RESUMO
This study sought to compare the myoelectric activity of the hip adductors (HAs) and rectus femoris (RF) when the hip was in a neutral position or externally rotated by 30° or 50° (H0, H30, and H50, respectively) during a parallel squat. Ten healthy subjects performed 10 repetitions of squats in each of the 3 hip positions and the myoelectric activities of the HAs and RF were recorded. The signal was then divided into categories representing concentric (C) and eccentric (E) contractions in the following ranges of motion: 0-30° (C1 and E1), 30-60° (C2 and E2), and 60-90° (C3 and E3) of knee flexion. From those signals, an root mean square (RMS) value for each range of motion in each hip position was obtained. All values were normalized to those obtained during maximum voluntary isometric contraction. We found that HAs showed a significant increase in myoelectric activity during C3 and E3 in the H30 and H50 positions, as compared with H0. Meanwhile, RF activity did not significantly differ between hip positions. Both muscles showed higher activation during 60-90° (C3 and E3) of knee flexion, as compared with 0-30° (C1 and E1) and 30-60° (C2 and E2). The results suggest that if the aim is to increase HA activity despite the low percentage of muscle activation, squats should be performed with 30° of external rotation and at least 90° of knee flexion.
Assuntos
Quadril/fisiologia , Músculo Quadríceps/fisiologia , Levantamento de Peso/fisiologia , Eletromiografia , Feminino , Humanos , Contração Isométrica/fisiologia , Masculino , Amplitude de Movimento Articular/fisiologia , Rotação , Adulto JovemRESUMO
Gait parameters have been investigated as an additional tool for differential diagnosis in neurocognitive disorders, especially among healthy elderly (HE), those with mild cognitive impairment (MCI), and Alzheimer's disease (AD) patients. A videogrammetry system could be used as a low-cost and clinically practical equipment to capture and analyze gait in older adults. The aim of this study was to select the better gait parameter to differentiate these groups among different motor test conditions with videogrammetry analyses. Different motor conditions were used in three specific assessments: 10-meter walk test (10mWT), timed up and go test (TUGT), and treadmill walk test (TWT). These tasks were compared among HE (n=17), MCI (n=23), and AD (n=23) groups. One-way ANOVA, Kruskal-Wallis, and Bonferroni post-hoc tests were used to compare variables among groups. Then, an effect size (ES) and a linear regression analysis were calculated. The gait parameters showed significant differences among groups in all conditions, but not in TWT. Controlled by confounding variables, the gait velocity in 10mWT at usual speed, and TUGT in dual-task condition, predicts 39% and 53% of the difference among diagnoses, respectively. Finally, these results suggest that a low-cost and practical video analysis could be able to differentiate HE, those with MCI, and AD patients in clinical assessments.
Assuntos
Doença de Alzheimer/fisiopatologia , Disfunção Cognitiva/fisiopatologia , Análise da Marcha/métodos , Gravação em Vídeo/métodos , Acidentes por Quedas , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estudos de Tempo e Movimento , Teste de Caminhada/métodosRESUMO
Motor dysfunction increases in the moderate and severe stages of dementia. However, there is still no consensus on changes in mobility during its early stages. This meta-analysis aimed to measure the level of single-task functional mobility in older subjects with mild cognitive impairment (MCI) and/or Alzheimer's disease (AD). In a search of the PubMed, ISI Web of Knowledge, and Scopus databases, 2728 articles were identified. At the end of the selection, a total of 18 studies were included in the meta-analysis. Functional mobility was investigated using the timed up and go (TUG) test in all studies. When compared to healthy elderly (HE) adults, the following mean differences (MD) in seconds were found for the investigated subgroups: no amnestic MCI (MDâ¯=â¯0.26; CI95% = -0.77, 1.29), amnestic MCI (MDâ¯=â¯0.86; CI95% = -0.02, 1.73), very mild AD (MDâ¯=â¯1.32; CI95%â¯=â¯0.63, 2.02), mild AD (MDâ¯=â¯2.43; CI95%â¯=â¯1.84, 3.01), mild-moderate AD (MDâ¯=â¯3.01; CI95%â¯=â¯2.47, 3.55), and mild-severe AD (MDâ¯=â¯4.51; CI95%â¯=â¯1.14, 7.88); for the groups, the following MD were found: MCI (MDâ¯=â¯0.97; CI95%â¯=â¯0.51, 1.44) and AD (MDâ¯=â¯2.66; CI95%â¯=â¯2.16, 3.15). These results suggest a transition period in motor capacity between healthy aging and dementia, wherein functional mobility analysis in a single-task (TUG) can contribute to the diagnosis and staging of predementia states and AD.
