RESUMEN
BACKGROUND: This study explores the potential benefits of an arm weight intervention for improving gait performance in stroke survivors. Consistent with an interlimb neural coupling mechanism, the investigators hypothesized that arm weight would improve gait performance. METHODS: Nine stroke and nine healthy participants (1 female; age: 58.0 ± 6.8 years) participated. Participants walked over-ground at their preferred speed in four conditions: no weight (C1), non-hemiparetic (healthy: dominant) side weights (C2), hemiparetic (non-dominant) side weights (C3), and bilateral weights (C4). Statistical analyses included repeated analysis of variance (ANOVA) and paired t-test planned comparisons to explore the effects of added weight on gait speed, step width, step length, cadence, and arm swing amplitude. Single-subject analyses used randomization tests to delineate further the weight's effect on gait speed. FINDINGS: The stroke group walked significantly faster with arm weight (p = 0.048), exhibiting large ANOVA (η2p = 0.28) and C1 vs. C4 planned comparison (p = 0.021; dD = 0.95) effect sizes. Four of nine stroke participants significantly increased gait speed in at least one condition, and seven of nine exhibited large effect size increases (d = 0.85-4.71). The stroke group's hemiparetic-side step length and cadence significantly (p = 0.008) increased in C4 compared to C1, exhibiting large effect size increases (rb = 0.96). Four of nine healthy participants significantly increased gait speed in at least one condition, with five of nine exhibiting large effect size increases (d = 0.80-6.63). INTERPRETATION: This study's exploratory results demonstrate arm weight's potential for improving higher-functioning stroke survivors' gait performance. Arm weight addition merits further investigation as a possible rehabilitation intervention in the stroke population.
Asunto(s)
Trastornos Neurológicos de la Marcha , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Humanos , Femenino , Persona de Mediana Edad , Brazo , Marcha , Caminata , Velocidad al CaminarRESUMEN
OBJECTIVE: The authors sought to examine the immediate effects of movement training aimed at improving use of gluteus maximus (GMAX) in the sagittal plane on hip internal rotation and self-reported patellofemoral pain (PFP) during single-limb landing. METHODS: Seventeen females with PFP participated. Lower extremity kinematics and kinetics, GMAX activation, and self-reported PFP were obtained before and after a single-session movement training program aimed at increasing the use of GMAX. Dependent variables of interest included self-reported PFP, average GMAX activation, average hip extensor moment, and peak hip internal rotation. Post-training changes were evaluated using paired t tests and Wilcoxon signed rank tests. RESULTS: Following movement training, self-reported PFP decreased significantly (mean [standard deviation]) (3.9 [1.1] vs 0.8 [1.3] on a 0-10 scale). Additionally, significant increases were observed for the average hip extensor moment (0.6 [0.3] vs 1.8 [0.4] Nm/kg) and average GMAX activation (41.0% [18.3] vs 51.6% [25.7] maximum voluntary isometric contraction), whereas peak hip internal rotation decreased significantly (8.5 degrees [5.8] vs 6.0 degrees [5.3]). CONCLUSION: Movement training aimed at improving the use of GMAX in the sagittal plane resulted in clinically relevant changes in self-reported pain, GMAX activation, and hip kinetics and kinematics. Improving the use of GMAX during movement merits consideration when designing rehabilitation programs for females with PFP. IMPACT: The current study highlights the clinical utility of movement training for persons with PFP and provides a biomechanical rationale for its use as a potential intervention in this population.
