The Fallacy of Periodization?

[Kimmo]

Any individual Olympic lift is one movement, done the same way every time. The effort isn't any longer then maybe 5 seconds and relies completely on the ATP-CP system. Even the most intense climbing is much longer then 5 seconds and relies on all 3 energy systems, high degrees of neuromuscular endurance, and in constantly dynamic and unrehearsed movements(lacking highly refined neuromuscular coordination). You can't compare the two.

 

sorry, didn't see this.

 

the above holds true in given situations, but is certainly not a hard and fast rule, applicable to all climbing situations.

 

many boulder problems boil down to one single move that overshadows the others in difficulty. if you can't do that single move, you can't do the problem. heck, i can show you routes like that, where the grade is entirely based upon 5 seconds of effort.

 

plus, peak strength development increases one's stamina (in some situations): if i only train one arms, by the time i can do one, you know i'll be able to do 20 two arm pull-ups without ever having done one. same principle applies to climbing, methinks.

[hafilax]

Not that Homer. A different one.

 

sorry my bad. only homer i know.

 

whether or not your post was serious, my response was. trying to outline some form of generic "improvement" program without knowing the goals of the individual is kinda tuff.

I figured you'd make something up for a generic climber or for yourself. The Homer thing was facetious.

 

How about a V4 boulderer in Squamish looking to improve over the winter at the gym.

[Kimmo]

constantly dynamic and unrehearsed movements(lacking highly refined neuromuscular coordination

 

another point: depending on the climb of course, but climbing can be broken down into some basic movements; get strong at these, and climbing is much easier. so in a sense, training is developing the strength to pull a somewhat limited repertoire of specific movements, making every climb somewhat rehearsed (finger strength being the most rehearsed algorithm, if you will).

 

then there's the whole business of red-pointing, which takes rehearsal to a gymnastics level....

Edited December 2, 2009 by Kimmo

[el jefe]

constantly dynamic and unrehearsed movements(lacking highly refined neuromuscular coordination

 

another point: depending on the climb of course, but climbing can be broken down into some basic movements; get strong at these, and climbing is much easier. so in a sense, training is developing the strength to pull a somewhat limited repertoire of specific movements, making every climb somewhat rehearsed 9finger strength

 

this was the old "system board" idea, i think, popularized by the hubers back in the 90s.

 

interesting thread for sure. kimmo, could you be more specific re: what you mean by "periodization"? are you referring to the "endurance-power-power endurance" type of phase training that the manuals talk about, or would you consider any variation of intensity of training effort "periodization"?

[rocky_joe]

kimmo, you're an idiot. Not one person has even suggested they thought you were telling climbers to begin power lifting. READING COMPREHENSION KIMMO!!!

 

But, really you ought to re-read what I originally wrote. You also ought to consult PT and ask about how long it can take tendons to gain strength, it's longer than you think. You want to know why? It is, like I said earlier, because tendons are non-vascular (they don't get blood.) Muscles are able to heal (read: strengthen) faster because they receive blood flow; since tendons do not strengthening them is a much more tenuous, precise and longer process.

 

So I say again. If ANY climber simply climbs as hard as they can all the time (follows the idea of the belgian power-lifters) they WILL destroy their tendons because the tendons can simply NOT handle the constant stress. There is a reason that all literature about training to climb hard suggests some form of periodization.

 

*note: kimmo, read this post and my last post at least 3x aloud each so that you understand what I wrote.

[rocky_joe]

sorry, didn't see this.

 

the above holds true in given situations, but is certainly not a hard and fast rule, applicable to all climbing situations.

 

many boulder problems boil down to one single move that overshadows the others in difficulty. if you can't do that single move, you can't do the problem. heck, i can show you routes like that, where the grade is entirely based upon 5 seconds of effort.

 

plus, peak strength development increases one's stamina (in some situations): if i only train one arms, by the time i can do one, you know i'll be able to do 20 two arm pull-ups without ever having done one. same principle applies to climbing, methinks.