Assuntos
Doença de Alzheimer/fisiopatologia , Disfunção Cognitiva/fisiopatologia , Idoso , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/psicologia , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/psicologia , Feminino , Humanos , Masculino , Programas de Rastreamento , Equilíbrio Postural , Estudos de Tempo e MovimentoRESUMO
Additional clinical tools should be investigated to facilitate and aid the early diagnosis of cognitive decline. Postural control worsens with aging and this may be related to pathological cognitive impairment. OBJECTIVE: to compare the balance of older adults without dementia in a control group (CG) and with Alzheimer's disease (AD), to observe the possible association with the independent variables (diagnosis, age, gender, and global cognition) and to verify the best posturographic analyses to determine the difference between the groups. METHODS: 86 older adults (AD = 48; CG = 38) were evaluated using the Berg Balance Scale (BBS) and postural control was assessed by stabilometry on the Wii Balance Board ® (WBB). Independent T, Mann-Whitney U-tests, Effect Size (ES) and a linear regression were performed. RESULTS: there was a significant difference for Elliptical Area, Total Velocity, Medio-Lateral displacements with closed eyes and open eyes, antero-posterior, with closed eyes and BBS between groups. These variables showed a large effect size for BBS (-1.02), Elliptical Area (0.83) with closed eyes, Medio-Lateral (0.80, 0.96) and Total Velocity (0.92; 1.10) with eyes open and eyes closed, respectively. Regression indicated global cognition accompanied by age, gender, and diagnosis influenced postural control. CONCLUSION: patients with AD showed impaired postural control compared to Control Group subjects. Total Velocity with closed eyes was the most sensitive parameter for differentiating groups and should be better investigated as a possible motor biomarker of dementia in posturographic analysis with WBB.
Ferramentas clínicas adicionais devem ser investigadas para facilitar e auxiliar o diagnóstico prévio do declínio cognitivo. O controle postural piora com o envelhecimento e este fato pode estar relacionado com o comprometimento cognitivo patológico. OBJETIVO: comparar o equilíbrio de adultos idosos sem demência no grupo controle (GC) e com doença de Alzheimer (DA), observar as possíveis associações com as variáveis independentes (diagnóstico, idade, sexo e estado cognitivo global) e verificar as melhores análises posturográficas para determinar a diferença entre os grupos. MÉTODOS: 86 idosos (DA = 48; GC=38) foram avaliados utilizando a escala de equilíbrio Berg (EEB) e o controle postural pela estabilometria no Wii Balance Board ® (WBB). Testes T independente, Mann Whitney U, o tamanho de efeito (TE) e uma regressão linear foram realizados. RESULTADOS: houve diferença significativa para AE, VT, ML com OA e OF, AP com OF e EEB entre os grupos. Estas variáveis mostraram um TE grande para EEB (-1.02), AE (0,83) com OF, ML (0,80; 0,96) e VT (0,92; 1,10) com OA e OF, respectivamente. A regressão indicou que a cognição global acompanhada da idade, gênero e diagnóstico contribuem para as alterações do controle postural. CONCLUSÃO: pacientes com DA apresentam comprometimento do controle postural quando comparados a idosos saudáveis. A VT com OF foi o parâmetro mais sensível para diferenciar os grupos e deve ser melhor investigada como possível biomarcador motor de demência na análise posturográfica com o WBB.
