Effects of Basketball Shoe Midsole Hardness on Lower Extremity Biomechanics and Perception during Drop Jumping from Different Heights

Round 1

Reviewer 1 Report

The paper deals with a complete investigation on the effect of midsole hardness on the biomechanics of drop jump. Authors propose Kinetics, kinematics and EMG measurements together with a subjective evaluation. A correlation analysis was preformed to investigate midsole and drop height effects.

The paper is very interesting I think it is well written and well oriented with the journal purposes.

I have just few suggestions/observations that perhaps might improve paper quality.

First of all as regards the group of participants to the experiment, I am well aware of the difficulties to set up a group of volunteers, but in this case the investigation regards small differences in hardness, midsoles are very similar and commercial grade. For this reason the set of subjects in my opinion has to be  really used to the gesture and well trained. So I wonder the reason for condition 6. I think that one time over a month is a too poor training rate, I would suggest to perform a further  analysis with fewer subjects but more trained.  May be the results will be different.

A further observation regards the shoes: they are new if I understand well.  So subjects has to manage not only different midsoles but also the feeling of new shoes to which they are not used. May this affect results? In case, is  a masking effect on the midsole differences feasible? What about letting the subjects to use the shoes for a set of training sessions with  a neutral (mid hardness) midsole, then proceed with the investigation?

As regards the kinematics measurements please give some details regarding the set of markers, do the authors follow a specific protocol? For example similar to the ones for gait analysis? Please comment about markers positioning on metatarsal heads  and lateral malleoli through the shoe surface. Are the authors able to guarantee markers position accuracy for all the subjects? And what about shoe movements affecting results?

As regards the experimental protocol please give some details regarding the six sets of five jumps: what does it mean? How many repetitions for each subject in each condition? This is important for ANOVA analysis!

Does the experimental results undergo a sort of validation or each experiment was considered valid? For example authors are excluding jumps landing out or on the border of the force platforms, but do they verify that kinematics /kinetics  data are reasonable and consistent during the gesture? A numerical table  of significant values (i.e. vGRF,  landing angles, rom….) with maximum, minimum mean, sigma,  values across all the tests for all the subjects in the different conditions would help in understanding experimental repeatability.

As regards inverse dynamics do they considered subject’s parameters (i.e. segment length, mass, inertia, …) from tables and/or from direct measurements? In case which tables?

Please give some more detail as regards forefoot and rearfoot landing (peak) GRF, to improve paper readability.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The article is a very interesting and present precise experiment. I appreciate the statement of three reserach questions in the Introduction section and followed answers to them.

There are only small weaks in the experiment. The amount of 18 male respondents is not large. More respondents in the experiment will be beneficial than 18. Also from the point of basketball sport, the average height 175.8 (SD 6.4) m is not high in that type of sport. Maybe discuss this parameter in the Discussion section. From that point, the results are maybe valid for sportsmen in Asia but not worldwide (e.g. USA).

Section 2.4 describes the test. The important part is pretraining (practising) before the entire testing. Please, describe more detailed this phase. If there any time delay between the pretraining phase and testing phase, how it is long, how many trials etc.

My comments from the point of typography and formalism:

All therms with abbreviation are very punctually introduced in the text without any missing. Also, all measurements and software are fully described (producer, version, etc.). The tables are well formatted with a bottom explanation.

Fig. 2 Graph on the right side at the bottom: there is a dashed line (for soft midsole). The second peak is nor correctly visible because the space in dashed line is there. Please, change may be the spacing (length) of the dashed line to express better the peak on the line. Also, the black and white form of graph worsens readability of graphs, especially where the concurrent  (parallel) lines are. The lines (solid and dashed lines) overlay each other. Maybe change it to colour pictures.

Author Response

Please see the attachment

Author Response File: Author Response.pdf