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The Effects of Number and Separation of Support Lines on the Size, Velocity, and Smoothness of Handwriting

Ivonne H.F. Duiser, Annick Ledebt, John van der Kamp, and Geert J.P. Savelsbergh

We examined the effects of number of and separation between support lines on handwriting characteristics of primary school students with satisfactory and unsatisfactory handwriting. Students (mean age 7.9 years) copied a text on paper with a baseline and with two or four support lines with a separation of 3 or 4 mm between the central lines. Handwriting size, velocity, and smoothness were determined for the four conditions relative to baseline. Children with unsatisfactory handwriting wrote larger and had more lifts during baseline condition. Writing between support lines, especially with small separation, immediately reduced the size of handwriting, but also adversely affected velocity and smoothness. Future research is needed to assess long-term effects.

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Volume 26 (2022): Issue 2 (Apr 2022)

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Cognitive and Physical Effects of Warm-Up on Young Soccer Players

Francisco Tomás González-Fernández, Hugo Sarmento, Sixto González-Víllora, Juan Carlos Pastor-Vicedo, Luis Manuel Martínez-Aranda, and Filipe Manuel Clemente

This study analyzed the effects of with (WC) or without conducting a warm up on youth soccer players immediately before performing physical and cognitive tests. Fourteen youth soccer player (age 11.64 ± 0.50) participated in a counterbalanced cross-sectional study in which three conditions were tested: (a) basal lineal condition; (b) WC (immediately before the physical and cognitive tests); and (c) without WC (passive resting for 15 min between the warm-up and physical and cognitive tests). A 30-m sprint test, countermovement jump, and psychomotor vigilance task were also applied. The WC revealed significant improvements in countermovement jump (p < .05), 30-m sprint test performance (p < .05), and reaction time in psychomotor vigilance task (p < .05) in comparison to basal lineal condition and without WC. A 15-min rest after a warm-up has a meaningfully decremental effect on the physical and cognitive readiness of youth soccer players, in comparison with when they warm-up immediately before the demands are imposed.

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Visual, Vestibular, and Proprioceptive Dependency of the Control of Posture in Chronic Neck Pain Patients

Alireza Alizadeh, Amir Salar Jafarpisheh, Maryam Mohammadi, and Amir H. Kahlaee

Sensory reweighting of postural control was compared in participants with and without neck pain. Center of pressure variables of 60 volunteers, the same in each group, were calculated under four standing conditions: (a) eyes open, neutral head posture; (b) foam interface, eyes open; (c) cervical extension, eyes open; and (d) cervical extension, eyes closed. All center of pressure variables except anterior posterior range/velocity increased significantly in Condition 2 compared with Conditions 1 and 3 (p < .001) and in Condition 4 compared with Conditions 1 and 3. The mediolateral range/velocity and path length in both groups, anterior posterior range in patients, and center of pressure area in the control group were significantly different between Conditions 2 and 4 (p < .001). No overweighting was observed on the vestibular or visual afferents in patients. Compensatory strategies seem to lie within the proprioceptive system.

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High-Intensity Interval Exercise Performance in Judo Athletes: Physiological, Perceptual, and Pacing Responses

Rafael L. Kons and Daniele Detanico

This study aimed to verify the behavior of physiological, perceptual, and performance responses during a high-intensity exercise in judo athletes and to identify if this protocol is able to discriminate athletes from different levels (national vs. state). Forty-five male judo athletes participated and were divided into two groups: state (age 24.2 ± 3.7 years) and national (22.1 ± 3.3 years). Judo athletes performed a judo-specific protocol contained high-intensity intermittent exercise consisted of 12 sets of 20 s in all-out intensity. During the protocol, the repetitions and heart rate were assessed over the sets, and at the end of the protocol, the rate of perceived exertion was measured. The results showed that the national group presented higher repetitions (29 ± 4 repetitions) during the high-intensity intermittent exercise compared with state (22 ± 2 repetitions). However, the national group showed a progressive decrease of repetitions up to the middle of the protocol, which coincided with higher values of heart rate compared with state (first and second sets). There was a decrease of repetitions from the first set (p < .001) and similar values of heart rate from the third set in the state. In conclusion, the performance (in repetitions) during the high-intensity intermittent exercise was able to discriminate athletes from different competitive levels. National athletes presented better performance, but worse pacing strategy compared with state.

