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BACKGROUND AND HYPOTHESIS: Early trunk rotation (ETR), which is a unique kinematics of the trunk that occurs during baseball throwing, is thought to be related to shoulder injuries. Pelvic rotation is a confounder when studying the effects of trunk rotation on shoulder biomechanics. The purpose of this study was to understand the "pure" effects of trunk rotation on shoulder biomechanics, with pelvic rotation under control. Our hypotheses were as follows: (1) throwers with ETR have a different shoulder kinematics pattern compared with throwers without ETR; (2) throwers with ETR have a lower ball speed performance than do throwers without ETR; and (3) throwers with ETR have a greater value of shoulder forces and moments, which may increase risks of shoulder injury, than do throwers without ETR. METHODS: Fifty-seven elite throwers were enrolled and divided into 2 groups (non-ETR and ETR) using an outdoor motion analysis. Several kinematics and kinetics parameters of the shoulder were analyzed and compared between the 2 groups. RESULTS: Ball velocity was faster in the non-ETR group (127 km/h) compared with the ETR group (120 km/h). The shoulders of throwers in the ETR group showed pathokinematics of "horizontal adduction lag" and "dropped elbow." The increases in maximal posterior force, inferior force, horizontal abduction moment, and vertical adduction moment were 9.2%, 13.6%, 21.3%, and 24.3%, respectively, in the shoulders of throwers in the ETR group. These results indicate that ETR may be hazardous for the throwing shoulder. With lower ball velocity and higher shoulder joint loading, ETR is not a proper pitching pattern for kinetic energy transfer. CONCLUSION: Improper pitching mechanics among baseball throwers, such as ETR, may result in higher shoulder joint loading and increased risk of shoulder injuries. When treating throwers with shoulder injuries, it is important not only to address shoulder anatomy and pathology but also to understand the possible pathomechanics and pathogenesis of the shoulder caused by ETR. Furthermore, special training programs focusing on trunk flexibility and core muscle strengthening should be implemented to prevent ETR and decrease the risk of shoulder injuries. Motion analysis is useful for the screening and early detection of improper pitching mechanics in throwers.
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Beisebol , Lesões no Cotovelo , Lesões do Ombro , Articulação do Ombro , Beisebol/lesões , Fenômenos Biomecânicos/fisiologia , Humanos , Articulação do Ombro/fisiologia , Tronco/fisiologiaRESUMO
Both the detrimental effect of prenatal exposure to di-(2-ethylhexyl)-phthalate (DEHP) and the beneficial effects of physical exercise on brain functions have been reported. The oxytocin pathway has been implicated in the onset of maternal behaviors. Epigenetic modification of the oxytocin receptor gene (OXTR) through DNA methylation has been associated with the pathogenesis of neuropsychiatric disorders. The purpose of this study was to investigate the effects of prenatal DEHP exposure on oxytocin-regulated maternal behaviors and to examine the protective effect of exercise. Pregnant rats (F0) were fed with vehicle or DEHP during gestation and the offspring females (F1) were assessed for their maternal behaviors by pup retrieval test at postpartum. The results showed that reduced pup retrieval activities without significant alteration of stress responses were observed in the prenatally DEHP-exposed females. Prenatal DEHP exposure decreased the expressions of oxytocin, Oxtr mRNA, and oxytocin receptor, and increased Oxtr methylation in the hypothalamus of postpartum female rats. There were no significant effects of exercise on behavioral, biochemical, and epigenetic measurements. These results suggest that prenatal DEHP exposure has a long-term adverse effect on maternal behaviors; Oxtr hyper-methylation may be a potential epigenetic mechanism for this alteration, which cannot be prevented by physical exercise during childhood.
