The 7 Most Common SFAS Base Building Mistakes

Selection train-up is a prolonged, multi-step process. Most SFAS programs range from 8-16 weeks in duration, which is usually an appropriate amount of time to train depending on your strengths and weaknesses. I’m a believer that a selection specific train-up should last 8-12 weeks, and no longer. However, this assumes you’ve spent the several months prior to that building a robust aerobic base.

Embarking on a 12 week SFAS specific program with no aerobic base is a losing strategy. Furthermore, a general aerobic base is insufficient - it needs to be more specific. It’s no secret that you’ll spend most of your time at selection rucking. Additionally, during the first week, you’ll be asked to display your middle distance running endurance on more than one occasion. 

A general aerobic base can be built using a plethora of different conditioning modalities. You can bike, swim, row, walk stairs, use a ski erg, pull a sled, etc. But running and rucking are unique in that they’re not only the two highest impact aerobic activities, but they’re also high skill activities of which the cost of not being skilled isn’t just poor performance, but also potential injury.

For comparison, let’s look at swimming. Swimming is certainly a high skill activity. If you have poor swimming technique, you will struggle with swimming performance. But swimming is one of the least impactful forms of cardio in existence. Yes, you’ll have sore muscles after a swim workout if you rarely swim. Novelty in exercise tends to cause delayed onset muscle soreness. However, the likelihood of developing overuse injuries in your joints and connective tissue is respectively low. Therefore, it’s what I call a “single cost activity” (you suck at swimming), whereas running and rucking (especially ruck running) are “double cost” activities (you suck at them AND increase your injury risk).

Time On Feet!

This implies that in order to build your base for a selection train up, you must spend time on your feet. Running, and to a lesser extent, rucking are both higher impact activities (ruck walking is lower impact than running - ruck running is higher impact than running). You can do all the biking and rowing you want and build a robust aerobic capacity, but these modalities miss an important aspect of selection prep. “Tissue tolerance” and durability. Running and rucking require not just aerobic capacity, but their inherently impactful nature and skill demands require specific, progressive training.

Another often overlooked aspect of base building is full body strength. Many individuals are already plenty strong for SFAS before they start to think about preparing for it. But some are not. If you’re weak, you may be able to run like the wind, but you’ll likely struggle on the PT assessment, obstacle course, team week, and the simple act of carrying a ruck for 3 straight weeks day after day. A base building program for someone lacking strength will look different than a base building program for someone with sufficient strength levels but poor endurance. This article will lean heavily towards aerobic base building, and part 2 will highlight strength considerations.

To illustrate my points, I’ll begin by explaining some of the most common mistakes I see selection hopefuls make in regards to base building. Just to reiterate - this applies to the base building phase prior to actual selection prep. 

Selection prep mistakes are also quite common, and if you’re interested in more detail on this subject, you can listen to this podcast episode. I also plan on writing an article on the topic in the future. Attached to the mistakes will be strategies to avoid falling victim to them in an effort to improve your chances of showing up to selection physically ready. Let’s dive in.

Mistake #1 

Skipping the base phase altogether - This mistake seems simple, but it’s hands down the most common mistake anyone (not just SFAS candidates) make when starting a run/ruck improvement plan. 

An aspiring Green Beret may hear they should train up for SFAS over 12 weeks and take it at face value. As mentioned previously, I personally recommend no longer than a 12 week train up - but that doesn’t mean you should start from scratch. It’s crucial to remember that although 12 weeks may be an appropriate duration to prepare for selection for the average candidate, that doesn’t mean you should sit on the couch or just do some general physical preparedness (GPP) but avoid running and rucking altogether till you’re 12 weeks out.

The duration of your base building phase will depend on a multitude of factors. It primarily boils down to your physical strengths and weaknesses, current training tendencies, and the style of training to which you respond best and worst.

If you’re an endurance-prone individual, or you have a background in high level endurance sports, your base building phase doesn’t need to be very long. Coincidentally, someone like this likely runs regularly as part of their training, because human nature is to gravitate towards things we’re good at. If this is you, your base is likely already sufficient to start your SFAS prep. 

That said, an endurance prone individual may want to consider focusing on strength in the gym while maintaining a running and rucking base. Those who excel in endurance often lack full body strength. If this resonates with you, part 2 will likely provide better insight as to where to focus your training.

