-by Uphill Athlete Coach and Tactical Training Specialist Drew Hammond
One of my favorite things to do as a coach is take broad, abstract concepts and create left and right boundaries such that prescribing sessions and cycles for my athletes becomes more streamlined and consistent. Three such concepts are endurance, stamina, and work capacity. To some, those words describe the same thing. To others, myself included, they denote three distinct ideas. What follows is my point of view as I’ve experienced it within the tactical space, as well as some examples of how we apply these ideas independently within Uphill Athlete.
I won’t get too far into the weeds in terms of heart rate zones, energy systems, etc., so have no fear.
The words endurance and stamina are often used interchangeably. For many, these terms indicate some form of long-distance, monostructural effort like running or biking. It’s not that I think this approach is inherently wrong; rather, I find that distinguishing between the two concepts can make prescribing them a little bit easier to understand.
Endurance: Open-ended distance that requires work to maintain but could be sustained for an extended period of time without much deliberate effort.
Stamina: Something at a specified distance that requires deliberate pace, strategy, and slightly more effort/work to maintain a sustainable effort.
Work capacity, on the other hand, is probably one of the most misunderstood concepts in human performance. Ask most professionals what work capacity means and you’re likely to get something like “the amount of work an athlete can do,” which is another way of saying “I have no idea.” CrossFit has done a heck of a job popularizing the concept without actually defining it. All that being said, it’s not something you should dismiss. In fact, by my own interpretation of what work capacity is and how to prescribe it, I’ve witnessed a lot of success with my athletes.
Of the three, endurance is probably the easiest to understand and explain. For my own purposes, I interpret endurance much as I described it above: long, continuous monostructural efforts extending up to and well beyond 60 minutes. By “monostructural,” I simply mean single modality (e.g., running OR rowing OR swimming). Where I might differ from other tactical specialists is that I throw rucking into this category as well.
In terms of prescription, you’ll usually see endurance sessions written something like this:
Complete a 60-minute ruck keeping heart rate around 55%–60% of HRmax.
Note both the time frame and the heart rate prescription. Sixty minutes is long enough to require an aerobic versus an anaerobic effort, which is obviously important. In the past I stayed away from heart rate prescriptions because I didn’t want things to get too complicated for the average exerciser. But the more I played with it the more I realized that most athletes have a general idea of what a “50 percent effort” feels like. Coupling that with some heart rate terminology can usually help get athletes into what you could consider Zone 1.
Creating a black-and-white separation between endurance and stamina may make me some enemies, but I think it’s important to differentiate between the two. Quite frankly, I’ve seen a lot of success with such a differentiation. As I prescribe it, stamina is the ability to grind out work for extended periods of time without rest. Work, to me, is the ability to maneuver through multi-modal prescriptions without reaching absolute fatigue or varying considerably from a consistent pace. When I prescribe stamina sessions, I often use terms like grind to capture that concept.
An example of a stamina session with a variety of modalities would look something like this:
A) 20-minute grind:
10x kettlebell clean and jerk/side
10x box step-ups/side
B) 20-minute grind:
8x burpee pull-ups
C) 20-minute grind:
1x Curtis P every minute until completion (95#/65#)
No rest between A, B, and C. Pace consistently from start to finish.
The overall duration is the same as in the example endurance session, but the body of work is very different. That inevitably creates some differences for the athletes who undertake both sessions, which I’ll explain next.
What’s the Difference between Endurance and Stamina?
In my opinion, the difference comes down to the inclusion of various modalities, and particularly modalities that are either weight based (e.g., KB clean, Curtis P, etc.) or bodyweight based (e.g. burpee pull-ups). Whereas an endurance session is generally single modality, the inclusion of two or more modalities in a stamina session requires that the athlete approach it very differently. Now instead of settling into a Zone 1 pace, they have to deal with different movement patterns, fluctuating heart rates, exercise transitions, etc. Generally speaking, this will move the athlete into more of a Zone 2 area and periodically into Zone 3, both of which are more realistic for an extended real-life tactical situation.
With that in mind, I also don’t want the athlete moving too quickly. That is why the prescription takes the form of longer components stacked together for continuous, nonstop work. The “nonstop work” concept is very important to my stamina theory, as it’s what separates it from what I would consider work capacity. There are certain times where I’ll include longer work-to-rest intervals for stamina prescriptions, but by and large you’ll experience this component as several longer blocks stacked one right after the next.
The third and final concept is work capacity, which as I’ve already explained is historically misunderstood. The biggest difference between work capacity and our other two concepts is the use of work-to-rest ratios to create higher levels of intensity followed by periods of rest. These working intervals can be as short as 10 seconds and as long as 5 to 10 minutes, with the general rule of thumb being that shorter intervals get longer rests and longer intervals get shorter rests. (If this is confusing, try an all-out sprint on an assault bike for 20 seconds and tell me how long you need to rest to repeat that effort.) From a physiological perspective, the length of the working interval depends on the energy system we’re trying to affect.
That duration then guides the makeup of the work capacity interval. A shorter, 20-second high-intensity interval must be simple due to the fact that 20 seconds leaves the athlete with virtually no time to rotate between movements. A longer, 3-minute effort can incorporate a broader variation of movements (e.g., power cleans, box jumps, and a quick row) because the time allows for it. Again, exercise selection depends on the energy system I’m looking to affect and the effort level I’m looking to achieve, but the principles remain the same.
An example of a work capacity prescription might look something like this:
Complete 4 rounds of the following:
3-minute max effort:
3x clean and press
4x box jumps
Rest 2 minutes between each round.
The athlete should be able to complete roughly the same amount of work across all four rounds. A significant drop-off from one round to the next tells me there’s either a pacing issue, a muscular endurance issue, or a combination of both.
I can’t stress enough that this article is meant to be an overview of my approach to the concepts of endurance, stamina, and work capacity, not a deep dive. You should now have some idea of what the differences are between the three and a rough idea of what it looks like to plan an endurance session versus, say, a work capacity one. For any athlete, and tactical athletes in particular, the mission set (or sport) has to drive not only the prescriptions but also the length of the working intervals, the type of work within those intervals, and the overall volume of training. That really is where the “art” takes over from the “science.”