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Dietilexilftalato/toxicidade , Hipotálamo/efeitos dos fármacos , Comportamento Materno/efeitos dos fármacos , Condicionamento Físico Animal , Efeitos Tardios da Exposição Pré-Natal , Animais , Metilação de DNA , Feminino , Hipotálamo/metabolismo , Gravidez , Ratos Sprague-Dawley , Receptores de Ocitocina/genéticaRESUMO
Early-life exposure to di-(2-ethylhexyl)-phthalate (DEHP) has been suggested to relate to hyperactivity, lack of attention, and working memory deficits in school-age children. Brain-derived neurotrophic factor (BDNF) and endocannabinoids are induced by aerobic exercises to provide beneficial effects on brain functions. This study investigated the mechanisms underlying working memory impairment and the protective role of exercise in prenatal DEHP-exposed male rats. Sprague Dawley dams were fed with vehicle or DEHP during gestation. The male offspring were trained to exercise on a treadmill for 5 weeks, which was followed by an assessment of their working memory with a T-maze delayed non-match-to-sample task. The expressions of BDNF, dopamine D1 receptor (D1R), cannabinoid receptor 1 (CB1R), and fatty acid amide hydrolase (FAAH) in the prefrontal cortex were detected by Western blot. The results showed that DEHP-exposed rats exhibited working memory impairments without significant alterations in locomotor activities. The reduced expressions of prefrontal BDNF and CB1R were obtained in the DEHP-exposed rats, while D1R and FAAH were barely affected. Importantly, aerobic exercise during childhood-adolescence prevented the impairment of working memory in the DEHP-exposed rats by recovering the BDNF and CB1R expressions in the prefrontal cortex. These findings suggest that exercise may provide beneficial effects in ameliorating the impairment of working memory in the prenatal DEHP-exposed male rats at late adolescence.
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Fator Neurotrófico Derivado do Encéfalo/metabolismo , Dietilexilftalato/toxicidade , Memória de Curto Prazo , Córtex Pré-Frontal/efeitos dos fármacos , Efeitos Tardios da Exposição Pré-Natal/etiologia , Receptor CB1 de Canabinoide/metabolismo , Amidoidrolases/genética , Amidoidrolases/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/genética , Feminino , Masculino , Atividade Motora , Córtex Pré-Frontal/embriologia , Córtex Pré-Frontal/metabolismo , Córtex Pré-Frontal/fisiologia , Gravidez , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Ratos , Ratos Sprague-Dawley , Receptor CB1 de Canabinoide/genética , Receptores de Dopamina D1/genética , Receptores de Dopamina D1/metabolismoRESUMO
BACKGROUND: Previous studies have reported that glenohumeral internal rotation deficit (GIRD) may increase the risk of shoulder injury. However, the effects of GIRD on baseball pitching among pitchers of different age groups are still unclear. METHODS: The study participants were 24 high school and 24 university pitchers. For each age group, the pitchers were evenly divided into a GIRD group and a normal group. The pitching motion of each participant was captured using a motion analysis system at a sampling frequency of 300 Hz. The kinematics and kinetics of the throwing shoulder and trunk were quantified, and statistical differences between the groups were examined by 2-sample t tests. RESULTS: For both age groups, significant differences were observed in shoulder external rotations of the GIRD and normal groups. Compared with the university pitchers in the normal group, the university pitchers with GIRD exhibited a greater shoulder loading and did more internal rotation work in the acceleration phase. The high school pitchers with GIRD showed a larger trunk tilt and less trunk rotation than the university pitchers with GIRD. However, the university pitchers with GIRD exhibited a larger shoulder posterior force and horizontal adduction torque than the high school pitchers with GIRD. CONCLUSION: Pitchers with GIRD do change their pitching motions, and the greater resulting shoulder joint loading predisposes them to a greater risk of shoulder injury, especially among university pitchers.