Conversely, if you already have a great deal of strength and/or a background in sports that require strength, speed and power, you’ll likely need to begin focusing on building an endurance base several months to a year + prior to your selection prep. If you’re genetically gifted to be a strong, powerful, muscular person, endurance likely doesn’t come naturally to you. 

Naturally stronger individuals usually already possess the prerequisite strength for selection success, and although that’s not a reason to quit strength work altogether, it is a reason to consider making aerobic base building priority “1a)” and putting strength on maintenance mode.

Finally, there exists a small percentage of individuals who possess more than enough strength and a sufficient running and rucking specific aerobic base. These “hybrids” are uncommon, but they do exist. This is what I call the “selection poster child”. This avatar could likely train for selection for 6 weeks and fare quite well. However, even if you’re fortunate enough to fall into this category, you may consider a longer train up if you want to fare very well.

Regardless of which category resonates with you most, it won’t hurt to consider building your base for a bare minimum of 3 months prior to selection. Remember, everyone is different, and some will need considerably more time. If you know you do, adjust accordingly. 

Mistake #2

Good base in general, not specific - another perplexingly common mistake, likely due to the plethora of misinformation available on the internet and/or through “Private News Network”. I briefly explained specificity in the intro, but since this mistake is so costly (“double cost”), I believe more depth is required.

Specificity in regards to training is the act of training for the specific disciplines in which you’ll need to perform well. A powerlifting specific training program should involve a lot of squats, bench presses and deadlifts. A triathlon specific program should include mostly swimming, biking and running. A (sound) selection specific program will feature plenty of running, rucking, bodyweight exercises, carries, and general strength work. Specificity matters most as you close in on the date of the event, but it should begin well before that.

The cost of nonspecific training isn’t something to overlook. It’s not a minor mistake. It’s important to remember that all training results in fatigue, fatigue requires recovery, and recovery is a finite resource. If you’re wasting your recovery reserves on non-specific training, it’ll detract from your ability to train the skill sets required for selection. Therefore, training specificity is a must throughout the last ~3 months prior to your selection start date.

But what about specificity in a base building program? To make this as simple as possible, I like to break it down to three words to live by “time on feet”. If you’re in the military, you’re familiar with back planning. Because the military is so keen on punctuality (one of the things they do right), back planning is a methodology implemented to avoid tardiness. You can also use back planning for selection prep and pre-selection prep base building. Here’s a breakdown:

Step 1: Write down your selection report date (e.g. 1 March)

Step 2: Subtract 3 months (not exactly 12 weeks, but let’s keep it simple) from your report date (= 1 December)

Step 3: Write down today’s date (e.g. 15 August)

Step 4: Assess your current running & rucking ability w/ the following options

Gold standard: perform a 2-5 mile run time trial and a 5-8 mile ruck time trial (if you haven't been ruck running at all, I suggest doing this at a walking only pace)

*If you’ve done little to no running and rucking recently, I don’t recommend giving yourself a time trial, as these activities can be risky when you’re not used to them and suddenly go all out in a time trial. Ideally, you’ll spend at least several weeks or months building your running base and doing occasional rucks before you test yourself.

Step 5: Determine your training priorities and put a plan in place

*If you’re already comfortably able to hold an ~11-12 min ruck pace and 6:30-7:00 min/mile run pace (these paces aren’t official, but they’re certainly sufficient), you can likely continue training the way you are right into your 1 December selection train-up start date. If you’re well under these times, you may consider a 1 January SFAS prep start date (some people don’t even need 8 weeks, but they’re not common). 

**If you’re nowhere close to these paces, you’ll want to begin slowly ramping up your running miles to build your base.

The takeaway - if you don’t spend a lot of time on your feet each week (running or rucking), you’ll benefit from starting to build your base at least 3 months prior to starting your selection prep (aka, 6+ months prior to your report date). If you already do a lot of running, at least an occasional ruck, and can already perform at or better than the standard, continue training as you are till you’re 2-3 months out. It’s certainly more nuanced than this, but these guidelines are enough to give you a general idea of how to approach your training.

Mistake #3

Too much rucking/ruck running - It’s no secret that SFAS is largely a ruck based event. The vast majority of your time throughout the 3 week process will be spent wearing a ruck. Common sense would tell you that your SFAS training program should involve rucking. And it absolutely should. But to what extent does rucking belong in your PRE selection prep base building phase? It certainly does belong, but not in excess.

