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 Crewman Selection (BCS) classes 78-89 (299 SWCC 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 BCS? 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 SWCC candidates in the study

  1. PST: 277
  2. Exit Test: 299

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 BCS. 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 SWCC 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. Standing Long Jump

In the Exit Test

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

Faster performance on these events indicates better odds of completing BCS 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 104.5 inches 67 inches
25lb Pull-up 17 reps 1 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
3-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 EFFECT SIZE OF EACH EXERCISE

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 SWCC candidates who are faster runners and swimmers and have good lower body power are more likely to complete BCS and less likely to get med-rolled from training. Upper and lower body strength plays less of a role for success.

Why? Simple. SWCC 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 BCS environment. SWCC 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 SWCC candidates who did not make it through selection (DROP) and those who finished BCS (COMPLETE), then dividing by the Standard Deviation for all SWCC candidates. A larger number (greater %) indicates that variable has a greater impact on BCS success. Results of this analysis show that running performance has the biggest effect on completing BCS (52%) while body weight bench and body weight pull-ups have small effects (10% and 2%).




Exercise Effect Size charts explained

An Effect Size is a simple statistic that can show the relevant importance of physical test scores to BCS success, even if the physical tests are measured differently (i.e., run and swim are measured by time while push-ups and sit-ups are measured by reps, long jump by distance, dead lift by weight, etc.) Effect Sizes were calculated by subtracting the average score for candidates who completed BCS from the average score of candidates who did not complete BCS, and dividing by the standard deviation of scores for all candidates. The result is a simple ratio or percent. 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 is the exact threshold for significance with this data is unclear; however, a larger Effect Size suggests a test result has more relevance to completing BCS.

The test scores with the largest Effect Sizes are for running (.52), swimming (.44), and 300-yard shuttle (.34). Effect Sizes for pull-ups, weighted pull-ups, bench press, dead lift, and 5-10-5 agility are all below the .20 threshold for significance. Push-ups, sit-ups, and standing long jump are all slightly above the threshold.

The Effect Sizes generally correlate with the graphs that show the % of candidates that completed BCS. For example, the “SWCC Physical Readiness Test, a.k.a. PRT” 3-mile run (Effect Size .52) shows a pretty linear relationship between run time and success (slower than 23 minutes means 20% BCS completion and faster than 19 minutes means 54% BCS completion). For pull-ups (Effect Size .02), the graph is all over the place – as pull-ups reps increase from less than 10 to more than 20, the completion % goes up and down and up and down. The graphs for push-ups (Effect Size .30) and sit-ups (Effect Size .29) show linear relationships between reps completed and success, but there is less difference between the lowest and highest completion %. In other words, it appears that being a slow runner is worse than doing fewer push-ups or sit-ups (results in even lower completion %).

The charts that compare rates of completion of BCS to rates of injury (being med-rolled) provide an opportunity to consider the risks as well as the benefits of training hard to improve performance on the various measures of fitness. If we compare the top half of performers for the various tests to the bottom half of performers, each graph suggests that better performance correlates with a higher ratio of Completion vs. med-rolled (C/M). But this is especially striking for three of the tests. For the SWCC PRT 3-milerRun, C/M was 3.7 for candidates who ran slower than 22 minutes, but 13.0 for those who ran faster than 22 minutes. That is, for candidates who ran three miles faster than 22 minutes, 13 completed BCS for every one that was med-rolled; for candidates who ran slower than 22 minutes, only 3.7 completed BCS for every one that was med-rolled. For the 800m swim, the C/M was 4.4 for candidates who swam slower than 15 minutes but 19.3 for those who swam faster. For the 300-yard shuttle, the C/M was 2.9 for those who ran slower than 64 seconds but 14.4 for those who ran faster. (For comparison, for push-ups the C/M for fewer than 80 reps was 5.2 while 80+ was 6.4; for sit-ups the C/M for fewer than 80 reps was 5.2 while 80+ was 7.0)

Overall, the data indicates that candidates preparing for BCS need to be physical fit in a variety of categories to improve the odds of completing selection while avoiding injury. The most important categories are running and swimming and these should be prioritized accordingly (without overtraining or increasing too rapidly leading to burnout or injury). Other categories (calisthenics and strength) should also be addressed but perhaps with less time and priority relative to preparation for run and swim tests.

SMART TRAINING GOALS TO SHOOT FOR

PST TRAINING
Event Smart training goal
Standing Long Jump 90 inches or more
25lb Pull-up 7-9 reps
Body Weight Bench 10-14 reps
Deadlift 1 Rep Max 1.75 x body weight
5-10-5 Agility 4.8-4.99 seconds
300-Yard Shuttle Run 60 seconds or less
3-Mile Run 21 minutes or less
800-Meter Swim (with fins) 13-14 minutes

EXIT TEST TRAINING
Event Smart training goal
1k Swim (with fins) 17 minutes or less
Push-up 90 reps or more
Sit-up 80 reps or more
Pull-up 14-16 reps
3-Mile Run 21 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 BCS) 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 BCS 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 SWCC candidates who record greater distance for the standing long jump are more likely to complete BCS, with the biggest increase in success coming for those who jumped farther than 100 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, SWCC 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 SWCC candidates with low scores (less than seven reps) on this test are at greater risk of dropping out before completing BCS. A certain amount of upper body pulling strength is necessary to complete BCS. But note that while the odds of completing BCS may increase with more reps until approximately 13 reps, at that point benefits plateau (and may even decrease for 16+ reps).