RESUMO
ABSTRACT. Additional clinical tools should be investigated to facilitate and aid the early diagnosis of cognitive decline. Postural control worsens with aging and this may be related to pathological cognitive impairment. Objective: to compare the balance of older adults without dementia in a control group (CG) and with Alzheimer's disease (AD), to observe the possible association with the independent variables (diagnosis, age, gender, and global cognition) and to verify the best posturographic analyses to determine the difference between the groups. Methods: 86 older adults (AD = 48; CG = 38) were evaluated using the Berg Balance Scale (BBS) and postural control was assessed by stabilometry on the Wii Balance Board ® (WBB). Independent T, Mann-Whitney U-tests, Effect Size (ES) and a linear regression were performed. Results: there was a significant difference for Elliptical Area, Total Velocity, Medio-Lateral displacements with closed eyes and open eyes, antero-posterior, with closed eyes and BBS between groups. These variables showed a large effect size for BBS (-1.02), Elliptical Area (0.83) with closed eyes, Medio-Lateral (0.80, 0.96) and Total Velocity (0.92; 1.10) with eyes open and eyes closed, respectively. Regression indicated global cognition accompanied by age, gender, and diagnosis influenced postural control. Conclusion: patients with AD showed impaired postural control compared to Control Group subjects. Total Velocity with closed eyes was the most sensitive parameter for differentiating groups and should be better investigated as a possible motor biomarker of dementia in posturographic analysis with WBB.
RESUMO. Ferramentas clínicas adicionais devem ser investigadas para facilitar e auxiliar o diagnóstico prévio do declínio cognitivo. O controle postural piora com o envelhecimento e este fato pode estar relacionado com o comprometimento cognitivo patológico. Objetivo: comparar o equilíbrio de adultos idosos sem demência no grupo controle (GC) e com doença de Alzheimer (DA), observar as possíveis associações com as variáveis independentes (diagnóstico, idade, sexo e estado cognitivo global) e verificar as melhores análises posturográficas para determinar a diferença entre os grupos. Métodos: 86 idosos (DA = 48; GC=38) foram avaliados utilizando a escala de equilíbrio Berg (EEB) e o controle postural pela estabilometria no Wii Balance Board ® (WBB). Testes T independente, Mann Whitney U, o tamanho de efeito (TE) e uma regressão linear foram realizados. Resultados: houve diferença significativa para AE, VT, ML com OA e OF, AP com OF e EEB entre os grupos. Estas variáveis mostraram um TE grande para EEB (-1.02), AE (0,83) com OF, ML (0,80; 0,96) e VT (0,92; 1,10) com OA e OF, respectivamente. A regressão indicou que a cognição global acompanhada da idade, gênero e diagnóstico contribuem para as alterações do controle postural. Conclusão: pacientes com DA apresentam comprometimento do controle postural quando comparados a idosos saudáveis. A VT com OF foi o parâmetro mais sensível para diferenciar os grupos e deve ser melhor investigada como possível biomarcador motor de demência na análise posturográfica com o WBB.
