RESUMO
Between-arm performance asymmetry can be seen in different arm movements requiring specific interjoint coordination to generate the desired hand trajectory. In the current investigation, we assessed between-arm asymmetry of shoulder-elbow coordination and its stability in the performance of circular movements. Participants were 16 healthy right-handed university students. The task consisted of performing cyclic circular movements with either the dominant right arm or the nondominant left arm at movement frequencies ranging from 40% of maximum to maximum frequency in steps of 15%. Kinematic analysis of shoulder and elbow motions was performed through an optoelectronic system in the three-dimensional space. Results showed that as movement frequency increased circularity of left arm movements diminished, taking an elliptical shape, becoming significantly different from the right arm at higher movement frequencies. Shoulder-elbow coordination was found to be asymmetric between the two arms across movement frequencies, with lower shoulder-elbow angle coefficients and higher relative phase for the left compared to the right arm. Results also revealed greater variability of left arm movements in all variables assessed, an outcome observed from low to high movement frequencies. From these findings, we propose that specialization of the left cerebral hemisphere for motor control resides in its higher capacity to generate appropriate and stable interjoint coordination leading to the planned hand trajectory.
Assuntos
Articulação do Cotovelo , Desempenho Psicomotor , Humanos , Cotovelo , Movimento , OmbroRESUMO
Transcultural approaches comparing the distribution of lateral preference between countries focused primarily on handedness. However, other laterality dimensions may also be susceptible to cultural variations. The present study compared lateral preference in five dimensions (hand, foot, trunk, hearing, and visual) of young adults from Brazil and Mozambique. Two hundred and two undergraduate students participated in the study, of which 101 were Brazilian (21.7 ± 1.66 years old) and 101 Mozambican (25.6 ± 6.2 years old). The participants' lateral preference direction and degree were assessed using the global lateral preference inventory. Most Brazilians were classified in the moderate preference category, while Mozambicans had a higher frequency of individuals with strong preferences. Hence, Mozambicans presented a higher lateralization degree for all dimensions. A subsequent analysis considering only preference direction (right, left or indifferent), and not degree, did not show the same outcomes, revealing similarities in preference distribution between the two groups. This finding highlights the necessity to incorporate preference degrees in future analysis to not overlook potential differences. We also conclude lateral preference investigations with transcultural approaches should analyse beyond handedness, as other dimensions can also be modulated by cultural characteristics.
Assuntos
Pé , Lateralidade Funcional , Adulto Jovem , Humanos , Adulto , Estudantes , Previsões , BrasilRESUMO
In elite-level soccer, the ability to take shots with both limbs from different positions in the pitch may be key to success. This research aimed to: 1) analyze footedness of elite-football players in European leagues during shooting by computing frequency of right- and left-foot use and accuracy; and 2) investigate whether an athlete's distance from the target (goal, penalty, and outside penalty area) and pitch zone (center, left, or right from the goal) can constrain foot selection during shooting. We analyzed 1826 games from the 2017/18 season, divided between: Spanish LaLiga (380 matches); Italian Serie A (380 matches); English Premier League (380 matches); German Bundesliga (306 matches); and French Ligue 1 (380 matches). Results revealed asymmetrical proportions of foot selection, favoring the preferred foot for right- and left-footed athletes. Frequency of preferred foot selection increased as a function of distance from the target (i.e., the farther the athlete, higher the percentage of preferred foot selection). Shots taken from the left side were more often performed with the right foot and vice-versa, for both left- and right-footed athletes. Interestingly, asymmetries were observed only in foot selection, but not in performance, as success rate did not vary between limbs in any position.
Assuntos
Desempenho Atlético , Futebol , Humanos , Atletas , Europa (Continente) , PéRESUMO
According to the dynamic dominance model, the left cerebral hemisphere is specialized for the control of intersegmental dynamics and the right hemisphere for impedance control. Our aim was to test predictions from the dynamic dominance model in children by comparing performance between the right (preferred) and left hands in aiming. Three groups were compared: 4-7, 8-11, and 18-38 years old. Results showed higher movement linearity in the performance with the right hand in all age groups (P < .01), while initial directional error and endpoint accuracy were equivalent between hands. These results provided partial support for the dynamic dominance model.
