There is something satisfying about strength because it is easy to measure.
The bar weighs what it weighs. You either lift it or you don't. Add five kilograms to your squat, pull a heavier deadlift, press more than you did last month, and there is very little ambiguity about whether you have become stronger.
I like that about strength training.
Strength has been a foundation of my training for years, and I still care about getting stronger. Heavy benching, squats, deadlifts, and other basic strength work have not suddenly become less valuable because I also run, ruck, and train for endurance.
But some of my clearest fitness lessons have come outside the gym.
A heavy set can make you feel extremely capable. Then you put on equipment, carry weight for kilometres, work for a while, and still need to lift, drag, climb or move quickly afterwards.
Suddenly the question is no longer just how strong you are.
It becomes:
How much of that strength can you actually use here, under these conditions, for as long as the task requires?
That is a very different question.
A heavy deadlift tells me something important about what you can do. It does not tell me how well you can carry a load for an hour, run several kilometres, move across poor terrain, or repeat demanding work when you are already tired.
That does not make the deadlift meaningless.
It means the task has changed.
And when the task changes, the qualities that determine performance change with it.
Strength is foundational. Capability is contextual.
The goal should not always be to become the strongest person in the room. It should be to build the physical qualities required by the life, sport, or job you actually need to perform in.
Strength Matters — A Lot
Before going any further, this needs to be clear: strength is one of the most valuable physical qualities you can build.
Resistance training improves far more than the number written beside your squat or deadlift. Modern resistance-training research shows improvements in maximal strength, muscular endurance, power, and broader measures of physical function. The ACSM's updated position statement on resistance training supports that broader view of what resistance training can develop.
Getting stronger also gives you a larger physical reserve.
Imagine two people who both need to lift an 80-kilogram object. For someone whose maximum capacity is close to 90 kilograms, that task is near their limit. For someone capable of lifting 180 kilograms, the same object represents a much smaller percentage of what they can produce.
The object has not changed. Their relationship with it has.
That principle carries over to plenty of real tasks. Stronger legs can make climbing under load easier. Stronger hips and back can help with awkward lifting and carrying. Upper-body strength matters when pulling, pushing, climbing, or moving another person.
This is why I have very little interest in the version of "functional fitness" that treats heavy strength training as unnecessary. Strength creates options. It gives you reserve capacity and makes many submaximal tasks less demanding relative to what you can produce.
If strength is still a weak part of your foundation, the major compound movements remain some of the most useful tools for building it. I cover those in more detail in my guide to compound lifts for strength.
The problem is not strength.
The problem is assuming that one physical quality can represent every form of fitness.
It cannot.
What Capability Actually Means
People often talk about being "fit" as though everyone is standing on one universal scale.
They are not.
Take a competitive powerlifter and a marathon runner. If the task is lifting the heaviest possible barbell once, the powerlifter is far better prepared. If the task is running 42 kilometres as quickly as possible, the marathon runner is far better prepared.
The comparison becomes less useful the moment we change the task.
What if you need to carry heavy equipment over uneven terrain? Move another person? Climb several flights of stairs while wearing protective equipment? Sprint, stop, change direction, lift something awkward, and then continue working?
Now we are asking for several qualities at once.
Systematic reviews in military and firefighting populations show that occupational performance relates to several physical qualities rather than one universal fitness measure. A systematic review of military occupational tasks found relationships involving cardiorespiratory endurance, lower-body strength, upper-body muscular endurance, and other fitness qualities depending on the task being tested.
The same pattern appears in firefighting. Recent research has linked both cardiorespiratory fitness and muscular and anaerobic performance with different firefighter occupational tasks.
The important point is not that one of these qualities matters more in every situation. It is that the task decides which qualities rise in importance.
That leads to a much better question than asking who is "fittest."
Capable of what?
A powerlifter, marathon runner, firefighter, soldier, climber, construction worker, and parent can all face very different physical demands. None of them needs to win every possible fitness test. They need qualities that match the tasks in front of them.
That distinction also removes a lot of unnecessary tribalism from training. Strength athletes do not need to mock endurance athletes for being weaker. Endurance athletes do not need to mock lifters for being slower. Hybrid athletes should not pretend that being reasonably good at several qualities makes them universally superior either.
Compare the demands, not the people.
Capability is almost meaningless without context.
Capability Depends on the Task
One of the most fundamental principles in training is specificity.
Your body adapts to what you repeatedly ask it to do.
