This readme.txt file was generated on 2023-03-15 by Danilo Gomes de Arruda


GENERAL INFORMATION

1. Title of Dataset: Dataset with the variables analyzed in the study: " Perception of affordances in female volleyball players: serving short versus serving to the sideline"
2. File Information:
   A. Filename: arrudetal_2023_dataset.xlsx
   B. Short description: Perceptual reports and performance of volleyball serves towards the sidelines and short serves. This file contains data of 24 young volleyball players for 13 variables. The variables will be described later in this document.
 

3. Principal Investigator Contact Information
   A. Name: Danilo Gomes de Arruda
   B. Institution: University of Minnesota
   C. Address: Cooke Hall, 1900 University Ave SE, Minneapolis, MN 55455 , APAL, Room 5a/b
   D. Email: arrud005@umn.edu

Additional data authors:
Barp, Fabio
Felisberto, Greysian
Tkak, Claudio
Wagman, Jeffrey
Stoffregen, Thomas

4. Date of data collection: The data collections occured in July and August of 2022.

5. Geographic location of data collection: The data collections took place in two volleyball clubs in Brazil.

6. Date files were created: November-2022


METHODOLOGICAL INFORMATION

1. Description of methods used for collection/generation of data: 

The experiment was conducted on a standard volleyball court. Among the teams involved in our study, the height of the net differed, such that some participants were used to playing with different net heights. Accordingly, in our study net height was adjusted to be at the typical height for each participant. For this reason, four participants were tested at a net height of 2.15 m, while the remaining participants were tested at a net height of 2.24 m. We placed on the floor two 9-meter tape measures, one 4.5 m parallel to and 4.5 m from the net and another perpendicular to the net and 4.5 m away from each sideline. A pyramidal “traffic” cone (45 cm in height) was used to define gaps relative to the net and sidelines. 

After a brief explanation of the testing procedures, the participant warmed up for 5 to 10 minutes as they usually would for practice, performing dynamic stretches and serves on the court. The experimental testing comprised two parts—first, perceptual reports and then performance (Peker, Böge et al., 2020).

Perceptual reports: 
Before making perceptual reports, participants were asked to stand on the back line in the location from which they would typically serve during a game (e.g., right, middle, or left side), and to indicate the type of serve that they typically would use (float, or jump float). For the Sideline condition, the participant also indicated the sideline to which they would serve (left, or right). In the Sideline Serve Condition, participants were asked to report the narrowest gap, relative to either the left or right sideline and extending from the net to the back line, into which they could serve the ball. In the Short Serve Condition, participants were asked to report the narrowest gap, relative to the net and extending from sideline to sideline, into which they could serve the ball. 
Perceptual reports were made using the method of adjustment. To make perceptual reports, participants stood on the end line in their chosen location (right, middle, or left) and instructed the Experimenter (standing on the opposite side of the net) to move a traffic cone until it marked the outer edge of a gap defined relative to the sideline or the net. In the Sideline Serve condition, half of the trials began with the cone at one sideline, and half of the trials began with the cone at the other sideline. In the Short Serve condition, half of the trials began with the cone at the net, and half of the trials began with the cone at the back line. These manipulation were such that, for each participant, we alternated trials on which gaps increased or decreased in width. After each perceptual report, the participant turned their back while the experimenter repositioned the cone for the next trial. The order of conditions was counterbalanced across participants. Participants gave six perceptual reports for each condition, for a total of 12 perceptual reports. 

Performance: 
After the perceptual reports for both conditions, the participants attempted to serve into the mean reported gap width in that condition. Separately for short serves and sideline serves, participants were required to stand in the same position along the back line from which they had made their perceptual reports. Then, the participant warmed up by performing five serves. Next, we positioned the cone on the average distance obtained from the participant’s perceptual reports, and the participant attempted to serve into the gap beween the cone and the relevant boundary (depending on condition). The order of the sideline and short serving conditions was counterbalanced across participants. 
Participants did not perform a predetermined number of serves. Rather, the participant continued to serve until they had completed three valid serves, where a valid serve was one that passed over the net and landed anywhere in-bounds, either within or outside the participant’s chosen gap. An experimenter recorded whether each valid serve landed within or outside of the gap. For each condition, the participant was required to stand in the same location from which they had made their perceptual reports. When a serve outcome was uncertain (e.g., whether the ball landed in or out of bounds), we asked the participant to repeat the serve. Final determinations were made later, from the video recordings.

2. Methods for processing the data:

To analyze perceptual reports (mean perceived minimum serve-able gap size), we performed mixed design 2 × 2 analysis of variance (ANOVA) using experience (Less vs. More experienced) and condition (Short vs. Sideline) as factors. The condition factor was within-participants, while the experience factor was between-participants. 
To evaluate actual serving performance, we analyzed the proportion of serves that landed within each participant’s self-selected gap. As the data were expressed as proportions, we analyzed serving performance using a quasibinomial logistic regression with a logit link function, which is more robust and less prone to errors than analysis of variance (Jaegar, 2008). We performed this analysis using the glm function in R. As post-hoc analysis we performed Chi-square tests for between-groups effects and McNemar’s tests for within-group effects. For all analyses the criterion  value was p < 0.05.
 

DATA-SPECIFIC INFORMATION

1. VARIABLES

The dataset is in long format and each column is a variable. The description of each variable and the corresponding coding is described below.

part_id: This variable is the unique identification number for each subject.
level: This is the experience level of the participants, 1= "Less-Experienced", 2= "More-Experienced"
club: This is the club to which subject belonged, 1= redacted, 2= redacted [note: locations were removed to protect participant privacy; contact investigators if this information is needed for future research.]
age: Age in years
years_experience: Experience in years
order: Order of protocol execution (judgments + performance): 1= Short-Sideline / Short-Sideline, 2=Sideline-Short / Short-Sideline, 3= Short-Sideline/ Sideline-Short, 4=Sideline-Short/Sideline-Short
condition: Type of serve/judgment, 1=Sideline, 2-Short
gap_size: average gap size determined by the protocol
confidence: average confidence determined by the protocol
amount_in_gap: The total number of serves that the subject could serve into the pre-determined gap
serve_type: type of serve that the subject performed the serve, F=Float, JF=Jump Float
amount_of_serves: Total amount of serves needed to finish that condition
proportion_of_successful: The proportion of serves in the gap by the amount of serves needed to finish the condition



SHARING/ACCESS INFORMATION 

1. Licenses/restrictions placed on the data: 
Attribution 4.0 International (CC BY 4.0)
https://creativecommons.org/licenses/by/4.0/

2. Links to publications that cite or use the data: The article is under review at Research Quarterly for Exercise and Sport
The title of the manuscript is "Perception of affordances in female volleyball players: Serving short versus serving to the sideline"

3. Recommended citation for the data:
Arruda, D. G., Barp, F., Felisberto, G., Tkak, C., Wagman, J. BB., Stoffregen, T. A., (2023). Perceptual reports and performance of volleyball serves towards the sidelines and short serves


Credits: Template provided by the University of Minnesota Libraries, http://lib.umn.edu/datamanagement