DISCOVER THE SPEEDS, REPS AND DISTANCES THAT CAN SABOTAGE YOUR TRAINING

By: Mike Caviston, Director of Fitness, Naval Special Warfare Center
Posted: March 4, 2020


The "I'm ready to push it to the limits" attitude has it's pitfalls. If you become overambitious it may backfire on you. There's a point when running faster, going farther, and lifting more can sabotage your training.

For three years the Naval Special Warfare's (NSW) Director of Fitness studied Basic Underwater Demolition/SEAL (BUD/S) classes 300 - 318 (2,208 SEAL candidates) at the NSW Preparatory School (NSW Prep) to find out if there's optimal speeds, reps and distances that improve the odds of completing BUD/S? Which physical abilities have the most impact on success? Are there thresholds for success? Do the effects plateau? Are there any negative effects?


The study was comprised of the NSW Prep Physical Screening Test (PST) and Exit Test.

Total SEAL candidates in the study

  1. PST: 1,291
  2. Exit Test: 2,208

What was discovered is that there's optimal "safe zones" to training - thresholds for success. Speeds, reps and distances you shouldn't break. If you push yourself past the "safe zones" of training, the odds of being medically rolled back/dropped from training increase dramaticaly. The graphs and tables below show just where the "safe zones" to training are.

Running and swimming proved to be the most important types of exercises you can do to prepare for BUD/S. And for those who do "push it to the limit" it was found that effects do plateau for each Event of the PST and Exit Test. The negative effect in the study is that when Event plateaus were reached, and surpassed, higher Event scores provide no additional benefit, and the odds of SEAL candidates being med-rolled may increase.


 

EVENTS THAT HAVE THE GREATEST IMPACT ON SUCCESS

In the PST

  1. 3-Mile Run
  2. 300-Yard Shuttle Run
  3. 800-Meter Swim

In the Exit Test

  1. 4-Mile Run
  2. 1k Swim (with fins)
  3. Push-ups

Faster performance on these events indicates better odds of completing BUD/S and lower risk of being med-rolled. Even for these high-value events, there appears to be a point where benefits plateau. For other events, such as those measuring strength, there are plateaus where higher scores provide no additional benefit, and the odds of being med-rolled may increase.

THE BEST AND WORST EVENT SCORES

COMPLETED THE PST
Event Best score Worst score
Standing Long Jump 111 inches 72 inches
25lb Pull-up 20 reps 5 reps
Body Weight Bench 24 reps 0 reps
Deadlift 1 Rep Max 2.33 x body weight 1.5 x body weight
5-10-5 Agility 4.33 seconds 5.55 seconds
300-Yard Shuttle Run 56.3 seconds 72.2 seconds
3-Mile Run 17:01 minutes 24:11 minutes
800-Meter Swim (with fins) 12:09 minutes 16:28 minutes

COMPLETED THE EXIT TEST
Event Best score Worst score
1k Swim (with fins) 14:51 minutes 19:13 minutes
Push-up 103 reps 57 reps
Sit-up 100 reps 60 reps
Pull-up 21 reps 9 reps
4-Mile Run 17:22 minutes 23:21 minutes

FAILED THE PST
Event Best score Worst score
Standing Long Jump 108.5 inches 66.5 inches
25lb Pull-up 19 reps 0 reps
Body Weight Bench 23 reps 0 reps
Deadlift 1 Rep Max 2.33 x body weight 1.5 x body weight
5-10-5 Agility 4.44 seconds 5.58 seconds
300-Yard Shuttle Run 58.9 seconds 69.6 seconds
3-Mile Run 18:14 minutes 24:42 minutes
800-Meter Swim (with fins) 11:05 minutes 16:53 minutes

FAILED THE EXIT TEST
Event Best score Worst score
1k Swim (with fins) 15:05 minutes 20:45 minutes
Push-up 115 reps 56 reps
Sit-up 101 reps 61 reps
Pull-up 23 reps 8 reps
3-Mile Run 18:31 minutes 23:50 minutes

The graphs in the statistical model below show the Effect Size (ES) of each exercise of the PST and Exit Test and the boundaries of smart training to maximize your odds of success without increasing your risk of injury. Data shows that SEAL candidates who are faster runners and swimmers and have good lower body power are more likely to complete BUD/S and less likely to get medically rolled back/dropped from training (med-rolled). Upper and lower body strength plays less of a role for success.

Why? Simple. SEAL candidates with more endurance are more resistant to fatigue and less likely to make injury-prone technical mistakes. Candidates with more lower body power may be better able to negotiate the challenging terrains in the BUD/S environment. SEAL candidates who develop too much strength may create imbalances that affect injury.

