Raúl Reina

Visual search strategies in experienced and inexperienced gymnastic coaches.

The visual search strategies employed by gymnastic coaches with different levels of expertise were investigated. Expert (n = 3) and novice coaches (n = 3) watched 9 video sequences of 3 gymnastic techniques and were required to highlight errors in performance. Visual search patterns were monitored by an ASL-5000SE eye-tracking system during observation. Expert participants showed longer and fewer visual fixations than the novice group.

Analysis of Effects of Distribution of Practice in Learning and Retention of a Continuous and a Discrete Skill Presented on a Computer

This investigation examined the effects of distributed and massed practice on the learning and retention of a discrete computerized skill (Exp. 1) and a continuous computerized skill (Exp. 2). 40 men were randomly assigned to one of four groups, of which two groups took part in Exp. 1 and two groups in Exp. 2. Performance was assessed at various points during acquisition and then on 8 retention tests conducted at varying times after acquisition. Learning curves for practice were highly similar for the two conditions. Participants in the distributed-practice group performed significantly better than those in the massed-practice group at the end of practice on both the discrete and continuous skills. However, participants in the distributed-practice group performed significantly more poorly on retention during 24 hr. and after acquisition. Participants in the massed-practice condition performed significantly better on retention tests than did those who learned in the distributed-practice condition.

Visual Search Strategies of Experienced and Nonexperienced Swimming Coaches

The aim of this study consists of the application of an experimental protocol that allows information to be obtained about the visual search strategies elaborated by swimming coaches. 16 swimming coaches participated. The Experienced group (n = 8) had 16.1 yr. (SD = 8.2) of coaching experience and at least five years of experience in underwater vision. The Nonexperienced group in underwater vision (n = 8) had 4.2 yr. (SD = 4.0) of coaching experience. Participants were tested in a laboratory environment using a video-projected sample of the crawl stroke of an elite swimmer. This work discusses the main areas of the swimmers body used by coaches to identify and analyse errors in technique from overhead and underwater perspectives. In front-underwater videos, body roll and mid-water were the locations of the display with higher percentages of fixation time. In the side-underwater slow videos, the upper body was the location with higher percentages of visual fixation time and was used to detect the low elbow fault. Side-overhead takes were not the best perspectives to pick up information directly about performance of the arms; coaches attended to the head as a reference for their visual search. The observation and technical analysis of the hands and arms were facilitated by an underwater perspective. Visual fixation on the elbow served as a reference to identify errors in the upper body. The side-underwater perspective may be an adequate way to identify correct knee angles in leg kicking and the alignment of a swimmers body and leg actions.

Visual behavior and perception of trajectories of moving objects with visual occlusion.

Experienced athletes in sports with moving objects have shown greater skill when using visual information to anticipate the direction of a moving object than nonexperienced athletes of those sports. Studies have shown that expert athletes are more effective than novices in occlusion situations in the first stages of the sports sequence. In this study, 12 athletes with different competitive experience in sports with moving objects viewed a sequence of tennis ball launches with and without visual occlusion, launched by a ball-shooting machine toward different areas with respect to the participants position. The relation among visual behavior, occlusion time, and the precision of the task is reviewed. The spot where the balls bounced was analysed by a digital camera and visual behavior by an Eye Tracking System. Analysis showed that the nonexperienced athletes made significantly more errors and were more variable in visual occlusion conditions. Participants had a stable visual search strategy.

Study of Reaction Time to Visual Stimuli in Athletes with and without a Hearing Impairment

This study analyzes the differences in manual reaction time (RT) to visual stimuli in two samples of physically active persons: a group of athletes without hearing impairment (n = 79; M age = 22.6yr., SD = 3.7) and a group of athletes with hearing impairment (n = 44, M age = 25.6 yr., SD = 5.0). Reaction time (RT) was measured and then differences between both groups were assessed by sex, type of sport (individual vs team sports), and competition level. RT to visual stimuli was significantly shorter for athletes with hearing impairment than for those without hearing impairment, with a significant sex difference (shorter RT for males), but no differences regarding type of sport or competition level. Suggestions for further research and sport applications are provided.

Role of vision in sighted and blind soccer players in adapting to an unstable balance task

This study tested whether a compensatory hypothesis exists on postural control during standing unstable balance tasks comparing blind soccer players (n = 7) to sighted soccer players (n = 15) and sighted sedentary individuals (n = 6). All subjects performed a pre-test, a training of ten practice trials on a single day, and a post-test balance test. All tests were performed on an unstable surface placed on a force platform and under closed-eyes conditions, and a final test was performed with open eyes. Balance performance was assessed by resultant distance (RD) and the magnitude of mean velocity (MV) of the centre of pressure (CoP) displacement, and EMG signals from the gastrocnemius lateralis, tibialis anterior, rectus femoris, and peroneus longus were measured with surface electromyography. Principal component analysis (PCA) on EMG muscular activation was used to assess EMG pattern differences during the balance tasks. All groups improved their performance, obtaining low scores for the closed-eyes condition balance task after the training period in RD, VM, and aids received to keep balance in the novel task, and no differences were found between groups or in interaction effects. Sighted individuals and the control group showed significantly lower RD and VM scores under open-eyes conditions than blind participants. As regards neuromuscular behaviour, three principal patterns explained 84.15% of the variability in the measured data. The theoretical improvement of the other senses caused by visual deprivation does not allow blind individuals to obtain better balance than sighted individuals under closed-eyes conditions, thereby reinforcing the prominent role of vision in integrating and processing the other sensory inputs. In addition, blind individuals seem to increase their muscular co-activation as a safety strategy, but this behaviour is not different to that shown by sighted people under closed-eyes conditions.

