Motor competence in fundamental motor skills is known to be positively related to youth physical activity levels, physical fitness across the childhood and adolescence, and cause the positive health outcomes throughout the lifecycle [10, 19, 20]. Further, it is very important in learning a sports motor, and performing sport-specific motor skills in team-athletes [20]. Recent study demonstrated that athletes with higher motor competence level in motor skills learned complex motor skills more easily than those with lower motor competence in motor skills [21]. Another study indicated that low motor competence in motor skills could be a barrier to achieve additional and transitional sports skills, independent of the practice schedule [20]. Regarding the studies mentioned above, it is one of the most important purpose of our study to determine the level of motor competence of young female volleyball players through the MCA tests battery, and to determine the reliability of these tests in this population. Moreover, the number of test trials could be important to the outcome of the performance on different motor skill tests [22]. While measuring performance with too few trials does not reflect the real performance of the individual, measuring performance with too many trials may also cause fatigue [23]. Therefore, it is important to understand how many trials (minimum and the most effective one) we can take to ensure the quality, efficacy, and reliability of the results in the MCA tests battery. Based on this, the second aim of our study is to compare the effects of the number of trials for each test in the MCA battery. The present study revealed that there was a significant difference between the first and second trial of the lateral jumps, standing long jump and 10 m shuttle run tests, while there was no significant difference between the two trials in all the remaining tests (shifting platforms, ball kicking and throwing velocity). No significant difference was noted between the second and third trial in any of the six tests. Furthermore, the level of correlation between two or three trials was high in all of these tests (ICC=0.821-0.987, good-excellent), however, the CV% value was acceptable in terms of reliability in all tests except “lateral jumps”.
The use of intra-class correlation coefficients (ICCs) in reporting intra-rater, inter-rater, and test-retest reliability is considered a "gold standard" method [14]. Regarding the motor competence tests, the present study showed that ICC values of reliability range was 0.821-0.987 (good-excellent) for six tests in three sub-dimensions. This result is in line with recent study that emphasized the ICCs for tests in MCA battery in preschoolers ranged between 0.77 and 0.96, which indicates an excellent reliability [24]. It was previously stated that the ICCs between the first and second trial for the Athletic Skills Track Test was 0.881 [25]. In the study of Rodrigues et al. [3] in which they showed the normative values of MCA between the ages of 3 and 23, they observed that locomotor, stability, and manipulative tests in MCA battery had excellent reliability (>0.950). Similarly, another study found that ICC values between two trials ranged from 0.75 to 0.94 in four different motor tasks (placing and building bricks related to manual dexterity; heel to toe walking walking/running in slopes related to dynamic balance) in Motor Competence Test [26]. Additionally, Barnett et al. [27] indicated that the ICC for the object control subtest from the Test of Gross Motor Development-2 (TGMD-2) were excellent (ICC=0.93), except the “catch” which showed good reliability (ICC=0.71) between two trials in children. In current study, it was found that the results of the reliability for ICC values were similar to the studies in the literature. According to the ICC classification made by Koo et al. [28], good and excellent reliability scores were found between two or three trials for locomotor, stability, and manipulative tests in MCA battery in our study. In an another study was carried out by Portney and Watkin [29] noted that the reliability coefficients ICC below 0.50 indicate poor reliability, from 0.50 to 0.75 represent moderate reliability, and values above 0.75 suggest high reliability. Accordingly, we can say that all tests in MCA battery performed in the form of two or three trials in our study showed high reliability.
The CV% (absolute reliability) analysis ensures information considering within-trial variability expressed as a percentage. i.e. it evaluates the stability of a measurement across repeated trials [30]. The coefficient of variation explained in the mean score percentage and a CV% below 10% are considered acceptable in terms of reliability [31]. To interpret CV% in our study, we accepted the criteria developed by Atkinson and Nevill [32], the authors reported that CV% of <10% was considered excellent, 10–20% medium, implying good precision, 20–30% high, meaning low precision and >30% was considered very high, indicating very low precision. The present study revealed that shifting platforms in two trials (CV%10.77-11.72), standing long jump (CV%9.81-11.19) and 10 m shuttle run (CV%4.47-7.07) in three trials showed excellent and moderate stability. Also, lateral jumps by ICC value appear reliable, but it is important to note that there are large individual differences in lateral jumps performance variability in both the first and second trial among players in the group (CV%: 39.43-39.61). Furthermore, the current study indicated that although the CV was over 20% on all three trials for the ball kicking velocity, and only the first trial for the ball throwing velocity, it was still considered acceptable level [32]. This result was supported by a previous study that demonstrated that CV% value of the jumping hope left performance in Performance and Fitness Test Battery was found to be 21%, and this value was stated to be at an acceptable level [33].