If you’re a seasoned rucker, you can most certainly do a lot of rucking in your base phase. You’ll likely want to avoid excessive ruck running when you’re more than 3 months out, but walking with a ruck is fine. If you do not ruck or run on a regular basis and possess a lackluster “time on feet” base, your base building phase should involve mostly running and consistent, but relatively infrequent rucks.

It’s quite common for selection candidates to be overzealous with rucking. Some examples of this include: 

-Beginning rucking without a baseline level of running endurance and strength

-Starting with too much load/adding load too rapidly

-Starting with too many miles/increasing mileage too rapidly

-Ruck running too many miles/too frequently/too early

There’s no perfect equation for how to determine what is considered “too much” or “too heavy” or “too hard”, but applying a bit of common sense goes a long way here. If at 5 months out you’re already smashing yourself weekly and struggling to recover from your training, you’re answering the question yourself.

If you do one or more of the above (most people do several of them), you may struggle maintaining a healthy body throughout your pre-selection prep, as well as your selection prep. My recommendation is to implement a crawl, walk run mindset with training.

Crawl: Running & strength work in the gym, occasional (bi-weekly/monthly) rucks w/35-50 lbs (6-12+ months out)

Walk: Consistent, progressive running, slightly less lifting, a bit more rucking (weekly, walking only) w/ 40-55 lbs (3-6 months out)

Run (selection specific): More rucking than running (unless you’re a certified ruck monster and a certified slow runner), begin to implement ruck shuffling and running, lifting to maintain full body strength, lots of calisthenics, carries & other strongman work. (Last 3 months)

Are there exceptions to these guidelines? Absolutely. There are people who can get away with a lot more ruck running than others. There are people who need to run sparingly in order to stay healthy. There are people who don’t need to ruck at all until they’re 3 months out. There are people who are poor runners and great ruckers that need to focus more on running. But this is the simplest way I can break it down to the masses. Again - remember to use common sense.

I personally ruck ran (not trotted/shuffled, but ran ~7:30-9:00 miles depending on duration) 3 times per week when preparing for SMU selection, and I benefited greatly from it. My train up was also only 9 weeks long because I was always maintaining a strong rucking and running base.

But if you’re unsure, just know that less is more when it comes to ruck running when you’re more than 3 months from selection. Be strong. Run well. Ruck 2-3x/month. If you do this, you’ll be more than ready to go nose to grindstone for the 3 months leading in.

Mistake #4 

Too much speed work (running) - To get faster at running, you need to run fast sometimes. Intervals/repeats (think 400s on the track or 200 meter hill repeats), fartlek (speed play - a form of intervals with active rest), and tempo runs are all examples of speed work for running. These types of runs are crucial to improving your chances to excel during gate week at SFAS. 

But an all common mistake amongst selection candidates and recreational runners alike is implementing speed work too soon before building the prerequisite base for it. If you rarely or never run and decide it’s time to build your base, your first session shouldn’t be speed work. In fact, you probably should perform little to no speed work in the first several weeks or even months.

So let’s expound on the first sentence to make it more complete: “To get faster at running, you need to run fast. But you shouldn’t run fast until you’ve spent plenty of time running slow.”

Speed work is important, but it’s a higher stress form of running. There’s no such thing as a free lunch with running, and even if you already have a great base, speed work is the equivalent of lunch at a high end restaurant in Los Angeles. Speed work without a base? That’s like going to the same restaurant for lunch, but also filling your gas tank en route, AND stopping to tie one on at a bougie cocktail joint after lunch. Before you know it, you’ve dropped ½ a paycheck in one afternoon.

Running for 30 minutes at a 140 heart rate is not going to crush someone like running for 30 minutes as hard as possible will. Going full-send on 10x400 meter repeats at your fastest repeatable pace will induce a great deal more fatigue than going out for a nice trail run for 40 minutes (even with a robust base). It’s crucial to build your running specific aerobic base before launching into regular speed work. 

Excessive speed work is not just a pre-selection train-up base building mistake. It’s also a selection specific train up mistake (and one that MANY aspiring runners make, regardless of goal). To reduce your chances of over-doing it and/or hurting yourself, focus on building a robust aerobic base before jumping into speed work.

Mistake #5 

Excess volume increases - This mistake is neck and neck with implementing speed work too soon or doing it too frequently. Although “too much, too soon” is not the only culprit for running (or rucking) injury, this seems to be the most common.