Asunto(s)
Cadera/fisiopatología , Extremidad Inferior/fisiología , Movimiento/fisiología , Fuerza Muscular/fisiología , Síndrome de Dolor Patelofemoral/fisiopatología , Síndrome de Dolor Patelofemoral/terapia , Fenómenos Biomecánicos , Terapia por Ejercicio/métodos , Femenino , Humanos , Contracción Isométrica , Músculo Esquelético/fisiología , Adulto JovenRESUMEN
CONTEXT: The abdominal-bracing maneuver, a volitional preemptive abdominal contraction (VPAC) strategy, is commonly used during resisted shoulder exercises. How VPAC affects shoulder-muscle function during resisted shoulder exercise is unknown. OBJECTIVE: To identify the effects of VPAC on selected parascapular and glenohumeral muscles during specific shoulder exercises with or without resistance. DESIGN: Cross-sectional study. SETTING: Clinical biomechanics research laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-two asymptomatic volunteers between 18 and 40 years of age. INTERVENTION(S): Participants performed arm elevation in scaption and D1 shoulder-flexion (D1F) patterns with and without resistance and VPAC. MAIN OUTCOME MEASURE(S): Electromyography was used to test the muscle-contraction amplitudes and onset timing of the anterior deltoid, posterior deltoid, upper trapezius, lower trapezius, and serratus anterior. Muscle-response amplitudes were quantified using root mean square electromyography. Shoulder-muscle relative-onset timing was quantified in reference to kinematic elbow-movement initiation. RESULTS: The VPAC increased serratus anterior amplitude during D1F ( P < .001) and scaption ( P < .001) and upper trapezius amplitude ( P < .001) in scaption. All muscle amplitudes increased with resistance. The VPAC decreased muscle-onset latencies for the anterior deltoid ( P < .001), posterior deltoid ( P = .008), upper trapezius ( P = .001), lower trapezius ( P = .006), and serratus anterior ( P = .001) during D1F. In addition, the VPAC decreased muscle-onset latencies for the anterior deltoid ( P < .001), posterior deltoid ( P = .007), upper trapezius ( P < .001), lower trapezius ( P < .001), and serratus anterior ( P < .001) during scaption. CONCLUSIONS: The VPAC affected only the parascapular muscles that had the greatest scapular-stabilizing roles during the specific open chain movement we tested. It decreased latencies in all muscles. These neuromuscular changes may enhance the stability of the shoulder during D1F and scaption exercises.
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Músculos Abdominales/fisiología , Contracción Muscular , Hombro/fisiología , Músculos Superficiales de la Espalda/fisiología , Adulto , Fenómenos Biomecánicos , Estudios Transversales , Electromiografía , Ejercicio Físico , Femenino , Humanos , Masculino , Movimiento , Rango del Movimiento Articular , Escápula/fisiología , Adulto JovenRESUMEN
Previous studies have investigated how additional arm weights affect gait. Although light weights (0.45â¯kg) seemed to elicit performance improvements in Parkinsonian patients, it was not studied how light weights affect gait parameters in healthy individuals. It is important to understand normal responses in a healthy population so that clinical effects might be better understood. Therefore, the purpose of this study was to investigate the effects of arm weights on arm swing amplitude, gait performance, and muscle activity in healthy people. Twenty-two subjects walked overground at their preferred speed under different weight carriage conditions (C1: no weight; C2: unilateral arm weight; C3: bilateral arm weights; C4: waist weights). Gait speed increased in C2 (pâ¯=â¯0.018) and C4 (pâ¯=â¯0.013) when compared with C1(C1: 1.21⯱â¯0.08; C2: 1.25⯱â¯0.11; C3: 1.24⯱â¯0.11; C4: 1.25⯱â¯0.11â¯m/s) with an increase in cadence during C2 (pâ¯<â¯0.001), C3 (pâ¯=â¯0.008), and C4 (pâ¯<â¯0.001) (C1: 105.5⯱â¯5.2; C2: 108.5⯱â¯5.6; C3: 107.9⯱â¯5.6; C4: 108.5⯱â¯5.3 steps/min) and in tibialis anterior electromyographic activity on the unweighted side in C2 (pâ¯=â¯0.048) (C1: 21.05⯱â¯4.59; C2: 25.10⯱â¯6.10; C3: 23.93⯱â¯4.75; C4: 24.33⯱â¯6.32⯵V). The results indicate that an additional sensory input with the application of the weights may result in an overcompensation with the whole body and facilitate faster walking speed when applied on one arm or around the waist. The locations of the weights and amount of the weights may elicit different responses. Various strategies of adding weights should be further investigated as a potential intervention to improve performance in individuals with various gait impairments. Although there is evidence for benefits of this intervention in Parkinsonian patients, further study is warranted in other patient populations, such as stroke patients, who might benefit from this intervention to improve gait performance.
