Human Movement 18 (4) 2017
Łukasz Wądrzyk, Leszek Nosiadek, Robert Staszkiewicz
Underwater dolphin kicks of young swimmers – evaluation of effectiveness based on kinematic analysis
Purpose. The aim of the study was to distinguish the kinematic indicators influencing the average horizontal velocity of swimming (vCOM) with underwater dolphin kicks (UDK).
Methods. The study involved 15 boys and 20 girls (mean age, 11.5 ± 1.00 years; height, 1.57 ± 0.09 m; training experience, 2.5 ± 1.00 years) practicing swimming 7 times a week. We determined the body height (H), the length of the body with the arms lifted (Lb), and the best result in the 50-m freestyle (pbt); characteristic anthropological points were marked on the body. The subjects performed UDK after a water-start for a distance of ca. 8 m (without a push-off from the wall). Movements were recorded with an underwater camera. The recordings were kinematically analysed with the SkillSpector program. On this basis, we calculated vCOM, frequency of movement (f), amplitude of movement (A), horizontal displacement in one cycle (Dpk), maximum flexion in the knee joints (KFmax), the product of f and A (IAf), the Strouhal number (St), and relative amplitude of toe movement (AREL).
Results. The movements of the subjects were characterized as follows: vCOM = 1.08 ± 0.13 m/s, f = 2.00 ± 0.39 Hz, A = 0.46 ± 0.08 m, Dpk = 0.58 ± 0.10 m, IAf = 0.90 ± 0.11, KFmax = 71.37 ± 9.15°, St = 0.83 ± 0.08, AREL = 0.22 ± 0.04. A statistically significant correlation was found between vCOM and: H (r = 0.35), pbt (r = –0.52), f (r = 0.47), IAf (r = 0.72), KFmax (r = –0.53), and St (r = –0.36).
Conclusions. UDK of young swimmers is characterized by low-speed swimming. This is effected by low swimming efficiency (low values of IAf and St, high value of KFmax). The proper amplitude and frequency of movements should be a priority in improving UDK. The UDK technique should be particularly enhanced among short competitors.
Key words: biomechanics, kinematics, swimming, youth sports
Michał Boraczyński, Tomasz Boraczyński, Robert Podstawski, James Laskin, Dariusz Choszcz, Adam Lipiński
Relationships between anthropometric features, body composition, and anaerobic alactic power in elite post-pubertal and mature male taekwondo athletes
Purpose. The paper describes the relationships between anthropometric features, body composition, and anaerobic alactic power (AAP) in elite post-pubertal and mature male taekwondo athletes.
Methods. The sample of 41 taekwondo athletes was divided into two groups: post-pubertal (P-P, n = 19, Mage = 15.6 ± 1.1 years) and mature (M, n = 22, Mage = 20.7 ± 2.8 years). Anthropometric features (WB-150, ZPU Tryb-Wag, Poland), body composition (BC-418 MA, Tanita, Japan), maturational status (Pubertal Maturational Observational Scale), and AAP (10-s version of the Wingate Anaerobic Test) were assessed.
Results. Post-hoc testing revealed significant between-group differences (3.2–20.4%, p < 0.01) in all anthropometric and body composition measures, with effect sizes (ES) between −0.79 and −1.25 (p < 0.001), except for fat content and percentage of skeletal muscle mass (SMM) (p ≥ 0.05). In group M, the maximal power output (Pmax) was greater (ES = −1.15, p < 0.001) and the time of its attainment shorter (ES = 0.59, p < 0.001) than in group P-P. Correlation analyses indicated notably strong associations between body mass (BM) and Pmax in group P-P (r = 0.950 [95% CI, 0.85–0.98], p < 0.001) and M (r = 0.926 [95% CI, 0.81–0.97], p < 0.001), and similar-sized strong correlations between fat-free mass (FFM) and Pmax in group P-P (r = 0.955 [95% CI, 0.86–0.99], p < 0.001) and M (r = 0.924 [95% CI, 0.82–0.96], p < 0.001). Additionally, a strong correlation was found between body height and Pmax in groups P-P and M (r = 0.805 [95% CI, 0.54–0.92], p < 0.001 and r = 0.819 [95% CI, 0.58–0.93], p < 0.001, respectively). Linear regression analyses demonstrated that FFM, BM, and absolute SMM best explained the variance in Pmax in both groups (r, 0.939–0.951; r2, 0.882–0.909).
Conclusions. The strong correlations observed in both groups between BM, FFM, SMM, and Pmax demonstrate the significant effects of body size and composition on AAP. By determining the current levels of these measures for individual athletes and via regressive modelling, one can anticipate the individual developmental dynamics of AAP. On the basis of anthropometric profiling, we recommend the recruitment and selection of tall and lean individuals with high anaerobic predisposition in taekwondo. Such a profile may enable coaches to better predict future athlete development, particularly in AAP.