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Levels of Gnostic Functions in Top Karate Athletes—A Pilot Study

Tatiana Tapajcikova, Dávid Líška, Ladislav Batalik, Clea P. Tucker, and Alena Kobesova

High-quality sensory perception and body scheme (somatognosis) are important aspects for sport performance. This study compares stereognosis, body scheme, and kinesthesia in a group of 36 competitive karate athletes against a control group of 32 general population participants. The stereognosis Petrie test, two body scheme tests, and three kinesthesia tests served as outcome measurement tools. No significant difference was found in the stereognosis Petrie test, for the dominant (p = .389) or the nondominant (p = .791) hand, nor in the kinesthesia test (dominant, p = .661 and nondominant, p = .051). Karate athletes performed significantly better in the body scheme tests, that is, fist width estimation (p = .024) and shoulder width estimation (p = .019), as well as in karate-specific kinesthesia tests, that is, single punch (p = .010) and triple punch (p = .001). This study confirms competitive karate athletes have significantly better somatognosis, and better accuracy when performing quick dynamic movements compared with the general population.

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Optimality, Stability, and Agility of Human Movement: New Optimality Criterion and Trade-Offs

Mark L. Latash

This review of movement stability, optimality, and agility is based on the theory of motor control with changes in spatial referent coordinates for the effectors, the principle of abundance, and the uncontrolled manifold hypothesis. A new optimality principle is suggested based on the concept of optimal sharing corresponding to a vector in the space of elemental variables locally orthogonal to the uncontrolled manifold. Motion along this direction is associated with minimal components along the relatively unstable directions within the uncontrolled manifold leading to a minimal motor equivalent motion. For well-practiced actions, this task-specific criterion is followed in spaces of referent coordinates. Consequences of the suggested framework include trade-offs among stability, optimality, and agility, unintentional changes in performance, hand dominance, finger specialization, individual traits in performance, and movement disorders in neurological patients.

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Effects of 4 Weeks of Variability of Practice Training in Padel Double Right Wall: A Randomized Controlled Trial

Carolina Gutiérrez-Álvarez, Joshua Colomar, Ernest Baiget, Santos Villafaina, and Juan Pedro Fuentes-García

This study aimed to analyze the effect of a variable practice training in the double wall right forehand by using wrist weights. Thirty-four experienced padel players participated in this study. Players were randomly distributed in two groups (control group [CG] and training group [TG]). The TG performed 1 month of variable training, induced by weighted wrist bands, twice a week, with the same number of sessions and volume of training as the CG. TG obtained significant difference in posttest measurements (effect size = 0.437) in terms of the number of successful shots compared to CG (effect size = 0.027). These findings showed a significant effect of the TG with respect to the CG. Results reinforce the role of variability in the exploration and reinforcement of motor learning.

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Feasibility of Volitional Reaction Time Tests in Athletes: A Systematic Review

Danica Janicijevic and Amador Garcia-Ramos

This systematic review aimed to synthesize the current evidence on the feasibility of volitional reaction time (RT) tests to evaluate the information processing abilities of athletes. Four databases were searched, and, finally, 38 studies exploring the reliability, validity, or sensitivity of RT tests were included. Seven studies explored the reliability, which ranged from poor to excellent, while only three studies explored the validity of RT tests. The most important downside of the majority of the implemented RT tests is their nonspecific nature (i.e., stimulus and response did not resemble the sports actions). Sports scientists should focus on developing RT tests that are specific for each sport and refine the testing procedures to obtain accurate, reproducible, and sensitive measurements of RT.

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Exploring Sex Differences and Force Level Effects on Grip Force Perception in Healthy Adults

Yan-Xia Li, Lin Li, Zhi-Qiang Cai, Xu-Xue Zhou, Xiu-Jun Hao, and Li Li

This study aimed to explore the effect of sex and force level on grip force reproduction in healthy adults by conducting a force reproduction task. Participants (n = 28) were instructed to replicate a range of reference grip force levels (10–130 N in 10 N increments). We found that women (absolute error: 16.2 ± 8.7 N) replicated these force levels more accurately than men (absolute error: 23.1 ± 9.5 N) at higher force levels (90–130 N). Furthermore, the force reproductions were most accurate at the 30–50 N range for men and the 50–60 N range for women. These results may offer significant insights into the higher rates of musculoskeletal disorders among women, enabling researchers and clinicians to design novel interventions and tools that can improve grip force perception and reduce hand injury rates in both men and women.