Effect Sizes were calculated for several different physical tests. The ES is determined by finding the difference between the values for SEAL candidates who did not make it through selection (DROP) and those who finished Hell Week (COMPLETE), then dividing by the Standard Deviation for all SEAL candidates. A larger number (greater %) indicates that variable has a greater impact on Hell Week success. Results of this analysis show that running performance has the biggest effect on completing Hell Week (67%) and dead lift has the smallest (6%).




Exercise Effect Size charts explained

Effect Size: the larger the Effect Size, the more important that test is for Hell Week success. If the 4-mile run has an Effect Size of .67, and push-ups have an Effect Size of .33, we can conclude that the 4-mile run is twice as important as push-ups regarding the chances of getting through Hell Week. Sports scientists generally believe that an Effect Size of less than .20 is trivial, that is, the test being considered has no significant relationship to the outcome in question. What the exact threshold for significance is with this data is unclear; however, a smaller Effect Size means that test has less relevance to completing Hell Week.

The Effect Sizes correlate with the graphs that show the % of candidates that completed Hell Week relative to test performance (e.g., run times or push-up reps). Let's compare data for run, swim, and shuttle tests (larger Effect Sizes, .45-.67) with push-ups, pull-ups, weighted pull-ups, and bench press (smaller Effect Sizes, .19-.33). Run-swim-shuttle have both the highest (31-35%) and lowest (0-2%) completion percentages. Push-pull-bench ranges from 7-12% at the low end to 16-23% at the high end. For run-swim-shuttle, being fast is a big advantage and if you are too slow, you have virtually no chance of making it through Hell Week. For push-pull-bench, more reps are better up to a point, but the best completion % is not for the most reps. Also, even with the lowest recorded scores, candidates still have around a 10% chance of completing Hell Week - not great, but definitely possible.

Success to injury ratio charts explained

Risk of injury (odds of being med-rolled) should be considered as well. This can be seen in the Success-to-Injury Ratio graphs. There are two stats to consider. One is the % of candidates med-rolled for each of the test increments. For example, 171 candidates ran 4 miles in 25-25:59 and 15 were med-rolled, or 9%; 27 candidates did 110+ push-ups and 6 were med-rolled (22%). For run-swim-shuttle, the highest % med-roll for any increment was 13-19%; for push-pull-bench, the highest rates were 16-23%. Another way to look at injury is the ratio between number that completed Hell Week and number that were med-rolled (a risk-benefit approach). The Success-to-Injury graphs show this relationship visually, and the actual ratios can be calculated. For example, for 4-mile run in 25-25:59, 46 completed Hell Week and 15 were med-rolled, a C/M ratio of 3.1. For bench press of 20-24 reps, 17 completed Hell Week and 11 were med-rolled, a C/M ratio of 1.5. The best C/M ratios associated with run-swim-shuttle were 6.0-3.1, and push-pull-bench were 2.5-1.9.

Finally, consider the performance curves that show Hell Week completion % for increments of each test. The run-swim-shuttle curves are essentially linear, with faster times linked to higher completion %. The push-pull-bench curves tend to look like an inverted U, with the highest completion % just past the middle, and lower % at the far right (highest reps). If injury curves were drawn, the push-pull-bench curves would all show a sharp rise at the far right (a large jump in injury rate for the most reps), while the lowest rep categories all show the lowest % injury. For run-swim, the highest rates of injury occur for the slowest and fastest times, with the lowest rates in the middle (for shuttle, higher injury rate occurs with slow times but not fast times). Consider the general relationships between success (completing Hell Week) and injury risk. For run-swim-shuttle, the penalty for being slow is extreme - low success, high injury. For the fastest times, success rates are greater, though injury risk also increases somewhat. For push-pull-bench, low reps are associated with less success (though not zero) but also less injury. For the highest number of reps, success drops and injury increases fairly dramatically.

Summing it all up

Overall, this is a simplified summary. I suggest it is possible to record high reps of push-ups, pull-ups, weighted pull-ups, and bench press, without increasing the risk of injury, if training is conducted properly. Review the Physical Training Guide to review good training practices. I encourage everyone to become the best runner and swimmer you can - but again, utilizing smart training practices, to avoid injuries that can occur if sound principles are not followed.

SMART TRAINING GOALS TO SHOOT FOR

PST TRAINING
Event Smart training goal
Standing Long Jump 90 inches or more
25lb Pull-up 13-15 reps
Body Weight Bench 10-14 reps
Deadlift 1 Rep Max 1.75 x body weight
5-10-5 Agility 4.4-4.8 seconds
300-Yard Shuttle Run 60 seconds or less
3-Mile Run 18-19 minutes or less
800-Meter Swim (with fins) 12-14 minutes

EXIT TEST TRAINING
Event Smart training goal
1k Swim (with fins) 17 minutes or less
Push-up 90-99 reps
Sit-up 80-89 reps
Pull-up 19-21 reps
4-Mile Run 27 minutes or less

PST AND EXIT TEST - SUCCESS VS. INJURY RATIO GRAPHS FOR ALL EVENTS

When looking at the data, consider the benefits of high scores (odds of completing Hell Week) as well as the risks (odds of being med-rolled). Bear in mind that in some cases, a particular score may indicate a higher or lower percentage for completing Hell Week or being med-rolled, but the difference may not be statistically significant – either the difference or the sample size are too small. You should strive for performances that maximize your odds of success without increasing your risk of injury, as explained below.

