Damer Thank you for openning this topic, and I totally agree with your idea on how it's highly dependent on what you do/ play.
I have this one question: Does being able to do 3x20 squats with 20lbs give me twice the leg endurance as 3x20 with 10lbs? It's not exactly the number per se but the math behind it.

I am not familiar with the terms "mechanical damage" and "metabolic load," but I am guessing the category of weighted activity is a combination of the two. I mean things like firefighter, the military, kendo , etc., in which you move, fight, or do everything with some weight on your body. I am not a very muscularly strong person, so every time I put on my kendo gear it makes a difference in performance. Several weeks ago I simply started doing single-leg forward hops with weight upon myself, but I did too much and got some injury (shin mostly) lately. These two weeks or so I am back to mixed lowerbody strengthening. It's a bit hard to plan around how to progress safely and effectively. I guess I am fine doing it on my own but it will nice if you can give some insight. I would like to hop further, too, which I have little idea about how.

It's actually a great exercise on it's own. I feel like it fixes my knee cave and even the flat feet because it forces all the related muscles to change, just in a brutal way, and it takes very little time.

kandy thank you for these questions. The math behind endurance development exercises is not quite an exact match the way you describe it, though on an approximate basis this is correct. If we can run 10km at half speed, we can easily run five at roughly twice the speed/intensity. The reason there is no exact match lies in that tricky combination of mechanical damage and metabolic load so this is a good opportunity to explain these further.

Mechanical damage, as the name suggests, is damage suffered by the muscles. Basically micro-tears which de-strengthen the muscle fiber and reduce muscle output. This will happen every time the muscle fibers exceed the tolerance dictated by their strength and strength as we have seen is itself a complex issue. Mechanical damage is desirable because its repair by the body delivers muscle fibers that are resistant to the level of intensity or duration that created the mechanical damage in the first instance. This makes the muscle fibers stronger, for sure, but it also gives them endurance as they can now work at the same level of intensity that damaged them without suffering ill effects.

Metabolic load, is the amount of metabolite built-up experienced by the muscles as they work. Metabolites are the by-products of the metabolic reactions that take place in the muscles as they work. The easiest, though not entirely accurate, way to think of them is like a freeway that is gradually filling up with traffic until it leads to a traffic jam. As the muscle's work harder and harder they exceed the body's ability to deliver nutrients to the muscles and take away metabolic by-products. This starves the muscles of fuel, they begin to tire, slow down (as the chemical messengers required to help them maintain their work rate get stuck in 'traffic'), they fatigue and may even experience a cramp or two.

Metabolite built-up is responsible for chemical damage to the muscles which, basically is chemically-induced mechanical damage. The effect is that muscles, again, become de-strenghtened which is why when we get metabolite-induced fatigue we can rest and our body can play catch-up and clear it but if we repeat the cycle enough times at some point we begin to really tire, our performance drops and our muscles don't work the way they are supposed to. We need to rest in exactly the same way as when we have experienced mechanical damage due to mechanical load.

To take this now to your own unique situation, when you do single leg hops you basically significantly increase the mechanical load onto your calves and ankles and, as they suffer mechanical damage, risk injury because the load is just too great. To give you an idea a single, one legged hop brings the body's weight x4 or x5 on the calf muscles and ankle joint. You'd do far better to bounce on both legs, increase the length of time you can do this for, add extra height to your two-legged hops occasionally for variety and introduce single-leg hops with really low numbers initially until your body adjusts and your strength increases.

I hope I've shed some light on this.

Damer This is something that I was thinking about when I did a run a couple of days ago, but it is not completely on topic. About halfway through my run I saw another runner who ended up going the same route that I was on. To my impression, I don't think that I was running faster, but I kind of felt like I should be until I caught up to the other person running. Equally when I got in front I felt this kind of invisible pressure from behind that the person was going to pass me back. My question, is this purely psychological, or is there some kind of an adrenaline rush fight-or-flight physiological response to a case like this?

I would like to hear the discussion on this as well.