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Brazo/fisiología , Marcha/fisiología , Adulto , Brazo/anatomía & histología , Fenómenos Biomecánicos/fisiología , Peso Corporal/fisiología , Electromiografía/métodos , Femenino , Voluntarios Sanos , Humanos , Masculino , Músculo Esquelético/fisiología , Caminata/fisiología , Velocidad al Caminar , Soporte de Peso/fisiología , Adulto JovenRESUMEN
BACKGROUND: Although a relationship between elevated patellofemoral forces and pain has been proposed, it is unknown which joint loading variable (magnitude, rate) is best associated with pain changes. The purpose of this study was to examine associations among patellofemoral joint loading variables and changes in patellofemoral pain across repeated single limb landings. METHODS: Thirty-one females (age: 23.5(2.8) year; height: 166.8(5.8) cm; mass: 59.6(8.1) kg) with PFP performed 5 landing trials from 0.25â¯m. The dependent variable was rate of change in pain obtained from self-reported pain scores following each trial. Independent variables included 5-trial averages of peak, time-integral, and average and maximum development rates of the patellofemoral joint reaction force obtained using a previously described model. Pearson correlation coefficients were calculated to evaluate individual associations between rate of change in pain and each independent variable (αâ¯=â¯0.05). Stepwise linear multiple regression (αenterâ¯=â¯0.05; αexitâ¯=â¯0.10) was used to identify the best predictor of rate of change in pain. FINDINGS: Subjects reported an average increase of 0.38 pain points with each landing trial. Although, rate of change in pain was positively correlated with peak force (râ¯=â¯0.44, pâ¯=â¯0.01), and average (râ¯=â¯0.41, pâ¯=â¯0.02) and maximum force development rates (râ¯=â¯0.39, pâ¯=â¯0.03), only the peak force entered the predictive model explaining 19% of variance in rate of change in pain (r2â¯=â¯0.19, pâ¯=â¯0.01). INTERPRETATION: Peak patellofemoral joint reaction force was the best predictor of the rate of change in pain following repetitive singe limb landings. The current study supports the theory that patellofemoral joint loading contributes to changes in patellofemoral pain.
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Articulación de la Rodilla/fisiopatología , Articulación Patelofemoral/fisiopatología , Síndrome de Dolor Patelofemoral/fisiopatología , Adulto , Fenómenos Biomecánicos , Electromiografía , Femenino , Humanos , Persona de Mediana Edad , Dimensión del Dolor , Carrera , Autoinforme , Soporte de Peso , Adulto JovenRESUMEN
Carrying weight while walking is a common activity associated with increased musculoskeletal loading, but not all individuals accommodate to the weight in the same way. Different accommodation strategies could lead to different skeletal forces, stimuli for bone adaptation and ultimately bone competence. The purpose of the study was to explore the relationships between calcaneal bone competence and biomechanical accommodation variables measured during weighted walking. Twenty healthy men and women (10 each; age 27.8⯱â¯6.8â¯years) walked on a treadmill at 1.34â¯m/s while carrying 0, 44.5 and 89â¯N weights with two hands in front of the body. Peak vertical ground reaction force and sagittal plane angular displacements of the trunk and left lower extremity during weight acceptance were measured and used to quantify accommodation. Calcaneal bone stiffness index T-score (BST) was measured using quantitative ultrasound. Correlation and stepwise multiple regression were used to predict calcaneal BST from the accommodation variables. Accommodations of the foot and ankle explained 29 and 54% (pâ¯≤â¯.015) of the variance in calcaneal BST in different regression models. Statistical resampling using 1000 replications confirmed the strength and consistency of relationships, with the best model explaining 94% of the variance in calcaneal BST. Individuals who change foot and ankle function when carrying heavier weight likely alter the control of gravitational and muscular forces, thereby affecting calcaneal loading, bone adaptation and bone competence. These novel findings illustrate the importance of gait accommodation strategies and highlight a potential clinical consequence that requires further investigation.
