Olympic Lifting Remodels Fast-Twitch Muscle Fibers
Olympic Weightlifting is popular sport and based on fast twitch fibers. Recently a study have been conducted for the muscle fibers required in this sport. Other sports disciplines can also use Olympic weightlifting exercises for the production and development of fast twitch fibers.
A study performed by the Human Performance Laboratories, The University of Memphis, Tennessee, took biopsies from the vastus lateralis muscle of male weightlifters and non-weight-trained men. The analysis of this data produced these revolutionary results.
These results suggest that successful weightlifting performance is not dependent on IIB fibers, and that weightlifters exhibit large percentages of type IIA muscle fibers and Myosin Heavy Chain IIa isoform content.
You can read the entire study here:
Muscle fiber characteristics and performance correlates of male Olympic-style weightlifters.
J Strength Cond Res. 2003 Nov;17(4):746-54.
Source: Human Performance Laboratories, The University of Memphis, Tennessee 38152, USA.
Biopsies fro the vastus lateralis muscle of male weightlifters (WL; n=6; X +/- SE, age=27.0 +/- 2.1 years), and non-weight-trained men (CON; n=7; age=27.0 +/- 2.0 years) were compared for fiber types, myosin heavy chain (MHC) and titin content, and fiber type-specific capillary density. Differences (p<0.05) were observed for percent fiber types IIC (WL=0.4 +/- 0.2, CON=2.4 +/- 0.8); IIA (WL=50.5 +/- 3.2, CON=26.9 +/- 3.7); and IIB (WL=1.7 +/- 1.4, CON=21.0 +/- 5.3), as well as percent MHC IIa (WL=65.3 +/- 2.4, CON=52.1 +/- 4.2) and percent MHC IIB (WL=0.9 +/- 0.9; CON=18.2 +/- 6.1). All WL exhibited only the titin-1 isoform. Capillary density (caps.mm(-2)) for all fiber types combined was greater for the CON subjects (WL=192.7 +/- 17.3; CON=262.9 +/- 26.3), due primarily to a greater capillary density in the IIA fibers. Weightlifting performances and vertical jump power were correlated with type II fiber characteristics. These results suggest that successful weightlifting performance is not dependent on IIB fibers, and that weightlifters exhibit large percentages of type IIA muscle fibers and MHC IIa isoform content.
If you have never studied muscle fiber types then it is important to know that Fast-Twitch muscle fibers are able to produce more power than Slow-Twitch muscle fibers. It is proven that elite power athletes like: High Velocity Pitchers, Olympic Sprinters and Jumpers have more fast-twitch than slow-twitch muscle fiber types. Now, to better understand the difference in these power focused muscle fibers and the demands of these athletes, we need to learn the sub types of Fast-Twitch muscle fibers.
A great description of the fast-twitch muscle fiber types is from Shannon Clark at BodyBuilding.com.
The Different Types
The Three Different Types Of Muscle Fibers Are:
- Type I fibers
- Type IIa fibers
- Type IIb fibers
Each one has it’s own characteristics and is suited to a particular type of movement. Another way to classify these fiber types is by their contractile and metabolic properties, thereby dividing them into slow and fast twitch fibers.
Type I: Slow Twitch Fibers.
The first type of fiber we will look at is the type I, or slow twitch fibers. These fibers are slow to contract (hence, slow twitch), and can sustain muscular contractions for an extended period of time. This factor makes them ideal for endurance type of events where one is exercising for long durations. They also contain large and numerous mitochondria which aid in their oxidative metabolism (the use of oxygen). These types of fibers are fatigue resistant but are only able to produce a relatively low level of force output.
Physically, these fibers are red in appearance, due to their iron containing cytochromes, have a small fibers diameter and have many capillaries throughout their structure. For the average sedentary child or adult, slow twitch fibers comprise approximately 50% of their muscular tissues. Endurance athletes, such as marathon runners, cross-country skiers and distance cyclists often possess up to 90% slow twitch fibers. On the other hand, athletes that rely on short bursts of energy possess the lowest levels of slow twitch fibers, often around only 25%.
Athletes with a higher proportion of slow twitch fibers also commonly have the highest VO2 max results, as this is a test primarily of aerobic capacity and these are the most important fiber types in relation to this measurement.
Type IIa: Fast Twitch Fibers.
The next category of muscle fibers is fast twitch fibers, divided into type IIa and type IIb. Fast twitch fibers are known for their ability to rapidly transmit action potentials and generate a high cross bridge turnover rate (responsible for quick muscle contractions).
These fibers also possess a high activity level of myosin ATPase and show a rapid rate of calcium release and uptake by the sarcoplasmic reticulum (Katch et al, 2000). Due to these properties, these fibers generate an explosive burst of power for a short period of time. This makes them most suitable to stop and go activities such as basketball, soccer, and hockey, as well as max output activities such as weightlifting, and many track and field events.
These fibers rely heavy on the glycolytic energy system (using the method of anaerobic glycolosis to produce ATP). Type IIa fibers are in the middle of the muscle fiber spectrum, as they are less fatigue resistance, produce more muscular force, and contract at a faster speed than slow twitch fibers.