 

Except that you are wrong again. Just because you crux out on one move in a route or problem does not mean that all climbing (as your language suggests) boils down to one move. Gaining muscle memory for one move does not encapsulate climbing.

 

Typically it goes like this:

try a climb

crux out

work crux

repeat

send

try a new route

crux out (new move)

work new route

repeat

send

 

for weightlifters (say a benchpresser)

benchpress

benchpress

benchpress

benchpress

benchpress

benchpress

benchpress

 

see the difference?

 

[eric8]

I see where Kimmo is coming from. Its well proven the best way to get good at something is to actually do it, specificity. I have always thought the best way to get good at climbing is to do it as much as possible without getting hurt. So if you can handle training/climbing everyday great, but I think it something you have to work up to. When you read about how elite climbers train its usually between 2-6 days on before a rest day, Dave Macleod, Rich Simpson, Alex Huber, Jon Cardwell, etc. The list goes on.

 

That kid that boulders V11 in the gym how many times a week do you see him in the gym?

 

Then again the reason why periodization workouts are in every book is because they work. They might not work as well as climbing hard everyday but for someone just starting you are probably less likely to be injured in a more structured program. And what ever you do getting injured is the best way not to improve.

 

So in conclusion climb/train as much as you can without getting hurt. Or that is my take.

[Kimmo]

I figured you'd make something up for a generic climber or for yourself. The Homer thing was facetious.

 

How about a V4 boulderer in Squamish looking to improve over the winter at the gym.

 

to improve your bouldering then?

 

oi vei. so many options. how much time/desire do you have to put into it? 3 hrs a week? 5? 10? are you light and lean right now? body fat below 15%? can you do 10 good pull-ups off a 2 cm edge?

if you are above 15% bf, then dropping 10 pounds (or more) might be all it takes to go up a number or two on the v scale, but this is probably the hardest option!

 

my favorite thing ever that helped my gym climbing and was super fun to boot was static climbing. at first i picked problems that were relatively easy for me, and did them statically. completely statically. that means the only thing that would move when reaching for the next hold was the hand doing the reaching. and my reach would be controlled, always; meaning i could hold my body in that position in control while my hand reached. what's so fun and practical about this is that it teaches body awareness, core control and strength, optimal pre-move body positioning, mindfulness, lock off strength, toe hooks, heel hooks, , creativity, and is low injury risk. i think i started doing this on v1's and v2's an dthen moved up, and after a few months of two or three times a week for an hour or two at a time, was staticing v7's and maybe a v8 or two. it's so fun too! it was especially fun when stoned, although my speed went to silly sloth slow and people made fun of me....the control aspect was key though: i NEVER let myself cheat. if i couldn't do the move statically, i'd work just that move til i either got it, or moved to a different problem. for me personally, this period of "training" changed my climbing. the strength improvement and the awareness of movement were the biggest things. (but mainly it was fun!)

oh and i did these mainly on the steeper walls.

 

 

fingerboarding was a big factor in improvement at one point (and continues to be). my fingerboard was pretty simple: some plywood with 3/4", 1/2", and 1/4" edges. tons of good routines on line and in books, but i'd warm up well, maybe 10 or 15 minutes of slowly increasing intensity hangs, then start. i think at first i simply worked up to being able to hang the 3/4" for a minute and a half. maybe it took 2 weeks, maybe 3. i'd just start hanging til i fell off! rest a few minutes, repeat. 10 times. that'd be the workout. two or three times a week. semi crimp position. then moved to 1/2", started doing the same thing. can't remember the length of hang i worked to here. i think i had to crimp this, and the 1/4".

 

then started adding weight so i could only hang the 1/2 for 5 secs. do once, rest a couple minutes, repeat. 10 15 times. workout done. then assorted stuff on the 1/4". get creative. at first this'll kick your ass and more climbing on these days will be hard to do, but you get used to them. again, i got big improevements, but: mainly it was fun!

