Have you seen studies done by Gunter Tidow et al. These are done on shot putters ans sprinters and after a prolonged and protracted hypertrophy phase type IIA take on the characteristics of slow faster type I muscle leading to performance decrement or stagnation in speed and strength. Hence my very statement that strength training causes transformations to the left of fast to slow. There is a type Ia variant I can refer you to the work of gunter tidow. Search on sports discus for his research and the Frieburg institute os sports research to see where I got my information from.
High volume short recovery strength training akin to hypertrophy will lead to a total sum of work that is akin to endurance strength. Muscles fall into an energetic emergency leading to a reliance on lactic oxidative pathways. If the muscle is damaged enough from the strength training then the MHC and LC become the slow type. So its not the fact that an exercise is anaerobic in nature but rather the after effects of the training on muscle. I may add that hypertrophy will more than likely lead to hormonal changes that may not be conducive to the promotion of the faster MHC. If cortisol ramps up and hypoinsulinism occurs then muscle myopathy can lead to the expression of slow fiber MHC. the hypo state can be prevented by simply ingesting a high carb protein drink after exercise.
The benefits of strength training out weigh its negatives by far as we already know. The fiber conversion can be checked by due diligence afforded to nutrition and regen.
You reap the gains from strength training during periods of lowered volume and tapering in particular.
There are type IC IB, I. Type IC contains S+Fa MH chains similar to type IIc.
A: You can sum up this entire debate by saying that stupid training will yield bad results and only smart training will yield good ones.
B: As near as I can figure, the arguement for non-plasticity is used to justify continuing outmoded training, as if there is a built-in protection mechanism to save you from yourself!
C: There isn’t! Back to point A.
according 2 baechle and earle, transformation within the muscle fiber subtypes appears typical, transformation from type I 2 type II or visa versa is doutfull and no recent evidence using modern techniques has been seen.
the chain of transformation goes something like this: physical activity= IIb to IIab to IIa to IIac to IIc. there is no proof that IIc converts 2 either of the 2 st muscle fibers I OR Ic.
The process exists and if thyroid hormone production drops then fast will take on slow characteristics. Chronic electrical stimulation of fast fiber causes fast to slow conversion for example.
There was a lot of work done with MS and CP patients showing conversion to ST fibre through the use of Low intensity/long duration EMS- 2sec on / 2 sec off at 20htz for up to 8 hrs at a time. One of the researchers was a lady named Vrebova.
Abernethy, P.J., Thayer, R. and Taylor, A.W. Acute and chronic responses of skeletal muscle to endurance and sprint exercise: a review. Sports Medicine. 10: 365-389, 1990
This study shows a decrease in type I fiber and an increase in type II fiber. If they decreased then where did they go? obviously they converted to fast fiber. There is no theory or genetic stop that would prevent this even if you seem to think so muscle IS plastic.
Boobis, L., Williams, C. and Wooton, S.A. Influence of sprint training on muscle metabolism during brief maximal exercise in man. J Physiol. 342:36P-37P, 1983.
Bouchard, C., Taylor, A.W., Simoneau, J.-A. and Dulac, S. Testing anaerobic power. In MacDougall, J.D., Wenger, H.A. and Green, H.J. (eds) Physiological Testing of the High Performance Athlete. Human Kinetics: Champaign, Il. 1991, 175-217.
Cheetham, M.E., Boobis, L.H., Brooks, S. and Williams, C. Human muscle metabolism during sprint running. J Appl Physiol. 61:54-60, 1986.
Green, H.J. Myofibrillar composition and mechanical function in mammalian skeletal muscle. Sport Sciences Reviews. 1:43-64, 1992.
Jansson, E., Esbjönsson, M., Holm, I. and Jacobs, I. Increase in the proportion of fast-twitch muscle fibers by sprint training in males. Acta Physiol Scand. 140:359-363, 1990.
START SUCKING YOUR THUMB AND STOP READING OLD RESEARCH ON FAST FIBER COMPOSITION FROM THE 1960s.
Abernethy, P.J., Thayer, R. and Taylor, A.W. Acute and chronic responses of skeletal muscle to endurance and sprint exercise: a review. Sports Medicine. 10: 365-389, 1990
This study shows a decrease in type I fiber and an increase in type II fiber after training at or above V02 max. If they decreased then where did they go? Obviously they converted to faster fiber. There is no theory or genetic stop that would prevent this even if you seem to think so, muscle IS plastic. Old methods of determining muscle fiber type are misleading. Thyroid concentration, testosterone and adrenal hormones and andrenergic hormones can change the percentage of fast fiber not just cause intra-transformation but full inter transformations where the percentage of slow fiber decreases.
Boobis, L., Williams, C. and Wooton, S.A. Influence of sprint training on muscle metabolism during brief maximal exercise in man. J Physiol. 342:36P-37P, 1983.
Bouchard, C., Taylor, A.W., Simoneau, J.-A. and Dulac, S. Testing anaerobic power. In MacDougall, J.D., Wenger, H.A. and Green, H.J. (eds) Physiological Testing of the High Performance Athlete. Human Kinetics: Champaign, Il. 1991, 175-217.
Cheetham, M.E., Boobis, L.H., Brooks, S. and Williams, C. Human muscle metabolism during sprint running. J Appl Physiol. 61:54-60, 1986.
Green, H.J. Myofibrillar composition and mechanical function in mammalian skeletal muscle. Sport Sciences Reviews. 1:43-64, 1992.
