What is stress?

[gudujarlson]

When physiologists and cyclists talk about "stress" what do they mean? I googled around a little and didn't find a better definition other than this one:

http://en.wikipedia.org/wiki/Stress_%28physiology%29

But I don't think this is what everyone uses as a definition and I think it might be leading some misconceptions and confusion.

It seems to me (and could be way off) that the stress to a cyclist can be broken down into 2 general categories:

1) stress caused by the increase in metabolic rate (see wikipedia article)
2) mechanical stress to the soft and hard tissues in the body, e.g. tendons, bones, muscles, skin

When physiologists use the term "stress" do they mean primarily #1?

When cyclists use the term "stress" do they mean primarily #2?

I'm wondering if the answer to both questions is "yes". It seems somewhat plausible that it is easier for the cyclist to perceive the effects of mechanic stress more than metabolic stress. For example, the day after a hard workout, the cyclist can easily feel the soreness caused by physical damage to the muscles and tendons, but they can't necessarily feel changes in their hormone levels.

Additionally, the relationship of each type of stress to workout intensity might be different. While metabolic stress might have a n^4 relationship, mechanical stress might be closer to linear (n^1). The above difference in perceptibly plus this difference in sensitivity to intensity might lead to the general feeling that TSS is not accurate, because TSS is based on metabolic stress. but the cyclist's perception is based on mechanical stress.

Am I making any sense or am I being completely naive?

 

[vspa]

TSS is a new concept proposed by power training books and specialists. Through different measurement methods and wide criteria they came up with a number, the Training Stress Score, that measures how hard you actually trained, stress is a renown concept used on all kind of different contexts, i think you should refrase your question or be more specific,

 

[tomw1974]

I'd say that cyclists (and most endurance athletes) are more interested in #1 with a secondary interest in #2. In cycling, strength in the muscle is secondary to aerobic efficiency and capacity.

Weight lifters, sprinters, and other power athletes are probably more interested in #2.

 

[gudujarlson]

Endurance sports cause mechanical stress and related damage to muscle tissue and other soft tissue as well. I think this is well documented. I have experienced this personally, because I have suffered various cases of tendonitis and muscle strains as a result of too much cycling. And like I said above, I speculate that the soreness felt the day after a hard ride is related to physical damage as opposed to metabolic "damage", but that is just speculation. I've been looking for some discussion of this in the literature, but have not found anything.

 

[dhk2]

Originally Posted by gudujarlson .

Endurance sports cause mechanical stress and related damage to muscle tissue and other soft tissue as well. I think this is well documented. I have experienced this personally, because I have suffered various cases of tendonitis and muscle strains as a result of too much cycling. And like I said above, I speculate that the soreness felt the day after a hard ride is related to physical damage as opposed to metabolic "damage", but that is just speculation. I've been looking for some discussion of this in the literature, but have not found anything.

Lots of references on delayed-onset-muscle soreness. Suggest you start with the wikipedia entry on DOM soreness, or sportsmed, or just do a google search to find those and lots more.

 

[tomw1974]

If you are talking about getting fitter, you should not regularly have DOMS after the first few months of training. Once in a while, maybe. All the time, no.

If cyclists really worried about muscular stress, they'd be lifting instead of riding, but that poor horse's carcass has been abused enough.

You're totally ignoring the metabolic stress, which is what cyclists are creating to get fitter.

Then again, after seeing several of these types of questions from you, I'm starting to think that you care more about academic debates than actually improving as a cyclist.

 

[gudujarlson]

Originally Posted by tomw1974 . Then again, after seeing several of these types of questions from you, I'm starting to think that you care more about academic debates than actually improving as a cyclist.

I exercise the mind and body.

 

[An old Guy]

Originally Posted by gudujarlson .

1) stress caused by the increase in metabolic rate (see wikipedia article)
2) mechanical stress to the soft and hard tissues in the body, e.g. tendons, bones, muscles, skin

Most likely you don't get one and not the other. But there are differences.

Some people think #2 stress caused by short duration high intensity #1 stess is desirable.

I prefer less #2 stress caused by longer duration but lower intensity #1 stress.

 

[gudujarlson]

Originally Posted by An old Guy .


Most likely you don't get one and not the other. But there are differences.

Some people think #2 stress caused by short duration high intensity #1 stess is desirable.

I prefer less #2 stress caused by longer duration but lower intensity #1 stress.

I'm not sure I am following you. Are you implying that longer lower intensity rides have lower mechanical stress than shorter higher intensity rides? My intuition says the exact opposite. I feel like I have more pain, cramping, etc. after a long slow rides than after short intense rides. Also I have had several cases of tendonitis after a series of long slow rides but never after a series short intense rides. I don't feel like TSS accounts for this extra perceived stress of long slow rides.

TSS remains a mystery to me. I have tried to dig up a reasonable explanation of it from a physiological perspective, but the best I have found is this paper.

http://velo-fit.com/articles/coggan-power.pdf

There is a lot of missing information in that paper. For example, he paper explains why the 4th power function comes from but not why you then take the 4th root of the average of that function. But any case, it seems to be all about metabolic stress and not mechanical stress, thus this thread.

 

[sfdigital]

The first thing that you should remember is that stress is definitely not "all in your head." As medical professionals will tell you, stress is a very real physiological phenomenon that can easily take a toll on the body. For instance, you will find that in stressful situations, you usually experience a quick heart beat, a raised metabolism level and you will also start to breathe rapidly.