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 seven weighted pull-ups will improve your odds of success compared to SWCC candidates who do fewer reps, but devoting too much time and effort to do even more will not necessarily improve your odds of success. While this data does not show a greater risk of injury with higher reps, risk has been shown with other populations (such as SEAL candidates), so use caution.



 

PST: Body Weight Bench

Data shows that this test has little relationship with success in BCS. A certain amount of upper body pushing strength is probably beneficial. But note the odds of completing BCS are not different for candidates with 0-14 reps. Odds appear to be greater for 15-19 reps, but this is a small sample size and the difference is statistically small (and odds may decrease for 20+ reps).

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 may be beneficial during BCS, but devoting too much time and effort to do even more will not necessarily improve your odds of success. While this data does not show a greater risk of injury with higher reps, risk has been shown with other populations (such as SEAL candidates), so use caution.



 

PST: Deadlift One Rep Max

Data indicates the ability to deadlift 175% of body weight (lifting 1.5 x body weight for five reps) demonstrates sufficient lower body strength to successfully complete BCS without significantly increasing the risk of injury. Lower body strength is measured by estimating 1-repetition maximum (1-RM) for the deadlift. Values are expressed as a per cent of body weight (%BW). SWCC candidates attempt to perform up to five reps of the deadlift 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.

Be careful when interpreting results for the deadlift. The majority of SWCC candidates tested have recorded values of 175% BW as 1-RM for the deadlift. This is accomplished by performing five reps lifting 1.5 x body weight. There are relatively few SWCC candidates with values lower or higher than 175%, making statistical conclusions less certain. In this sample of SWCC candidates, there was a general trend for greater success with larger deadlift 1-RM, and the risk of injury does not appear to differ significantly. However, given the low Effect Size, SWCC candidates should weigh the potential risks of performing the deadlift carefully against the possible benefits.



 

PST: 5-10-5 Agility

Data shows that this test has little relationship with success in BCS. In theory, a certain amount of lower body power as measured by this test would be beneficial. But note the odds of completing BCS are not significantly different for candidates across the entire range of times (the higher value for 4.8-4.99 seconds is not statistically significant).

The 5-10-5 agility test measures lower body power. SWCC 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. SWCC 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

The odds of completing BCS go up and the odds of being med-rolled go down as scores get faster for the shuttle run. The Effect Size is larger than any test except the 3-mile run and 1k swim, so it appears that developing anaerobic power will benefit SWCC candidate for completing BCS. Note there is a low correlation between 3-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 utilizes a variety of methods including: long slow distance running and also short and long interval running.

The 300-yard shuttle run is a measure of anaerobic power and capacity. SWCC 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 BCS. 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 BCS improve, though benefits may plateau at 20 minutes. The risk of being med-rolled appears to be less for 21 minutes or faster.

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 BCS. Use good judgment when training to reduce the risk of getting injured while running.



 

PST: 800-Meter Swim with Fins

Swim performance correlates well with success in BCS. Data for the 800-meter swim indicates that faster swimmers are more successful, though benefits plateau around 13 minutes.

The conclusion is that swim performance is important for success in BCS and SWCC 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, SWCC candidates at NSW Prep perform a 1k swim. Because the formats of the two assessments are different, the 1k swim appears to correlate better than the 800-meter swim with success in BCS. The 1k swim performance correlates strongly with success (it has the next largest Effect Size after running). Data for the 1k swim indicates that faster swimmers are more successful, though benefits plateau around 17 minutes. Sub-18 minute swimmers also appear to be at less risk of being med-rolled than slower swimmers.

Taking both swim tests together, the conclusion is that swim performance is important for success in BCS and SWCC 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 BCS. The data shows a trend of more reps corresponding to greater odds of completing BCS, though the differences between rep ranges are not statistically significant. While this data does not show a greater risk of injury with higher reps, risk has been shown with other populations (such as SEAL candidates), so use caution.

The take-home message is that I want you to develop the ability to perform at least 90 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 BCS.



 

Exit Test: Sit-up

The data shows a trend of more sit-ups corresponding to greater odds of completing BCS, though the differences are not statistically significant. The relationship with injury is not clear. More reps 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 BCS.



 

Exit Test: Pull-up

The ability to do body-weight pull-ups shows little correlation with completing BCS, and has the smallest Effect Size of all exercises measured for SWCC candidates. SWCC candidates who can do eleven pull-ups may have greater success than those who can do less, but more does not appear to provide an additional advantage. The lowest risk of injury occurred for candidates in the 14-16 rep range, while the highest occurred for 20+ reps.

The take-home message is that if you train to the point where you can do about 15 pull-ups, it may not be wise to try to do more.



 

Exit Test: 3-Mile Run

In addition to the 3-mile run during the PST, SWCC candidates perform a 3-mile run during the NSW Prep Exit Test. Though the format of each assessment is different, the results of both 3-mile runs are consistent. Running ability correlates strongly with success in BCS, 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 BCS improve. Statistically, completing this 3-mile run in less than 22 minutes provides the biggest advantage compared to slower runners, with a general trend of faster scores corresponding to greater success. Sub-21 minute runners also appear to be 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 BCS. Use good judgment when training to reduce the risk of getting injured while running.