Jansson, E., Esbjönsson, M., Holm, I. and Jacobs, I. Increase in the proportion of fast-twitch muscle fibers by sprint training in males. Acta Physiol Scand. 140:359-363, 1990.
Morphological changes during fiber type transitions in low-frequency-stimulated rat fast-twitch muscle
Journal Cell and Tissue Research
Publisher Springer Berlin / Heidelberg
ISSN 0302-766X (Print)
Subject Biomedical and Life Sciences and Medicine
Issue Volume 277, Number 2 / August, 1994
DOI 10.1007/BF00327784
Pages 363-371
START SUCKING YOUR THUMB
Low intensity will not necessarily cause fiber conversion but chronic will, according to rat models and the inference and transfer to the human model can be made.
the study that u quoted proves the oppisite of what u claim where is the proof of what u claim.
actually the reference i use was from 2000, human kinetics. so it looks like ur book is atleast 10yrs out dated compared 2 mine. i’m 2 old 2 suck my thumb so i will rather keep ahead of the times with the latest studies
does that mean u r saying cf is wrong with regard 2 his low intensity statement?
Sigh… we could go on and on and on exchanging and trading references and I could provide you with a slew of studies from 2003 onwards that catergorically blow away your position on this debate and your singular research reference out of the water…but I am not going to bother. The fact is muscle is plastic and can change inbetween fiber and between fiber types, its affected by hormones and activity and lack of. There are some muscles like the levators of the eyelid (the muscles responsible for the phrase “in the blink of an eyelid”) that will not change in their composition but the majority of muscle fiber can be affected by hormones and activity that can change not just the size but percentage.
Regulation of Muscle Fiber Type and Running Endurance by PPARδ
Yong-Xu Wang,1 Chun-Li Zhang,1 Ruth T Yu,1 Helen K Cho,1 Michael C Nelson,1,2 Corinne R Bayuga-Ocampo,1 Jungyeob Ham,3 Heonjoong Kang,3 and Ronald M Evans1,2
1Gene Expression Laboratory, Salk Institute, La Jolla, California, United States of America, 2Howard Hughes Medical Institute, La Jolla, California, United States of America, 3Marine Biotechnology Laboratory, School of Earth and Environmental Sciences, Seoul National University, Seoul, Korea
Received March 22, 2004; Accepted July 6, 2004.
"Adult skeletal muscle shows plasticity and can undergo conversion between different fiber types in response to exercise training or modulation of motoneuron activity (Booth and Thomason 1991, Jarvis et al. 1996; Pette 1998; Olson and Williams 2000; Hood 2001). This conversion of muscle fiber from type IIb to type IIa and type I is likely to be mediated by a calcium signaling pathway that involves calcineurin, calmodulin-dependent kinase, and the transcriptional cofactor Peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1) (Naya et al. 2000; Olson and Williams 2000; Lin et al. 2002; Wu et al. 2002). Muscle fiber specification appears to be associated with obesity and diabetes. For instance, rodents that gain the most weight on high-fat diets possess fewer type I fibers (Abou et al. 1992). In obese patients, skeletal muscle has been observed to have reduced oxidative capacity, increased glycolytic capacity, and a decreased percentage of type I fibers (Hickey et al. 1995; Tanner et al. 2002). Similar observations have been made in type 2 diabetic patients (Lillioja et al. 1987; Hickey et al. 1995). Recently, it has been shown that increasing oxidative fibers can lead to improved insulin action and reduced adipocyte size (Luquet et al. 2003; Ryder et al. 2003).
We have previously established that peroxisome proliferator-activated receptor (PPAR) δ is a major transcriptional regulator of fat burning in adipose tissue through activation of enzymes associated with long-chain fatty-acid β-oxidation (Wang et al. 2003). Although PPARδ is the predominant PPAR isoform present in skeletal muscle, its in vivo function has not been determined. Our current study uncovers PPARδ as the first transcription factor able to drive the formation of functional type I muscle fibers, whose activation entrains complex pathways both enhancing physical performance and creating a state of obesity resistance.
"
I am done saying what I got to say. The evidence is there go search for it yourself I have nothing to add…
The overwhelming evidence is in favour of plasticity through intra and inter transformations.
remember that this discustion started with u saying that resistance training causes a st adaption, i am intrested with ur reference 2 this claim.
i know that the muscles r plastic bt even plastic has it’s limitations. according 2 highly reliable sources the above mentioned convertion does not occur.
i beg u pls, prove that these sources r wrong. because it just does’nt make sense y resistance training which helps 2 build strength will have an endurance adaption.
The concept was to give them endurance throughout their day particularly in support structures that seemed to be effected the most, as being laid up causes a conversion to FT.
They did benefit, both through increased motor abilities and through growth in the case of CP childern, often moving from the 20th to the 50th percentile in about a year, indicating that growth hormone is stimulated (or normalized perhaps??)
Strength training (bodybuilding methods) cause fast to slow conversion over a protacted period of time. In bodybuilders it is common to find NO type IIB and an INCREASE in slow fiber. Max strength causes fast to slow but the changes are not so marked. The point is, these effects are reversible and an overshoot is likely to occur with rest and taper. Fast eccentric work such as plyometrics and sprinting promotes fast twitch with a slow to fast conversion occuring.
The benefits outweigh the disappointing fact that strength training decreases twitch speeds and duty cycles when you remember that a decrease in the volume of training, rest and an increase in speed intensity causes slow to fast.