Strength gained through resistance training can transfer beyond the exact exercise used to build it, but that transfer is not unlimited. A recent systematic review and meta-analysis on task specificity in resistance training found substantially larger improvements in the trained dynamic strength task than in untrained isometric strength.
General strength gives you potential. Specific practice determines how much of that potential becomes useful in a particular task.
Strength creates potential. Specific training determines how much of that potential transfers.
If you want to become good at rucking, stronger legs help. But eventually you still need to ruck. Your feet need exposure to the work. Your shoulders and trunk need to tolerate the load. You need to learn how to pace yourself and how your body responds over distance.
If you want to become a better runner, stronger legs may improve several useful qualities, but eventually you still need to run. If you need to climb effectively, pulling strength helps, but you still need to climb.
General physical preparation gives you the tools.
Specific training teaches you how to use them.
That distinction stops us from expecting one exercise or one quality to solve every physical problem.
Where Strength Alone Isn't Enough
Maximum strength tells us how much force you can produce in a particular task.
Many real-world demands are not limited by your ability to produce force once. They require you to keep producing useful output.
Think about moving a heavy person.
First, you need enough strength to lift or drag them. Now move them fifty metres. Grip becomes more important. Your legs have to continue producing force. Your trunk has to maintain position. Your cardiovascular system has to support the effort.
Then change the situation again.
Imagine that the carry was not the first thing you did. You had already been walking under load. You had already been working. You were already breathing harder than normal before the heavy task even started.
This is one of the biggest differences I notice between gym training and military training.
The gym usually lets you approach a hard effort fresh. You know the weight and movement. You have a stable surface, a predictable setup, and time to rest before the next set.
Physical work outside the gym does not always give you that luxury. You may already have spent significant time moving with equipment before something suddenly needs to be lifted, dragged,d or carried.
The strength requirement has not disappeared. It now exists inside a larger performance problem where fatigue, grip, breathing, terrain, equipment, and recovery all influence what you can actually do.
Strength still matters.
It just has company.
Capability Appears Where Qualities Overlap
Broad capability does not mean trying to become elite at everything.
For most people, that would be unrealistic anyway.
What matters is developing enough of the qualities required by the tasks you care about so that one obvious weakness does not constantly limit everything else.
A soldier may need enough strength to move another person, enough aerobic fitness to reach them without being completely exhausted, enough muscular endurance to continue carrying them, and enough recovery capacity to keep working afterwards.
A firefighter may need strength for equipment and victim rescue, aerobic fitness for prolonged work, power for forceful tasks, and enough mobility and balance to move effectively while wearing protective equipment.
Even everyday situations can create the same overlap. Carrying something awkward up several flights of stairs is not purely a strength test and not purely an endurance test.
It is both.
Capability appears where the qualities overlap.
More strength can reduce the relative difficulty of a heavy task. Better aerobic fitness can help you sustain work and recover between efforts. Muscular endurance helps you produce submaximal force repeatedly. Power matters when force needs to be produced quickly. Movement skill, balance, and adequate range of motion help you express those qualities in the positions the task requires.
You do not need to maximize every one of them.
You need enough of the right ones.
Why Carrying, Running and Moving Change the Equation
Load carriage is one of the clearest examples of how a task can change what matters.
Put a heavy rucksack on someone and even ordinary walking changes. Posture changes, energy expenditure increases, and the muscles around the legs, hips and trunk have more work to do.
Research on military load carriage and gait shows that increasing external load can alter posture, lower-body mechanics and muscle activity during walking.
Carrying weight is not simply normal walking with a higher number attached to it.
A strong person still has an advantage. A review of the relationship between lower-body strength, power and load-carriage performance suggests that lower-body strength and power are important contributors to performance under load.
If the external load represents a smaller percentage of your strength capacity, part of the task becomes easier.
But strength alone does not guarantee that you will be good at carrying that load over distance.
At some point, you still need to ruck.
You need to tolerate thousands of repeated steps under load. Your feet and lower legs have to handle the work. Your shoulders and trunk need to tolerate the pack. Your aerobic system has to support the effort.
You also need experience. Pacing with a load is different. Moving uphill is different. Moving through forest terrain is different. Add mud, uneven ground, or long duration, and the problem changes again.
If rucking itself is new to you, start with my guide to rucksack marching, its benefits and risks.
I also prefer building tolerance through walking before adding more aggressive forms of loaded locomotion. If weighted running is something you eventually want to use, I explain why I would build the base through loaded walking before weighted running.