Differences in Physiological Responses During Wheelchair Basketball Matches According to Playing Time and Competition

ABSTRACT Purpose: The main purpose of the present study was to determine physiological responses in wheelchair basketball (WB) matches in relation to heart rate (HR), match load (ML), differentiated perceived exertion (dRPE), lactate concentrations (LA), and tympanic temperature (TEMP), while specifying the individual player’s playing time during different types of matches. Method: Nine Spanish First Division WB players participated in the study. Three groups were determined for each observation (i.e., HR, ML, dRPE, LA, and TEMP) according to the minutes played by the WB players: players who had played 30 min to 40 min (WB30–40), those who played 20 min to 30 min, and those who played 0 min to 20 min. Results: The WB30–40 group attained statistically significantly higher results in mean HR than the other groups in league and playoff matches (p < .05; Δ% > –25.73%; ES > –1.31, large). With regard to the difference in each variable between league and playoff matches, the differences were highlighted in the WB30–40 group according to ML (Edwards, p < .05, Δ% = –11.14%, ES = –0.87, large; Stagno’s modified TRIMP, p < .05, Δ% = –16.95%, ES = –0.77, large). Tympanic temperature also reached higher values in playoff matches compared with league matches in WB30–40 (p < .05; Δ% = 1.1%; ES = 0.67, moderate) but not in LA values. Conclusions: Coaches should take into account that playoff matches were more demanding than league matches, thus forcing coaches to try to peak WB players’ physical performance for the former.

How does the ball influence the performance of change of direction and sprint tests in para-footballers with brain impairments? Implications for evidence-based classification in CP-Football

The aims of this study were: i) to analyze the reliability and validity of three tests that require sprinting (10 m, 25 m, 40 m), accelerations/decelerations (Stop and Go Test) and change of direction (Illinois Agility Test), with and without ball, in para-footballers with neurological impairments, and ii) to compare the performance in the tests when ball dribbling is required and to explore the practical implications for evidence-based classification in cerebral palsy (CP)-Football. Eighty-two international para-footballers (25.2 ± 6.8 years; 68.7 ± 8.3 kg; 175.3 ± 7.4 cm; 22.5 ± 2.7 kg·m-2), classified according to the International Federation of Cerebral Palsy Football (IFCPF) Classification Rules (classes FT5-FT8), participated in the study. A group of 31 players without CP was also included in the study as a control group. The para-footballers showed good reliability scores in all tests, with and without ball (ICC = 0.53–0.95, SEM = 2.5–9.8%). Nevertheless, the inclusion of the ball influenced testing reproducibility. The low or moderate relationships shown among sprint, acceleration/deceleration and change of direction tests with and without ball also evidenced that they measure different capabilities. Significant differences and large effect sizes (0.53 < ηp2 < 0.97; p < 0.05) were found when para-footballers performed the tests with and without dribbling the ball. Players with moderate neurological impairments (i.e. FT5, FT6, and FT7) had higher coefficients of variation in the trial requiring ball dribbling. For all the tests, we also obtained between-group (FT5-FT8) statistical and large practical differences (ηp2 = 0.35–0.62, large; p < 0.01). The proposed sprint, acceleration/deceleration and change of direction tests with and without ball may be applicable for classification purposes, that is, evaluation of activity limitation from neurological impairments, or decision-making between current CP-Football classes.

Manual Dexterity and Intralimb Coordination Assessment to Distinguish Different Levels of Impairment in Boccia Players with Cerebral Palsy

Background Boccia is a paralympic sport played by athletes with severe neurological impairments affecting all four limbs. Impaired manual dexterity (MD) and intralimb coordination (ILC) may limit individuals’ ability to perform certain activities such as grasping, releasing, or manipulating objects, which are essential tasks for daily life or to participate in para sports such as boccia. However, there are currently no specific instruments available to assess hand–arm coordination in boccia players with severe cerebral palsy (CP). Purpose To design new sport-specific coordination tests to assess impaired MD and ILC in boccia players; afterward, quantify to what extent their coordination is impaired compared to a control group (CG) without neurological impairments. Methods Seventy-three recreational boccia players with severe CP (BC1: age = 34.01 ± 16.43 years; BC2: age = 33.97 ± 14.29 years), and 19 healthy adults (age = 27.89 ± 7.08 years) completed the test battery. The Box and Block test (BBT) and Box and Ball test (BBLT) were used to assess MD and four tapping tests to assess upper ILC. Results Both MD tests were able to discriminate between sport classes. Boccia players obtained better scores in the BBLT in comparison to the BBT, showing that the BBLT had more appropriate testing features. On the other hand, only one of the ILC tests was able to discriminate between sport classes, displaying the highest practical significance (d = −1.12). Participants with CP scored significantly worse in all the coordination tests compared to the CG. Conclusion Using sport-specific equipment facilitated grasp function during the MD assessment. Regarding the ILC, the type of movement (continuous vs. discrete) seems to be more relevant for classification than the movement direction (vertical vs. horizontal) or the presence of a ball.