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Beisebol , Movimento , Rotação , Articulação do Ombro/fisiopatologia , Ombro/fisiopatologia , Tronco/fisiopatologia , Adolescente , Fatores Etários , Desempenho Atlético/fisiologia , Beisebol/lesões , Fenômenos Biomecânicos , Humanos , Masculino , Amplitude de Movimento Articular , Torque , Universidades , Adulto JovemRESUMO
BACKGROUND: To understand the impacts of disease chronicity and hyperglycaemia on sensorimotor control of hands of diabetic patients, this study investigated the differences in hand sensation, strength and motor control by applying the pinch-holding-up activity test for patients with diabetes mellitus (DM) with different levels of glycaemic control and disease chronicity. METHODS: One hundred and fifty-nine patients with clinically defined DM were included. Semmes-Weinstein monofilament, static two-point discrimination and moving two-point discrimination, maximal pinch strength precision pinch performance tests and nerve conduction studies (NCS) of the subjects were carried out. Forty-seven (29.6%) patients were in the HbA(1c) < 7% category, and 112 (70.4%) patients were in the >7% group. There were 87 (54.7%) patients with the disease duration <10 years, and 72 (45.3%) patients with disease duration â§10 years. RESULTS: The severity of hyperglycaemia significantly impacts the results for Semmes-Weinstein monofilament, precision pinch force control, sensory and motor NCS tests (p < 0.05). In addition, the chronicity of disease influences the motor control of precision pinch performance and the amplitude of motor NCS (p < 0.05) for the diabetes patients. CONCLUSIONS: The evidence suggests that disease chronicity and hyperglycaemia have impacts on sensorimotor control in the hands of DM patients. In addition, the efficiency of prehensile forces of hand-to-object interactions in the pinch-holding-up activity test could be significant for identifying hand function, as well as pathologic changes in median nerve function, for patients with DM.
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Neuropatias Diabéticas/sangue , Retroalimentação Sensorial , Hemoglobinas Glicadas/análise , Hiperglicemia/etiologia , Neuropatia Mediana/complicações , Regulação para Cima , Idoso , Diabetes Mellitus/fisiopatologia , Diabetes Mellitus/terapia , Neuropatias Diabéticas/epidemiologia , Neuropatias Diabéticas/fisiopatologia , Feminino , Mãos , Força da Mão , Humanos , Hiperglicemia/fisiopatologia , Masculino , Neuropatia Mediana/sangue , Neuropatia Mediana/epidemiologia , Neuropatia Mediana/fisiopatologia , Pessoa de Meia-Idade , Destreza Motora , Condução Nervosa , Força de Pinça , Estudos Prospectivos , Fatores de Risco , Índice de Gravidade de Doença , Taiwan/epidemiologiaRESUMO
This research aims at developing a flexible strain module applied to the strengthening of back muscles. Silver films were sputtered onto flexible substrates to produce a flexible sensor. Assuming that back muscle elongation is positively correlated with the variations in skin surface length, real-time resistance changes exhibited by the sensor during simulated training sessions were measured. The results were used to identify the relationship between resistance change of sensors and skin surface stretch. In addition, muscle length changes from ultrasound images were used to determine the feasibility of a proof of concept sensor. Furthermore, this module is capable of detecting large muscle contractions, some of which may be undesirable for the prescribed training strategy. Therefore, the developed module can facilitate real-time assessments of the movement accuracy of users during training, and the results are instantly displayed on a screen. People using the developed training system can immediately adjust their posture to the appropriate position. Thus, the training mechanism can be constructed to help user improve the efficiency of back muscle strengthening.
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Terapia por Exercício , Exercícios de Alongamento Muscular/instrumentação , Músculo Esquelético/fisiologia , Tecnologia de Sensoriamento Remoto , Músculos do Dorso/fisiologia , Eletromiografia , HumanosRESUMO
Repetitive overhead throwing may result in overuse injuries and a change in the pitching mechanics of a baseball pitcher. Accordingly, the purpose of this study is to quantify the changes in the muscle strength and pitching motion kinematics in the late-innings stage of a baseball game. Sixteen healthy baseball pitchers (16.77 ± 0.73 years) recruited from a high school, which won the National High School Baseball Championship in Taiwan in 2011; each performed 100 pitches in a bullpen throwing session. Isometric muscle strength measurements and joint kinematic data were obtained before and after the throwing session. The mean Borg's Rating of Perceived Exertion index was found to have a value of 14.14, indicating a medium-to-large degree of perceived tiredness. The results showed that the ball velocity and horizontal abduction angle decreased significantly as the pitchers became tired. Moreover, the upper torso forward tilt and knee flexion angle both increased significantly at the moment of ball release. Finally, the muscle strength of the upper extremity remained decreased 2 days after the bullpen throwing session. Overall, the results suggest that an adequate amount of rest and specific strengthening programs for the shoulder external rotator, shoulder internal rotator, shoulder flexor, shoulder extensor, shoulder adductor, and shoulder abductor muscles are recommended to the coaches and for adolescent baseball pitchers. In addition, the changes in pitching mechanics noted in this study should be carefully monitored during the course of a baseball game to minimize the risk for overuse injuries.
