I have read several articles all saying that after training, (around 4 weeks onwards) most IIb fibres, will convert to the slower type IIa.
and after several weeks (the study i read, 3months) rest after the training, fibre IIa converts to IIb. and us as sprinters cannot do this as we would prob lose more than any gain from fibre conversion. but there must be away, and i think i am looking in the wrong place for the answers.
any ideas guys??
Anything extremely fast or with heavy weight where the muscle must contract maximally. Usually long rest periods between reps.
Rest could simply involve(among other elements trained) strength maintenance with a reduction in both intensity and volume while changing the loads among such things as the vol. and int. in the actual sprinting, plyos, etc . In other words, rest does not necessarily mean a cessation of training but rather adjusting of certain variables i.e. strength maintenance. CF has pointed out in the past that such a program will actually produce the most optimal time or opportunity for peaking(probably with the wanted fiber conversion) and will take place many weeks after beginning such an adjustment to the training load.
However, this can be a bit tricky because there will be a point where the loss of fitness and work capacity will surpass the increased freshness/rebound that a taper-along with the IIb conversion will bring about.
The main point, I guess, is that rest does not necessarily mean stopping training but rather adjusting the load of the respective qualities. In this study, I suppose, they used total rest from the previous program but in CF’s system(nor most others I’m aware of) it’s simply a case of adjusting/altering the load.
I think you have both hit the nail on the head. Maybe a marginal fiber conversion over the 10 day taper is all that is needed. In other words a 1-3% conversion to type IIb due to high intensity long recovery and decreased loading, as experienced in a taper is all that is need. A small amount of conversion may gear up to a large change in an athletes preparedness. Also the hormonal profile is likely to be more anabolic and less catabolic, with adrenal output of adrenaline improving, and cortisol decreasing, leading to maybe more testosterone available as a stimulant along with norepinephrine and epinephrine. Remember that high intensity runs lead to an increase of adreanl hormone production and the release of endorphines, these I speculate may also aid fiber conversion even if small in magnitude may gear up to big improvements in performance… if the taper is skillfully employed.
Dafydd, what articles are you referring to?
http://www.pponline.co.uk/encyc/0625.htm
here is what we need to know from the link above…
Training effects on fibre type
Virtually all the available evidence suggests that the answer to the last question is no. In fact, it has been suggested that type IIb MHC and therefore IIb fibres constitute a ‘default’ fibre type setting in humans when activity is absent, and evidence of high proportions of this fibre type in paralysed muscle support this theory(5). It has also been known for some time that increases in activities like strength or power training can lead to conversion of muscle fibres. But, unfortunately, this conversion operates in one direction only, changing fast type IIb fibres into slower type IIa fibres(6). Moreover, if heavy loading of muscles continues for a month or more, virtually all type IIb fibres will transform to type IIa, with obvious consequences for sprinting potential(7).
What happens when heavy strength training stops? Do the newly formed type IIa fibres revert back to type IIb? The answer is yes, but recent research has revealed some extraordinary results to which a simple yes does not do justice. Scientists from the Copenhagen Muscle Research Centre examined training and detraining effects on muscle fibre type distribution(8). Biopsies (muscle samples) were taken from the vastus lateralis muscle of nine young sedentary males. All the subjects then undertook three months of heavy resistance training, aimed predominantly at the quadriceps muscle group, which ended with a second muscle biopsy. The subjects then abruptly ceased training and returned to their normal sedentary lifestyles before providing a third biopsy three months later.
Biopsies from the vastus lateralis were analysed for muscle fibre type distribution and number. As was expected, there was a decrease in the proportion of fast twitch IIb fibres (from around 9% to 2%) during the resistance training period. The researchers expected that the proportion of IIb fibres would simply be restored to pretraining values during the detraining period. However, they found to their surprise that the proportion actually doubled to around 18% after three months of sedentary living!
