Do Fiber Types Make Sprinters Fast?

“Statistically, athletes who are highly trained for sprinting tasks have a greater proportion of fast fibers in their vastus lateralis muscles compared with athletes who are highly trained for marathon running. However, such a fiber type difference probably has a negligible effect on their performance and is probably genetically determined rather than induced by training. Sprinters are fast based on their large, strong muscles that can accelerate their body mass rapidly. Most of the larger muscle fibers are also fast types. It is more appropriate to state that sprinters are so fast based on the large Physiological Cross-Sectional Area that results from their muscle architecture. In fact, as sprinters train for high speeds, their muscles become stronger, but intrinsically become slower!”

Box 2-8 from Skeletal Muscle Structure, Function, and Plasticity- second edition
Richard Lieber, PhD.

Comments?

Tom,
Your statement is correct but there are other factors that determine a successful sprinter. One key factor being the type of nervous system a sprinter “possesses”. The nervous system determines the type of muscle fibre, higher the innervation frequency, the greater the percentage of fast isoforms (fast fibres). You could have a very very large cross-section of muscle fibres of both fast and slow but if your CNS is firing at lower frequencies you will not run fast. You are correct in stating that large cross-sectional fibres allow sprinters to run fast but it must be qualified by stating that sprinters have selectively hypertrophied the fast fibres that they possess, and in the case of marathon runners it is the opposite. Strength and power training is essential because they selectively increase fast fibre cross-sections. A sprinter with 30% fast fibres can achieve comparable results of a sprinter with 70% fast fibres if he SELECTIVELY hypertrophied the fast fibres to occupy 70% of the cross-sectional area of his muscles. I once read an article from Poland about their 400m runners becoming world class by achieving this selective hypertrophy. In short, your statement is correct, but a man or woman with higher % fast fibres than a “lesser” athlete will always have the edge if all things are equal, ie all are doing the same training.

Also the hormonal balance of an athlete (higher levels of male hormone) the more likely he/she will run faster. Endurance training kills this dead.

A sprinter with 30% fast fibres can achieve comparable results of a sprinter with 70% fast fibres if he SELECTIVELY hypertrophied the fast fibres to occupy 70% of the cross-sectional area of his muscles.

I really agree with this. Also I would say the less FT one is the more “targeted” their training has to be to succeed. Guys that are disadvantaged in the FT department can’t get away with as much non FT specific conditioning work as say someone like a Herschel Walker who would jog 5 miles every day. This has been my experience anyway.

I would say the greatest limiting factor is the length and compliance of the calcaneal tendon.

David,

I do not agree totally. Assuming that reactive strength is related only to the compliance of the achilles tendon, then yes. But other factors also come into play. For example, Carlo vittori et al have discovered that reactive power as related to sprinting the 60m, 100m and 200m has a significant glycolysis function. In other words MUSCLE STIFFNESS is also responsible for a major part of the lower ground contact times achieved because MUSCLE STIFFNESS is improved as the glycolytic fraction of anaerobic power is developed; yes tendon stiffness will be improved or be potentially greater with longer achilles tendons but if your muscles can’t keep up, forget it. After the first 20-30m of a sprint,which is more related to muscle contraction and maximal strength (explosive contractile strength), explosive reactive reflex strength takes over. This is where the length of the achilles may play a part, but it is disputable. This is very similar to the discussion on the last forum about top sprinters and the length of their calf and achilles tendon.

David,

I do not agree totally. Assuming that reactive strength is related only to the compliance of the achilles tendon, then yes. But other factors also come into play. For example, Carlo vittori et al have discovered that reactive power as related to sprinting the 60m, 100m and 200m has a significant glycolysis function. In other words MUSCLE STIFFNESS is also responsible for a major part of the lower ground contact times achieved because MUSCLE STIFFNESS is improved as the glycolytic fraction of anaerobic power is developed; yes tendon stiffness will be improved or be potentially greater with longer achilles tendons but if your muscles can’t keep up, forget it. After the first 20-30m of a sprint,which is more related to muscle contraction and maximal strength (explosive contractile strength), explosive reactive reflex strength takes over. This is where the length of the achilles may play a part, but it is disputable. This is very similar to the discussion on the last forum about top sprinters and the length of their calf and achilles tendon.