Type IIb: Fast Twitch Fibers.
The type IIb fibers are the most fatigable out of all the fibers but also generate the most power and force, and therefore are the fastest twitch muscles fibers. These types of fibers are recruited in activities that require an all out burst of power and only act for an extremely short period of time, as the total length of their contractions usually last only 7.5 milliseconds.
In terms of general recruitment, they are also the last to be recruited. For example, upon normal activities, slow twitch fibers are recruited first, followed by type IIa when the type I can no longer suffice, and then finally the type IIb, which are recruited to produce maximal strength.
What Is The Difference?
In regards to physical appearance, type IIa are pink in color, have an intermediate diameter, capillary level and mitochondria volume. The type IIb fibers are white in color, have the largest diameter and have a low capillary and mitochondrial volume. Most strength athletes possess a higher % of fast twitch fibers, as do those in short duration, quick moving activities.
The primary reason why fast twitch fibers are not resistant to fatigue is because they rely on anaerobic glycolysis to produce ATP. During this process lactic acid begins to accumulate and a condition called acidosis occurs which brings about muscular fatigue. Due to their low capillary level, they do not make use of oxygen nearly like slow twitch fibers do (which also explains their reliance on anaerobic metabolism).
Although each muscle fiber type has certain characteristics that make it more suited for certain activities, this does not mean that an athlete with a predominance of one type of muscle fiber can only participate in those activities that call for that type.
With proper training, they still can learn many of the skills and techniques used in different sports and can achieve success across a wide variety of activities.
It is common however, that athletes with a predominance in one type of fiber do naturally tend to be drawn to the types of activities more suited to their body as they tend to naturally be better at those actions and therefore often enjoy participating more.
At the elite level of competition, you may find that those athletes who do possess the certain characteristics in their muscle fiber that are required by the sport do tend to be able to push the envelope slightly further, as their body may react better to training methods and will show faster improvement.
How To Train Fast Twitch Muscle Fibers?
There are a number of proven methods that target the fast twitch muscle fibers (FTF’s). By following these guidelines you will ensure that your muscles are provided with the right type of training stimulus for developing your vertical jump.
- In the weight room try to lift in excess of 60% of your 1RM.
Generally speaking, the heavier you lift the greater the recruitment of FTF’s. The exception to this is if you are doing ballistic weighted exercises such as barbell jump squats. In these instances it is ok to use a lower % of your 1RM – see the next point.
- Aim for maximum speed on all your movements.
Whether it is lifting a weight, skipping, jumping, bounding, or throwing, try and do it flat out. Short burst (10 seconds or less) of very high intensity work will cause the type of positive muscular adaptations you are after.
- Train eccentrically.
Eccentric training refers to emphasizing the work done as you lower a weight or descend in a jump. For weighted work this would be done using bands to accelerate gravity, or using drop and catch motions such as reactive squats. For jumping exercises the eccentric portion is emphasized in movements such as the various types of depth jump and altitude landings (see next point).
Plyometrics involves the activation of the stretch-shorten reflexive response to create more powerful contractions. These contractions are primarily the domain of the fast twitch muscle fibers so doing this type of training will really stimulate those type II’s.
- Contrast Load Training.
This is one of our favorite training techniques and real jump improver. To use contrast load training you might perform a very heavy set of squats, say 75-95% of your 1RM, rest 1-2 minutes, and then perform a lighter more explosive movement such as unweighted jump squats. The initial heavy set fires up a process known as potentiation that triggers higher recruitment of fast twitch fibers in the subsequent exercise.
- Over-speed Training.
Overspeed training is where you add some form of assistance such as having a partner pull you along, using bands to pull you along, or simply running down a slight hill. This trains your body to move faster than it otherwise would have by forcibly recruiting the FTF’s for the extra speed, and it reinforces to your brain how to send those messages that fire up the FTF’s.
- Mental Training.
If you have ever seen an Olympic lifter before a lift you will know what a psyche up is. This is part of mental training. Those lifters are essentially getting into a frame of mind that tells their bodies to literally fire up the fast twitch fibers. It works equally in your jumping and training. Spend 20 seconds before a jump mentally preparing for the effort and you will jump higher than if you just go and do it. Why does this work? Because the psyche up is a method of getting your brain ready to send the signals to the fast twitch muscles that they are about to do some maximum effort work.
Scientific Proof that Olympic Lifting Enhances Force Production
A study performed by the Department of Environmental Medicine, Karolinska Institutet, Stockholm, took tissue samples from a group of Olympic Lifters, Power Lifters and Body Builders. The analysis of the tissue produced these revolutionary results.
Body Builders displayed greater fiber size than Olympic Lifters and Power Lifters. Fast-Twitch and Slow-Twitch area was greater in Olympic Lifters and Power Lifters than Body Builders. It is suggested that long-term heavy-resistance training results in specific metabolic adaptations of Fast-Twitch and Slow-Twitch fiber types. These changes appear to be influenced by the type of resistance training.
Khizer Hayat Raja
Sr. Lecturer in Physical Education & Sports
International Weightlifting Coach & Expert