Talent Identification in Football: Different Effects of Maturation on Sprinting, Change of Direction and Jumping in 13-Year-Old Players

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 

Overall this is an interesting paper with implications for sports coaches involved in youth sport, though physical attributes should be considered as only one part of the equation.  The authors have done a nice job in presenting relevant research to support their hypotheses and methodological approach.  The methods are a bit unclear in some places and need to improved.  In the results the authors introduce biological age as a descriptor.  It would improve the paper if this was addressed sooner.  Last the discussion of each metric gets a bit muddled.  Taking a more systematic approach to each metric may aid the reader.  Further, the reasons discussed for deviations from previous work as well as ascribing them to limitations in the study need to be clearer.  Overall, this project provides insight into the development of football players that seem to be in an enclosed environment where training is consistent across participants.  Specific comments follow.

 

Line 76 – Agility tasks require an unanticipated quality, you measured a change of direction task that included a 3 different locomotive patterns.

Line 94 – Why did you chose the age of 13?

Line 124 – The differences in anthropometry in the participants is striking and in a different direction than one might think.  For example, it is intuitive to think that the late maturation participants would be taller and heavier, perhaps this contributed to the direction of the differences you found and could aid in your explanations in your discussion.

Line 201 – It is not clear how you are extracting acceleration and max speed.  Please expand.  Your description implies you are calculating average velocity and not max speed.  Sewio sensors are accelerometers, how are you calculating max speed? What is acceleration speed?

 

 

Line 206- Your description of the unilateral tripled jump is confusing.  Did they use the same leg for all three hops? Did they start on the right leg, for example, hop off the right leg, land on the right leg, hop off the right leg, land on the right leg and take off of the right leg and then land on 2 feet?  Please clarify

 

 

Line 224- Did you use projectile motion equations to calcualte the height?  Did you require them to land on on toes or heels or flat footed...was this standardized?

Line 241 - does biological age = maturation group? Perhaps this study would have been stronger if maturation age was a continuous variable

 

Line 242- How did you know that the data you were receiving was in the 20-30 m area?

 

Line 254 – Please explain to what CMJA refers.

 

Line 262- unilateral hop test would mean that they would only hop on one leg for all three hops, your description of this tasks implies that they switched legs?

Line 273 - Your symbols do not indicate differences between the groups your text says

 

Line 288- This section title does not match the content

Line 311- poor word usage – “more reasons”, please revise

Line 314 – You say that late mature participants had shorter step lengths….1- you must say that you suppose and 2- you need to relate that back to your anthropometry table to explain that they were shorter though more mature.

Line 357 – does not support or is not appropriate for comparison to the present study?

 

Line 375 – Though the late mature participants were shorter and lighter than the other 2 groups, it is possible that they had not completely adjusted to the new height that they attained.  I think that the counterintuitive situation of the more mature participants being shorter and lighter is a tremendous hindrance to your study and should be made more prominent in your explanations.

Author Response

We would like to thank you for the time taken to review the manuscript and your insightful comments which we feel have helped to improve the quality of the manuscript.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

found this nicely produced and researched.  it would be helpful and informative to have access to blood values as way to ascertain biological age and muscle maturation.

Author Response

Thank you for your valuable feedback and incentive suggestion. We appreciate it.

Comments and Suggestions for Authors

-I found this nicely produced and researched.  It would be helpful and informative to have access to blood values as way to ascertain biological age and muscle maturation.

Response: Unfortunately, as far as the biochemical indicators, in this research we did not have a possibility to use them. Nevertheless, we will consider this suggestion in our future studies.

Reviewer 3 Report

Comments and Suggestions for Authors

I read this with great interest, as this is a subject area that I feel needs greater attention. 

I think you should state "agility t-test" for the first two mentions to eliminate any confusion with the statistical test. 

I have  a preference for graphs over tables of data, so that differences can easily be seen.  

Page 4 line 13:  "... of the organism of the monitored subjects" - I would replace this text with ".. of each participant."

These are all minor issues.  My biggest issue is that you are comparing the results of non-parametric tests with parametric tests.  When there is such contradictory results in the published literature it is best to eliminate any differences in the testing, so that the focus can be on the  results and explaining any differences with reasons around the physiology and training.  Why did you not undertake a power test initially, in order to determine the optimal participant number required?  This might have resulted in normally-distributed data, and the potential to run parametric tests.  As it is, the reader is left wondering that if the sample size was changed, might we have different results?  I would therefore like to know, 1) if the studies that you are making comparisons with had normal distribution and used parametric testing; and 2) the results of a power test for sample size, so that we can see how far away you were from obtaining normally distributed data.  What was the exact result of the Shapiro-Wilk test?

I am not against non-parametric testing.  I would like to know if comparing like with like.  

Author Response

We would like to thank you for the time taken to review the manuscript and your insightful comments which we feel have helped to improve the quality of the manuscript.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I commend the authors for their attention to my concerns.  I feel that the authors have sufficiently satisfied my reservations regarding this paper.

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for making appropriate responses to all suggestions.