Characteristics of the intervals of higher and lower exertion on soccer friendly games (part 1).
In this series (it will be 4 videos), I will show you some data related to the characteristics of the higher and lower exertion interval duration of some friendly soccer games.
This will include the analysis of two friendly games of a spanish first division soccer team, and one friendly game of a spanish amateur soccer team.
For the analysis we have use the metabolic power data obtained based on the formulas proposed on the papers of Minetti 2001, Di Prampero et al. 2005, 2009, and Osgnach et al. 2010, and the work of R. Colli.
I will show you the data of the dynamics of the average team exertion metabolic power, filtered for a 30" period (so I have used the average data for 30"), in order to see how is the collective (team) exertion during those games.
For one professional soccer friendly game we have analyzed the video of the same higher exertion periods, in order to see which is the tactical performance of the team.
With all these data I want you to think about the specificity of interval times applied in specific training tasks (in case we want them to be so specific ...).
Enjoy,

Relationship between maximal running speed, maximal running acceleration and power and explosiveness values in professional soccer players.
I hope you find this information as useful as me.
The data have been measured by a GPS system (1Hz) and with a linear encoder, in a different professional international soccer players (Spain, Greece).
Maybe the more interesting finding is the relationship with the age of players, what give us an idea of the importance of being able to give to this players the optimum stimulus in the optimum moment, when the player feels that he is able to demonstrate maximum intensity in the exercise o task proposed for these target.
Enjoy,

Analyzing a soccer specific task by metabolic power. Effect of filtering.
In order to have a clearer idea of how metabolic power evolves when playing in a soccer specific task, I show you the comparison of some data obtained by a 15(5)hz GPS system, where you can see how evolves these data when applying different filters: average of 1 second  and average of 30 seconds, and how it affects on the general understanding of the (in this case) metabolic power expressed during the task.
Enjoy,

Metabolic power in 1 hz - 15(5) hz GPS system.
Everybody who works with any short of technology must be aware of its limitations and capabilities, in order to take the best profit of it.
Despite this obvious statement, sometimes we are not conscious of this limitations - capabilities.
Several authors have correctly state that working with GPS systems applied to control the loads when training or playing a game, has some limitations based on the frequency of the system.
In that way, I want to share with you this simple study, in which raw data get by a 5 hz (extrapolated to 15 hz) is used to obtain the metabolic power (see Di Prampero et al. 2005, 2009, Osgnach et al. 2010, and R. Colli in his italian web for further information about metabolic power) of a possession game 8 against 8 (small sided game) has been used to compare with the same data obtained as 1 hz system (the difference is just that with 15 hz you have 15 data per second, and with 1 hz you just take one data each second).
General conclusion: maybe for general comparisons of average data can be used without loosing info, but clearly is not useful for studying maximal values.
Enjoy,

Eccentric force in traditional strength exercises (bonus).
In this post I show you some graphs of force and velocity applied in each of the strength exercises analyzed, but remember that the data correspond just to the descending phase ("eccentric"). You will see in the graph the relationship between the initial point of force applied and the maximum force applied in each exercise.
Remember the intrinsic characteristics of each exercise, which are different not only in their execution (slow and controlled as in the half squat with high external load, as fast as possible as in the fast half squat, explosive as in the drop and depth jump, etc).
You will also have to relate this data with other characteristics, as the moment of force that is different in some of the exercises anlyzed here.
Enjoy,

Eccentric force in traditional strength exercises (part 3).
And, at least, the data obtained in this analysis for each exercise.
It's important to relate the data presented here about contact time or time of force applied during each exercise with the same data of the specific exercise, that is (in this case), of sprinting (acceleration), deceleration and change of direction.
Another important issue that you will see soon (in another post) is the relationship between exercises and the time at which maximal force is applied (because its relationship with explosiveness and with how the type of muscle fibers are acting in this situation).
Enjoy,

Eccentric force in traditional strength exercises (part 2).
In this part I will explain you the general characteristics of the strength exercises used in this analysis.
Enjoy,

Eccentric force in traditional exercises (part 1).
These week a colleague that works in a Spanish first division team, phone me in order to consult the relationship between one of the variables that a GPS System (that includes a triaxial accelerometer A3X), that is the total number of impacts (number of times that the A3X get's a value higher than a threshold value previously defined), and some type of injuries (bone fractures).
Apart from the importance of knowing the limitations that each short of technology has, and the limitations related to the way we use it, he has wake me up an old issue that last years has been rising up in soccer conditioning world because of it's relationship with the production and prevention of some injuries: the eccentric force.

So I start today a set of audiovideos in which I'll show you some data obtained years ago in order to clarify some concepts sometimes forgotten about how the force is applied in the "eccentric" phase of a movement, in this case in traditional exercises, starting with some data get by a A3X in some soccer specific movements (sprint, change of direction, deceleration).

You must know that the system used to get this data is a linear encoder working at 1000 hz, with software Isocontrol 6.0 (2012). All the exercises has been performed by the same player (veteran and with good experience in strength training).
Enjoy,

Relationship between maximal acceleration in a sprint and specific horizontal strength in professional soccer players.
This data have been collected with a GPS system of 1 hz for GPS speed and 100 hz for triaxial accelerometer acceleration.
As you know (at least in a more simplistic approach ...) in a sprint, the value of the strength applied should depend directly on the acceleration demonstrated, specially the horizontal acceleration applied by, in this case, the soccer players, as F=m*a, where "F" is force, "m" is mass and "a" is acceleration, so for a sprint (horizontal F = m* horizontal a).
Few studies has showed us the relationship between speed and horizontal relative force applied, and also this relationship with the possibility of hamstrings injuries. Here I show you the relationship I have founded between maximal acceleration in a sprint with the value of the horizontal acceleration applied by soccer players in their first steps.
Conclusion: nothing new but most of time forgot, the importance of highlight the use of different means and methods specifically oriented to the development of specific horizontal acceleration for soccer players, based on the use of EXPLOSIVE longer steps.
Enjoy,

Evolution of external load and it's relationship with competitive results.
After the previous two posts based on the control and evolution of external load, I present you this new audiovideo in which you can find the relationship between general explosive strength data (number of sets per week), specific explosive strength data (average maximal acceleration value of the team per month), and the special "bonus": their relationship with the number of points won in matches per month.
It's specially important to avoid a general and more simplistic thinking that in any condition the results will be the same that this we have had in this team. In other post I will show you other data analysis in which you will be able to understand widely what and why I'm saying that.
Just follow and enjoy,

Evolution of external load during the preseason (part 2).
This is the continuation of the audiovideo about the evolution during the preseason, in which you can see the relationship between the volume of variables used actually (distance, high intensity distance and time at high intensity of HR) with the volume of time used in tasks with or without ball depending on the exertion demonstrated in them (for further comprehension see the post about "Intermittence and metabolic power".
Enjoy,




Evolution de la charge externe au cours de la pré-saison (partie 2).
Il s'agit de la continuation de la audiovidéo sur l'évolution au cours de la pré-saison, dans lequel vous pouvez voir la relation entre le volume des variables utilisées effectivement (distance, la distance à haute intensité et de temps à haute intensité de FC) avec le volume de temps utilisé dans les tâches avec ou sans ballon en fonction de l'effort démontré en elles (pour mieux comprendre, voir le post sur "l'intermittence et la puissance métabolique».
Profitez-en,