 

i think if you did the finger workout 2 or 3 times a week, and the static 3 times a week, you'd absolutely notice a big improvement in two or three months.

 

sample schedule:

 

Mon

 

static climbing, 1 hour in evening, ~15 to 20 climbs. fingerboarding after, 3/4" edge. 5 hangs to failure.

 

tues rest

 

wednesday same as monday

 

thursday rest

 

friday same as monday

 

rest weekend

 

2nd week, same as first, except hang to failure 10 times

 

i think this might be a good place to start, and see if you are recovering well and staying relatively fresh. maybe it's too much, or not nearly enough. if you can, start doing more climbing per session, and add a saturday hangboard session.

 

if anything hurts, rest it quickly before it becomes a problem. some aches are just part of the territory, but always better safe than sorry.

 

whew. ok i'd love to hear if you end up doing this stuff, and the progress you make. 3 weeks to start noticing improvements, 3 months to really notice big jumps. but mainly, i'd hope you have fun with these.

Edited December 2, 2009 by Kimmo

[Kimmo]

hey rocky joe, i have no interest in corresponding with you. you're a blow-hard who climbs what, v3?, and you think you're an expert. i don't have time for that. seriously. you and john frieh can go effin blow each other and trade notes on scripture, and in the mean-time, you are the first person in all my years here that i will put on "ignore". congratulations.

 

effin 4 years for tendons to begin to strengthen. fool.

[Kimmo]

So I say again. If ANY climber simply climbs as hard as they can all the time (follows the idea of the belgian power-lifters) they WILL destroy their tendons because the tendons can simply NOT handle the constant stress.

 

but before i ignore you completely, let me again tell you what a fool you are:

 

most climbers i started climbing with, myself included, simply went out and climbed as hard as we friggin could EVERY TIME WE CLIMBED. YO FOOL, DO YOU HEAR THIS? i didn't read any effin theory, or damn training books, or follow nutrition guidelines or gym jones nonsense or "periodization", or "tendon development theory". shit, we climbed cuz WE LOVED IT. EVERY FRIGGIN DAY UNTIL OUR FINGERS THREATENED TO FALL OFF. and i got decent at it, onsiting up to 12b back in the late '80's, after a couple of years of climbing. no great feat, but ok for the time. occasional injuries of course, happens with climbing, but all ok.

 

so please just stop with your nonsense. go back to your theory, go back to your v3 world, but just stop pretending you know it all, cuz you don't know poopydoop.

 

ok you are now on ignore.

[genepires]

prediction: Kimmo will be asking Layton for advice on a blown tendon in 6 months.

[Kimmo]

many boulder problems boil down to one single move that overshadows the others in difficulty.

 

Except that you are wrong again. Just because you crux out on one move in a route or problem does not mean that all climbing (as your language suggests) boils down to one move.

 

you see that "many" word up there? see it? i know it's kinda hard to figure out what words mean sometimes, but that one isn't cryptic, it's pretty straight-forward: "numerous" is a good synonym. and yes, once you get out and do a little climbing, you'll come across boulder problems which have their difficulty defined by one move. ONE move. yes, one, less than "numerous", but more than "none", which in this case is "one".

 

ok, back to "ignore" with ya.

[Kimmo]

prediction: Kimmo will be asking Layton for advice on a blown tendon in 6 months.

 

well heck. and all i wish for you is the best.

 

but i hope you aren't right. been pretty good about avoiding injuries, even though this last year is the first year in my life that i've really climbed and trained hard pretty close to full time: multiple days in a row, monos, campusing, one arms, intense stuff and quite a bit of it. i'd like to keep that going!

[rocky_joe]

Kimmo,

you are clinical. first of all, does it matter how hard I climb? Whether I (or anyone for that matter) climb 5.9 or 5.14 is irrelevant to the conversation. What I have done is explain why your theory is bunk and been straight up in telling you why you are wrong.