Assuntos
Braço/fisiologia , Lateralidade Funcional/fisiologia , Mãos/fisiologia , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Adolescente , Adulto , Fenômenos Biomecânicos , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Modelos Neurológicos , Inquéritos e Questionários , Adulto JovemRESUMO
Handedness ontogenesis is still under debate in science. This systematic review analyzed articles regarding the theories and basis of handedness formation, highlighting the historical knowledge path that this literature underwent. Cochrane Library, LILACS, Web of Sciences, Science Direct and PubMed databases were searched. This review included review studies with handedness as the main topic. Only papers written in English with analyses exclusively in neurotypical humans (any age range) were included. Different approaches (genetic, neural, social, and behavioural) were reviewed in light of growing evidence, summarizing the current state of the art. Genetic and environmental/social impacts are common points in most of the reviews, each given more or less importance, depending on the author and theory proposed. Multifactorial, developmental approaches to handedness formation seem to be the most up to date view of the phenomenon. Different control mechanisms between hemisphere and neural asymmetries are also contributing factors to handedness formation.
Assuntos
Lateralidade Funcional , Adoção , Criança , Educação Infantil , Cultura , Dominância Cerebral/fisiologia , Feminino , Sofrimento Fetal/fisiopatologia , Sucção de Dedo , Lateralidade Funcional/genética , Lateralidade Funcional/fisiologia , Interação Gene-Ambiente , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Recém-Nascido Prematuro , Metanálise como Assunto , Modelos Neurológicos , Gravidez/sangue , Efeitos Tardios da Exposição Pré-Natal , Seleção Genética , Testosterona/sangueRESUMO
Lateral preference is influenced by many different factors. Although studies that assessed handedness contributed greatly to our understanding of the phenomenon, looking to other dimensions of motor laterality, such as lower limbs, trunk, visual and hearing preference, may be an interesting strategy to further advance in the field. Comparing different age groups with a complete inventory also contributes to understanding the ageing impact on these variables. Our aim, therefore, was to assess six motor laterality dimensions in younger adults and older people. Two hundred subjects participated in this study (102 adults, 30.6 ± 11.2 years old, and 98 elders, 70.4 ± 7.22 years old) and lateral preference was assessed by the Global Lateral Preference Inventory. We verified significant differences between groups in all dimensions, except the visual one, with proportionally stronger right preference in the older group. Compared to other dimensions, higher frequency of ambidexterity was observed in trunk, hearing and visual preference for both groups. These results might indicate that lateral preference is, indeed, multifactorial, being affected by ageing, task complexity and other possible related aspects.
Assuntos
Envelhecimento/fisiologia , Envelhecimento/psicologia , Comportamento de Escolha/fisiologia , Lateralidade Funcional/fisiologia , Adulto , Idoso , Distribuição de Qui-Quadrado , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Objetivo: Analisar o efeito de contrações voluntárias isométricas máximas e da eletroestimulação no torque isométrico e na ativação muscular do tríceps braquial em adultos fisicamente ativos. Métodos: Dezenove homens foram submetidos a testes de força isométrica (FI) como pré-teste, por meio de contração voluntária isométrica máxima durante 10 segundos e atividades condicionantes (ACs) randomizadas: isometrias durante 7, 10 e 12 segundos e eletroestimulação em 70 e 120Hz por 10 segundos cada. Após as ACs, foram realizadas duas contrações voluntárias isométricas máximas de 10 segundos com intervalo de 4 e 8 minutos, respectivamente. A atividade elétrica do tríceps braquial (porções medial e lateral) foi registrada. Resultados: Não foi verificado efeito em nenhuma das condições para o torque máximo ou médio, bem como para atividade elétrica do tríceps braquial (P>0,05). Conclusão: O intervalo adotado entre as ACs e o teste de FI não foi suficiente para induzir a melhoria do torque isométrico. (AU)
Objective: To analyze the effect of maximal voluntary isometric contractions and of electroestimulation on isometric torque and muscle activation of the brachii triceps in physically active adult males. Methods: Nineteen men underwent isometric force tests as pre-test, through 10-second long maximal voluntary isometric contractions and conditioning activities randomized: isometric contraction during 7, 10 and 12 seconds and electric stimulation in 70 and 120 Hz for 10 seconds each. After the conditioning activities, two voluntary isometric contractions were performed for 10 seconds with interval of 4 and 8 minutes, respectively. The muscle electrical activity of brachii triceps (medial and lateral portion's) was measured. Results: It was not verified effect in any conditions to maximal or mean torque (P>0.05), likewise to muscle electrical activity of brachii triceps (P>0.05). Conclusion: The interval adopted among the conditioning activities and the isometric force test was not enough to induce the isometric torque improvement. (AU)