At some point during the process of coaching an ultramarathon runner, the subject of weight vests invariably comes up. More generally, the question is whether adding external resistance is beneficial for improving ultramarathon performance.
Running up and down hills is the most common and sport-specific way runners add resistance and build leg strength. Running uphill is also a very effective way to increase cardiovascular intensity for interval training. As coaches, we often have athletes perform VO2 max intervals going uphill because the added resistance allows them to reach the desired intensity. Running downhill builds strength for eccentric contractions, as ground reaction forces increase to 2.5-3x bodyweight.
Ultramarathons often feature massive amounts of climbing and descending. While athletes who live in hilly or mountainous areas can simply incorporate more climbs into their training, athletes who live in flatter regions often look to alternative sources of resistance. Many crank up the incline on a treadmill, and some turn to weighted vests.
Weighted vests have their place in ultramarathon training, but there are some misconceptions about what they are good for and how to use them. Here are recommendations from the CTS Ultrarunning Coaches:
Goal: Maintain intensity at reduced velocity
There’s a lot of hiking in ultramarathons, so from a sport specificity standpoint it is important to incorporate hiking into training. The tricky part, especially for athletes who have limited time to train, is achieving enough cardiovascular stress to create an aerobic training stimulus during a lower-intensity activity. Weighted hiking helps deliver the cardiovascular stress of an endurance run while you’re moving at a slower velocity.
Load up your running pack
Rather than going out and buying a tactical vest with pockets for lead weights or sandbags, load up the pack you intend to use in your event. Fill the hydration bladder with more water than you’ll need. Put full bottles in the front storage on your chest. Carry your heavier gear instead of going light. Using your pack is more sport-specific because you’re distributing the weight as it would be distributed during your event. In contrast, tactical vests aim to distribute weight uniformly around your torso.
When training with a weighted vest or loaded pack, more weight is not necessarily better. Bending forward is the natural response to shouldering a heavy load. That’s problematic for a runner because it significantly changes your biomechanics. At minimum the altered biomechanics diminish the specificity of the workout. The much bigger risk is that it leads to injury.
Aim for 10% of bodyweight
The weight of your pack doesn’t need to be exactly 10% of your bodyweight, but should be close. The primary result of the 10% recommendation is that it generally keeps packs under 20 pounds. Once vests get above 20% of bodyweight or more (>30 pounds for a 150 pound runner), the sport specific benefits typically decrease due to altered biomechanics, and injury risk increases.
Keep it relatively close to event date
As Jason Koop wrote about in “Training Essentials for Ultrarunning”, athletes should train the least race specific aspect of fitness farthest from their events and the most race specific aspects closer to their events. You’re likely to hike at least 20% of a 50- or 100-mile race, so hiking should be part of your training in the final weeks and months before your event.
Be conservative going downhill
You’re probably going to run and hike downhill wearing your pack during your event, so you should do it in training. However, if you are carrying a pack that is purposely heavier than you’re going to use in your event, be cautious about running at high speeds downhill. With each footstrike you are – by yourself – hitting the ground with more force than you would on level ground due to acceleration from gravity. With added weight you have even more mass accelerating due to gravity.
Skip pushing sleds, pulling tires, or using parachutes
A weighted packs/vest is not the only way runners can add resistance, but it’s the only one that’s really applicable to distance and ultradistance running.
Dragging a tire harnessed to your waist or chest makes it harder to move forward and increases aerobic and muscular workload, but you’re not going to drag the tire for miles. For similarly short efforts, you could achieve the increase in aerobic and muscular workload by running faster, harder intervals.
Pushing or pulling a sled is a great strength training activity for recruitment of lower body musculature, but the biomechanics and force generation have very little in common with distance running. Sleds are more useful for short, high-intensity efforts for power athletes, like football players.
A parachute is a legitimate training tool, but primarily for sprinters. Sprinters need strong Achilles tendons and ankles, and as they get faster the parachute becomes necessary to generate sufficient force to stimulate the desired adaptations.
Weighted Vest: Yes or No?
As an ultramarathon runner, the wisest and most sport-specific use of added resistance it hiking with a weighted running pack slightly heavier than what you would carry on race day. Going harder and heavier increases the risks more than it is likely to increase your performance.