If your muscles could be some type of vehicle, which would you rather be? Top Fuel Dragsters, Toyota Prius or mopeds?



Each of these vehicles has their assets and liabilities. The dragster, while fast, is not made to travel long distances. The Toyota Prius is somewhat fast and definitely more energy efficient but nowhere near as economical as the moped. These three vehicles and their properties can be compared to the three types of human skeletal muscles.

Analogy to Muscles

The human body is made up of three types of skeletal muscle fibers, Type IIb fast twitch, Type IIa fast twitch endurance and Type I slow twitch.

Type IIb Fast Twitch Muscles

Type IIb fibers are called fast twitch glycolytic and are the dragsters of the muscles. They create energy anaerobically and are capable of super high speed, high force production. Their only drawback is that they have little resistance to fatigue.  Many sports that require moments of explosive effort or bursts of speed with some rest in between are perfect for these muscles. Baseball, football, soccer, volleyball, tennis, golf, basketball all require these moments of pure explosive energy that comes from these muscles.
 
Type IIa Fast Twitch Muscles

Type IIa fibers are called intermediate fast twitch fibers or fast twitch oxidative fibers. They are the Toyota Prius of muscle fibers. They can use the anaerobic or aerobic system to create energy (just as the Prius can use battery or gas power). It is fast but not as fast as the dragster but can go longer distances before needing rest. Type IIa fibers are moderately fatigue resistant, have moderate firing rates and have a medium high force production. Events like the 200m dash and many events that combine pure explosive speed and endurance like soccer, tennis, football, basketball are well suited for these fibers.

Type I Slow Twitch Muscle

Type I muscles are called "slow twitch oxidative." They are the mopeds. Characterized by being fatigue resistant, having slow firing rates and low force generation. As you can imagine, athletes with a high amount of these slow twitch fibers will be better at endurance sports like running marathons or triathlons.

Which type of muscle (vehicle) is the best to have?
The correct answer is... ... ... ... actually, you cannot know until you decide first what sport you want to focus on. If you were playing an explosive sport, you would want dragsters. If you are playing a speed endurance sport, then you'd better have Prius. And if you want to run marathons or do triathlons, then you should have mopeds.

But hold on, it isn't quite that simple. Once we add in the effects of training, interesting "things" can happen to your muscles.

Muscle Plasticity
Muscle plasticity can be broadly defined as how your body adapts to your environment. And more specifically, in our case, the "environment" refers to any training or exercise program. Advances in modern medical research and procedures have allowed scientists to bring to light new information regarding plasticity. Muscle biopsies are now being performed to obtain muscle tissue, which is then subjected to gel electrophoresis and ATPase histochemical analyses.

Using these new techniques, researchers have discovered that the skeletal muscle possesses tremendous plasticity in that it adapts structurally (in muscle fibers and associated structures like capillaries) and functionally (contractile properties, metabolic pathways and regulatory mechanisms) to endurance exercises (contractile activity) and resistance training (loading conditions). Gene expression profiling analysis has demonstrated that adaptations are also occurring in skeletal muscle at the genetic level.

In essence, this means that the muscle adaptations to physical training go down deep into the chemical, molecular, nuclear, and genetic levels. It's not just about your biceps getting bigger or stronger. These adaptations manifest themselves as increases or decreases in your power output and muscle contraction speed. Simply put, if you're not moving as fast as you want, there are all of these underlying components ultimately influencing your performance.

The Studies
Listed below are studies that use the new techniques to examine the effects of endurance exercise and weight training, the two mainstays of all fitness programs.

Many studies will refer to myosin heavy chain isoforms sometimes noted as MHC or MyHC. They are part of the chemical reactions involved in muscle contractions. For the sake of simplicity, they are corresponding Type I, Type IIa, and Type IIb chemical counterparts of the muscle fiber types.

Endurance training effects

Each study is listed separately and briefly summarized using direct quotes.  My attempt to simply the technical quotes in layman's terms follows each summary.     Bibliography will follow.