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Beisebol/fisiologia , Fadiga/fisiopatologia , Força Muscular , Músculo Esquelético/fisiologia , Adolescente , Fenômenos Biomecânicos , Humanos , Contração Isométrica , Masculino , Esforço Físico , Rotação , Ombro , Articulação do Ombro/fisiologia , Taiwan , TroncoRESUMO
[Purpose] This study aimed to investigate the effect of shoulder positions and speeds on internal and external rotation torque of college baseball players and age-matched non-players. [Subjects] Twenty first-level collegiate baseball players and 19 college students were recruited. [Methods] A dynamometer system was used to evaluate the shoulder rotation strength in sitting postures. Three testing positions, namely shoulder abduction of 45°, 70°, and 90° in the scapular plane, were combined with three testing speeds at 60°/s, 120°/s, and 210°/s. [Results] The maximum external and internal rotation torques both occurred at shoulder abduction of 70°. However, only external rotation torque was affected by the speed, with the peak value observed at 60°/s. The internal rotation torque of baseball players was larger than that of the control group under all testing conditions, but the external rotation did not show any difference. The ratio of external to internal rotation torque changed with the testing positions and speeds in both groups. The ratio in the control group was greater than that in the player group. [Conclusion] The shoulder position could affect the rotational strength, and the baseball players could strengthen their external rotators for better performance and injury prevention.
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Motor skill learning is essential for environmental adaptations during everyday life. It has been shown that the cerebellum plays an important role in both the adaptation of eye movements and the motor skill learning. However, the neuronal substrates responsible for consolidation of complex motor skills rather than simple reflexes are still uncertain. Because the induction of immediate-early genes activity-regulated cytoskeleton-associated protein (Arc) and zinc finger binding protein clone 268 (Zif268) has been regarded as a marker for recent neuronal activity, therefore, in the present study, a rat paradigm of motor skill learning was used to investigate the protein expression of Arc and zif268 in the cerebellum after motor skill learning. Rats were trained to traverse the runway apparatus for 5 days. Protein samples were collected from the cerebellar cortices 1 hour after the training on days 1, 3, and 5, and analyzed by western blotting. The results showed that the expression of Arc, but not zif268, was significantly increased in the cerebellum following motor skill learning. These findings suggest that motor skill learning induces Arc expression in the cerebellum, which may play a role in acquiring complex motor skills.
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Córtex Cerebelar/fisiologia , Proteínas do Citoesqueleto/metabolismo , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Aprendizagem/fisiologia , Destreza Motora/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Animais , Western Blotting , Expressão Gênica , Imuno-Histoquímica , Masculino , Ratos Sprague-DawleyRESUMO
Patients with type 2 diabetes mellitus (T2DM) are at a three-fold increased risk of developing sarcopenia compared to those without diabetes. The objective of this study was to investigate whether an intervention involving progressive sandbag exercises is beneficial to patients with T2DM and possible sarcopenia in terms of enhancing muscle strength and controlling blood sugar levels. Forty patients with T2DM and possible sarcopenia (age > 50 years) were recruited and randomly divided into resistance training and control groups. Resistance exercises for the upper and lower extremities were performed using sandbags (0.5 kg at the beginning to 1 kg after 1 month). Patients in the control group were asked to maintain their usual daily lifestyle. After 12 weeks, the training group were significant better than the control group in terms of glycosylated hemoglobin, the five times sit-to-stand test, skeletal muscle mass and calf circumference, and the physiological domain of the World Health Organization Quality of Life Questionnaire. In conclusion, these simple home exercises are beneficial to patients with T2DM combined with possible sarcopenia. This approach can assist patients in controlling their levels of glycosylated hemoglobin as well as improve physical fitness and quality of life.