Assuntos
Humanos , Idoso , Biomarcadores , Demência , Equilíbrio Postural , Doença de AlzheimerRESUMO
OBJECTIVE: To examine the influence of a preventative training program (PTP) on sagittal plane kinematics during different landing tasks and vertical jump height (VJH) in males. DESIGN: Six weeks prospective exercise intervention. PARTICIPANTS: Fifteen male volleyball athletes (13 ± 0.7 years, 1.70 ± 0.12 m, 60 ± 12 kg). INTERVENTIONS: PTP consisting of plyometric, balance and core stability exercises three times per week for six weeks. Bilateral vertical jumps with double leg (DL) and single leg (SL) landings were performed to measure the effects of training. MAIN OUTCOME MEASUREMENTS: Kinematics of the knee and hip before and after training and VJH attained during both tasks after training. The hypothesis was that the PTP would produce improvements in VJH, but would not generate great changes in biomechanical behavior. RESULTS: The only change identified for the SL was the longest duration of landing, which represents the time spent from initial ground contact to maximum knee flexion, after training, while increased angular displacement of the knee was observed during DL. The training did not significantly alter the VJH in either the SL (difference: 2.7 cm) or the DL conditions (difference: 3.5 cm). CONCLUSIONS: Despite the PTP's effectiveness in inducing some changes in kinematics, the changes were specific for each task, which highlights the importance of the specificity and individuality in selecting prevention injury exercises. Despite the absence of significant increases in the VJH, the absolute differences after training showed increases corroborating with the findings of statistically powerful studies that compared the results with control groups. The results suggest that short-term PTPs in low risk young male volleyball athletes may enhance performance and induce changes in some kinematic parameters.
Assuntos
Traumatismos em Atletas/prevenção & controle , Exercício Físico/fisiologia , Extremidade Inferior/anatomia & histologia , Extremidade Inferior/fisiologia , Educação Física e Treinamento/métodos , Avaliação de Programas e Projetos de Saúde , Voleibol/fisiologia , Adolescente , Fenômenos Biomecânicos , Humanos , Masculino , Estudos ProspectivosRESUMO
OBJETIVO: Comparar a atividade muscular antes e após o contato com o solo entre as aterrissagens unilateral (AU) e bilateral (AB) em atletas do sexo masculino. PARTICIPANTES: Quinze atletas masculinos de voleibol sem sinais e sintomas de lesões nas extremidades inferiores (13 ± 1 ano, 1,70 ± 0,12m, 60 ± 12kg). MENSURAÇÕES:Os participantes realizaram dois saltos verticais, aterrissando unilateralmente e bilateralmente. A atividade mioelétrica do reto femoral (RF), bíceps femoral (BF), adutores de quadril (AQ) e a relação BF/RF foram comparados entre as duas aterrissagens e entre as fases caracterizadas por 100ms antes (PRE) e 100ms após (POS) o contato com o solo. RESULTADOS: Em ambas as aterrissagens, a ativação do RF foi maior na fase POS em relação à PRE. Na comparação entre as aterrissagens dentro da mesma fase não encontramos diferenças estatísticas. Apesar de o BF não ter apresentado diferenças entre as fases PRE e POS em cada aterrissagem, sua ativação foi maior na AU. Os AQ apresentaram maior ativação na fase POS durante a AU, no entanto não houve diferenças quando comparadas as duas aterrissagens. A relação BF/RF apresentou valores maiores em ambas as aterrissagens na fase PRE. No entanto, não encontramos diferenças entre as aterrissagens. CONCLUSÃO: Os resultados sugerem que cada músculo apresenta um papel diferente durante a fase de aterrissagem em homens. Enquanto que o RF possui como principal função a frenagem da articulação do joelho e do movimento descendente, caracterizada pelo aumento da ativação na fase pós-contato, o BF parece atenuar a tensão articular do joelho em atividades de maior impacto, mantendo-se mais ativo durante todo o ciclo da AU. Já a maior ativação dos AQ após o contato com solo na AU evidencia a importância da região lombo-pélvica na estabilização pélvica em situações de grande instabilidade. Estudos futuros são necessários para determinar os efeitos da ativação muscular apresentada na imposição de cargas mecânicas potencialmente lesivas no joelho em atletas do sexo masculino.