How heavy training followed by tapering produces ‘overshoot’
So it seems that a pattern of heavy resistance training followed by decreased activity causes first a decrease then an overshoot in the proportion of the fastest fibre type in the trained/detrained muscle group. An explanation for this overshoot currently eludes researchers, but the findings accord with the theory that muscle fibres ‘default’ to type IIb with a (relatively) decreased level of activity(5).
Further research using trained athletes as subjects would add weight to these findings. But until then, sprinters may draw the following conclusions: a large increase in training volume for approximately three months will decrease the proportion of IIb fibres in the trained muscles; a subsequent reduction (not cessation) in training volume relative to the heavy resistance training phase should not only reverse this decrease but lead to a significant overshoot in the proportion of IIb fibres. In consequence, the potential for the rapid and forceful muscle contractions so crucial to sprint performance should be enhanced.
This conclusion is in line with the current training practices of many sprint athletes: a heavy resistance training phase followed by a taper in training volume and intensity in the lead up to the competitive season(9). And on the evidence of the Copenhagen research, others would be advised to follow their example, with three months of heavy resistance training followed by three months of relative detraining, with relatively reduced training volume in the run up to key targeted events.
However, as is usually the case, new research findings will probably refine these recommenda-tions over the coming years.
Alun Williams and Mick Wilkinson
this link is great; (http://www.bodybuilding.com/fun/kelly13.htm)
i just realised something too! for all those ppl trying to lose weight:
"Fast to slow (IIB to IIA) transformations are also seen in hypothyroidism which is characteristic of the body being in a starved state. When in a food shortage the main thing the body wants is “survival.” Thus, the body sacrifices display of FT IIB fibers and adaptations related to the display of fight or flight are done away with because they would use up too much energy.
This also partially explains why those who think they can shed a metric crapload of bodyfat in an effort to better display power are often met with less then satisfactory results. They may lose the weight yet, depending on the amount of weight they lose and how lean they get, they will eventually begin to lose speed-strength and strength-speed proficiency."
and this is what happened to Patrick Johnson, i think he ran 10.43 last year at a major meet in australia and he confirmed that he was trying to lose body fat, but prob doing it the wrong way!
If you are doing tempo and eating correctly you should be fairly lean anyway.
yes true. I wish i could do tempo and relax for a week without gaining more then 2% bodyfat.
yes definately but im sure there are the minorities. anyway…fibre conversion…
Checkout
BAUMANN. H. ET.AL. (1987):
Exercise training induces transitions of myosin isoform
suhiunits within histochemically typed human skeletal
muscle fibres. In: Pflügers Archiv 4(W. pp. ,l.jy-3W)
I see that you are on a path of discovery with fiber transformations and so on. Remember that alot of this already occurs without us being aware. To do justice to this subject are you need to read practical and definitive information that relates directly to athletic performance. Without a doubt the work of Tidow et al ( I am forever quoting him lol) is a must read. Check out the article below it can be downloaded from the highly respected NSA journal archive.
Muscular adaptations induced by
training and de-training *
http://194.213.2.7/wps/portal/iaaf
Goto above link click high resolution option. Type 1995 into search engine of site. Then scroll through to find the article. DO NOT try to open the article. Select it by ticking the relevant box then goto the actions drop down menu choose email, and email to yourself or an address that has a large capacity for attachments.
Some more modern results that in part conflict with Tidow’s conclusions (particularly that regarding hypertrophy).
From Bottinelli (Journal of Physiology (1996), 495.2, pp.573-586), these are measured rates of shortening (Vmax)for skinned human muscle fibers:
Fiber_Type Max_Shortening_Velocity(length/sec)
I 0.317
I-IIa 0.638
IIa 0.718
IIx 0.936
IIb 1.286
The difference in velocity between IIb and IIa is almost as great as between I and IIa. So, merely a 1-2% transition toward IIb is not what one wants to shoot for–you want more than that.