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Diabetes Mellitus Tipo 2 , Sarcopenia , Humanos , Pessoa de Meia-Idade , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/terapia , Exercício Físico , Hemoglobinas Glicadas , Controle Glicêmico , Força Muscular/fisiologia , Qualidade de Vida , Sarcopenia/terapiaRESUMO
While rocker-shaped soles have become popular for running shoes, whether or not this type of shoe benefits other functional movements has rarely been discussed. The purpose of this study was to investigate the effect of rocker-soled shoes on lower extremity biomechanics during different exercises. Seventeen healthy university students were recruited. A motion capture analysis system and surface electromyography were used to measure kinematics and muscle activation while walking (10 m), running (10 m), cutting, jumping, and ascending and descending stairs. The results showed that when wearing rocker-soled shoes, greater peak external ankle rotation was present during most exercises. Smaller peak joint angles were observed in hip extension and external rotation when walking, and in ankle dorsiflexion when ascending stairs and jumping. The vastus medialis and vastus lateralis contracted more in most exercises when rocker-soled shoes were worn. However, the biceps femoris and medial gastrocnemius showed less muscle contraction. Wearing rocker-soled shoes during testing movements change the kinematics and muscle contractions of the lower extremity. These findings may provide information for choosing shoes for different exercises or training purposes.
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Contração Muscular , Sapatos , Humanos , Fenômenos Biomecânicos , Extremidade Inferior , Músculo Quadríceps , RotaçãoRESUMO
Ligament reconstruction is indicated in patients with an isolated posterior cruciate ligament (PCL) injury who fail conservative treatment. To eliminate the need for PCL reconstruction, an ideal rehabilitation program is important for patients with an isolated PCL injury. The purpose of this study was to investigate the improvement in functional outcome, proprioception, and muscle strength after a Both Sides Up (BOSU) ball was used in a balance combined with strength training program in patients with an isolated PCL injury. Ten patients with isolated PCL injuries were recruited to receive a 12 week training program as a study group. In the control group (post-PCL reconstruction group), ten subjects who had undergone isolated PCL reconstruction for more than 2 years were enrolled without current rehabilitation. The Lysholm score, IKDC score, proprioception (active and passive), and isokinetic muscle strength tests at 60°/s, 120°/s, and 240°/s, were used before and after training on the injured and normal knees in the study group, and in the post-PCL reconstruction group. The results were analyzed with a paired t-test to compare the change between pre-training, post-training, and the normal leg in the study group, and with an independent t-test for comparisons between the study and post-PCL reconstruction groups. Both the Lysholm and IKDC scores were significantly improved (p < 0.01) after training, and no difference was observed compared to the post-PCL reconstruction group. The active and passive proprioception was improved post-training compared to pre-training, with no difference to that in the post-PCL reconstruction group. Isokinetic knee quadriceps muscle strength was significantly greater post-training than pre-training in PCL injured knees at 60°/s, 120°/s, and 240°/s, and in hamstring muscle strength at 60°/s and 120°/s. Muscle strength in the post-training injured knee group showed no significant difference compared to that in the post-training normal leg and the post-PCL reconstruction group. The post-training improvement of muscle strength was higher in the PCL injured leg compared to the normal leg and there was no difference between the dominant and non-dominant injured leg in the study group. After 12 weeks of BOSU balance with strength training in patients with an isolated PCL injury, the functional outcome, proprioception, and isokinetic muscle strength were significantly improved, and comparable to the contralateral normal leg and the post-PCL reconstruction group. We suggest that programs combining BOSU balance and strength training should be introduced in patients with a PCL injury to promote positive clinical results.
