I am doing the JMT (http://www.pcta.org/images/elevation_new.jpg) and only have 14 days with which to do it. The hike is in 7 weeks and I am training for it. This weekend I plan to do 2x 16 mile 4,000 elevation gain hikes back to back, hitting some stairmaster during the weekdays.

The most I've hiked before 4,400 elevation up to 11,500 in a 16 mile round trip, then felt sore and rested the next day. (didn't train for it).

What I'm wondering is, given that most of my hiking days will have to be around the 20 miles per day mark, what's best? Is it easier to do the high miles early? (I realize the first day will be brutal, but I mean early). In the middle? Towards the end (think maybe not with Mt Whitney being so tall).

I could sincerely use some thru hiker experience here. Thanks!

Trying to do big miles early may be tough for your heart if you're not already acclimated to high elevations. A few months ago I hiked I did this hike which is similar to the one you mentioned, and with a late start, I was pushing so hard that my heart felt like it was going to explode and I was wheezing for a week. Hydrating very well, stretching and massaging your muscles at the end of the day and ibuprofen at night should help a lot with the soreness.

Haha Eugene that's awesome, that's exactly the hike I was talking about.

Good reminder though about the acclimation. That'll be big hanging out at 10k or so.

Cardio is one thing, but I'd be more concerned about foot problems by day 3 or 4; pain, blisters, etc. Not to sound grim, but the stairmaster won't prepare you for being on your feet on dirt and rocks 8+ hours a day for 14 days straight, not to mention wet feet, etc. Make sure you figure out something to keep your feet healthy...a good sock/shoe system, tape and blister treatment/prevention, dry sleep socks, etc. Unfortunately, in my experience, this is very subjective and really dialed through experience.

Not trying to come across pessimistic, just suggesting not to underestimate foot care.

Absolutely. My plan is to use hydropel, sleep socks, and leukotape when needed. I'm trying to mix in as much hiking as possible to prep too, but with living in flatland urbanville it's just not something I can do on weeknights.

Your pack is going to weigh much more in the beginning due to food/consumable weight. So trying to do big miles in the beginning is going to be doubly taxing to your body which most likely isn't a linear increase in difficulty. So between acclimatizing and heavier pack, just steadily increase your mileage as time goes by. This should feel intuitive while on the trail.

Also while you're training, you should really be carrying about 110-125% the weight that you will start off with. It's standard practice in high level training to train harder than you intend to compete. That way when you do compete (or just hike in this case) your body feels "happy" that things are easier than the grueling pace it's used too. This has great physiological (and psychological) benefits to maintain max performance. This of course assumes that you're already at a high level of athleticism and that your body is accustomed to rigorous training regimes.

20 a day with full pack on rough ground demands well broken in boots with stout soles in my opinion. I'd be wearing them as daily footwear from now until I went. Plenty here will disagree though. I don't know the trail, but from what I've seen in pictures, it isn't at all well graded and smooth.

Don't be put off by the weight of strong boots. They help swing tired legs along the trail. Anyway, better tired legs than excruciating feet.

There's been some good advice given. Get in as much training as possible before hand with steep ground much as possible, with the same shoes and pack as you'll be using, except the pack should be heavier than you'll have on the trail.

Presumably you will resupply along the way so you'll have a heavier pack more than once. I think it is key in thru-hiking to listen to your body. It's good to plan ahead, but then to modify that plan to suit what's actually happening. Hike longer days if you're feeling good, back off the miles if it's starting to beat you up. If you don't chew up your feet or body too badly early, you'll likely toughen up by the end.

Stout boots are a good choice for some people, but I think it's fair to say that most experienced thru-hikers, carrying lighter packs than the days of old, are using trail running shoes or similar nowadays. Personally, I think heavy boots make it harder to swing my feet down the trail. : )

I might suggest skipping the stairmaster to put in some time on intense walks with a loaded pack, preferably loaded heavier than it'll ever be on the trail. Don't go nuts and screw up your back, of course, but more weight than you'd really want to backpack with.