PST: Standing Long Jump

Data shows that SEAL candidates who record greater distance for the standing long jump are more likely to complete Hell Week, with the biggest increase in success coming for those who jumped farther than 90 inches. There does not appear to be much of a relationship between injury risk and standing long jump, though those with lower values may be at greater risk of being med-rolled.

The standing long jump is a measure of lower body power. When tested, SEAL candidates stand behind a line and jump as far as possible, taking off and landing on two feet without falling forward or backward. Distance is measured to the heel closest to the line. The best of three attempts is scored.



 

PST: 25lb Pull-up

Data shows that SEAL candidates with low scores on this test are at greater risk of dropping out before completing Hell Week. A certain amount of upper body pulling strength is necessary to complete Hell Week. But note that while the odds of completing Hell Week increase with more reps until approximately 13 reps, for 19+ reps the odds of completing Hell Week drop while the risk of injury increases significantly.

Upper body pull strength is measured by doing pull-ups while wearing a weighted vest (25 pounds). Strict standards are enforced for proper pull-up technique.

The take-home message is that developing the ability to complete at least thirteen weighted pull-ups will improve your odds of success compared to SEAL candidates who do fewer reps. But devoting too much time and effort to do even more will not necessarily improve your odds of success, and may increase your risk of injury. While this data does not show a greater risk of injury with higher reps, risk has been shown with other populations (such as SWCC candidates), so use caution.



 

PST: Body Weight Bench

Data shows that SEAL candidates with low scores on this test (fewer than ten reps) are at greater risk of dropping out before completing Hell Week. A certain amount of upper body pushing strength is necessary to complete Hell Week. But note the odds of completing Hell Week are not significantly greater for candidates with 15+ reps compared to 10-14 reps (even for 20-24 reps, the odds increase, but the difference is not statistically greater). And for this sample of SEAL candidates, the odds of completing Hell Week with 25+ reps are zero! Meanwhile, above 19 reps, the odds of being med-rolled increase.

Upper body push strength is measured by max reps of the bench press with a weight equal to body weight loaded on the bar. Strict standards are enforced for proper technique.

The take-home message is that developing the ability to complete 10 or so reps of body weight bench will improve your odds of success compared to SEAL candidates who can’t even do 10. But devoting too much time and effort to do even more will not necessarily improve your odds of success, and may increase your risk of injury.



 

PST: Deadlift One Rep Max

Data indicates the ability to dead lift 175% of body weight (lifting 1.5 x body weight for five reps) demonstrates sufficient lower body strength to successfully complete Hell Week without significantly increasing the risk of injury. Lower body strength is measured by estimating 1-repetition maximum (1-RM) for the dead lift. Values are expressed as a per cent of body weight (%BW). SEAL candidates attempt to perform up to five reps of the dead lift using 1.5, 1.75, or 2.0 x body weight, depending on ability and technique. A formula is used to convert the weight lifted and number of reps to a 1-RM value.

We must be careful when interpreting results for the dead lift. The great majority of SEAL candidates tested have recorded values of 175% BW as 1- RM for the dead lift. This is accomplished by performing five reps lifting 1.5 x body weight. There are relatively few SEAL candidates with values lower or higher than 175%, making statistical conclusions less certain. However, in this sample of SEAL candidates, there was no penalty for lifting <175% for the dead lift (candidates completed Hell Week at the same rate as those who lifted 175%), and those who lifted >175% actually had the worst completion rate.

Furthermore, the odds of being med-rolled may be greatest for SEAL candidates lifting >175%. SEAL candidates should weigh the potential risks of performing the dead lift carefully against the possible benefits.



 


PST: 5-10-5 Agility

In general, performing better on this test correlated with greater success during Hell Week and less chance of being med-rolled, except for the very fastest SEAL candidates (<4.4 seconds), where success rate decreased and injury rate increased. The best combination of high success and low injury occurred for scores between 4.8-4.4 seconds.

The 5-10-5 agility test measures lower body power. SEAL candidates straddle a line and sprint 5 yards to one side, touch a line and sprint 10 yards to the other side, touch a line and sprint 5 yards back to the starting point. SEAL candidates get two attempts starting to the right and two attempts starting to the left. The recorded score is the average of the best attempt starting to the right and the best attempt starting to the left.