1. Chronic low frequency stimulation and endurance exercise "induce fast-to-slow transitions in myofibrillar protein isoforms and fibre types." 1 This means that with endurance exercise, your dragsters turning into Prius.
2. "Regular endurance exercise training had no effect on fiber size, but with prolonged durations of daily training it depressed Po (peak force) and peak power. When the training is maintained over prolonged periods, it may even induce atrophy of the slow Type I and fast Type IIa fibers." 2 This means endurance training will cause you to have lower peak power and force. Atrophy means losing muscle mass of both mopeds and Prius.
3. Elite masters endurance runners vs. sedentary men of similar age. "Master runners' type I and IIa fibers were smaller in diameter and produced less peak force than Sedentary men's type I and IIa fibers. The absolute peak power output of master runners type I and IIa fibers was 13 and 27% less, respectively, than peak power of similarly typed Sedentary men's fibers." 3 This means that for higher peak power, you are better off being a couch potato than run long distances.
4. Endurance training effects. "There was a clear and consistent shift from fast to slow MyHC isoform expression." 4 Dragsters are turning into Prius and Prius turning into mopeds.
5. Aging and endurance training affects MHC even more. "At baseline, MHC I mRNA was unchanged with age, whereas IIa and IIx declined by 14 and 10% per decade, respectively MHC IIa and IIx protein declined by 3 and 1% per decade with a reciprocal increase in MHC I After training, MHC I and IIa mRNA increased by 61 and 99%, respectively, and IIx decreased by 50%." 5 Aging causes the decrease in dragsters and Prius but not necessarily mopeds.
6. This study found that it is worse for speed if you do strength and endurance exercise at the same time." The present results suggest that even the low-frequency concurrent strength and endurance training leads to interference in explosive strength development mediated in part by the limitations of rapid voluntary neural activation of the trained muscles." 6 Endurance training decreases explosive strength and speed.
7. This study found that after a decade of endurance training, "The percentage of type I fibres in Decade Training group was 70.9% vs 37.7% in Non-Trained group, while the type IIa fibres in DT (25.3%) was much lower than NT (51.8%). The results revealed that endurance training may promote a transition from type II to type I muscle fibre types and occurs at the expense of the type II fibre population." 7 A decade of aerobic training leads to almost double the amount of mopeds than in non-trained men. Once again, couch potatoes rule!
8. This study focused on long distance swim training. They found, "the force-velocity relation was not significantly altered in either fiber type by the swim training; however, the intensified training significantly depressed the velocity of the type II fiber at all loads studied." 8 Long distance swimming makes you slower. So why do sprint swimmers swim so many laps at slow speeds?

Strength Training Effects

1. This study investigated the effects of heavy strength training on muscle type transformations." The results show that after training, IIb MHC composition decreased from 19 +/- 4 to 7 +/- 1%. IIa MHC, in contrast, increased from 48 +/- 3 to 60 +/- 2%. These responses were essentially mirrored by alterations in fiber type distribution. The percentage of type IIb fibers decreased from 18 +/- 3 to 1 +/- 1%, whereas the percentage of type IIa fibers increased from 46 +/- 4 to 60 +/- 3%. Neither I MHC composition nor type I fiber percentage changed with training." 9 Strength training turns dragsters into Prius.
2. The effects of 12 weeks of strength/resistance training led to these findings. "Electrophoresis of muscle cross sections revealed an approximately 7% increase in MHC IIa proportion in both groups, whereas the MHC IIx decrease by 7.5 and 11.6% post-Progressive Resistance Training in Young Women and Young Men, respectively. MHC I proportions increase in YM by 4.8% post-PRT." 10 Strength training turns dragsters into Prius and increases the amount of mopeds.
3. This study was done with strength training for soccer players and found "traditional myofibrillar ATPase histochemistry demonstrated a decrease in type IIA fibres with strength-training (35.4% vs. 26.7 %). This was not observed in the non-training group (25.7 % vs. 23.8 %)." 11 Soccer players doing strength training are losing Prius that they need for speed and endurance.
4. This study on horses doing heavy carriage training led to" These results suggest that carriage training alters MHC composition in equine skeletal muscle, reflecting a conversion of MHC isoforms in the order IIX-->IIA-->I and suggesting a reduction in the velocity of shortening of the muscle, but an increase in fatigue resistance." 12 Resistance training in horses causes dragsters to turn into Prius and Prius into mopeds. BUT at least they don't get tired!
5. Here's a study comparing the fiber types in body builders vs. sedentary men. They found "the body builders had a higher proportion of fibres containing only MHC type IIa but a lower proportion of fibres with a coexistence of MHC types IIa and IIb and nearly no fibres containing only MHC type IIb" 13 Strength training makes you gain Prius and lose all your dragsters.
6. This study found with progressive resistance training of 12 weeks that "The Progressive Resistance Training provide a stimulus for alterations in MHC isoforms, which demonstrated a decrease in all hybrid isoforms (ones that can express both MHC Type I and Type II) and an increase in MHC I expression" 14 Losing Prius and gaining mopeds.
7. The results of a 24 week study on heavy resistance training on elderly subjects found, "results clearly show that elderly subjects undergoing heavy resistance training have the ability to produce a similar shift in the expression of MHC isoforms from MHC IIb to MHC IIa, as has been shown to occur in younger subjects. This highlights the plasticity of human skeletal muscle in response to heavy resistance training, even at older ages." 15 Even old people can turn dragsters into Prius with resistance training.
8. 10 week study with progressive resistance training yielded these results. "No changes occurred in the muscle fiber distribution of type I during the training, whereas the proportion of subtype IIab increased from 2% to 6% in Young Men and that of type IIb decreased in both YM from 25% to 16% and in Old Men from 15% to 6%." 16 Old and young men alike lose dragsters and gain Prius with resistance training.
9. This study on strength training for jump height is pointing to the right direction for increases in explosive movements. Their conclusion is quite telling. "Furthermore, our study suggests that a change in maximal strength and/or explosive strength does not necessarily cause changes in combined movement such as the stretch shortening cycle." 17 All the strength you gain might not be usable in explosive movements in sports.

