Planning and Preparing for a 14 Day Thru Hike of the John Muir Trail
The first in the five-part JMT Series. What to expect from the JMT and the endurance training required.
The John Muir Trail is a 220 mile hiking trail through the Sierra Nevada mountain range of California that is traditionally backpacked as a single, 3-week endeavor. Over the course of its 220 miles, the JMT achieves a vertical gain and loss of 42-47,000 feet (northbound-southbound, respectively), crossing over 10 high mountain passes and terminating at the highest point in the lower 48, Mount Whitney.
On August 25th, 2021 I arrived at the Whitney Portal Trailhead, the trailhead nearest to the JMT’s southern terminus on the Whitney summit. I hung my backpack on a scale at the trailhead that read 43 ½ lbs. My hiking partner, Shae, weighed in at 41 ½ lbs. We started walking with the intention of reaching the JMT Northern Terminus at Happy Isles in Yosemite Valley less than 15 days later.
Wondering if we succeeded?
Read the trip report here.
This five-part series will document the preparation, gear and execution of our John Muir Trail experience to serve as a resource to future JMTers or future backpackers considering any long trail. In this article, we’ll focus on the early-stage preparation and planning for a long backpacking trip like what prior experience is needed, the specific demands of the JMT compared with other common backpacking trails, and the physical training required to match those goals (and ideally have fun while doing it). Here's the breakdown of what we’ll cover in each of the five-part John Muir Trail Series:
Table of Contents:
Part 1: Previous Experience and Physical Training
Part 2: Setting your Itinerary, Permitting, and Logistics
Part 3: Meal Planning
Part 4: Gear List Deep Dive
Part 5: Hiking the JMT in 14 Days
Both Shae and I had our first backpacking days behind us before we started the JMT. Shae had spent 4 weeks in remote Washington State as part of a National Outdoor Leadership School (NOLS) course in the summer of 2015. My first and only other backpacking experience was on the Appalachian Trail (AT) during the same summer with a lifelong friend named Jack. We spent 6 weeks on the AT, traveling over 400 miles from the New York State line northbound into New Hampshire.
The backpacking experiences Shae and I had been on before provided some valuable takeaways that would drastically improve our JMT experiences. I’ll shed some more light on what these takeaways were throughout this series.
An additional bit of context for this series is that Shae and I have been avid trail runners for years. 2021 was my 8th year of training and racing events ranging from road 5K to ultra trail. Having years of training already in the bank helps the body to build durability (injury resistance) before you arrive at exceptionally strenuous events like the John Muir Trail, but years of experience is not required to succeed in a long trail thru-hike .
The Demands of the Trail
Multi-day backpacking is a physically demanding pursuit no matter how you stack it. Long distance goals each day mean more hours on foot, but shorter distance goals often means more days in between resupplies, and more food weight on your back.
Whatever your goal, having the fitness to meet that goal is a huge asset. Back-to-back high mileage days can take a toll on your strength faster than most people realize, so training for the physical demands can be the difference between a fun trip and a sufferfest. As with any physical endeavors, it’s best to consider and train for the specific demands of your event. The JMT is long, includes exceptional vertical gain and loss, and is almost entirely 8,000 or more feet above sea level, meaning significantly less oxygen availability.
The JMT can take thru-hikers as little as 67 hours or as much as 4 weeks, so the fitness required is somewhat relative to your goals. The schedule Shae and I were aiming for– hiking from trailhead to trailhead in under 15 days– was more aggressive than most attempts. The faster-pace itinerary we aimed for meant building significant trail fitness before our hike would be more critical than if we were on a more relaxed schedule. Read on for more detail on exactly what that training looked like.
Building the Fitness for Success
Living in Colorado, Shae and I were lucky that we had a good environment to train for the JMT’s specific demands, particularly the altitude. Shae’s training for the JMT was in large part a continuation of the training for her first 50K ultramarathon. After her 50K and the subsequent recovery period, it was back to the trails for more long, slow, vertical running.
My training in the 8 months leading up to the event progressed from an 18-week road marathon training cycle followed by a gradual shift towards trail running volume. As I made that shift, I put special emphasis on climbing and descending. The metabolic fitness gained in a marathon cycle is perfect for backpacking, but the trail training component is essential for preparing the required muscular adaptations in the legs and feet.
We both performed a dress rehearsal about 6 weeks out from our start date, hiking the tallest mountain in Colorado, 14,339 foot Mt. Elbert, with all of our backpacking gear. We considered Elbert a perfect close-to-home simulation of the climb to Mt. Whitney’s 14,505-ft summit.
Less than a month before the trail, I helped pace my friend Kevin for 50+ miles of his race at the Bigfoot 200 Mile Endurance Run, which afforded me more valuable time-on-feet training. Pacing this event meant moving in the mountains for eight to thirteen hours straight (plus the memory of a lifetime watching him cross the line in 5th place overall).
Not everyone does or should train for a backpacking trail the same way. Shae and I were able to prepare well using trail running because the added impact of running, especially downhill, strengthens the legs well to handle the added weight of a backpack while hiking. For some backpackers, functionally similar muscle adaptations can be achieved to an equal or greater extent through a weight lifting routine. A good strength routine can also incorporate core, back, and shoulder exercises to prepare the upper body for the burden of pack weight, whereas running will not. Trekking poles can also allow a hiker to use their arms and back to help propel them up the steepest climbs, which can be another benefit of good upper body strength.
Should anyone choose to take a more strength focused approach, the optimal routine will still be endurance-focused, consisting of many sets with lots of reps (e.g. 3+ sets of 10-12 reps) as opposed to power-focused (3 or less sets with 8 or less reps at a higher weight). For more aggressive mileage goals, aerobic base training in some form is probably mandatory.
Planning your Trip
That wraps up our discussion of the most early-stage factors in prepping for a long trail thru-hike. Prior backpacking experience for shorter durations and “dress rehearsal” hikes can offer critical insight into what’s realistic for setting your itinerary and choosing your gear on longer trips, where you’re more committed to your decisions.
Read next: The Itinerary and Logistics of a 14 Day John Muir Trail Thru Hike
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