Lately I don't have a car and I live about 3 miles out of town in a yurt, so occasions like grocery shopping or doing laundry involve walking a bit with a decently heavy pack, often 30 pounds or more. Once I started doing this my progress with running, which had been just slowly coming along, made a sudden jump, and walking for hours on end with a lighter backpack became a lot easier. I'm sure the stairmaster will give you a good workout, but there's just something about moving around under a heavy pack that shores up just the right sets of muscles to really up your mobility and endurance. It seems to improve just about everything having to do with the legs.

I would also second not using a stairmaster. There was a guy on here a while ago that sounded like he gave himself a repetitive stress injury by training with a pack on a stairmaster. Real hiking varies the slope and terrain, each step is different...

We really tried to sleep below passes so we tackled them when we were fresh from sleep. It won't always be possible with a 14 day plan, like we had, and you may even do two passes in one day.

In the end we actually did a few of them in the evening, and were even hiking on the backside of them at dusk, and even dark. It sounds good, in theory to do them in the morning, but it just seemed like it was better "to just get it overwith" some days.

We were on a strict schedule, with stays lined up at Red's and MTR, and with friends meeting us below Baxter Pass. So we didn't have the luxury to slow down when we were tired. The first few days were really hard, I was not prepared for it. By about the eight day mark, my endurance was fine, but our feet were beginning to really take a toll, you just end up living with sore feet if you don't prepare them. I had the gear and logistics extremely figured out, but not the training.

I would concur that the Stairmaster isn't a very good training option. However, if you absolutely can't get out in the hills or on an urban trail, for work related reasons or whatever, a machine called the Step Mill is a good alternative. Unlike the Stairmaster, you will be climbing a set of stairs and will have to lift one foot off the stair at a time, just like going up a flight of stairs. You can adjust the speed up or down to suit your personal training pace and get as hard a workout as you will be able to handle, guaranteed. A lot of climbers up here in Seattle use them when they can't get out in the Cascades, with or without a pack depending on the specific purpose of the workout. A lot of gyms have them these days, so look around if this idea appeals to you.

My couple of thoughts:
Plan for longer days later on. The altitude acclimatization will make a BIG difference in your capacity.
To make the most miles per day, plan on long days. Get going early and take two lunch breaks - one late morning, one early afternoon Breaks the day yp a little more and ensures that you spread your calories out more. I find it's easier to do more miles by way of doing more hours than by going faster.
Also, optiimize your resupply plan to reduce your packweight. If going N-s, start at happy isles with 2 lunches, 1 dinner, 1 breakfast; takes you to tuolumne where you spend the night and have breakfast & dinner - you never carried those two meals. and so on. Always eat where you resupply so you cut down the total food load you carry.
I second the notion of always wearing the shoes you will hike in from now till you start. The more familiar your feet and the shoes are, the better. And take the shoes off every chance you get, at lunch and rest breaks. Keeps the feet drier and that'a always good.

I hiked a short section of the JMT last summer wearing Chaco sandals. I really think the whole "the JMT is so rugged look at all those rocks" scares people more than it should. What will slow you down is snow and it's a high snow year. But rocks? Heck, I met a lady on that trip who was hiking in flip-flops and bare feet and had been doing it that way since she was 16 years old.

What I would do is just go out with the plan to do the best you can. Listen to your body. Don't push too hard at first but do hike long days if you can. Recently I was hiking on San Jacinto and I wasn't feeling good at all and I could really feel the altitude. I just went very slowly but oddly slowing way down didn't really slow me down very much. Time really is more important than speed.

The worst thing that can happen is you don't finish in the allotted time. Well, the real worst is you hurt yourself trying to do more than you can. There are so many places you can leave the trail and hop on a bus if you can't finish in 14 days.

But I highly doubt that will happen. You're young and strong and going light. Most people out there are plodding along at 8mpd rest-stepping under enormous loads like you wouldn't believe.