By Rob Shaul, Founder
BLUF (Bottom Line Up Front)
Ten 60-minute sessions of sandbag drags at a controlled Zone 2 heart rate resulted in an 11% improvement in a loaded step-up assessment, also conducted at Zone 2. While this is a single-subject case study, it suggests that extended, loaded drags may effectively train uphill movement under load.
Background
Uphill movement under load is a specific mode of endurance best trained on a steep hill with a loaded backpack. However, this ideal isn’t always practical or accessible. Years ago, MTI began using loaded, extended step-ups as a surrogate training mode, with great success. Our own research and thousands of anecdotal reports from both mountain and tactical athletes have supported the efficacy of loaded step-ups for this purpose.
Still, step-ups can be brutally monotonous. Stair machines are expensive and not much more enjoyable. We previously tested biking as a potential training mode for uphill movement but found negligible transfer. We’ve also studied short, intense sled drags, which proved effective for strength and work capacity.
Early in MTI’s history, we experimented informally with extended, 1-mile tire drags. Currently, our Denali Training Plan includes extended sled drags to prepare athletes for the long hauls pulling sleds en route to basecamp. But until now, we’ve done no focused research on extended sled pulls as an endurance training mode, particularly for uphill movement under load.
Extended loaded dragging is intriguing due to its similar movement demands: more quad/leg strength than flat-ground running, and often the foot strikes on the ball only—similar to steep hiking. Attached the line from the sled to the body ssing a shoulder harness mimics the full-body fatigue of a heavy pack: legs, shoulders, and core all get taxed just like hiking uphill under load.
One longstanding challenge: friction variability. Sled pushes and drags are notoriously hard to load consistently. In our gym, the same sled is easier to push one direction on turf due to how the turf was manufactured. Outdoors, surface type—concrete, asphalt, gravel—and weather conditions further complicate load consistency. And metal sleds are noisy and expensive; tires are cheaper, but still friction-dependent.
The breakthrough may be shifting from load-based progression to heart-rate-based control. Instead of tracking drag weight, the athlete adjusts pace to maintain a consistent Zone 2 heart rate. This allows for real-time effort adjustments and largely removes the friction variable. The sled just needs to be heavy enough that the athlete stays walking, not jogging or running.
Study Design
This was a case study with a single athlete (myself).
• Initial Assessment:
A 5-minute step-up warm-up, followed by a 40-minute step-up assessment wearing a 20-pound plate carrier, targeting a Zone 2 heart rate.
Zone 2 was defined as 180 minus age; for me (age 56), that’s 124 bpm, with an allowable range of 119–129 bpm.
• Intervention:
Ten 60-minute sessions of sandbag drags on the beach over 12 days, maintaining the same Zone 2 heart rate range. The line from the sandbag was attched to me though the bottom of the shoulder straps on a small empty backpack – so when I pulled, I leaned forward and felt the pressure on my shoulders, not my hips – similar to loaded uphill hiking.
• Post-Intervention Assessment:
Repeated the 40-minute step-up assessment under identical conditions.
Results
Step-up Assessment:
• Pre-Intervention: 765 reps in 40 minutes
• Post-Intervention: 853 reps in 40 minutes
• Improvement: +88 reps / 10.88% gain
Both assessments were performed wearing a 20-pound plate carrier and at a controlled Zone 2 heart rate.
Heart rate and performance data were tracked using a Garmin Fenix 7X Pro and external heart rate monitor.
Discussion
These initial results are promising. They suggest that extended, loaded drags may be an effective—and possibly more engaging—alternative to loaded step-ups for building uphill endurance under load.
Next steps:
• Conduct a mini-study with more participants.
• Include a functional uphill movement assessment an actual loaded hill climb, with a regulated Zone 2 heart rate.
• Compare two groups: one doing step-ups, one doing drags. Re-assess uphill movement to see if one mode outperforms the other.
This could potentially expand the endurance training toolbox for mountain and tactical athletes alike.
Questions or Feedback?
Email: rob@mtntactical.com