 

You really do love semantics, as we all have seen, however you are quite awful at playing the game. You continually fail to choose, out of a paragraph, the operative word and the complete idea.

example: in the last post you decided to reiterate your thoughts that because many (in fact most) boulder problems have one crux move that rock climbing must therefor be one repetitive motion that all climbers must learn. Apart from this being utter rubbish on it's own there is a logical fallacy within. If many (all or most) boulder problems are centered on one move; therefor making climbing about one move, then a v4 climber should be able to climb ALL v4s because they have mastered the "v4" move. I am not making this claim (I feel compelled to say this because you are the only one here who might think I am,) rather this is the direct line of logic throughout all your previous posts.

 

second, I never once claimed to be an expert, I merely attempted to add to the conversation (on the defense of periodization) by bringing up the FACT that tendon strengthening CAN take up to 4 YEARS. If you don't believe me feel free to look at any number of climbing specific training guides or better yet ask someone who would know (a physical therapist or practicing sports medicine doctor).

 

About you and your friends crushing as hard as you could all the time when you started...great. Glad it worked for you and that you didn't suffer a blown tendon. My experience has, however been quite different...my overtraining (too much intense bouldering) last winter left me with a broken finger. Needless to say, I have since read up on a lot of training methods for injury prevention and all the best lit out there suggests some form of periodization.

 

Finally, tendons are fragile, they are slow to strengthen and slower to heal. Periodization (theoretically) minimizes the chance of over-stressing tendons and thus reduces injuries.

[Kimmo]

Kimmo,

you are clinical. first of all, does it matter how hard I climb? Whether I (or anyone for that matter) climb 5.9 or 5.14 is irrelevant to the conversation. What I have done is explain why your theory is bunk and been straight up in telling you why you are wrong.

 

aw man, i can't just be ignorin' ya when you got so much to say and i'm so lonely!

 

but yeah, it matters how hard you climb, sure. would i go to some poor dude livin in the gutter for financial advice? well maybe actually, he might have some really good advice, come to think of it. so i guess it doesn't matter that much that you only climb 5.9, but it does matter that you act like you are such an expert, making claims about how EVERYONE will blow their tendons if they go hard all the time (false), and how tendons don't START to strengthen until 4 years down the road (false), and how i make claims that one move defines the difficulty of all boulder problems (false) etc etc etc. get the picture? probably not....

 

and as far as explaining how my "theory" is bunk, you might have "explained" it to yourself, but hell, i don't think you even know what my theory is. do you?

 

in the last post you decided to reiterate your thoughts that because many (in fact most) boulder problems have one crux move that rock climbing must therefor be one repetitive motion that all climbers must learn.

 

hmmm i think you're having that reading comprehension problem again, cuz you ain't making any sense. "because many (in fact most) boulder problems have one crux move that rock climbing must therefor be one repetitive motion that all climbers must learn."

 

you seem to make things up about what i'm saying, my friend.

 

tendon strengthening CAN take up to 4 YEARS.

 

what on earth are you talking about? Can take up to 4 years? and what, then it magically stops? and before the 4 years, no strengthening occured? dude, just start pasting your articles directly here, cuz something's getting lost in translation yo.

 

About you and your friends crushing as hard as you could all the time when you started...great. Glad it worked for you and that you didn't suffer a blown tendon. My experience has, however been quite different.

 

earlier you said it was impossible to climb hard all the time. hmmm. now it seems you think one can. hmmmmm. it's your use of absolutes that is so silly, rocky.

 

and one last thing (again): tendons are strong. way strong. think of what they do on a regular basis in your body. think, man.

[rocky_joe]

To this discussion, how hard either of us climb is irrelevant because we are not the ones who are creating new theories, rather we are arguing the merits of opposing training philosophies. I happen to think yours is wrong while you cannot seem to muster a single reason that periodization is not a) effective and b) better than your side of the argument.

