Injuries: are they “part of the game”? – example: hamstring injuries in soccer.

It seems to be a hot topic nowadays, sports injuries, and especially the hamstring injury in soccer gets a lot of attention, if it only due to the frequent occurrence.

So let me takes the hamstring injury in soccer as an example.

Soccer clubs seem to have the best and biggest technical staff to their disposition, the best doctors, physios, sport scientists, dieticians, sports psychologists, data analysts, mental coaches, lifestyle specialists,  performance coaches, S&C experts, speed coaches. You name it, elite soccer clubs got it all.

Also equipment and facility-wise. They possess all the tools and technologies to control the player’s fitness and physical state. In recent years a lot of effort has been put into the prevention of hamstring injuries, such as introducing the Nordic hamstring curl into training programs. (1)

But despite all these efforts it seems to no avail, hamstring injuries in soccer are still on the rise.

Let me try and analyse the problem, without turning this into rocket science.#

  • Sprinting at maximum speed is a quality that demands the recruitment of fast twitch or type II muscle fibers. Fast animals like cheetahs possess high percentages of these fast fibers. (2,3)  Also the best human sprinters possess predominantly fast twitch fibers in the relevant muscle groups, mainly leg muscles. (4)

However, soccer is not a sprint event, it is high intensity intermittent with repeated sprints. And also the 90-minute matches require endurance capabilities, for which the presence of slow twitch or type I muscle fibers is necessary.

To have speed as well as endurance qualities, an optimal mixture of type I and type II is, dependent of the position of the player, required. Too much type II fibers make you fast, but this does not last 90 minutes, too much of type I fibers will give you the endurance, but you will lack the high speed.

Having tested a lot of elite soccer players, I found that the majority tends to have the most often found 50/50%  type II/type I ratio or have a tendency of predominantly type I fibers. In other words, they are not designed for high speed.

To change from type I to type Ii or to selectively create hypertrophy of type II fibers  (making slow muscles fast) is quite a task, but it can be done, (as a matter of fact I do this on a daily basis working with sprinters).

Knowing that many soccer players are not designed for high speed, it is like trying to win a Formula One race with a Volkswagen, or a cow beating a jaguar in the sprint.

Of course, the fiber type is not the only factor on which the ability to sprint at high speed depends: technique, balance between elasticity and stiffness, etc. also play an important role.

Training any of these two fiber types for speed needs a different approach, a fact that many coaches don’t realize. Trying to copy training methods or programs of elite sprinters or giving the same training program for type II and Type I dominant players is doomed to fail and leads to….. hamstring injuries.

One cannot make type I dominant players fast by giving them programs and exercises designed for type II players or elite sprinters.

Steps to take: 1 analyse the fiber type of a player, 2 train him/her accordingly

  • Sprinting at high speed is a skill, a complex one. Since sprinting is so natural, basic and simple… everybody can sprint, even if nobody ever told you how to do it.

Improving speed by improving skills is an activity that takes time, patience, knowledge and experience. It is not something you can improve overnight with a simple correction of the skill. Even if commercially driven courses, seminars, podcasts etc. promise you this is possible. Yeah, get rich quick and get fast. The skills also demand an analysis of the potentials, the strengths, and the limitations of the individual player. And remember:  if it ain’t broken, don’t try to fix it….

The problem with speed training is that only high or maximum intensity will lead to optimal adaptation. Jogging or 80% Intensity work with high volume does not make you faster. But at the other hand, the volume of maximum intensity work is limited in time, duration or repetitions. One cannot run 10 x 100m at 100%, because soon the technique will suffer, the type II fibers fatigue, the intensity and quality (running speed) will go down, the athlete starts to struggle and injury is around the corner.

And once again, don’t try to copy the drills of Usain Bolt or any other elite sprinter, thinking these will help your players to get faster as well.

About injuries in general:

Many coaches and athletes think and state that “injuries are part of the game…”  I always think and say “they might be part of your game, but certainly not part of my game….”. If they think like this, it is better for us, because often they are the opponents of my athletes.

Personally I try to avoid injuries at any cost, we spend lots of time adapting and changing the program, leaving out any exercise that has a high injury risk, since there are always safer alternatives to find. In the long run this strategy works out very well.

Why spending so much effort on avoiding injuries? Well, it is simple. As a coach you make the best possible program for the athlete, let’s say program A. Now the athletes gets injured, e.g. pulls a hamstring.

  • obviously the athlete cannot compete, not win a medal, break a record, make money or qualify  for championships. Often a whole season in the short career of an athlete is lost.
  • now he/she is out for training for some weeks, interrupting the program, the planning and the periodisation. And if the training can continue, it will only be a less optimal program, your second choice, not training A, but training B.
  • the self-confidence and motivation will go down, the frustration and stress levels will go up.
  • the injury will leave scar tissue creating a weak spot or a vulnerable spot somewhere else by compensation.
  • the injury will leave a scar in the brain as well, a mental scar (which often takes longer than the scar in the muscle to heal).
  • the athlete will not compete optimally the first series of competitions, often afraid for recurrence of the injury, also knowing that training and preparation were less than optimal.
  • not to mention the frustration of the coach, the time and money spent/wasted on therapy and treatment.

It seems to me that avoiding injuries should become an important component of the high-performance training process. Way too many athletes’ and players’ careers are interrupted, limited or ended by injuries. Many of them never reached their full performance potential due to injuries.

The main reason for injuries? Overkill! Spending too much time in the zone where the training load is higher than the athlete’s body can handle at that moment. Many coaches and athletes live by the idea that  “what does not kill me, makes me stronger”. Right, it might not kill you, but it still might kill your sports career and your dreams, or make you cripple.

  1.  A.E.Elerian et al.:  Effect of Pre-training and Post-training Nordic Exercise on Hamstring Injury Prevention, Recurrence, and Severity in Soccer Players; Ann Rehabil Med. 2019 Aug; 43(4): 465–473.
  2.  Goto, M., et al., Distribution of muscle fibers in skeletal muscles of the cheetah (Acinonyx jubatus).Mammal. Biol. (2012),
  3.  T. M. Williams; G. P. Dobson et al.:  Skeletal muscle histology and biochemistry of an elite sprinter, the African cheetah; J Comp Physiol B (1997) 167: 527±535
  4. D L Costill, J Daniels, W Evans, W Fink, G Krahenbuhl, B Saltin: Skeletal muscle enzymes and fiber composition in male and female track athletes; J Appl Physiol. 1976 Feb;40(2):149-54, doi: 10.1152/jappl.1976.40.2.149.


  1. Stuart Dempster

    Hi Henk,
    I read your article and you are correct. Football, despite all the expertise and money still poor in this area.
    I would like your opinion please if you have a moment
    I have just started coaching a 13 year old boy who is in the local Football Academy

    The Academy have him training 6 days per week with the sessions being 2 to 3 hours in duration, does strength work on top of this and I have advised that this is too much.Or am I wrong ?
    One example of the running sessions they do is to “sprint” the length of the pitch with 5 secs break!
    I would appreciate your thoughts

    1. Hello Stuart, a rather typical example of survival-of-the-fittest training., How much do they expect him to train when he is 23? 25 hours a day? How rong can you be as a coach, there is no scientific rationale or experience in the world supporting a crazy program like this…. Why doing this? Only one reason, because you can and you have a huge potential of disposable and replaceble young athletes and their parents, reading have at least their dreams broken within a few years. This is showing the dark side of sports. Uneducated coaches with a heart, Henk

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