workouts, unless you have a trip coming up shortly.

You will find this article on Muscular Endurance helpful. Read ME Caveat.

So I do Aerobic hiking with weight. My goal is very long day hikes, summits, and climbing, and trail running is secondary.

I started with bodyweight and had to go very slow but after some time that got too easy. Meaning I had to go very fast to keep my HR even in Z1.

I started adding weight 5# at a time if it got too easy and am at 20# now, which is 11% bodyweight. There is an article out there that talks about adding weight incrementally when training your aerobic base training, but to never go above 30% of bodyweight.

To quantify and gauge improvement if you are using a treadmill then doing a HR drift test every week will help you see improvement trends. IE if you are hiking on a treadmill with 10# and your HR Drift is < 2% maybe it’s time to add 5#.

I made a big mistake my first season and counted all my ME time (60# pack) as aerobic training simply because my HR was < AeT. Big mistake so I had a 8 week period where I did hardly any aerobic training and it showed that ice season.

I hope my story makes sense, helps, and answers your questions. If I find that article I will post it here. Cheers

Jake

To restate what Jake said, the intensity from ME is not represented by heart rate. The load is local (in the legs) and HR will likely be lower than the actual intensity. HR may be Z1/2 while the leg load is Z3.