The present study revealed that significant differences were found between the first and the second trials for lateral jumps, standing long jump and 10 m shuttle run test. Moreover, in our study, no significant differences were found in the shifting platforms, ball throwing and kicking tests between the first and second trials. These findings indicate that it is sufficient to perform MCA test battery twice instead of three times but using familiarization session is recommended to minimize the learning effect and achieve for reliability and quality results in lateral jumps, standing long jump, 10 m shuttle run test. The familiarization of the assessed participants with the test procedures is a critical factor that can affect reliability in a motor skill tests such as TGMD-2. It can be suggested that participants need to become familiar with the lateral jumps, standing long jump, 10 m shuttle run test protocols with at least one trial before the measurement starts [22, 34]. As in this study, recent studies conducted on children and adolescents showed that stability tests (lateral jumps and shifting platform) were applied two times, while locomotor and manipulative tests (standing long jump, 10 m shuttle run, ball kicking and throwing velocity) were performed three times in the MCA test battery [15, 16, 18]. In the literature, scoring of performance in standardized test batteries varied according to a wide variety of procedures. Some studies used only best out of two trials with allowing for familiarization session in some tests such as the Peabody Developmental Motor Scales [22], and Performance-Fitness (PERF-FIT) test battery [33], and other studies used at least two trials (best or sum of two trials) in tests such as Movement Assessment Battery for Children, the Test of Gross Motor Development (TGMD-2) [27, 35], and Agility and Skill Test (sum of three trials) for soccer players [36]. Wiepert and Mercer [22] also noted that the best and quality performance results for the Peabody Developmental Motor Scales was observed in three trials compared to the best of two trials. Moreover, MCA test battery and TGMD-2 have a moderately significant correlation; this indicates that the two batteries partially measure similar aspects of motor competence [24]. Our results in all six motor tests were similar to previous studies that reported that second trial was better than the first trial for object control subtest from the TGMD-2 [27], and also Athletic Skills Track test [25], the authors suggested that the use of two trials for these tests gave reliable results. Similarly, another study indicated that performing each of the 12 gross motor skills-locomotor and object control- in the TGMD-2 test twice in Kindergarten children had good and excellent reliability. Coppens et al. [19] were tested the validity of motor competence test with KTK (Körperkoordinationstest für Kinder) in children and adolescents aged 6 to 19 years. As a result of applying the jumping sideways and moving sideways tests twice, and the balancing backwards test three times in this battery, the authors obtained the valid and reliable results. Additionally, Williams et al. [37] reported that reliability and validity (R=0.88 to 0.90) were similar for 2 and 4 four trials for CHAMPS Motor Skill Protocol in preschool children. Considering the above-mentioned studies, we can say that mostly at least two trials and in some cases two trials + practice trials were used before different motor skill tests. This is in line with the results of our study. However, the reason of the differences in the number of trials before the motor skill tests in studies in literature may be related to the motor skill test applied, the difficulty/complexity of the motor skill test, the characteristics of the tested population, and the characteristics of the sports branches.
The present study has some limitations. Firstly, this study was carried out only in female and amateur athletes. In future studies, the study can be repeated in male and elite athletes. Second, the biological maturation or menstrual cycle periods of the participants were not evaluated. Considering the relationship of physical activity to motor competence, the present study showed that reliable results were obtained in all tests in MCA battery with a small number of trials (two) in studies conducted on athletes compared to studies performed in children and adolescents. This may be related to the fact that athletes have more consistent motor control and motor performance. In future studies, the reliability, discrimination and validity of gender (male, female) and sport specific versions of the wide range of motor competence tests, including MCA battery could be evaluated in detail.