Lars Andersen, et.al,“Changes in the human muscle force-velocity relationship in response to
resistance training and subsequent detraining.”
http://jap.physiology.org/cgi/content/full/99/1/87
The Andersen paper is a following study to the the one showing IIx overshoot, but this one gives force-velocity and power velocity curves. What’s interesting is that for velocities of 400 degrees/sec and greater (what you would find in high-end sprinting), the actual force and power produced in the DETRAINED state is actually greater than in the weight trained state. Given that track sprinting itself has been shown to favor a transformation toward faster fibers, this raises some serious questions about squats/DLs following a max strength or concentrated loading phase.
D’Antona et.al.,“Skeletal muscle hypertrophy and structure and function
of skeletal muscle fibres in male body builders,”(J. Physiol. 2006;570;611-627)
Along with some studies of sprinters shifting the fibers toward fast, D’Antona contradicts some of Tidow’s (and others) conclusions about hypertrophy/neural training and fiber conversions. Several studies on hypertrophy showing a conversion from IIb->IIa, including Staron (several) and Campos (2002), have used heavy-weight hypertrophy methods (80% 1RM and greater), while D’Antona used experienced bodybuilders with lighter weights (60-80%, but LESS than 80%), and D’Antona shows greater IIx proportion than active controls and in fact slightly greater–during training–than the IIx overshoot (during detraining) in Aagard’s studies.
There seem to be several differences in D’Antona’s subjects/methods showing a transition TOWARD IIx fiber in competitive bodybuilders:
(1) Experienced. committed bodybuilders may have genetic advantages for the training done, as would good-elite sprinters showing a tendency toward faster fibers in other studies;
(2) Training age. The bodybuilders in D’Antona’s study were training for >2 years, compared to the 6-12 weeks in typical physiological studies.
(3) Weight loads, of 60-60%, compared to higher loads in many studies that show a conversion toward slow. Russian competitive PL methods also seem to use intensities of not more than 80% in the initial stages–and the 80% includes the shock phase in the article that I have.
As Tidow pointed out, IIb/IIx fibers are very susceptible to overloading. Avoiding conversion seems to require either short contractions with long rest (if the load is high enough to cause conversion otherwise), or in D’Antona’s case, more moderate loads which allow higher contraction velocities without causing conversion. See also the Maurice Green article in the August issue of Muscle and Fitness, where Mo talks about using conventional bobybuilding methods–if these methods didn’t work for higher speeds, why are some many top sprinters using them?
brilliant you guys are champs!
the human body tends to adapt to the form that is most needed. so if you are training properly for your event then you shouldnt need to worry about fiber conversion as it will take on the properites needed for the given task. so if you are training with loads and rep schemes which are best suited to your event then the transformation will be what it should, type 2b dominate or type 2a. that being said my experience and evidence gathered from various texts is that if ur training under condtions that require the recruitment and power output that only ft fibers can deliver and you will adapt postivily towards a greater number of ft fibers. i have no biopsy studies to prove this but as the genetic phenotype of any give muscle fiber allows for great plasticity dependent on mechancial loading. basically train explosivly requiring powerful maximal muscular contractions and fiber conversion will turn in your favor.
Read carefully Tidow is not in conflict I speculated that only a small percentage switch maybe enough for an advantage over the competition the 1-2% overshoot suggestion is MY own conclusions not Tidow’s necessarily; have you actually downloaded the study yourself or are you taking my word and interpretations as given? I suggest you download and read from start to finish you will be suprised that there is no contradictions as you have intimated. Isokinetic measurements are DIFFERENT from explosive ballistic muscle actions. So the two studies differ in that respect. In a ballistic muscle action, the rate coding principle occures. Isokinetic depending on the speed allowed will dampen the recruitment of the fastest fibres.
Tidow in his own studies has actually demonstrated that bodybuilding training LEADS to an improvement of sprint speed. Do a search for my posts you will find a link to Tidow and Wiemann’s extensive research on the effects of bodybuilding, NAM and speed strength resistance training respectively was in FAVOUR of bodybuilding.
Have you actually read and understood the Tidow study, the more i read your response the more I realise that you have not. The Staron study is referenced by Tidow and those findings discussed extensively.
