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 and how much energy you expend when you move. Targeted physical training, strategic packing, and wearing your ruck correctly can go a long way to prevent injuries and make the job easier.
Physical training
It’s common belief that to improve your rucking ability, you should just load your pack and set off on a march. While this might work in the short term, rucking too often or increasing your load too quickly can lead to overuse injury. Rucking under heavy loads increases ground reaction forces (GRF)—the forces 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. The Army Public Health Center recommends limiting ruck marches to one every 10–14 days, planned in coordination with resistance training and cardio days. It can also take 2–3 days to recover from a ruck, so try to plan active recovery days after ruck days.
Muscular strength and endurance
Both upper- and lower-body muscular strength and muscular endurance training are good compliments to ruck training. Improving lower-body strength helps your body absorb increased GRF, reduce fatigue, and decrease risk of overuse injury. When you improve your endurance, it delays fatigue, which allows you to operate for longer. Strengthening your upper body will help you maintain good upright posture and reduce fatigue. Relative strength—being strong for your size—as opposed to absolute strength—lifting as much weight as you can, regardless of your size—is most important for load carriage. That means training so you can bench press and squat more than your body weight. This is because when you’re rucking you need to move both yourself and your gear, which is ideally weighed out as a percentage of your body weight. However, the reality is that the mission dictates the gear, and the gear weighs what it weighs, regardless of your body size. So rather than training so you can lift and move the weight of your ruck, you train to move the weight of you and your ruck.
Core strength and agility training
It’s also important to work on your trunk strength to maintain proper posture and minimize the negative effects of a ruck lean. Agility training, in which you train to move your feet and change direction quickly, will help you stay upright and reduces the risk of a fall, which can lead to hand, arm, and shoulder injuries. Maintaining balance is about keeping your center of mass within your base of support (the area between your feet). For men, the center of mass is at about the navel, while it’s slightly lower for women. When you add a ruck, your center of mass shifts due to the added weight of the pack. When you stand still, your base of support is fairly small, but it gets bigger when you take a step. You fall when your center of mass goes too far outside your base of support and you aren’t able to recover, either by moving the mass back over your base or by moving your base back under the mass. Having “fast feet” from agility training will improve your ability to get your base of support back under your center of mass if you trip.
Cardio fitness
Finally, cardio training is important for longer marches, especially when you’re 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.
Aim to get in 3–4 resistance training and cardio workouts each week for at least 4 weeks to get the most benefit. Be sure to schedule them around ruck days to prevent overtraining. A long program is important. You won’t be able to “cram” for an upcoming event by going out on a march 3 times a week for a couple weeks leading up to it. That will just lead to fatigue, blisters, and increased injury risk. While planning your ruck training, take your daily battle rhythm into account. The physical demands of work and other areas of your life also put physical stress on your body that you need to recover from. So while you might have the best PT program to promote rest and recovery, you can still overtrain if your program isn’t balanced with your other physically demanding tasks. Work with an experienced strength-and-conditioning coach, USMC Force Fitness Instructor, or Army Master Fitness Trainer to develop a periodized workout plan to best improve your rucking ability.
Load distribution
Load distribution is how the weight of your ruck is spread within your pack and where it is located on your body. How you load your pack will change where most of its weight is, which affects both how hard you need to work to carry it and your ability to catch yourself if you start to fall.
Try to take the terrain into account when loading your pack. For mostly flat, stable terrain, it’s easier on your body to load your pack so the majority of the weight is up high and close to your body. This will help you keep a more normal posture and reduce the amount of energy you use to move.
For unstable terrain, such as rocky ground or through mountains, place heavier items near the bottom of your pack, around your mid- to low back. 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 load towards the bottom of your pack will lower your overall center of mass. So, when you start to fall, the load doesn’t move as far outside your base of support. While you will need to work a little harder to march, it will be easier to catch yourself when you start to fall, reducing the risk of fall-related injuries.
Whether you load your pack with the weight up high or down low, having the heavy objects close to your body rather than on the far side of your pack makes it easier to move and reduces stress on your body.
Many packs come with frames and hip belts to take some of the stress off your shoulders. This prevents nerve-compression injuries that lead to tingling, numbness, and weakness in your arms and hands. This type of injury 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 good load carriage is how you walk. Obviously, there are times when you have to run, but it is usually not a good idea to run when under a heavy load. Marches are generally done at a walking to trotting pace. If possible, walk at a pace and a stride length (the distance between steps) that’s 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’s best to take longer and faster walking steps (so you always have one foot on the ground) rather than running (where there is a point in your gait when both feet are off the ground).
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.