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Fenómenos Biomecánicos/fisiología , Huesos/fisiología , Talón/fisiología , Caminata/fisiología , Soporte de Peso/fisiología , Adaptación Fisiológica , Adulto , Tobillo/fisiología , Brazo/fisiología , Huesos/diagnóstico por imagen , Estudios Transversales , Femenino , Pie/fisiología , Gravitación , Talón/diagnóstico por imagen , Humanos , Masculino , Modelos Biológicos , Fuerza Muscular , Ultrasonografía , Adulto JovenRESUMEN
AIM: Central arterial hemodynamics is associated with cognitive impairment. Reductions in gait speed during walking while performing concurrent tasks known as dual-tasking (DT) or multi-tasking (MT) is thought to reflect the cognitive cost that exceeds neural capacity to share resources. We hypothesized that central vascular function would associate with decrements in gait speed during DT or MT. METHODS: Gait speed was measured using a motion capture system in 56 women (30-80y) without mild-cognitive impairment. Dual-tasking was considered walking at a fast-pace while balancing a tray. Multi-tasking was the DT condition plus subtracting by serial 7's. Applanation tonometry was used for measurement of aortic stiffness and central pulse pressure. Doppler-ultrasound was used to measure blood flow velocity and ß-stiffness index in the common carotid artery. RESULTS: The percent change in gait speed was larger for MT than DT (14.1±11.2 vs. 8.7±9.6%, p <0.01). Tertiles were formed based on the percent change in gait speed for each condition. No vascular parameters differed across tertiles for DT. In contrast, carotid flow pulsatility (1.85±0.43 vs. 1.47±0.42, p=0.02) and resistance (0.75±0.07 vs. 0.68±0.07, p=0.01) indices were higher in women with more decrement (third tertile) as compared to women with less decrement (first tertile) in gait speed during MT after adjusting for age, gait speed, and task error. Carotid pulse pressure and ß-stiffness did not contribute to these tertile differences. CONCLUSION: Elevated carotid flow pulsatility and resistance are characteristics found in healthy women that show lower cognitive capacity to walk and perform multiple concurrent tasks.
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Arteria Carótida Común/fisiopatología , Disfunción Cognitiva/fisiopatología , Marcha/fisiología , Comportamiento Multifuncional/fisiología , Flujo Pulsátil/fisiología , Rigidez Vascular/fisiología , Velocidad al Caminar/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Velocidad del Flujo Sanguíneo/fisiología , Arteria Carótida Común/diagnóstico por imagen , Disfunción Cognitiva/diagnóstico , Femenino , Humanos , Persona de Mediana Edad , Ultrasonografía Doppler/métodos , Caminata/fisiologíaRESUMEN
AIM: Cognitive dysfunction is associated with slower gait speed in older women, but whether cognitive function affects gait performance earlier in life has yet to be investigated. Thus, the objective of this study was to test the hypothesis that cognitive function will discriminate gait performance in healthy younger women. METHODS: Fast-pace and dual-task gait speed were measured in 30 young to middle-aged (30-45y) and 26 older (61-80y) women without mild cognitive impairment. Visuoperceptual ability, working memory, executive function, and learning ability were assessed using neuropsychological tests. Within each age group, women were divided by the median into lower and higher cognitive function groups to compare gait performance. RESULTS: Younger women with higher visuoperceptual ability had faster fast-pace (2.25±0.30 vs. 1.98±0.18m/s, p≤0.01) and dual-task gait speed (2.02±0.27 vs. 1.69±0.25m/s, p≤0.01) than women with lower visuoperceptual ability. The difference in dual-task gait speed remained significant (p=0.02) after adjusting for age, years of education, and other covariates. Dividing younger women based on other cognitive domains showed no difference in gait performance. In contrast, working memory and executive function discriminated dual-task gait speed (p<0.05) in older women after adjusting for age and education. CONCLUSION: To our knowledge, this is the first study to show that poorer cognitive function even at a relatively young age can negatively impact mobility. Different cognitive functions discriminated gait performance based on age, highlighting a possible influence of aging in the relationship between cognitive function and mobility in women.