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Lesões do Ligamento Cruzado Anterior , Ligamento Cruzado Posterior , Treinamento Resistido , Humanos , Articulação do Joelho , Força Muscular , Ligamento Cruzado Posterior/cirurgia , Propriocepção , Resultado do TratamentoRESUMO
Standing yoga poses strengthen a person's legs and helps to achieve the goal of musculoskeletal rehabilitation, but inadequate exercise planning can cause injuries. This study investigated changes in the electromyogram and joint moments of force (JMOFs) of lower extremities during common standing yoga poses in order to explore the feasibility and possible injury risk in dealing with musculoskeletal problems. Eleven yoga instructors were recruited to execute five yoga poses (Chair, Tree, Warrior 1, 2, and 3). The results revealed significant differences in hip, knee, and ankle JMOFs and varying degrees of muscle activation among the poses. Among these poses, rectus femoris muscle activation during the Chair pose was the highest, Warrior 2 produced the highest muscle activation in the vastus lateralis of the front limb, while Warrior 1 had the highest muscle activation in the vastus medialis of the back limb. Therefore, all three poses can possibly be suggested as a therapeutic intervention for quadriceps strengthening. Warrior 1 was possibly suggested as a therapeutic intervention in order to reduce excessive lateral overload of the patella, but the possible adverse effects of Warrior 2 with the highest knee adductor JMOF in the back limb could raise joint reaction forces across the medial condyles. In single-leg balance postures, Warrior 3 had unique training effects on the hamstring, and is therefore suggested as a part of hamstring rehabilitation exercises. The Tree pose induced low lower-extremity JMOFs and a low level of thigh muscle activations when it was performed by senior instructors with excellent balance control; however, for yoga beginners with insufficient stability, it will be a useful training mode for strengthening the muscles that help to keep one upright. This study quantified the physical demands of yoga poses using biomechanical data and elucidated the structures and principles underlying each yoga movement. This is crucial for yoga practitioners.
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Yoga , Eletromiografia , Humanos , Articulação do Joelho , Extremidade Inferior , Músculo Esquelético , Músculo QuadrícepsRESUMO
The purpose of this study was to build on existing qualitative to quantitative approaches to develop a new quantitative method for evaluating pelvic and trunk rotational pitching mechanics. Thirty pitchers were divided into two groups ("Pattern1": closed "hip-to-shoulder separation"; "Pattern2": open "hip-to-shoulder separation"). Several parameters were analyzed. Higher ball speeds were found in group of Pattern1, four key characteristics of which were identified. Based on the results, a new evaluation method was developed. Pelvic and trunk rotational mechanics were classified into four types. Type1 (proper mechanics) enabled significantly higher ball speed than the other three types and was thought to involve proper energy transfer from the stride foot to the throwing upper limb. Types 2-4, however, were regarded as "improper mechanics", which could result in slower ball speeds and less efficient energy transfer. A qualitative approach, based on "expert opinion", can specify optimal pelvis and trunk rotational mechanics. However, quantitative analysis is more precise in identifying three improper types of pelvis and trunk rotational mechanics. Furthermore, special programs, such as core strengthening and flexibility training, can be developed for various improper practices in order to improve pitching mechanics.
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Beisebol , Fenômenos Biomecânicos , Pelve , Rotação , Ombro , TroncoRESUMO
Walking performance changes with age. This has implications for the problem of falls in older adults. The aim of this study was to investigate the effects of Yuanji-Dance practice on walking balance and the associated attention demand in healthy elderly. Fifteen community-dwelling elderly (comparison group, no regular exercise habit) and fifteen Yuanji- Dance elderly (exercise group, dancing experience: 5.40 ± 1.95 years), aged 60-70 years, were included in this study. The subjects in exercise group participated in a 90-minute Yuanji-Dance practice at least three times per week and the comparison group continued their normal daily physical activity. Walking balance measures (including walking velocity, step length, step width, and percentage of time spent in double limb support, COM velocity and COM-COP inclination angles) and attentional demand tests (button reaction time and accuracy) were conducted under different conditions. Our results showed that stride lengths, walking velocities, peak A/P velocities (AP V) of the COM, medial COM-COP inclination (M angle) angles, reaction time, and accuracy decrease significantly as the dual-task (walking plus hand button pressing tasks) applied for either the comparison or exercise groups. These results demonstrated that walking performance is attenuated in our elderly participants as the cognitive tasks applied. Analysis also identified a significantly faster RT for our exercise group both in standing and walking conditions. This may indicate that physical exercise (Yuanji-Dance) may have facilitating effects on general cognitive and perceptual- motor functions. This implies that Chinese Yuanji-Dance practice for elderly adults may improve their personal safety when walking especially under the condition of multiple task demand. Key pointsThe purpose of this study was to investigate the training effects of a Chinese traditional exercise, Yuanji-Dance, on walking balance and the associated attention demand in the healthy elderly.Walking performance is attenuated in elderly participants as the cognitive tasks applied.A significantly faster reaction time for our exercise group both in standing and walking conditions.Yuanji-Dance exercise training can improve the information processing speed of elderly people and has no influence of the dynamic walking balance.