Again, running and rucking are unique in that they must be adapted to, not just aerobically, but structurally. Your joints and connective tissue need time to adapt to “time on feet” volume. The hardest part to avoiding this mistake is the mental aspect, especially for Type-A individuals (most SF candidates). When you first start, you’ll feel like you’re not doing enough. Running for 60 total minutes one week and 70 the next next at virtually the same pace feels like you’re barely progressing. But guess what? It’s the right way to do it. 

You may be familiar with the 10% rule, which states that runners should increase their weekly mileage by no more than 10% each week. Although this rule may be a safety net for some, and if you’re just a regular person looking to build a long term, consistent running plan consisting of 15-20 miles per week, the 10% rule is great. 

But I do think it’s lacking nuance, especially for the audience reading this. I prefer using a different recommendation when I program for my candidate clients. The problem with the 10% rule is that it’s not scalable. At lower weekly volumes, the 10% rule results in tiny increases in volume. If you ran 7 miles last week, the 10% rule would put you at 7.7 miles this week, which is safe, but also underkill in most cases. On the higher volume side, if you ran 60 miles last week, the 10% rule would put you at 66 this week. That is a significant increase, especially if the runner decides to add that extra 6 miles to 1 single run. 

Instead, I like to use the 5 minute rule. I prefer to program all base building runs and rucks using duration, rather than mileage. The reasons for which are too tangential to describe here, and it’s not “better” than mileage based training for everyone in every situation. But I still prefer it, especially for type A individuals who tend to overanalyze things. 

In any case, the 5 minute rule is simple. It involves 1st grade math at most. Here’s how I suggest doing it.  On each run throughout the week, add 5 minutes to the previous week. So if you did 3 runs last week totalling 30, 45, and 60 minutes (135 minutes total), this week you’ll run 35, 50, and 65 minutes, adding 15 total minutes of running from last week for a total of 150 minutes. 

If you want to only add duration to a single run (e.g. 2 shorter runs during the week and a longer run on a weekend day - common running programming), add only 7-10 minutes at a time to the longer run and keep the other two runs constant. Why not 15? You want to be careful not to add too much volume to any single run week to week. Spreading 15 additional minutes of running throughout the week is far more reasonable. Adding all 15 minutes to one run can be fine for a little while, but I recommend erring on the side of caution.

Either way, if you’re adding 30, 45, 60 minutes to your weekly volume, you’re in the danger zone. Sticking to the 5 minute rule is a simple way to track your progression and limit the likelihood of succumbing to an overuse injury. The word “limit” is key - it will not make you overuse injury proof, because although too much too soon (volume and/or intensity) with running (same with rucking, with the addition of ruck weight) is easily the most common cause of overuse injury, it’s not the only consideration.

You also need to train with sound technique. You can muscle through everything, but that doesn’t mean you should muscle through everything. If you can self identify with having subpar running technique (the average Army soldier does), I highly recommend checking out this article.

Mistake #6

Too much lifting - Strength is important for SFAS. Building a good baseline of full body strength well before you begin a selection train up will undoubtedly increase your chances of success at SFAS. However, some people take this too far. There are certain individuals that need to add considerable strength before they attend SFAS, and and others who are already sufficiently strong. Regardless of where you stand on the strength spectrum, do not make the mistake of excessive lifting. More isn’t better.

This isn’t groundbreaking news by any stretch, but it’s worth repeating either way: building strength and muscle does not occur while you’re in the gym. You provide a stimulus to your body to grow while training in the gym, but the adaptations occur outside the gym. You grow while you sleep. You grow when you provide your body the right nutrition. Many people think that more is always better with strength training, and this is not the case. 

It’s not uncommon to see people following a high volume powerbuilding or bodybuilding routine while also trying to improve their running and rucking. This is a recipe for disaster. 

The reality is, the world's strongest individuals (strongmen and powerlifters) usually train 3-4 days per week. That’s right - the strongest humans on earth take 3-4 days per week off from lifting weights. 

Professional bodybuilders, the world's most muscular individuals (at an advanced level, training for muscle size is quite different from training for strength) typically train 5 days per week. That’s right, most of them take 2 days off every week. Why? They know the importance of rest and recovery. 

Add to that, strongmen, powerlifters and bodybuilders are not simultaneously adding to their weekly workload with high volume running and rucking. They make every attempt possible to maximize their recovery, which certainly involves some conditioning (for many, not all), but it’s usually done at a lower intensity (e.g. incline walking on a treadmill) and requires little to no recovery. They’re not looking to become monsters at running and rucking. 