Running changes the equation again.
Now you are repeatedly moving your own body through space. As locomotion becomes a larger part of the task, body mass becomes part of the workload, which means absolute strength alone gives us a less complete picture of performance.
A 200-kilogram deadlift is impressive regardless of who performs it. But it does not tell us everything about how efficiently that person can repeatedly move their own body over distance.
That does not make absolute strength less impressive or useful.
It simply shows why one number cannot describe every type of physical performance.
Peak Capability vs Repeatable Capability
This distinction may be one of the most important in the entire conversation.
What can you do once?
And what can you continue doing?
I think of these as peak capability and repeatable capability.
Peak capability might be your maximum deadlift, fastest sprint, or hardest single effort in a particular task. There are situations where producing a very high force or power output once is exactly what determines success.
But many real tasks do not end after the first effort.
They look more like this:
Lift → carry → move → climb → recover → repeat.
A one-repetition maximum tells us something valuable about the highest force you can produce in a specific movement. It does not tell us how much useful output remains after ten minutes, thirty minutes,s or several hours of physical work.
In military training, this difference is hard to ignore. Physical tasks rarely arrive perfectly isolated from everything that came before them. A sprint, carry, or heavy effort may happen after you have already spent hours moving, standing, carrying equipment, or working in uncomfortable conditions.
Research gives us a measurable example of this accumulated-fatigue problem. A 2026 systematic review and meta-analysis on military foot marches reported reductions in several measures of subsequent physical performance, including lower-body strength, trunk strength, lower-body power, er and postural stability.
The physical capacity available at the start of a task is not necessarily the capacity still available after prolonged work.
Someone with enormous maximal strength may have a huge reserve during the first heavy effort. If their conditioning is poor, however, performance can decline as tasks accumulate. Someone with excellent endurance may recover quickly between efforts but still struggle when the external load becomes too heavy.
Broader capability sits between those extremes: enough strength that the load is manageable, and enough conditioning that you can continue using that strength.
This is also why I use the term work capacity carefully.
It is not one clean measurement in the same way VO₂max or a one-repetition maximum is. I use it practically:
Work capacity is the ability to perform useful physical work repeatedly, recover sufficiently, and continue producing acceptable output over time.
Strength, aerobic capacity, muscular endurance, task-specific conditioning, and recovery all influence that ability.
Peak capability matters.
Repeatable capability matters too.
Which one deserves more emphasis depends, once again, on the task.
The Cost of Specialization
None of this means specialization is bad.
In many cases, specialization is exactly what good training looks like.
If your goal is to become an elite powerlifter, spending large amounts of training time trying to become an exceptional distance runner would probably move resources away from your primary objective. If you are preparing for a marathon, maximizing muscle mass and one-repetition maximum strength is unlikely to be the centre of your training.
Specialists become good precisely because they direct a large percentage of their training toward specific adaptations.
Specialization is excellent when the task demands specialization. The problem is mistaking specialization in one quality for complete physical capability.
There are also real trade-offs.
Some hypertrophy can contribute to greater strength, but substantial increases in muscle and body mass may, under some conditions, create trade-offs for sprint or endurance performance. A 2024 review on resistance training for sprint and endurance athletes discusses several of these potential interactions, including body mass and muscle architecture.
Large endurance volumes can also increase fatigue and create additional recovery demands. Maximizing strength, hypertrophy, endurance, speed, and power simultaneously is much more difficult than prioritizing one or two qualities.
Training time and recovery are finite.
Giving one quality more priority usually means accepting less emphasis somewhere else.
That is not failed programming.
That is programming.
The correct balance depends on what you need the body to do.
You Don't Have to Choose Between Strength and Endurance
Hybrid training is sometimes treated as though strength and endurance are natural enemies.
The usual fear is the interference effect: add running or endurance work to your strength training, and you will automatically sacrifice your gains.
There is a legitimate physiological discussion behind interference, but the reality is much more nuanced than the old gym version of the argument.
Recent high-level evidence suggests resistance and endurance training can coexist far better than the old "cardio kills your gains" narrative suggests. A 2026 umbrella review of concurrent training found comparable strength, power and hypertrophy outcomes between concurrent training and resistance training alone, while concurrent training also improved aerobic capacity.
That does not mean programming no longer matters.
Training volume, exercise selection, session organisation and recovery still matter. If you add large amounts of endurance work on top of already demanding resistance training without adjusting anything else, fatigue will eventually become a problem.