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Previous studies have reported that pitchers with glenohumeral internal rotation deficit (GIRD) may increase the risk of shoulder injury. However, limited information is available regarding the specific effects of GIRD in baseball pitching. The purpose of this study was to investigate whether baseball pitchers with GIRD change their pitching mechanism. Fifteen baseball pitchers with GIRD and 15 pitchers without GIRD were recruited from university or senior high-school teams. A three-dimensional motion analysis system (Eagle System, Motion Analysis Corporation, Santa Rosa, CA, USA) was used to capture the pitching motion while performing fastball pitches. The kinematics and kinetics of the throwing shoulder and trunk were analyzed based on motion captured data. The Mann-Whitney U test was used to test the differences of the analyzed parameters between two groups. At the instant of ball release, the GIRD group showed lower shoulder external rotation and trunk rotation, and larger shoulder horizontal adduction. In addition, the GIRD group exhibited a significantly larger shoulder inferior force in the cocking and acceleration phase, and a significantly larger internal rotation torque in the acceleration phase. The present results suggested that pitchers with GIRD need stretch training to enlarge joint range of motion, and to improve trunk strength and flexibility to alleviate potential problems associated with pitching in GIRD pitchers.
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Beisebol , Articulação do Ombro , Amplitude de Movimento Articular , Rotação , OmbroRESUMO
Purpose This study investigates the effects of kinematic disturbances in rheumatoid thumb on patient's hand functions via objective and patient-perceived measurements. Method Twenty-one patients with rheumatoid arthritis (RA) and 21 healthy age- and gender-matched individuals were recruited to receive the objective evaluations, including the Purdue Pegboard Test, Jamar dynamometer, pinch-meter, Permanent Impairment Scale and self-administrated measurements, including the Health Assessment Questionnaire (HAQ) and Manual Ability Measure-36 (MAM-36). An electromagnetic tracking system was used to measure thumb kinematics. The differences in the measures between the RA and control groups and the dominant and non-dominant hands of the RA group were examined. The relationships between the thumb kinematics and hand functional capabilities, as well as impairment levels, were also explored. Results The RA group showed significantly smaller thumb movement capabilities and hand strength, as well as worse scores in hand dexterity, MAM-36 and HAQ than healthy controls. The movement workspace of the RA thumb showed moderate correlations with the factors of hand strength, dexterity, impairment scale, MAM-36 and HAQ scores. Conclusions The findings indicate deficits related to the movement capability of the RA thumb may negatively influence hand dexterity and functional hand performance, as well as life quality, for the patients with RA. Implications for Rehabilitation A deformed rheumatoid thumb might limit the movement workspace of the thumb and consequently impair the hand performance as well as the life quality. The dominant thumb of the RA patients might have greater structural and functional deterioration than the non-dominant side. Suitable joint protection strategies, exercises and orthotics should be early applied to the RA patients for preserving hand functions.
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Artrite Reumatoide/fisiopatologia , Artrite Reumatoide/reabilitação , Polegar/fisiopatologia , Atividades Cotidianas , Fenômenos Biomecânicos , Estudos de Casos e Controles , Feminino , Força da Mão/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Taiwan , Resultado do TratamentoRESUMO
Mechanical neck disorder is a widespread and non-neurological musculoskeletal condition resulting from modern lifestyles. Presently, the fundamental electrophysiological properties of the motor units of the sternocleidomastoid muscles and the characteristics of the short-term synchronization of the motor unit in patients with neck pain are ambiguous. This study therefore aims to clarify the fundamental electrophysiological properties of the motor units of the sternocleidomastoid muscles in patients with mechanical neck disorder and in asymptomatic individuals. We further investigated whether alterations in the degree of motor unit short-term synchronization occur. The surface electrophysiological signals of the bilateral sternal heads of the sternocleidomastoid muscles of twelve patients with mechanical neck disorder and asymptomatic individuals were detected at 25% of the maximum voluntary contraction during cervical isometric flexion and then decomposed into individual motor unit action potential trains. We found that the patients with mechanical neck disorder showed significantly higher initial and mean firing rates of the sternocleidomastoid muscles and displayed substantially lower motor unit short-term synchronization values compared with the asymptomatic subjects. Consequently, these convincing findings support the assertion that patients with mechanical neck disorder display altered neuromuscular control strategies, such as the reinforcement of motor unit recruitment firing rates in the sternocleidomastoid muscles. The motor units of these patients also revealed neural recruitment strategies with relatively poor efficiency when executing the required motor tasks.