“significant glycolysis function…” Could it be suggested that HIGHER rep plyos or indeed sprints where you may have over 20 ground contacts per leg can improve the reactive speed/strength a great deal becuase of th glycolytic energy system?

Tendons are significantly more efficient in reutilising energy than muscle. Muscle fibre type and motor control can be manipulated through training but tendon length and insertion point are fixed.

Your statement is correct, and that is the reason why athletes and their coaches should work with what can be improved and not worry about height, tendon insertions and lengths which are all fixed but not necessarily performance limiting if you do not fit the norm.

The father of “plyometrics” (Yuri Verhokoshansky), or as he likes to call it shock training did a study over an eight month period in the former Soviet Union. In that study four groups were assigned short plyo( standing jumps, depth jumps and squat jump like exercises), another group was assigned a range of alternate bounds v similar to ones in use these days over 30-200m YES 200m (I would not recommend this personally) and bounds over obstacles. Another group was assigned both loads and a fourth group was assigned only the usual track weights work. The groups were a mixture of class 1 (10-10.30 secs), and other lower class sprinters. Other training was done in conjunction as these were competing athletes.

The group that did only short bounds improved their 0-30m significantly
The group that did only long bounds with obstacle jumps, improved their 30-60m significantly.
The group that did both improved both parts of the sprints significantly.
The group that did non of the above except the usual sprint training made some improvements but no particular part of the timed sprints improved significantly.

I hope this answers your question. Remember, Charlies speed end runs as recommended will serve this purpose along with other plyo work.

Though the tendon length and insertian points are fixed, can we not atleast
strengthen the tendons to a big degree? Would this not increase their ability to re-use or store energy etc?

Is the amount of energy that a tendon can store and re-use ONLY dependant on it’s length and insertian point, or is some of it influanced by the tendon thickness and strength aswell?

Elastic Energy stored in the foot and ankle.

Just as a drawn bow stores the energy from the draw and then delivers this energy to the arrow, the tendons are elastic and can store energy. A tightened muscle can also store energy elastically. The amount of stretch in a tendon is small so the total amount of energy is small.

Experiments with the human foot arch show that this system is fairly elastic but that the amount of energy which can be stored in the arch is only about 20 J.

For a 70kg athlete, this only adds to their jump a height of:

mgh = 20 J, h = 20/700 = 0.028 m

The achilles tendon is one of the thickest tendons in the body. The tendons are elastic; the achilles tendon can store about 40 J.

The combination of the achilles tendon and the arch stores 60 J of energy and this gives a bounce height of h = energy/mg = 60/700 = 0.086 m which isn’t much for vertical jumping but is significant in running.

Note that the hang time for this jump is 0.26 seconds. In a sprint, at 10 m/s, the runner would advance 2.6 m in one step during this hang time. [This is an upper limit for a perfectly elastic foot.] This is about right, a world class sprinter takes 44 steps for the 100 m dash or an average of 2.3 m per step with shorter steps at the start and big ones in the body of the race.

Improve the elastic quality of your calf and foot structures and you give yourself a chance of reaching your potential.

OK, but the $64,000 question is “How?”

I thought I had posted this on the old site-

Med Sci Sports Exerc. 2000 Jun;32(6):1125-9.

Fascicle length of leg muscles is greater in sprinters than distance runners.

Abe T, Kumagai K, Brechue WF.