You are confusing the discussion here. In fact ALL the authors you have mentioned including Tidow are in agreement that type IIa is the outcome of type IIb conversion due to strength training.
Tidow goes on to recommend THREE different methods of deloading that could be utilised. Anti gravity, taking the load off the legs through bed rest. Reduced volume and longer rest intervals between training sessions to cause re-transformation to type IIB.
Regardless of percentage loads, both max strength and sub-max cause fiber conversion to the left. So whether it is 60% or 80% or 100% type IIb to type IIA conversion occurs as Tidow pointed out (had you read the article you would not have made such a statement), type IIb are specialised muscle used for ballistic actions and are only called upon when for instance you trip over.
Merely having higher contraction rates with moderate resistance doesn’t guarantee prevention of left transformation or promotion of right transformation. Had you read the Tidow study you would realise that using moderate weights 40-60% explosively, can be considered a from of speed-strength endurance if not managed properly and the fact that such training LEADS to hypertrophy suggests that left transformation occured.
That is why they convert when called upon by strength training because that muscle action is USUALLY tonic in nature.
Please read articles before making such conclusions that are not true and actually may ruin progress in a discussion…
There are no contradictions in the studies, all agree that hypertrophy causes left transformations, de-loading using one of three methods identified by Tidow causes re-transformations. Loads of differing intensities cause left transformations BUT resistance training with intra set pauses actually PREVENTS or aids re-transformation to the right. Had you downloaded the article as I suggested and read it and not just the abstracts or my speculations which you assumed to be Tidow’s you would not have made such conclusions. I still stand by my suggestion that 1-2% marginal transformations to the right maybe enough… and that is NOT Tidow’s suggestions or conclusions had you actually read the article you would know that.
Extracts from the Tidow study:HYPERTROPHY TRAINING
1.2 Hypertrophy truinin)> and Ihe fibre
spectrum
When using hypertrophy methods (‘HM’)
the possibility of achieving a seleelive
increase of the areas of type II fibres
(RoKHZKi el al. 1991) or even an increase of
tbe proportions of lype II fibres (ZEMAN et
al. 19K8) Ihrough Ihc administration of anabolic
steroids or beia|-reeepIor ag<misis must
be ruled out because of doping controls.
Gains in eoniraciile poieniial. which are
achieved in fast muscles in a physiological
way - and which can be measured very precisely
by means of nuclear magnetic resonance
imaging (NARICI et al. 1988} - are
accompanied by a iransformalion of Ihe fibre
speclrum to Ihe lefi.
The arrows in Figure 2
show thai this means a
decrease of the proportion
of type lib fibres to Ihe
advantage of Ihe neighbouring
fibre fractions: After a
13 lo 20 week hypertrophy
training of Ihe vasius laieralis
muscle, STARON el al.
(1991) could delect hardly
anv ivpe Mb fibres. The
dynamics of Iransformation
to the lefl was 5 to 7% per
week. Similar findings were
made by KLITGAARD el al.
(1990) in ihe biceps brachii
muscle.
1.3 Neuronal activation training
i’NAM’) and the fibre spectrum
Thc method of maximum slrength efforts
against high and maximum (a '•){)%) resistances
CNAM") is usually applied after hypertrophy
Iraining (‘MM’) in order lo reduce
slrenglh deficits. The model in Figure 3 shows
ihal in 'mixed" skeletal muscles ihis is only
possible by increased “rale coding”, because
Ihc recruiiing limii of these muscles is normally
around 8(1% of maximum slrength.
This means thai only in Ihe case of resistances
higher than S()% is ihe voluntary central-
efferent excitation so high that in each
attempt longer lasting ma.Ktmal activations of
higher-ranking moior neurones are enforced.