I experience the same feeling when I am running all the time. If someone runs along the way and gets in front of me, I always have the urge to chase them until I'm ahead of them and then have the feeling that they always behind me and make me unsure of my pace.
In my situation, I think that the competition spirit (or like you said - adrenaline rush) of the former (being left behind) leads to the latter (fear of being defeated). Or you could say that it's the aggressiveness doing the work.
I find it really affects the effort of my run, in a negative way. Then, I discovered that listening to something helps a lot to distract me from that feeling, especially podcasts. Not that I would focus on what the topic is but it shifts me into a kind of spacing-out condition, in which I feel like I can re-adjusting my breath and pace, get me back on track.

CaptainCanuck and Haidare thank you both for bringing this question up. Although not entirely related to endurance it is related to performance and, as we shall see, motivation.

First of all let's start by noting that this "chase response" is universal. I feel it too (always) and I know many other runners who I have discussed this with, report similar feelings. When so many of us from different age groups, fitness levels, cultures and backgrounds experience something similar the feeling is that it is neurobiological in origin rather than purely psychological. I am going to explain the mechanism behind it here but before I do you may want to leap into the threads I started on motivation as they explain some of what I am going to say here.

Basically, when we see another runner ahead of us our brain runs an automatic assessment that compares their speed to ours. Irrespective of how far ahead they are or how fast they are running we experience a degree of excitation. Cortisol levels (the stress hormone) rise as we assess the situation and then, depending on how far ahead we are we give 'chase' wanting to either keep them in sight (if they are far ahead and running fast) or gain on them and overtake them (if they are not that far ahead and we are, or can be, a little faster).

The question of course is why? Why should we feel the need to do that? Well, part of what we experience is the response to what we call social comparison (there is a book about this). Social comparison is complex. We are hardwired to do it because it helps us establish our position and role in the pecking order (so to speak). If I chase a runner that's slower than me, for example, and catch them and overtake them I immediately feel better about my own prowess. This gives me a massive dopaminergic boost in my brain that activates the reward system and makes me feel good. If I chase a runner who is faster and better than me, the fact that they already have a headstart will make me re-adjust my aims (i.e. keep them in sight) in order to get the same boost. The re-adjustment of my targets, in this example, is key.

Social comparison is not without stress. This is called psychosocial stress (which is why cortisol levels rise). If we are better we feel under pressure to prove it and if we are worse we feel under pressure to not fail by a lot. Either way we are competing. (There is a study on this here). Cortisol levels are never good for us, though we do need them to prepare us for action as the hormone elevates body temperature, accelerates the metabolic rate and prepares the body and brain for action.

Once we decide on the course of action however, in order to continue (i.e. to stay motivated) we need that dopamine kick that activates our reward system and makes us feel good. Dopamine and the attendant hormones, serotonin and noradrenaline reduce the levels of cortisol in the bloodstream and make the body (and brain) feel good. A study on this counteractive effect is here.

So, to get back to your direct question, having seen the runner and decided to give chase and overtake them we feel constantly rewarded as we gain on them and our brain is awash with feel-good hormones as we overtake them. Now, having overtaken them we feel we are under pressure to maintain our lead because this feeds into our sense of our position (i.e. momentarily superior in our running). Cortisol levels spike again and we feel fearful, anxious and now have to work harder to maintain the distance. Hence the level of anxiety you feel. This can also mess up your pace and exhaust you prematurely.

Now, there are several more dimensions to all this and we could easily use it as a parable for life and living . First, there is the component called attitude. Speaking from direct experience, for example, I never overtake a runner without being prepared to race to maintain my lead afterwards. So, I know it's not going to be an easy run and if they want to overtake me back they should be prepared to go flat out all the way. This also means that if all I want is an easy run, then I decide not to chase. Then, there is resilience. You have to be able to deal with the mental pressure and, also, properly contextualize the situation so it doesn't always lead to the chase response.

There are times when I do see a runner and I feel the urge to chase and then I tell myself that I am on a conditioning run, not a race. I really have nothing to prove and focus my attention elsewhere in my mind and the urge dissipates. Resilience is key in order to deal with the situation regardless of whether you chase or not. You need to feel confident in yourself and your abilities and also in the reason why you do what you do. When I do chase, for example, I do frame it as a game in my mind. I obviously want to win but regardless I am there to enjoy it, even if I 'lose'.