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Contração Isométrica , Doenças Musculares/fisiopatologia , Músculos do Pescoço/fisiopatologia , Cervicalgia/fisiopatologia , Recrutamento Neurofisiológico , Potenciais de Ação , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Doenças Musculares/diagnóstico , Cervicalgia/diagnósticoRESUMO
Lactational exposure to vanadium can reduce the locomotor activity in adult animals. In this study, we investigated whether lactational vanadium exposure impairs the motor coordination and whether exercise ameliorates this dysfunction. Sprague-Dawley dams were treated with or without vanadium during lactation. The weaned male offspring were trained to treadmill running for 5 weeks and then examined their motor coordination on a rotarod. The neuroprotective effect of exercise was evaluated by the brain-derived neurotrophic factor (BDNF) in plasma and cerebellum. The results demonstrated that vanadium-exposed rats exhibited impaired motor coordination and reduced plasma and cerebellar BDNF levels. Treadmill running during childhood-adolescence prevented the impaired motor coordination in the lactational vanadium-exposed rats. The beneficial effect of treadmill running on motor coordination in the vanadium-exposed rats was correlated to the normalization of plasma and cerebellar BDNF levels, as well as the increased TrkB phosphorylation in the cerebellum. The result suggests that exercise may prevent the impairment of motor coordination in the lactational vanadium-exposed rats.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Lactação/metabolismo , Leite/metabolismo , Destreza Motora/efeitos dos fármacos , Condicionamento Físico Animal , Vanadatos/toxicidade , Animais , Calbindinas/metabolismo , Feminino , Masculino , Atividade Motora/efeitos dos fármacos , Fosforilação , Células de Purkinje/citologia , Células de Purkinje/efeitos dos fármacos , Células de Purkinje/metabolismo , Ratos Sprague-Dawley , Receptor trkB/metabolismo , Vanadatos/metabolismoRESUMO
This study combines an ergometric wheelchair, a six-camera video motion capture system and a prototype computer graphics based musculoskeletal model (CGMM) to predict shoulder joint loading, muscle contraction force per muscle and the sequence of muscular actions during wheelchair propulsion, and also to provide an animated computer graphics model of the relative interactions. Five healthy male subjects with no history of upper extremity injury participated. A conventional manual wheelchair was equipped with a six-component load cell to collect three-dimensional forces and moments experienced by the wheel, allowing real-time measurement of hand/rim force applied by subjects during normal wheelchair operation. An ExpertVision six-camera video motion capture system collected trajectory data of markers attached on anatomical positions. The CGMM was used to simulate and animate muscle action by using an optimization technique combining observed muscular motions with physiological constraints to estimate muscle contraction forces during wheelchair propulsion. The CGMM provides results that satisfactorily match the predictions of previous work, disregarding minor differences which presumably result from differing experimental conditions, measurement technologies and subjects. Specifically, the CGMM shows that the supraspinatus, infraspinatus, anterior deltoid, pectoralis major and biceps long head are the prime movers during the propulsion phase. The middle and posterior deltoid and supraspinatus muscles are responsible for arm return during the recovery phase. CGMM modelling shows that the rotator cuff and pectoralis major play an important role during wheelchair propulsion, confirming the known risk of injury for these muscles during wheelchair propulsion. The CGMM successfully transforms six-camera video motion capture data into a technically useful and visually interesting animated video model of the shoulder musculoskeletal system. The CGMM further yields accurate estimates of muscular forces during motion, indicating that this prototype modelling and analysis technique will aid in study, analysis and therapy of the mechanics and underlying pathomechanics involved in various musculoskeletal overuse syndromes.