Predictors of Rucking Performance
Rucking is Important
The data is clear. Rucking is the single most important predictor for success at Army Special Forces Assessment and Selection (SFAS). This is confirmed in three studies on SFAS from 1990, 2010, and 2019. For a deep dive on the how ruck performance is the single greatest predictor of selection at SFAS, review the article here.
How to Improve Rucking
Now that we know that rucking is critical to success at SFAS, the next logical question is how to improve rucking for selection? There are massive divergences in how soldiers, candidates, and coaches view rucking. Here are a few of the soundbites we often hear from about rucking:
- You ruck everywhere at SFAS, so the best way to prepare is ruck – do it at least twice per week!
- Rucking with heavy weights is a great way to destroy your body and get injured prior to selection. Don’t do it!
- The fastest runners are the best ruckers! The best way to prepare for rucking is by improving your running.
- If you’re going to ruck, make sure your ruck light and infrequently.
So, who’s right? How much rucking should a candidate do to prepare for SFAS? Fortunately, we don’t have to rely on hearsay or broscience. We have multiple studies (and client success stories) on how to improve rucking performance safely.
Get Strong and Aerobically Fit to Improve Rucking
A study by Kraemer, et al. (1987) evaluated the effect of strength training and aerobic training on a maximal effort 3.2KM (1.99 mile) ruck with 45KG (99lbs). 35 male soldiers were randomly assigned to four groups with each group training four times per week for three months.
The study demonstrated that strength training combined with aerobic training resulted in significant improvements in ruck march time (12% – 16%). However, zero improvement was seen in the group which performed aerobic training only, and little improvement was seen in the group which performed strength training alone. These results indicate that aerobic exercise (unloaded running) alone will not improve ruck times. Instead, an optimal regimen to improve ruck performance should incorporate a combination of strength training and aerobic exercise.
Another study by Kraemer et al. (2001) reached the same conclusion. In the study, 93 female soldiers were randomly assigned to one of four groups and trained for six months:
- Total body resistance + aerobic training
- Upper body resistance + aerobic training
- Field (plyometric training) + aerobic training
- Aerobic training alone
The women in the total body strength training, upper body strength training, and field work groups showed significant improvements in 3.2KM (1.98 miles) ruck times with a 34.1KG (75lb) load. On average the improvements were 17%, or 350 seconds. Interestingly, again – aerobic exercise alone did not improve ruck times. As demonstrated in Kraemer’s 1987 study, it’s indicated that a combined regimen of strength training and aerobic exercise are critical to improving ruck march times.
Predictors of Rucking Performance
Table 3-7 from a North Atlantic Treaty Organization (NATO) technical report titled, “Optimizing Operational Physical Fitness“ lists the greatest physical predictors of ruck march performance across nine studies. All of the studies note that fat mass (more is bad), muscle mass (more is better), and height (taller is better) are highly predictive of rucking performance. Interestingly, VO2 max was consistently at the bottom of the list, although it was correlated to performance.
There is nothing a candidate can do about their height, but candidates can should take steps to build muscle mass and strength, lose fat, and improve aerobic capacity.
Conclusion
The data tells us that higher lean body mass and height are associated with faster ruck march times, while unloaded running is less correlated with ruck performance. Separate data indicates that the optimal method to improve ruck march performance is to include a combination of strength training and aerobic exercise. A program which ignores either strength training or aerobic exercise will yield inferior results.
Read More
How Important is Rucking for SFAS?
How to Join Special Forces as a Civilian
Resources to Train for Special Forces
Weight Lifting Program for Special Forces