What does this mean? Well, all too commonly, I see SF candidates on a 5-6 day per week lifting program. The most common is a 6 day per week push/pull/legs (PPL) split. There’s nothing wrong with a PPL split as a whole - I love this split and use it myself. But doing it over 6 days with only 1 rest day on day 7 is excessive, even without doing any extra conditioning work outside the gym. Think about it - on day 6 you’re hitting legs. If you train properly, you know that legs are hands down the most fatiguing muscle group to train. 

Even if you’re only lifting weights (not doing conditioning) and your recovery is elite, there’s no way in hell you’re able to put in enough effort to get something out of this session after 5 consecutive days of hard training. Even if you do, there’s no way in hell you’re recovering enough each week from your 1 rest day to come back week after week and train 6 days in a row without overdoing it. 

Yet, here we are. Plenty of SF candidates are lifting 6 days per week WHILE simultaneously trying to improve their aerobic ability. The result? Fatigue. Overuse. Plateaus. The result you want? Progress.

In the several months leading into your SFAS train up, I highly suggest a 4 day per week split if you’re very weak and already a good runner, a 3 day per week split for most people, and potentially as little as a 2 day per week split for those who are already beyond sufficiently strong to be successful at SFAS.

This will allow you to build or maintain strength and muscle, sure. But it’ll also give you some time to focus on endurance, which is hands down the most important physical trait for selection success. Most importantly, it’ll allow you to recover and make progress. I highly suggest you take these guidelines seriously. 

Don’t make the mistake of overdoing it in the gym. It will cost you.

Mistake #7

Not enough lifting - The final mistake isn’t mentioned last because it’s not important. It’s last because it’s the least common mistake based on my observation. These days, most type-A, hard charging alpha males strength train regularly and consistently (toxic masculinity, am I right?). But there remains a small percentage of SF candidates who lean too heavily on aerobic training and/or don’t do much training at all. 

As mentioned previously, endurance (ruck & run) is the most important physical trait for selection success. It’s non-negotiable. However, ruck endurance, as well as team week events require a requisite level of strength that when not addressed, will greatly reduce your chances of selection success.

If you fall into the trap of only focusing on endurance work, or lifting “just to check the block”, you’ll struggle. This is especially the case if you fall into one of the following categories:

-Former high level runner (Division 1 collegiate, road racing, ultra running)

-Former triathlete (competitive level)

-Former high level endurance athlete (any endurance activity)

-Non athletic regular person (NARP)

The former endurance athletes often struggle carrying a heavy ruck around. They may make it through gate week with flying colors, but when they get to land nav week, and especially team week, if they didn’t do their due diligence with strength work in the gym, they often struggle. NARPs generally don’t excel in strength OR endurance (at least not yet), and they need to develop both for a considerable amount of time (9-18 months at least) prior to starting their selection prep.

This is the mistake that resonates closest with me personally, because I approached my own strength work very haphazardly during my selection prep. I was predominantly an endurance guy from the time I finished high school football my senior year, all the way to when I joined the army as a 21 year old 18X-ray. I had built a decent level of strength in high school, but I largely quit doing true strength work altogether after my senior year. Although I was a running and rucking machine, strength was my biggest weakness at SFAS. That being said, I was still strong enough, and I was strong at the right things - so it wasn’t a deal breaker. It doesn’t take much, but it takes more than nothing.

Whatever you do, don’t be the guy who shows up and wins every run by 5 minutes but can’t handle a heavy ruck during land nav or aid their team in carrying the sandman (downed pilot). If you fall into this category, I highly suggest finding a sound strength program well before you start your selection prep. You can find strength programs all over the internet - you do not need to purchase mine. But the following are good options for most intermediate trainees who also want to maintain their aerobic capacity: Jacked Gazelle (powerbuilding + endurance hybrid), Bro split + (10 week program - great to follow 6+ months out from SFAS), T-850 (subscription based tactical athlete program).

Wrapping it up

The take home point from this entire article is that although you don’t need to follow a 6 month, 9 month, 1 year SFAS training plan, you certainly should start thinking about building a base before you start your SFAS training plan. Specificity is key. To prepare yourself to handle the rigors of high weekly running and rucking mileage, you’ll want to increase your “time on feet”. There are plenty of ways to approach this process. Common sense is highly encouraged. A sound, reasonable approach is always best.

Thank you for reading! If you have questions or comments on any of the topics within this article, or about SFAS prep in general, feel free to leave them in the comments!