Question - do people select the sport they like, train hard at it and become champions? Or, do they gravitate towards sports that they are good at from childhood, train hard and become champions?
Personally, I believe the latter. Most elite level athletes are born with their genetic gifts and refine these through years of training, often across a broad range of activities before settling on one sport.
One of the defining characteristics of your ability to excel in a physically dominated sport is muscle fibre type. This is mostly determined through your genes, and there’s not much you can do to change things. For example, Mark Cavendish just doesn’t have the correct make-up of his muscle fibres to ever win the Tour De France, in the same way Chris Froome would have never have been able to train himself to be the Olympic 100m champion. It's predetermined and you need to work with what you’ve got, to a point at least.
Fibre Types:
There are three types of muscle fibre:
Type I (slow oxidative). These fibres use aerobic metabolism (in the presence of oxygen) to produce low power contractions over long periods, are more efficient and are slow to fatigue.
Type IIa (fast oxidative). These fibres use aerobic metabolism to produce ATP (energy) but produce faster muscle contractions than Type I fibers.
Type IIx (fast glycolytic). These fibres use anaerobic metabolism to produce powerful, high-tension muscle contractions but fatigue quickly.
To be a successful endurance athlete, I will categorise endurance as anything above 2min in duration, you essentially need to be full to the eyeballs of Type I fibres. This is true of any cycling discipline except track sprinting and running anything further than the 1500m. Most of us are born with roughly a 50:50 distribution between Type I and Type IIa/x fibres, which explains why most of us are pretty average at most sports when compared to the top performers. One caveat is that each muscle leans towards the dominance of one fibre type or the other. For example, the 2 major muscles in the calf are the soleus and gastrocnemius, the soleus can contain more than 80% Type I fibres, whereas the gastrocnemius is more 50:50 (4).
The Research:
For this blog, I will summarise some recent work by a research group from Australia and Belgium (1, 3) which has done a good job of trying to clarify how fibre type influences performance, recovery and overreaching. It’s a complex subject but I will try to summarise the key findings.
Immediate fatigue:
The group (3) has reported how athletes of predominantly Type I or Type II fibres respond to a training session. Athletes were categorised into 2 groups, a Type I dominant group and a Type II dominant group. Each athlete completed 3 maximal 30s sprints with 4 minutes rest between efforts. Results showed a significant difference between the groups. In the first effort the Type II athletes were able to produce much more power as expected, but in the 2nd and 3rd efforts the power dropped significantly to the point that in the 3rd effort athletes with type I dominance actually hit better peak power numbers than the Type II group (fig 1). The power drop for the Type II group was 61%, whereas it was only 41% for the Type I group. This trend was also shown over the next 5 hours, with the Type II group taking much longer to fully recover (fig 2). This shows the more high intensity work Type II athletes do, the less they are able to repeat it.
Overreaching/Overtraining:
To explore the influence of fibre type on increased training volume, the same research group (1) categorised 24 highly trained runners into 2 groups, Type I dominant or Type II dominant. Over 7 weeks they completed identical training protocols, 3 weeks normal training followed by an increase in volume each week to 10%, 20% and 30% of the normal week. This was followed by a 55% reduction in volume for the final week, essentially a 7 day taper. Results showed the Type I group were able to tolerate the increase in volume with no reduction in performance and achieve a supercompensation of improved time to exhaustion following the taper. They were able to run for longer at a set speed. The Type II group athletes saw a decrease in performance even after the taper, their time to exhaustion was 49s shorter than at the start of the 7 weeks. Essentially, the Type II group was non-functionally overreached and may have needed a longer taper to see any supercompensation to improve their performance.
Key outcomes - What does this mean?
When implementing strength training, Type II dominant athletes may need more recovery between resistance sessions and intense aerobic sessions.
Type II dominant athletes may respond better to lower volumes and less frequent training as this facilitates better recovery. Type I athletes may respond better to more frequent training and higher volumes.
Taper durations for Type II athletes may need to be longer prior to big competitions >7 days.
Recovery duration between high intensity sessions may need to be longer for Type II athletes.
Are you fast twitch or slow twitch?
In truth, the best way to find this out is via a muscle biopsy, but that’s not a very pleasant or accessible option to most. But, there is a rather crude test you can do to give an indication of your dominant fibre type, the method has it's flaws but could help understand what fibre type in most dominant. It involves finding your 1 repetition maximum on a given exercise (I’d suggest the squat or leg press), then see how many good quality repetitions you can do at 80% of this number. The results have been shown to be 'moderately correlated' with identifying the correct fibre type (2), so your results might give you an indication but I wouldn’t bet your house on it. Here’s what it could mean:
• Less than 7 repetitions = Type II dominant
• 7 to 9 reps = probably a 50:50 balance between Type I and II
• More than 9 repetitions = Type I dominant
**Disclaimer** don’t try this alone or in an untrained state. Work up to this over a couple of months if you've been out of the gym for a while.
Cyclists - The unique nature of power meters gives a lot of cyclists the ability to apply this in the real world. The power-duration curve can give you an indication of your fibre type distribution without the need for a gym. Providing you've tested for maximal efforts over 5sec, 60sec, 5min and 20min+, many of the software tools available will classify your ‘rider type’. For example, I use Intervals.icu which categorises more fast-twitch dominant athletes as a ‘sprinter’ or an ‘attacker’ for those with high power values of less than 60sec. Additionally training peaks offer similar categorisations (https://www.trainingpeaks.com/blog/power-profiling/). Again, these are not without their flaws but will help you understand a little more about your make up as a cyclist.
To summarise, it’s important to know what type of athlete you are or who you’re working with before implementing your training plan. This comes back to one of my key principles of training, personalisation. Everything needs to be specific to that individual to get the best gains from your training.
How I can help you:
Strength Coaching - https://www.rwperformance.net/winterperformancepackages
Cycle Coaching - https://www.rwperformance.net/cyclingcoaching
References:
1- Bellinger, P., Desbrow, B., Derave, W., Lievens, E., Irwin, C., Sabapathy, S., Kennedy, B., Craven, J., Pennell, E., Rice, H., & Minahan, C. (2020). Muscle fiber typology is associated with the incidence of overreaching in response to overload training. Journal of applied physiology (Bethesda, Md. : 1985), 129(4), 823–836. https://doi.org/10.1152/japplphysiol.00314.2020
2- Hall, E., Lysenko, E. A., Semenova, E. A., Borisov, O. V., Andryushchenko, O. N., Andryushchenko, L. B., Vepkhvadze, T. F., Lednev, E. M., Zmijewski, P., Popov, D. V., Generozov, E. V., & Ahmetov, I. I. (2021). Prediction of muscle fiber composition using multiple repetition testing. Biology of sport, 38(2), 277–283. https://doi.org/10.5114/biolsport.2021.99705
3- Lievens, E., Klass, M., Bex, T., & Derave, W. (2020). Muscle fiber typology substantially influences time to recover from high-intensity exercise. Journal of applied physiology (Bethesda, Md. : 1985), 128(3), 648–659. https://doi.org/10.1152/japplphysiol.00636.2019
4- Vikne, H., Gundersen, K., Liestøl, K., Maelen, J., & Vøllestad, N. (2012). Intermuscular relationship of human muscle fiber type proportions: slow leg muscles predict slow neck muscles. Muscle & nerve, 45(4), 527–535. https://doi.org/10.1002/mus.22315