Key words: combat sports, physical features, anaerobic capabilities, Wingate Anaerobic Test
Guilherme S. Nunes, Shelley Uhlig, Luciane Mari do Amaral Ribas, Fernanda Bottin Gonçalves, Bruna Wageck,
Marcos de Noronha
Influence of neural mobilization of lower limbs on the functional performance and dynamic balance in asymptomatic individuals: A cross-over randomized controlled trial
Purpose. To verify the influence of neural mobilization (NM) applied to the lower limbs on functional performance and dynamic balance in asymptomatic individuals.
Methods. The total of 30 asymptomatic participants (15 women and 15 men; age, 30.1 ± 6.7 years; height, 1.70 ± 0.1 m; body mass, 73.1 ± 13.4 kg) were enrolled in this cross-over randomized controlled trial. The participants received NM of the femoral, sciatic, and tibial nerves, as well as static stretching (SS) of the following muscles: hamstring, lumbar, piriformis, hip adductors, hip flexors, quadriceps, and triceps surae. The order of applying NM and SS was randomly decided and the interventions were performed at least 48 hours apart. Functional performance was measured by performance in vertical jump (VJ) and dynamic balance was measured with the Star Excursion Balance Test (SEBT).
Results. There were no differences between NM and SS for height (cm) in VJ (p = 0.16) or in the distance reached (%) in the SEBT, normalized by lower limb length (dominant limb: anterior, p = 0.35; posterolateral, p = 0.69; posteromedial, p = 0.50 / non-dominant limb: anterior, p = 0.68; posterolateral, p = 1.00; posteromedial, p = 0.77).
Conclusions. NM did not exert any influence on functional performance or dynamic balance. Thereby, having no positive or negative impact on performance, NM can be used at any time of treatment.
Key words: nervous system, lower limbs, exercise therapy, motor activity, postural balance
Panagiotis Tsaklis, Savvas Alexandros Zorzos, Dimitra Mertyri
Gait adaptations, after vestibular stimulation, in children with congenital visual impairments: a comparative study
Purpose. The study is based on the hypothesis that individuals with congenital total or partial loss of vision develop more effective gait adjustments compared with those who are sighted, after stimulation of the vestibular system. Therefore, they are able to manage their motor control better. The aim was to investigate the way individuals with congenital total or partial vision loss adjust their gait following vestibular stimulation, compared with sighted blindfolded individuals.
Methods. The total of 10 children with congenital visual impairments constituted the experimental group and 10 children with normal vision (blindfolded with special mask) formed the control group. We performed gait analysis (forward and backward gait direction) with a three-dimensional gait analysis system. The walking speed (m/s) of each group, before and after the vestibular stimulation, during forward and backward gait, was analysed.
Results. The average walking speed of the children in the experimental group, statistically, revealed no significant differences before and after the vestibular stimulation. Conversely, in the control group, statistically significant differences in the mean walking speed before and after the vestibular system stimulation were found.
Conclusions. Children with congenital total or partial blindness may adapt their gait strategy more adequately, after vestibular stimulation, during forward and backward gait, as compared with sighted blindfolded children. Consequently, the first group is in the position to manage their motor control more sufficiently.
Key words: children, vestibular system, gait, stimulation, blindness, motor control
Thaís Cardoso da Silva, Lilian Assunção Felippe, Rodrigo Luiz Carregaro, Gustavo Christofoletti
Postural instability in subjects with Parkinson disease undergoing different sensory pitfalls
Mariam Abd-Elmoneim Ameer, Amr Almaz Abdel-aziem
Relationship between anthropometric measures and sagittal spinal curvatures in adult male handball players
Maria Edilma da Silva Bezerra, Lysleine Alves de Deus, Thiago dos Santos Rosa, Edson Eduardo Leal da Silva,
Herbert Gustavo Simões, Elaine Vieira
Acute effects of cycling exercise on post-exercise blood pressure in individuals with Down Syndrome
Daniel V. Chagas, John Ozmun, Luiz Alberto Batista
The relationships between gross motor coordination and sport-specific skills in adolescent non-athletes
Human Movement 18, Special issue
SCIENCE IN SOCCER
Leandro Rechenchosky, Paulo Henrique Borges, Vanessa Menezes Menegassi, Matheus de Oliveira Jaime,
José Guilherme, Israel Teoldo, Wilson Rinaldi
Comparison of tactical principles efficiency among soccer players from different game positions
Rodrigo Aquino, Enrico F. Puggina, Isabella S. Alves, Júlio Garganta
Skill-related performance in soccer: A sytematic review
Renato Tavares Fonseca, Rodolfo de Alkmim Moreira Nunes, Juliana Brandão Pinto de Castro, Vicente Pinheiro Lima,
Sérgio Gregorio Silva, Estélio Henrique Martin Dantas, Rodrigo Gomes de Souza Vale
Aquatic and land plyometric training on the vertical jump and delayed onset muscle soreness in Brazilian soccer players
Felipe A. Moura, Ana L. Marche, Fabio G. Caetano, Ricardo D.S. Torres, Luiz E.B. Martins, Sergio A. Cunha
Analysis of high-intensity efforts of Brazilian professional soccer players