Thus NAM demands loads which are higher
than 90%. If one performs squais at 100% of
maximal strengih. there are tension limes of 3
to 6sec per allempi (HÄKKINEN 1993). In spite
of maximal activation or calcium release, ihe
rale of cross bridge cycles/sec is very much
reduced. CAIOZZO et al. (1992) examined the
influence of high k)ads on the fibre speclrum
of fast animal muscles. Even 4 sels of 10 repetitions
againsi resisiances of 90 (concenlric
As hypertrophy Iraining is
characterized by only a slow
cross bridge cycling because
of resistance and aclivalion.
the inirinsic coniraclion velocitv
of ihe fibres is also reduced
(Ei)MAN 1979), These
effecis of coniractiliiy reduction,
which are a conci)milani
to hypertrophy, can only
partly be compensated for
by a higher strength maximum.
Consequenlly. HM
leads to a reduction of speed
strength.
TIDOW ON 40-60% moderate weights training:
1.4 Orthodox speed-strength truining
and the fibre spectrum
The invesiigalions by St HMIDIBLEICHER &
BüHRLE (1987) in parlicular show ihat the
effect of maximal dynamic slrenglh efforls
against low or medium resisiances - 30 to
45% of maximal slrenglh with 8 to 10 repetitions
per set - performed according to the
speed-strenglh method does not correspond
wilh the training goal. Allhough a signifleanl
increase of maximal strengih as well as of the
total cross-section could be verified, there
was no change of the explosive slrenglh parameters.
Although here no muscle specimens
were taken. Ihe mere hyperirophv of lhc
muscles trained by means of hench-press
exercises is evidence of a fibre transformation
to the left. It may be assumed that Ihe cause
of this was the energetic “overtaxing” of the
fast triceps brachii muscle, which has a high
proportion of type tib motor units (JOHNSON
et al. 1973). b>’ the rhythmic-serial exercise.
The study by CAIOZ/O el al. (1992) mentioned
above shows thai fasl muscles •reaci"
to deficits in energy balance caused by
(slrength) loads primarily by a transformation
of their originally high proportion of
type lib fibres. Only the prolonged duration
of the exercise (from 2 sec to 4 sec) - the
stress being otherwise absolutely identical -
led Io a hypertrophy only in second plaee.
TIDOW ON DELOADING:
1.6 Ueluading and the fibre spectrum
There is a considerable range of "deloading
methods’. These meihods include, for example,
rcduced training, complele rests from
iraining of different durations, immobilisation,
reduction or even elimination of gravitation.
When STARON ei al. (1991) re-examined
the hyperlrophy-lrained sample meniioned
above after an 8 month “deiraining”. ihey
found an almosl complete rel runsformufion
to the original fibre speclrum. Contrary to ihis.
a greal extent of the training-induced hvper-
Irophy remained. Presumably this finding is
due lo the everyday anii-gravilalion function
of ihe analvsed vastus lateralis muscle.
Research findings by HATHER et al. (1991)
corroborate ihis rest-induced relransformation.
More accenlualed meihods of deloading
I am opposed to the whole idea of training fiber types. Your CNS has ultimate control of contraction speeds and those speeds have been proven to be independent of fiber type as long as the proper neuron is in control.
The saying, “Train movements not muscles” comes to mind. Really it should say, “Train neurons, not fibers.”
My philosophy is that the human body is always capable of more. As speed athletes we are training mostly for the reduction of inhibition which has major psychological and neuro-physiological roots.
Learn about how physiological adaptations happen from your training, but make the major focus on your goal. To run fast!
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How does the conversion or make up of fiber types effect the (energy) cost of running?
I know thats shown to be the case when a neuron is “artificially” attached to a certain fiber type outside of the body but has this been shown to actually occur as a result of training? Can you point me to any literature?
Thanks
Good question. This is something I was wondering about recently. I would have thought that fast twitch fibers would have a greater RFD and therefore allow for more energy to go to the tendons during GCT which would allow for more “free” force. However, as Mort said in your log, slow twitch have better isometric force sustaining abilities (or whatever the actually wording was) and Frans Bosch says that they actually allow for better loading of the tendons. Anyway, I’m interested to hear what others have to say.