After reading the irrefutable evidence, it is incredibly important that athletes understand the implications of these studies so that they can be in the driver's seat when it comes to designing their training program. Training correctly or incorrectly can make a huge difference in your adaptations.

Have The Right Fiber Types?

To help with designing your training program and setting training goals, here is some important information on fiber type percentages in a variety of sports. Reaburn and Jenkins (1996) in their book "Training for Speed and Endurance" found differences in the distribution of fiber type of elite athletes involved in different sports. 18 Here's what they found:



These percentages can be a benchmark for athletes to achieve. Sprinters possess a lot of dragster Type IIb fibers and very little moped Type I fibers. This would explain why super quick and fast athletes may fatigue easily and can't run the mile fast.

According to Frank W. Dick (2002) "Sports Training Principles", sprinters had 84% fast twitch muscle fibers, (as compared to the 70% in the above study).  It's even higher than that of a cheetah (83%).  

Although the authors did not differentiate between Type IIa or Type IIb fibers for these studies, one can infer from previously listed studies that even if powerlifters may have 55% fast twitch muscles, they are likely to be only Prius Type IIa fibers. This is why training must be so specific to your event. It is NOT enough to just have fast twitch muscles, they must be dragster Type IIb fibers in order for you to have the highest possible speed and power.

Few events are pure sprints like the 100-meter dash. Most sports consist of sprints mixed with speed endurance moments and rest periods such as football, basketball, tennis, baseball, soccer or volleyball. This is where a lot of confusion occurs with training. If you want more pure speed, you must train for pure speed. If you are looking for more endurance, then train for more endurance but don't expect to increase your speed.  In fact, expect the opposite. Training for endurance is NOT going to help with pure speed bursts. Only by training for speed bursts will your muscles and associated structures adapt and become dragsters.

Final note

There are many trainers and coaches who have their own agenda, namely STRENGTH FIRST.  They see all training through cast iron colored glasses and probably learned their trade at a time when the listed studies were not yet in their college textbooks. Their education can be likened to learning about Beta or VHS video cassette recorders while the fast-moving techno world is already into High Definition DVD's or Blu-ray discs. To give them the benefit of the doubt, they are doing the best jobs they can with the knowledge they've been given. The studies that I've discussed as well as other research are openly available for all to learn and benefit from, but the problem is the "expert" minds are closed and therefore do not realize the need nor care to keep up with the latest research that can help their clients. As a result, it is the athletes they train who suffer the most.

I once asked a nationally known strength coach how long it would take an athlete to increase his bat speed by 10%. He replied that it would take six to eight months. When I asked why it would take so long, he said that one must go through the periodization phases (overall body strength and conditioning first, muscle hypertrophy next, and then finally the athlete could get to the speed work). Deciphering the code, this meant that the athlete would be put through weight training and endurance work (turning dragsters into Prius and mopeds?) for months before being "allowed" to do speed work.  

The moral of the story is that you, the athlete, must think clearly on your own and take charge of your own training. As ye train, so shall ye be! Be careful, you might be training yourself into a Prius or worse yet, a moped. Speed or the high speed application of strength is of utmost importance in most sports and the only way to go is to train for dragsters by doing complex exercises at event speeds while using the stretch shorten cycle.

In my next article, I will review more of the latest studies regarding stretching, resistance band training, sprint training, plyometrics, anabolic steroids and more.

Richard Dizon is our new speed trainer at Ohana Batting Cages in Aiea. Here's what he had to say about using that SpeedChains for four months,  "Throughout my life I've played many sports, from baseball and basketball to tennis and martial arts and, most recently, golf. Since training with the SpeedChain, I've noticed a dramatic improvement in my overall fitness. But more so, in my agility, muscle tone and speed--and that's just in four months. As someone in his early 50s, I never thought I'd get my quickness back and improve my golf swing this fast. My drives are about 20 yards longer. And if someone like me can improve, the SpeedChain can help any athlete to get faster and better."  

Visit www.speedchaintraining.com for more information or call Richard at 783-2687 for a free demo workout at Ohana Batting Cages.

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