But that is very different from saying you must choose between being strong and having an aerobic engine.
Most people do not need to choose. They need to decide which quality takes priority and how much of the others they need to support their goal.
A powerlifter may maintain a relatively small aerobic base. A marathon runner may maintain strength with a lower resistance-training dose. Someone training for broad physical capability can sit somewhere between those extremes.
You do not need maximal development of every quality.
You need enough of the right ones.
If you want to go deeper into the programming side, I have a separate guide on how to combine cardio and strength without unnecessarily sacrificing either.
How to Build Capability Without Giving Up Strength
If you already have a strength-training background, I would not throw it away and start chasing random "functional" exercises.
I would use three principles instead:
Keep the foundation. Fill the gaps. Train the task.
Keep the Foundation
Continue lifting.
Keep the major movement patterns and maintain enough heavy resistance training that your body still has a reason to remain strong.
If strength gives you physical reserve, giving it away unnecessarily makes very little sense.
The goal is not to replace strength.
It is to build around it.
Fill the Gaps
Look at what actually limits you.
If you are strong but a short run leaves you completely exhausted, your aerobic capacity may deserve more attention.
If you can run for hours but struggle with moderate external loads, strength may be the larger limitation.
If you lift and run well but fall apart when carrying equipment, load carriage itself may need to become part of training.
If repeated efforts destroy your output, muscular endurance, conditioning, or recovery between efforts may be the missing piece.
Do not add training just because it looks hard.
Add it because it solves a problem.
Train the Task
Eventually, important tasks need specific exposure.
Want to become better at rucking? Ruck.
Want to run better? Run.
Need to climb? Climb.
Need to carry awkward objects? Carry them.
General training develops qualities. Specific training teaches you how to combine those qualities under the conditions that matter.
Ask three questions:
- What quality am I trying to improve?
- What task is that quality supposed to support?
- Does my training actually prepare me for that task?
Those questions are more useful than asking whether an exercise looks tactical, athletic, or functional.
What I Actually Train For
My own training makes much more sense when viewed through this lens.
I still want to be strong. I enjoy heavy training, and I want my numbers in the gym moving in the right direction.
But my training week can also contain running, rucking, sled work, and conditioning alongside those heavy strength sessions.
Sometimes those goals compete.
A hard ruck can leave fatigue in the legs before the next strength session. Heavy leg training can make a run feel worse. A demanding conditioning session can affect recovery.
If I specialized completely in one quality, I could probably optimize it more aggressively.
But that is not my goal.
I do not want strength that only exists when I am fresh, standing on a flat gym floor and working for a few seconds at a time.
I want to be able to carry weight, run, move through terrain,n and work while tired — then recover and perform again.
That requires compromises, and I am comfortable with them.
The goal is not to maximize one number at the expense of everything else. It is to build a body with enough strength, endurance, and work capacity to handle a wider range of demands.
That is what hybrid training means to me.
I have gone deeper into the physical qualities behind that approach in What a Hybrid Athlete Trains For and Why It Matters.
Hybrid training is not adding random burpees after a strength session. It is not running after every workout simply so the training looks harder. And it is not choosing exercises because they look military.
It should have the same discipline as any other good programming:
- Define the demands.
- Identify the qualities.
- Prioritize what matters.
- Manage fatigue.
- Train specifically enough that the adaptations actually transfer.
The result may not make you the best powerlifter in the room or the fastest runner.
That is fine.
The target is different.
Build for the Life You Need to Perform In
There is no universally most capable athlete.
There are people who are exceptionally well prepared for particular demands.
That is why the strongest person is not always the most capable. But the fastest runner is not always the most capable either. Neither is the person with the highest VO₂max, the most muscle mass, the fastest sprint, or the largest number of pull-ups.
Every measurement tells us something.
None tells us everything.
Strength is still one of the best places to start because it creates such a useful foundation.
Then build outward.
Develop enough endurance to keep moving. Learn to carry load if carrying matters to you. Build enough power to produce force quickly. Develop the ability to repeat difficult efforts. Practise the tasks that actually matter.
And accept that your ideal balance may look completely different from somebody else's.
That is not a weakness in the concept.
That is the entire point.
Fitness should serve the task.
Training should serve your life.
Build the physical qualities your life actually demands.
That is capability.
And that is what Viking Muscles is built around.
Tactical Hybrid Base was built around exactly this philosophy: strength as the foundation, with endurance and work capacity developed around it.
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