Wedding Photographer Hertfordshire | Destination Wedding Photographer | Top Wedding Photographer

 

[danfoz]

Originally Posted by gudujarlson .

I'm not sure I am following you. Are you implying that longer lower intensity rides have lower mechanical stress than shorter higher intensity rides? My intuition says the exact opposite. I feel like I have more pain, cramping, etc. after a long slow rides than after short intense rides. Also I have had several cases of tendonitis after a series of long slow rides but never after a series short intense rides. I don't feel like TSS accounts for this extra perceived stress of long slow rides.

I can do long slow rides almost everyday. I limit high intensity interval work to twice weekly at a maximum, and then only during an 8 or 9 week peaking cycle. The wear and tear factor is just too much for any greater frequency.

If you have more pain and/or cramping from shorter rides, it's a possibility you are not fueling/hydrating enough, or are running out of salts/electrolytes (which would be more likely on a longer ride).

 

[quenya]

To the OP, I think you hit the nail on the head! Physiologists referring to stress in the context of cycling are probably more interested in metabolic than mechanical, simply because of the demands of the activity, as are informed cyclists (or they should be). Look at some of the answers your post received; I'm pretty sure a few people didn't read past the title and answered a totally different question. Then, there was a post by yourself equating 'pain and cramping' from long rides to 'stress'; I think that's a misguided association. Stress, is something your body adapts to so that in time it will not be stressful. Depending on the cause your pain may or may not be inducing adaptations. Cramping, depending on the cause, may or may not be something that your body can adapt to. It's also safe to say that even mechanical stress and the adaptations imposed are not nessesarily perceivable to the athlete, running or lifting weights imposes stress on bones and the body adapts by strengthening those bones.

 

[martincarlsson]

Stress is a general term applied to various psychologic (mental) and physiologic (bodily) pressures experienced or felt by people throughout their lives. You can manage your stress in several ways. Rehab centre like Rygginstitutet( http://www.rygginstitutet.se/) helps you to manage stress.

 

[Viking55803]

All strenuous exercise, anaerobic and aerobic, cause an increase in cortisol which is the "stress" hormone. This has many effects metabolically, so all stress operates on a metabolic level. Psychological stress is the same way. Of course, this kind of metabolic stress in careful doses results in adaptations that we call strength and fitness. Too much stress causes overtraining.

 

[AlexKabam]

People are definitely referring to #1 primarily. #2 is a far lesser concern among cyclists as we are more concerned about the wear on our metabolism rather than our muscles. That is why cycling is so great for developing muscles while also being great to prevent and rehabilitate after injuries.

 

[An old Guy]

I'm not sure I am following you. Are you implying that longer lower intensity rides have lower mechanical stress than shorter higher intensity rides? My intuition says the exact opposite. I feel like I have more pain, cramping, etc. after a long slow rides than after short intense rides. Also I have had several cases of tendonitis after a series of long slow rides but never after a series short intense rides. I don't feel like TSS accounts for this extra perceived stress of long slow rides.

TSS remains a mystery to me. I have tried to dig up a reasonable explanation of it from a physiological perspective, but the best I have found is this paper.

http://velo-fit.com/articles/coggan-power.pdf

There is a lot of missing information in that paper. For example, he paper explains why the 4th power function comes from but not why you then take the 4th root of the average of that function. But any case, it seems to be all about metabolic stress and not mechanical stress, thus this thread.

TSS is a mystery to Andy Coggan also. He has been unable to even explain the basis for IF either on the boards he posts on or in published papers. He gets more vague talking about TSS. (Don't look for his papers. He claims to have never published a paper on the subject. He claims it is only a hobby so he need not produce a scientific basis or argument.)

Most days I do 200TSS above 70%IF - about 4 hours at 80%FTP. According to Andy Coggan above 70% constitutes training. And according to Andy Coggan 200TSS is not maintainable.


I don't know how you do your rides. No one can diagnose your medical issues on the internet. High power output rides require more force on the pedals than low power output ride (at the same cadence). High power output rides require more repetitions than low power output rides (at the same force on the pedals). So they produce more mechanical stress.

Longer rides require riding at a lower average power output than shorter rides. So they produce less mechanical stress.

Most people mix their rides. They hit some hills or nice flats hard on long rides. They do repeats incorporating low power into short high power rides.

 

[SolarEnergy]

Additionally, the relationship of each type of stress to workout intensity might be different. While metabolic stress might have a n^4 relationship, mechanical stress might be closer to linear (n^1). The above difference in perceptibly plus this difference in sensitivity to intensity might lead to the general feeling that TSS is not accurate, because TSS is based on metabolic stress. but the cyclist's perception is based on mechanical stress.

Am I making any sense or am I being completely naive?

Not completely naive, but not perfect sense neither.
It is very hard to distinguish between these 2, and these 2 aren't the only components of what is meant by "stress". I believe that for several athletes, performance (or lackof) is a better indicator of "stress". I can think of several names, very good riders that don't feel the "pain" that much.

The nervous system (whole network, that is peripheral and central) is a very important component of stress as well. TSS as a whole (i.e. its application rel to PMC) does not focus on metablic stress that much in my opinion, otherwise I would expect the ATL time constant to be shorter than 7 days (the default). What I mean here, and that, whether one believes in the accuracy of this model or not, the reason why we allow so much time in tapering is not limited to glycogen replenishment, getting the minerals balance optimal, getting re-hydrated. Soft tissue micro damage and peripheral nervous system fatigue accounts for a lot of this time required to get the taper right.