 

I made up nothing about what you said, I simply read what you wrote and replied. In regard to the part of the conversation related to movement. You keep coming back to the point that many (hell, all) boulder problems have on definitive crux. I AGREE. But the fact that to send the problem requires a climber to learn that one specific movement and get it "dialed" in order to send is not equatable to the repetitive motion performed by weight lifters (again say a bench press specialist.) This is so, because once you have mastered the crux move of a boulder problem (especially one outside) it is typical to move on to another problem that will undoubtedly have an entirely different move for its crux (while some moves may be similar no two moves outside are exactly the same.) The difference (if you are having trouble inferring it) is that the bench presser will continue to bench press and build that one specific group of muscles and reinforce the muscle memory of the one specific movement, while the climber will learn a move and then continue on to the mastery of another move entirely. Like John said early in the thread, comparing weight lifting to climbing is like comparing apples to slugs.

 

Next, I never claimed that no climber ever could climb as hard as they want all the time and not get injured, again if you and your buddies did that, great, congrats, you beat the odds. But the real fact is that pulling too hard too often will, in all likelihood, result in a blown tendon. If you don't believe me check out the Dr. 8a section of 8a.nu and see for yourself how many tendon related over-use (read: too much hard climbing) injuries are suffered by climbers across the board and around the globe.

 

Finally, tendons are strong, but that does not make them fragile. Tendons take a lot of time (up to 4 years, conservatively) to increase in strength (after which they will continue, albeit slowly) to get stronger. But yes, it usually takes tendons that long to adapt to higher stress levels. This is seen in sports other that climbing (see: jumper's knee, runner's knee, tennis elbow, ACL/LCL/MCL tears.) All these happen in athletes because tendons are NOT strong enough to handle above normal stress levels despite the surrounding muscle having the capacity to handle it. Mike Anderson gives an even longer number for the time it takes for tendons to strenthen:

Furthermore, the supporting structure of the fingers (tendons and ligaments) take up to six years (not a typo) to respond to additional stress. That means, that if you have been climbing for six years, your ligaments may now just be starting to get stronger, whereas your forearm muscles respond in about two weeks.

 

please don't butcher this post to bad when you respond.

[Kimmo]

and one last thing (whew, hard work here):

 

if allayou haters check my first post, i said "if your body can handle it" and "experiment". Damn. it's not like i was saying to go out and start effin yourself up and ignoring your body.

 

 

[layton]

this isn't a very emotional subject, why the emotion?

can't we all just ... get along

[Kimmo]

 

Next, I never claimed that no climber ever could climb as hard as they want all the time and not get injured

 

So I say again. If ANY climber simply climbs as hard as they can all the time (follows the idea of the belgian power-lifters) they WILL destroy their tendons because the tendons can simply NOT handle the constant stress.

[rocky_joe]

i stand corrected. I should have written, in the first post, that the vast majority of climbers....

[Kimmo]

Tendons take a lot of time (up to 4 years, conservatively) to increase in strength (after which they will continue, albeit slowly) to get stronger.

 

Langberg et al.[17] have found that the human peritendinous Achilles tendon tissue reacts with a reduced collagen synthesis immediately after exercise, followed by a dramatic increase in subsequent days.[17] However, the changes occurring immediately after strength training observed in the present study cannot be explained by metabolic effects.

 

It is interesting to speculate over how the acute response to training involving increased tendon volume (and increased cross-sectional area) at exercise affects the biomechanics of the tendon. In terms of force transfer, a thick tendon may be advantageous, as there would be a decrease of the average force per area, thereby lessening the potential risk for injury. However, this may only be adequate if the water retaining capacity of the noncollagenous matrix contributes to the mechanical properties. Further, fluid may act as a lubricant at the endotenon, thereby reducing the intratendinous shear forces

 

[Kimmo]

Many researchers study the mechanical characteristics of mammalian tendons [3-8] and have yielded insight into the baseline elastic and viscoelastic properties in both animals and humans. Typical elastic tendon properties are characterized by Young's modulus and stiffness. Young's modulus is classically defined as the modulus of elasticity (E) of a material calculated by the rate of change of stress with strain and is an intrinsic property. Stiffness is the resistance of an elastic body to deformation by an applied force, typically defined by the ratio of change in tensile force with change in length of the material, thus an extrinsic property.

