Load carriage strategies to improve military fitness

Moving under load is one of the most common and difficult physical tasks for grunts. The load you carry changes how you walk and run—if you could call the “airborne shuffle” either of those—and the amount of energy you expend when you move. Targeted physical training, strategic packing, and wearing your ruck can go a long way to prevent injuries and to make the job easier.

Physical training

A common belief that to improve your rucking ability, you should load your pack and set off on a march. However, this doesn’t improve your rucking ability much and can lead to overuse injury. Rucking under heavy loads increases ground reaction forces (GRF), or the force sent up from the ground through your body when you step down with your foot. Increased GRF can lead to bone-stress and other overuse injuries. This is why rucking is limited to missions, and it is not to be used as a form of regular physical training.

The best way to improve your rucking is through lower-body muscular strength and muscular endurance training. Improving your strength helps your body absorb increased GRF, reduce fatigue, and decrease risk of overuse injury. When you improve endurance, it delays fatigue, which allows you to operate for longer.

It’s also important to work on your core conditioning to maintain proper posture and minimize the negative effects of a ruck lean. This helps you stay upright and reduces the risk of a fall, which can lead to hand, arm, and shoulder injuries.

Finally, cardio training is important for longer marches, especially when carrying heavier approach loads. The longer you march, the greater the demand on your cardiorespiratory system. Cardio should be performed unloaded to safely improve endurance. While it’s important for ruck marches, cardio is secondary to resistance training when it comes to reducing muscle fatigue.

Load distribution

Load distribution is how the weight of your pack is spread within your pack and where it is located on your body. Most of the weight of your pack should be close to your body’s center of mass, which for men is at their navel and for women slightly lower.

How does that translate to loading your pack? When loading it, place heavier items at the bottom of your pack, close to your body. For example, if you’re packing your plates and plate carrier, the plates should go near the bottom and on the side closest to your back. The carrier can go next to the plates, further away from your body. Having the heavy objects close to your body, as opposed to the far side of your pack, makes it easier to move and reduces stress on your body.

It’s usually best to wear your pack up high on your back. This will place the heavy bottom close to your center of mass. This makes it easier when hiking uphill, since it will give you a slight forward lean. If you are hiking downhill or across unstable terrain, it’s better to lower the pack to sit further down on your back. This will lower your total center of mass, making you more stable and less likely to fall forward down the hill.

Many packs come with frames and hip belts to take some of the stress off your shoulders. This prevents “nerve-compression injuries.” This happens when most of the weight is on your shoulders and the straps dig into your armpits. Hip belts work best when worn up high around your navel, resting on your hip bones. This allows the weight of the pack to go down through your hips and legs. It also prevents the belt and pack from sliding down.

Moving under load

The last part of load carriage is how you walk. First, it is generally not a good idea to run when under a heavy load. Obviously, there are times when you have to run. Marches are generally done at a walking to trotting pace. If possible, walk at a pace and a length of stride (the distance between steps) that is comfortable for you. This can be difficult when you’re on a ruck march with a lot of other people. When you need to move faster than a walk, it is best to take longer and faster walking steps (meaning you always have one foot on the ground), as opposed to doing the “airborne shuffle.” The airborne shuffle takes more energy and might increase GRF because of the trot-style gait.

If you have questions about how to pack or wear your ruck, your senior enlisted unit members are often good resources. You can also submit an Ask the Expert question through HPRC’s website. Include the type of pack you use, and we can help you with the proper fit.


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References

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Brenes, A. N., Caputo, J. L., Clark, C., Wehrly, L. E., & Coons, J. M. (2015). Comparisons of the airborne shuffle to standard walking while torso loaded. Journal of Strength and Conditioning Research, 29(6), 1622–1626. doi:10.1519/jsc.0000000000000801

Looney, D. P., Santee, W. R., Blanchard, L. A., Karis, A. J., Carter, A. J., & Potter, A. W. (2018). Cardiorespiratory responses to heavy military load carriage over complex terrain. Applied Ergonomics, 73, 194–198. doi:10.1016/j.apergo.2018.07.010

Walsh, G. S., & Low, D. C. (2021). Military load carriage effects on the gait of military personnel: A systematic review. Applied Ergonomics, 93, article 103376. doi:10.1016/j.apergo.2021.103376