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Envejecimiento/psicología , Cognición , Función Ejecutiva , Marcha/fisiología , Aprendizaje , Memoria a Corto Plazo , Percepción Visual , Velocidad al Caminar/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Envejecimiento/fisiología , Femenino , Humanos , Persona de Mediana Edad , Pruebas Neuropsicológicas , Proyectos Piloto , Caminata/fisiologíaRESUMEN
The purpose of this study was to examine the nature of the intra-subject independence among strides during treadmill walking. We investigated the strength of the relationships among strides sampled in different ways from a population of observed strides. Eighteen asymptomatic subjects walked on a treadmill at 1.4±0.1m/s. Maximum angles and ranges of motion from the ankle, knee and hip joints, as well as stride duration were obtained and autocorrelation coefficients (AC) for 3 lags were calculated among 12 strides sampled consecutively (CS), in order but non-adjacently (NA), and randomly (RA). Ninety-nine percent of AC values were within Bartlett's 95% confidence interval limits and thus the strides were not considered significantly autocorrelated. The results support the hypothesis that strides obtained from an individual walking on a treadmill can be statistically independent. This supports the theoretical assumption that in some circumstances humans can be modeled as random sample generators due to inherent movement variability. The ability to assess statistically clinical intervention provides objective rigor for evaluating rehabilitation outcomes.
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Marcha/fisiología , Extremidad Inferior/fisiología , Caminata/fisiología , Adulto , Articulación del Tobillo , Fenómenos Biomecánicos , Femenino , Articulación de la Cadera , Humanos , Articulación de la Rodilla , Masculino , Persona de Mediana EdadRESUMEN
Weighted walking is a functional activity common in daily life and can influence risks for musculoskeletal loading, injury and falling. Much information exists about weighted walking during military, occupational and recreational tasks, but less is known about strategies used to accommodate to weight carriage typical in daily life. The purposes of the study were to examine the effects of weight carriage on kinematics and peak ground reaction force (GRF) during walking, and explore relationships between these variables. Twenty subjects walked on a treadmill while carrying 0, 44.5 and 89 N weights in front of the body. Peak GRF, sagittal plane joint/segment angular kinematics, stride length and center of mass (COM) vertical displacement were measured. Changes in peak GRF and displacement variables between weight conditions represented accommodation. Effects of weight carriage were tested using analysis of variance. Relationships between peak GRF and kinematic accommodation variables were examined using correlation and regression. Subjects were classified into sub-groups based on peak GRF responses and the correlation analysis was repeated. Weight carriage increased peak GRF by an amount greater than the weight carried, decreased stride length, increased vertical COM displacement, and resulted in a more extended and upright posture, with less hip and trunk displacement during weight acceptance. A GRF increase was associated with decreases in hip extension (|r|=.53, p=.020) and thigh anterior rotation (|r|=.57, p=.009) displacements, and an increase in foot anterior rotation displacement (|r|=.58, p=.008). Sub-group analysis revealed that greater GRF increases were associated with changes at multiple sites, while lesser GRF increases were associated with changes in foot and trunk displacement. Weight carriage affected walking kinematics and revealed different accommodation strategies that could have implications for loading and stability.
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Fenómenos Biomecánicos/fisiología , Caminata/fisiología , Soporte de Peso/fisiología , Accidentes por Caídas , Adulto , Femenino , Marcha/fisiología , Humanos , Masculino , Equilibrio Postural/fisiología , Torso , Adulto JovenRESUMEN
The purpose of this study was to determine the effects of constraining arm swing on the vertical displacement of the body's center of mass (COM) during treadmill walking and examine several common gait variables that may account for or mask differences in the body's COM motion with and without arm swing. Participants included 20 healthy individuals (10 male, 10 female; age: 27.8 ± 6.8 years). The body's COM displacement, first and second peak vertical ground reaction forces (VGRFs), and lowest VGRF during mid-stance, peak summed bilateral VGRF, lower extremity sagittal joint angles, stride length, and foot contact time were measured with and without arm swing during walking at 1.34 m/s. The body's COM displacement was greater with the arms constrained (arm swing: 4.1 ± 1.2 cm, arm constrained: 4.9 ± 1.2 cm, p < 0.001). Ground reaction force data indicated that the COM displacement increased in both double limb and single limb stance. However, kinematic patterns visually appeared similar between conditions. Shortened stride length and foot contact time also were observed, although these do not seem to account for the increased COM displacement. However, a change in arm COM acceleration might have contributed to the difference. These findings indicate that a change in arm swing causes differences in vertical COM displacement, which could increase energy expenditure.