OBJECTIVE: To compare the myoelectric activity before and after ground contact between single leg (SL) and double leg (DL) landings in male athletes. PARTICIPANTS: Fifteen male volleyball athletes without signs and symptoms of lesions in the lower extremities, with a minimum of three years experience in the sport (13 ± 1 years, 1.70 ± 0.12 m, 60 ± 12 kg). MEASUREMENTS: Participants performed two vertical jumps, landing unilaterally and bilaterally. The myoelectric activity of the rectus femoris (RF), biceps femoris (BF), hip adductors (HA) and the BF/RF ratio were compared between the two landings and between the phases characterized by 100ms before (PRE) and after 100 ms (POST) ground contact using ANOVA two-way test with post hoc test of Bonferroni (á = 5 percent). RESULTS: In both landings activation of RF was higher in the POST in relation to the PRE (p <0.0001). Comparing the landings in the same phase statistical differences (p = 0.2212) were not found. Although the BF did not present significant differences between the PRE and POST in each landing (p = 0.2321), its activation was higher in SL (p = 0.0051). The HA showed greater activation in the POST during the SL (p = 0.0013), however there were no differences when comparing the two landings (p = 0.9233). The BF/RF ratio was higher in both landings during PRE (p = 0.0012). Nevertheless, no differences between the landings (p = 0.7037) were found. CONCLUSION: The results suggest that each muscle has a different role during landing tasks in men. While RF has the main function to decelerate the knee and the downward movement, characterized by increased activation in the POST, BF seems to attenuate the loads on the knee in activities of higher impact, staying more active throughout the cycle in the SL. The increased activation of HA after ground contact in the SL highlights the importance of core region in stabilizing the pelvis in situations of great instability. Further studies are needed to determine the effects of muscle activation at the imposition of mechanical load on the knee that are potentially harmful to male athletes.
Assuntos
Humanos , Masculino , Adolescente , Ligamento Cruzado Anterior , Fenômenos Biomecânicos , Fatores de Risco , Atletas , VoleibolRESUMO
As lesões no ligamento cruzado anterior (LCA) são frequentes no âmbito esportivo. O estudo dos mecanismos de lesão demonstrou que a maioria das lesões é oriunda tanto de aterrissagens unilaterais quanto bilaterais. Apesar de estudos terem demonstrado diferenças no comportamento cinemático de membros inferiores entre homens e mulheres, não há evidências de como homens se comportam em diferentes condutas. O objetivo neste estudo foi comparar a cinemática angular e temporal dos membros inferiores, manifestaem aterrissagens de saltos com propulsão bilateral, realizadas sobre um e dois membros inferiores. Aterrissagens unilaterais e bilaterais no plano frontal e sagital de quinze atletas masculinos de voleibol foram registradas e processadas por meio de técnicas videogramétricas. Os resultados indicam que, na aterrissagem unilateral, os atletas apresentaram menor flexão do quadril e joelho, assim como maior valgismo do joelho, quando comparada coma aterrissagem bilateral. A diferença no tempo de aterrissagem entre as duas condutas não foi estatisticamente significante. Em conclusão, os resultados deste estudo apóiam a premissa de que a cinemática dos membros inferiores se altera em função da configuração da conduta motora realizada em homens. Estudos futuros são necessários para explorar o impacto das diferenças cinemáticas encontradas na tensão ligamentar e relacioná-las comos mecanismos de lesões no LCA em homens.
Anterior cruciate ligament (ACL) injuries are common in sports. Studies investigating injury mechanisms have demonstrated that most injuries arise from landing tasks. Despite the demonstration of differences between male and female kinematics, there are no studies showing how males behave during different landing tasks. The objective of this study was to compare theangular and temporal kinematics of the lower limbs between two different landing tasks. Double leg and single leg landings were recorded in the frontal and sagittal plane in 15 male volleyball athletes by videogrammetry. Reduced hip and knee flexion and increased knee valgus were observed in the single leg landing task compared to the double leg landing task. No significantdifference in landing time was observed between the two tasks. In conclusion, the results support the premise that lower limb kinematics change according to the task performed. Further studies are necessary to explore the impact of these kinematic differences on knee loading and to relatethem to ACL injury mechanisms in men.