Feedback is one of the most influential factors for motor skills learning. Physical Education teachers commonly use verbal cues to provide knowledge of process (KP) when teaching motor skills, but the ideal presentation frequency for KP in adolescents is unclear. The aim of this study was to compare the effectiveness of the frequency of KP (i.e., 100%, 67%, 0%) on dynamic balance. Thirty adolescents, age 14–15 years, participated in the study. Performance on a stabilometer platform was used to assess dynamic balance. Participants received feedback after each trial (100%), in two out of three trials (67%), or no feedback during 12 30-s trials of practice. Adolescents who received feedback (67% or 100%) required lower mean velocity to maintain similar dynamic balance performance (i.e., root mean square). Moreover, adolescents receiving 100% feedback had a higher α-scaling than those who did not received it. During the post-test and the retention, both 67% and 100% KP frequencies were effective at improving postural control, compared to the no feedback control.
Julián Gandía, Xavier García-Massó, Adrián Marco-Ahulló and Isaac Estevan
Jose Morales, Emerson Franchini, Xavier Garcia-Massó, Mónica Solana-Tramunt, Bernat Buscà and Luis-Millán González
To adapt the work endurance recovery (WER) method based on randori maximal time to exhaustion (RMTE) for combat situations in judo.
Eleven international-standard judo athletes (7 men and 4 women; mean age 20.73 ± 2.49 y, height 1.72 ± 0.11 m, body mass 67.36 ± 10.67 kg) were recruited to take part in the study. All participants performed a maximal incremental test (MIT), a Wingate test (WIN), a Special Judo Fitness Test (SJFT), and 2 RMTE tests. They then took part in a session at an international training camp in Barcelona, Spain, in which 4 methods of load quantification were implemented: the WER method, the Stagno method, the Lucia method, and the session rating of perceived exertion (RPEsession).
RMTE demonstrated a very high test–retest reliability (intraclass correlation coefficient = .91), and correlations of the performance tests ranged from moderate to high: RMTE and MIT (r = .66), RMTE and WIN variables (r = .38–.53), RMTE and SJFT variables (r = .74–.77). The correlation between the WER method, which considers time to exhaustion, and the other systems for quantifying training load was high: WER and RPEsession (r = .87), WER and Stagno (r = .77), WER and Lucia (r = .73). A comparative repeated-measures analysis of variance of the normalized values of the quantification did not yield statistically significant differences.
The WER method using RMTE is highly adaptable to quantify randori judo sessions and enables one to plan a priori individualized training loads.
Isaac Estevan, Sergio Gandia, Israel Villarrasa-Sapiña, José Luis Bermejo and Xavier García-Massó
This paper describes a study on postural stability and cognitive function according to the difficulty increment of a working memory task (WMT) and age group in adolescents. One hundred and twenty-three participants (13–16 years) performed single and dual tasks in a bipedal standing position while barefoot. Four trials were conducted, consisting of single and dual tasks in three progressively difficult WMT conditions (i.e., 3-, 5-, and 7-digit sequences). Friedman’s analysis of variance and Kruskal–Wallis tests were conducted to test the effect of the WMT and age group, respectively. Both the WMT and age were found to affect performance (p < .01). As the cognitive requirements increased, the adolescents were not able to maintain their performance in both balance and cognition, while postural control and cognition were found to evolve with age.
Xavier García-Massó, Isaac Estevan, Roberto Izquierdo-Herrera, Israel Villarrasa-Sapiña and Luis-Millan Gonzalez
The purposes of the present study were a) to establish postural control profiles for individuals 6–12 years of age, b) to analyze the participants’ characteristics (age, sex, weight, height, and physical activity) in those profiles, and c) to analyze the influence of visual information in the profiles found. Two hundred and eight typically developing children aged 6–12 years performed two trials in bipedal standing position with eyes open and closed. Feature extraction involved time, frequency, and sway-density plot variables using signals from the center of pressure. A Self-Organizing Map was used to classify and visualize the values of the participants in all the postural control variables tested. A k-means cluster analysis was applied to generate a small number of postural control profiles. The results determined six postural control profiles; three with participants denoting high stability and three considered as low stability profiles. Age, sex, and height were related to the postural control profiles. Boys were more frequently allocated in high stability clusters than girls, while the other factors yielded unclear difference between high and low stability profiles. The analysis of children’s profiles reflecting postural stability should therefore involve more than one factor including the individuals’ age, sex, and height.
Xavier García-Massó, Adrià Marco-Ahulló, Israel Villarrasa-Sapiña, Julio Álvarez-Pitti and Jose-Luis Bermejo
Introduction: Overweight/obese children have postural control differences compared with normal-weight children. Nevertheless, there are not studies that analyze the effect of obesity during the entire period comprised between childhood and adolescence. The objective of this study was to determine the differences in postural control between normal-weight and overweight/obese participants during early and middle childhood and adolescence. Methods: 359 children were divided into six groups according to age and weight status. Each participant carried out one 30-s trial with eyes open (EO) and one 30-s trial with eyes closed (EC). Center of pressure signals were acquired using a Wii Balance Board. Mean velocity in antero-posterior (MVAP) and medio-lateral (MVML) directions and the 95% confidence interval ellipse area were calculated. Results: A Mann Whitney U-test showed significant differences between normal-weight and obese 8- to 12-year-old children in MVAP and MVML in both EO and EC. In 13- to 17-year-old adolescents, there were differences between normal-weight and overweight/obese in ellipse area and MVML, both in EO and EC condition. There were no differences in postural stability between normal-weight and overweight/obese 4- to 7-year-old children. Conclusions: Obesity reduces postural stability only in middle childhood and adolescence but not in early childhood.
Alexandra Valencia-Peris, José Devís-Devís, Xavier García-Massó, Jorge Lizandra, Esther Pérez-Gimeno and Carmen Peiró-Velert
Previous research shows contradictory findings on potential competing effects between sedentary screen media usage (SMU) and physical activity (PA). This study examined these effects on adolescent girls via self-organizing maps analysis focusing on 3 target profiles.
A sample of 1,516 girls aged 12 to 18 years self-reported daily time engagement in PA (moderate and vigorous intensity) and in screen media activities (TV/video/DVD, computer, and videogames), separately and combined.
Topological interrelationships from the 13 emerging maps indicated a moderate competing effect between physically active and sedentary SMU patterns. Higher SES and overweight status were linked to either active or inactive behaviors. Three target clusters were explored in more detail. Cluster 1, named temperate-media actives, showed capabilities of being active while engaging in a moderate level of SMU (TV/video/DVD mainly). In Cluster 2, named prudent-media inactives, and Cluster 3, compulsive-media inactives, a competing effect between SMU and PA emerged, being sedentary SMU behaviors responsible for a low involvement in active pursuits.
SMU and PA emerge as both related and independent behaviors in girls, resulting in a moderate competing effect. Findings support the case for recommending the timing of PA and SMU for recreational purposes considering different profiles, sociodemographic factors and types of SMU.