What I have noticed is that nine times out of ten, the people we overtake get 'broken'. Without thinking too much about it they feel that we are already better than them, because we overtook them. Because we had to speed up to overtake them we already have more speed and acceleration. This deflates them and without realizing they slow down because their negative emotional response makes the feel more tired than they really are. If they decide to chase back they usually do so in a half-hearted way. They soon give up and fall behind even if our own pace decreases to just maintain the distance from them. What they fail to realize, of course is that by speeding up to catch them and overtake them we are already more tired than they are. If they do decide to chase us they would probably give us a run for our money.

This shows us several important things. First, the key role played by the brain and mental resources in our physical ability. Second, the deep-seated drives that guide our behavior in any social setting. Finally, the importance The Hive has for us. As a non-competitive, welcoming, judgement-free space it allows us to find, develop and exercise the self care we need to become more balanced inside our head. This is then externalized in better behavior elsewhere.

I hope I have explained this fully and it helps.

Damer How does endurance relate to stamina?

Damer Thanks for the great answer. I think in this last case of mine I was over thinking things, because I told myself "don't worry just a conditioning run" as you suggest, but then also seemed to be passing the other runner, who I thought was going fast. I couldn't tell if I was speeding up or not, hence my question.

Basically comes down to the fact that we are in this for ourselves, and anyone that wants to compete in fitness is kind of missing the point. If your personal best is 1 or 2 pushups, and then you do 3 that is the real accomplishment, not competing against a guy that can do 200.

Damer What an answer!
Now you mention it, I do realize that most of the time I have a physical reaction to the "chase response" (running after someone without much thought) is often in the un-planned runs.
In other scheduled runs, I do have a kind of subconscious counter to that physical reaction to shut it down and focus on my run.

CaptainCanuck your comment is more on-point than you may realize. The social comparison response (and the 'instinct' to chase another runner) only kicks in when we are in similar social groups (i.e. runners of more or less the same ability). By telling our self to focus on our own goals we remove our self from that perceived social group so the need to chase goes away. A lot of what we experience and everything we perceive starts from inside our self.

leep00 endurance is the body's biomechanical and neurochemical ability to perform at a high rate of work for an extended period of time. The time we take into account is always subject to the intensity of the work performed. Stamina however is the mental component of this. A lot of the time we use the terms interchangeably but really stamina is our ability to focus long enough to overcome the first threshold of fatigue and still maintain form and work output even though the body's natural inclination is to reduce its rate of work or stop.

I hope this helps.

Love the question and response about running. Generally, I don't respond much to other runners passing me or me passing them. It took time to stop responding but necessary to be able to progress and not injure myself. It's a different story when my husband wants to run with me, this becomes an issue. He's way faster than me, which means, when he runs with me, he's always slightly ahead and I feel like he's pulling me. Sometimes on single track trails, he'll run behind and then I feel I'm getting pushed. I have to consistently try to ignore that he's with me and just run like I do alone if I'm only out for conditioning. However, it's great for races. Did my best 1 mile time in 4 years this weekend, and 30 seconds better than my last race for the 5K. He insists on running with me during our races bc he doesn't care about times, he's just there for the social aspect of an event.

VLogan great addition to this thread! The pro-social response that makes us want to "up our game" to keep up is exactly why runners need pacers to bring out the best in them. It turns out, entirely on our own we are not capable of performing our best (socially or otherwise).

I run better having someone there to encourage me when my hips roll and I get light headed. I wear glasses but cant when working out due to headaches from not getting enough oxygen due to my bottom lobe of my lungs not inflating (problem i found out about in 2000) it helps me push past my best i try to get a former teammate to run with me they know how to push me yet also know when i do need to ease up. NOw my question : Is it dstanima or endurance if you run 5 miles a day to do a 3 mile race?

DustyQOTF it is both. You develop physical endurance by making your body withstand the demands of physical activity for prolonged periods of time which, in this case, exceed the distance you will run. But it takes stamina, the mental component of running, to do this day after day, to battle your body's limitations and seek ways to improve. I hope this helps.