 

PST: 300-Yard Shuttle Run

As scores get faster the odds of completing Hell Week go up and the odds of being med-rolled go down, though the benefits may plateau or decrease for scores faster than 58 seconds. The Effect Size is large and the success rate is high for fast scores, so it appears that developing anaerobic power will benefit SEAL candidates being selected for BUD/S. Note there is a low correlation between 3-mile or 4-mile run times and this test, which means they measure different things and will be improved with different types of training. Complete training of all metabolic systems includes a variety of methods including: long slow distance running and also short and long interval running.

The 300-yard shuttle is a measure of anaerobic power and capacity. SEAL candidates sprint back and forth between two lines spaced 25 yards apart, going down and back a total of six times (down and back once is 50 yards; six times is 300 yards). The test consists of two max-effort 300-yard shuttles with exactly two minutes of recovery in between. The recorded score is the average of both attempts.



 

PST: 3-Mile Run

Running ability correlates strongly with success in BUD/S. It has the largest Effect Size. Running quantifies aerobic fitness, which impacts your ability to sustain work output and recover quickly after physically demanding evolutions. As run times get faster, the odds of completing Hell Week improve and the risk of being med-rolled gets smaller, though benefits seem to plateau when runners are faster than 19 minutes for the 3-mile run.

The take-home message is to improve your running to the best of your ability, because it is the single most important factor for completing Hell Week. Use good judgment when training to reduce the risk of getting injured while running.



 

PST: 800-Meter Swim with Fins

Swim performance correlates strongly with success (along with the shuttle run, it has the next largest Effect Size after running). Data for the 800-meter swim indicates that faster swimmers are more successful, but the benefits plateau around 13 minutes. Those who swam faster than 12 minutes completed Hell Week less frequently and were med-rolled more often than swimmers in the 12-14 minute range.

The conclusion is that swim performance is important for success in BUD/S and SEAL candidates should prepare accordingly. The usual recommendations apply to increase training mileage and intensity gradually to avoid causing injury with poor training.



 

Exit Test: 1k Swim with Fins

In addition to the 800-meter swim, SEAL candidates at NSW Prep perform a 1k swim with fins. Because the formats of the two assessments are different, the 1k swim appears to correlate better than the 800-meter swim with success in BUD/S. For the 1k swim with fins, faster swimmers complete Hell Week more frequently with no plateau and in general are med-rolled less often.

Taking both swim tests together, the conclusion is that swim performance is important for success in BUD/S and SEAL candidates should prepare accordingly. The usual recommendations apply to increase training mileage and intensity gradually to avoid causing injury with poor training.



 

Exit Test: Push-up

Historically the ability to perform push-ups has been considered essential for success in BUD/S. The data clearly indicates that SEAL candidates in the lower ranges (70-79 and 80-89 reps) are less likely to complete Hell Week than those who complete 90 or more. Statistically, above the 90-99 range the odds of completing Hell Week improve only slightly (in fact, for the 110+ range they begin to drop).

The take-home message is that I want you to develop the ability to perform at least 100 push-ups, but don’t spend valuable time and energy trying to do more. Make your push-up training economical, so you leave time to train the many other qualities important for success in BUD/S.



 

Exit Test: Sit-up

SEAL candidates who can perform more sit-ups have a greater chance of completing Hell Week, but statistically the benefits appear to plateau in the 80-89 rep range. More may be better, and there does not seem to be greater risk of injury, but don’t expend too much time and energy trying to increase your sit-ups at the expense of other important qualities as you prepare for BUD/S.



 

Exit Test: Pull-up

As with 25lb (weighted) pull-ups, the ability to do body-weight pull-ups correlates with completing Hell Week. SEAL candidates who can do 19-21 pull-ups succeed more than those who can do less. But more than 21 reps does not provide an additional advantage, and for SEAL candidates who performed 25+ reps the odds of completing Hell Week were low and the risk of being med-rolled were high.

The take-home message is that if you train to the point where you can do about 20 pull-ups, it may not be wise to try to do more.



 

Exit Test: 4-Mile Run

In addition to the 3-mile run, SEAL candidates perform a 4-mile run. Running ability correlates strongly with success in BUD/S, with the largest Effect Size. Running quantifies aerobic fitness, which impacts your ability to sustain work output and recover quickly after physically demanding evolutions. As run times get faster, the odds of completing Hell Week improve. Statistically, completing the 4-mile run in less than 27 minutes provides the biggest advantage compared to slower runners. Sub-27 minute runners are also at less risk of being med-rolled than slower runners.

The take-home message is to improve your running to the best of your ability, because it is the single most important factor for completing Hell Week. Use good judgment when training to reduce the risk of getting injured while running.