Study area
The study was conducted at Injibara town, located in Awi Zone, Amhara region, which lies 445km north-west of Addis Ababa, the capital city of Ethiopia, and 122km south-west of Bahir Dar, the capital city of the Amhara National Regional State (ANRS). Injibara is a relatively high-altitude town whose elevations vary from 2,540m to 3,000m above sea level (Town Administration Office of Injibara, 2018).
Study design
To achieve the purpose of this study, a true experimental design in a randomized pre-test post-test control group design was employed. This design controls all internal threats to validity. Because of the strict random assignment of subjects, it is assumed that the two groups are equivalent on all important dimensions.
Population, sampling, and sampling techniques
For this study, fifty Injibara town u-17 male volleyball players were selected purposely from the target population. Based on the inclusion criteria, only forty-four volleyball players fulfilled the criteria and volunteered to participate in the study, of which four volleyball players declined to participate in the study. However, to manage the study, only forty volleyball players were selected by simple random sampling techniques. Then the study subjects were randomly assigned to two equal groups of EG (n = 20) and CG (n = 20).
Inclusion and exclusion criteria
Subjects were included in this study after signing a participation agreement and attending the training program until the trial ended. Only male volleyball players between the ages of 15 and 17 were eligible to take part in this study. On the other hand, subjects in the pilot study were not included. Subjects with bone and joint problems and those who were using medications were excluded from the study. However, all subjects selected to participate in the study were in good physical condition.
Source of data
Both primary and secondary sources of data were utilized in this study. Therefore, the primary data was collected from u-17 male volleyball players based on the experimental parameters, and secondary data was gathered from a variety of sources, including papers, periodicals, books, online sources, and unpublished booklets.
Variables and tests
Based on the purpose and the appropriateness of variables to be determined in relation to u-17 male volleyball players, the T-test for agility, the thirty-second jump test for endurance, and the vertical jump test for power were chosen to carry out this experimental research.
Control of data quality
The tools employed to measure the test variables were of good quality and standard. Therefore, measurements were obtained three times from each variable of the study subjects at the same time of day and in identical environmental conditions to ensure uniformity, dependability, and consistency of measurements. Therefore, to ensure the measurements were properly calibrated and taken by the same examiner for each test.
Training protocol
For systematic data collection, the EG was exposed to game-based training programs for twelve weeks on three non-consecutive days per week, i.e., Monday, Wednesday, and Friday, each lasting two hours in the afternoon session. The CG did not perform game-based training other than the usual volleyball training given by the coach. Therefore, prior to the commencement of experimental interventions, pre-test measurements were done within the first week of the twelve-week training program, while post-tests were performed within the first week following the completion of the training program.
Data analysis
The collected data for this study was analyzed and interpreted using descriptive and inferential statistics. In sum, all the statistical tests were calculated using SPSS version 26 software. However, the level of statistical significance was set at p ≤ 0.05. The test results were interpreted and displayed in tables in connection to physical fitness qualities.