Department of Exercise and Sport Science, Tokyo Metropolitan University, Hachioji, Japan. abebe@comp.metro-u.ac.jp

PURPOSE: The purpose of this study was to compare architectural characteristics of leg muscles of sprinters and distance runners. METHODS: Skeletal muscle architectural characteristics were studied in 23 elite male 100-m sprinters (SPR, 10.0-10.9 s for 100 m), 24 elite male distance runners (DR, 13.5-14.5 min for 5000 m), and 24 untrained male controls. Fascicle pennation angle and isolated muscle thickness of the vastus lateralis and gastrocnemius medialis and lateralis muscles were measured in vivo by ultrasound, and fascicle length was estimated. RESULTS: Standing height and upper and lower limb lengths were similar among the groups. Body weight was significantly greater in SPR than in either DR or controls, which were similar. Muscle thickness of the vastus lateralis and gastrocnemius medialis and lateralis muscles was significantly greater in SPR than in either DR or controls, which were similar. In all muscles, pennation angle was similar between SPR and controls, but less than DR. Fascicle length of the vastus lateralis muscle (absolute and relative to limb length) was greatest in SPR and least in DR with control values being between the athlete groups. Fascicle length of the gastrocnemius medialis muscle (absolute and relative to limb length) was greater in SPR than in either DR or controls, which were similar. Fascicle length of the gastrocnemius lateralis muscle (absolute and relative to limb length) was significantly greater in SPR than DR. Absolute fascicle length in gastrocnemius lateralis muscle was similar between DR and controls; however, relative to limb length DR was significantly less. CONCLUSION: Greater fascicle length and lesser pennation angle observed in leg muscles of SPR, compared with DR, would appear to favor shortening velocity as required for greater running speed.

EMS treatment for your arches, specific plyo work that targets the achilles tendon and calf muscles. One legged med ball hops. One legged hops with emphasis on rolling and pushing off the ball of the foot. Choosing the correct footwear to train in and compete. All these elements of training over time will improve the elastic qualities of your lower legs. I hope that gives you some idea. Remember when you do plyo you are trying to improve this part of your body as well as the muscle stiffness of your legs.

Hope this helps.

Here is another-

J Appl Physiol. 2000 Mar;88(3):811-6.

Sprint performance is related to muscle fascicle length in male 100-m sprinters.

Kumagai K, Abe T, Brechue WF, Ryushi T, Takano S, Mizuno M.

Department of Exercise and Sport Science, Tokyo Metropolitan University, Hachioji, Tokyo 192-03, Japan.

The purpose of this study was to investigate the relationship between muscle fascicle length and sprint running performance in 37 male 100-m sprinters. The sample was divided into two performance groups by the personal-best 100-m time: 10.00-10.90 s (S10; n = 22) and 11.00-11.70 s (S11; n = 15). Muscle thickness and fascicle pennation angle of the vastus lateralis and gastrocnemius medialis and lateralis muscles were measured by B-mode ultrasonography, and fascicle length was estimated. Standing height, body weight, and leg length were similar between groups. Muscle thickness was similar between groups for vastus lateralis and gastrocnemius medialis, but S10 had a significantly greater gastrocnemius lateralis muscle thickness. S10 also had a greater muscle thickness in the upper portion of the thigh, which, given similar limb lengths, demonstrates an altered “muscle shape.” Pennation angle was always less in S10 than in S11. In all muscles, S10 had significantly greater fascicle length than did S11, which significantly correlated with 100-m best performance (r values from -0.40 to -0.57). It is concluded that longer fascicle length is associated with greater sprinting performance.

Free Full Text Article is Available at-

http://jap.physiology.org/cgi/content/full/88/3/811

EMS treatment for your arches, specific plyo work that targets the achilles tendon and calf muscles. One legged med ball hops. One legged hops with emphasis on rolling and pushing off the ball of the foot. Choosing the correct footwear to train in and compete. All these elements of training over time will improve the elastic qualities of your lower legs. I hope that gives you some idea. Remember when you do plyo you are trying to improve this part of your body as well as the muscle stiffness of your legs.

Hope this helps.

Isn’t the gap from 10.00 to 10.90 much to large to make this a coherent group? It seems most studies are grouping the elite the sub-elite and the average against the large group of less than average.

  1. Can running barefoot help strengthen the foots ability to store and re-use energy ( elastic ), or is this just a foot flexability type exercise?

  2. What are more important plyo’s?;
    Plyos where you feel muscle stiffness (hops etc.)
    Plyos where you feel more explosive (box jumps, depth jumps.)

What about the length and width of the feet? Do they have any influences?