 

Repetitive mechanical loading can predispose tendons to injury with damage initiation occurring in the extracellular matrix [9-11]. The accumulation of micro-damage in tendons tends to degrade their mechanical properties, and may ultimately lead to failure. However, tendons can adapt to mechanical usage as evidenced by increases in stiffness and the Young's modulus after strength training or a combination of resistance and stretch training that were commensurate with muscle strength and size gains in humans [3,12] and in animals [10]. Also, tendon stiffness and ultimate strength have also increased in response to endurance training [6,13]. Viidik examined the response of rabbit tibialis anterior and Achilles tendon to 40 weeks of treadmill exposure and reported an increased stiffness of 10% in both tendons [13]. Nielsen et al. [14] also studied the effects of 18 months of treadmill training on rat limb muscle tendons and found that exercise had no effect on the biomechanical properties of the tibialis anterior tendon. Simonsen et al. [6] investigated whether tendon would respond differently to resistance or endurance training regimens in rats. Their results indicated that strength training did not result in increases in ultimate strength; however, swim-trained rats did have tendons with significantly higher ultimate strength than age-matched controls. The authors suggested that tendon may respond more favorably to the number of cycles of loading rather than the magnitude of loading [6]. This was supported by findings from Buchanan and Marsh where treadmill exposure for 8–12 weeks was found to increase tendon stiffness in the Achilles tendon of guinea fowl [10]. This result was reinforced in humans where long distance runners exhibited significant increases of approximately 20% in vastus lateralis stiffness compared to control subjects [15]. However, exposure to stretch training alone did not increase stiffness in human tendons [16].

 

As we age, it is not surprising that tendon properties such as stiffness and Young's modulus can change along with other physiological changes [7,17,18]. There is an increase in tendon strength up to a certain age, where tendon properties then start to degrade [19]. In fact, investigators found that the strength of 23 month-old rat tail tendons was higher than those from 5 month-old rats [19]. In another study, Nielsen and colleagues found that aging rendered the rat tibialis anterior tendons stiffer and reduced the strain to failure [14]. In contrast to the findings by Viidik et al. and Nielsen et al., Simonsen and colleagues found that aging reduced the ultimate failure force and yield point in rat Achilles tendon [6]. However, tendons in aging subjects have been shown to be highly responsive to training. Specifically, resistance training increases stiffness and Young's modulus [7,8,17,18,20], and decreases hysteresis [18] in older humans. These results in humans were supported by studies conducted in rats [21]. Also, Simonsen found that swim training counteracted the negative influence of aging on Achilles tendon strength [6]. In contrast, chronic running exercise did not benefit the musculo-tendon unit in aged runners [22].

 

Stretch-shortening cycle (SSC) exercise effectively introduces resistance exercise to skeletal muscle [23] via reciprocal concentric and eccentric muscle actions which are physiologically representative of natural muscle function used in common activities such as locomotion, and in athletic and occupational environments [24,25]. Additionally, SSCs also produce muscle injury due to the eccentric component of the loading cycles [26-30], which provides an improved physiologically relevant exposure model over the traditional eccentric-only injury model [24,31]. Recently, a chronic exposure (14 exposures) of repetitive SSCs was shown to produce skeletal muscle hypertrophy and significant muscle performance gains in young rats (12 weeks age) while inducing substantial performance deficits and a lack of muscle hypertrophy in old rats (30 months age) after 4.5 weeks of exposure [23]. This study showed that muscles from aging rats did not tolerate exposure to repetitive mechanical loading that is beneficial in their younger counterparts. Thus, it would be interesting to investigate whether tendon from aging rats also does not tolerate this repetitive loading protocol that resulted in muscle maladaptation.

 

To date, there is little known about the effects of resistance exercise and ageing on tendon mechanical properties. The resistance training paradigms studied in humans [7] and animals [21] thus far have resulted in improvements in both muscle and tendon; however, the biomechanical loading was not controlled or recorded during the exposures. In addition, the results from previous studies are not equivocal. Thus, it is important to study tendon response to a chronic exposure of repetitive maximal SSCs, shown to produce muscle maladaptation in aged animals, where the biomechanical loading signature is controlled, and muscle response is recorded in real-time. The purpose of this study is to determine if aging affects the ability of tendon to respond to repetitive high-force mechanical exposures. This inquiry will help determine if tendon adaptation is coupled with skeletal muscle response. We hypothesize that tendons from old rats not exposed to repetitive loading will have lower stiffness, Young's modulus, and total strain at failure than their younger counterparts. In addition, we hypothesize that exposure to repetitive mechanical loading will increase the stiffness, Young's modulus, and strain at failure in both old and young tendons.

 

[rocky_joe]

acute increases in tendon size have not conclusively been shown to yield significant effects on strength and ability to cope with additional stress over the short run (ie less than a year.)

 

http://www.engin.umich.edu/class/bme456/ligten/ligten.htm

[rocky_joe]

the article you posted does not conclusively support short term tendon strengthening.

[Kimmo]

Expression of collagen and related growth factors in rat tendon and skeletal muscle in response to specific contraction types

K. M. Heinemeier1, J. L. Olesen1, F. Haddad2, H. Langberg1, M. Kjaer1, K. M. Baldwin2 and P. Schjerling3,4

+ Author Affiliations

 

1Institute of Sports Medicine, Bispebjerg Hospital, Copenhagen, Denmark2Department of Physiology and Biophysics, University of California, Irvine, CA, USA3Department of Molecular Muscle Biology, Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark4Department of Biomedical Sciences, University of Copenhagen, Denmark

Corresponding author K. M. Heinemeier: Institute of Sports Medicine, Bispebjerg Hospital – Building 8, 1st floor, 23 Bispebjerg Bakke, DK-2400 Copenhagen NV, Denmark. Email: katjaheinemeier@hotmail.com

Abstract

Acute exercise induces collagen synthesis in both tendon and muscle, indicating an adaptive response in the connective tissue of the muscle–tendon unit. However, the mechanisms of this adaptation, potentially involving collagen-inducing growth factors (such as transforming growth factor-β-1 (TGF-β-1)), as well as enzymes related to collagen processing, are not clear. Furthermore, possible differential effects of specific contraction types on collagen regulation have not been investigated. Female Sprague–Dawley rats were subjected to 4 days of concentric, eccentric or isometric training (n = 7–9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve. RNA was extracted from medial gastrocnemius and Achilles tendon tissue 24 h after the last training bout, and mRNA levels for collagens I and III, TGF-β-1, connective tissue growth factor (CTGF), lysyl oxidase (LOX), metalloproteinases (MMP-2 and -9) and their inhibitors (TIMP-1 and 2) were measured by Northern blotting and/or real-time PCR. In tendon, expression of TGF-β-1 and collagens I and III (but not CTGF) increased in response to all types of training. Similarly, enzymes/factors involved in collagen processing were induced in tendon, especially LOX (up to 37-fold), which could indicate a loading-induced increase in cross-linking of tendon collagen. In skeletal muscle, a similar regulation of gene expression was observed, but in contrast to the tendon response, the effect of eccentric training was significantly greater than the effect of concentric training on the expression of several transcripts. In conclusion, the study supports an involvement of TGF-β-1 in loading-induced collagen synthesis in the muscle–tendon unit and importantly, it indicates that muscle tissue is more sensitive than tendon to the specific mechanical stimulus.