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1.
Medicine (Baltimore) ; 99(12): e19519, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32195954

RESUMO

BACKGROUND: The purposes of this study were to examine the feasibility of using the MyotonPRO digital palpation device in measuring the passive stiffness of gastrocnemius muscle belly and Achilles tendon; to determine between-days test-retest reliability of MyotonPRO; and to evaluate the acute effect of paraffin therapy on stiffness measurements in healthy participants. METHODS: It is a randomized controlled trial. Twenty healthy participants (male, n = 10; female, n = 10; total, n = 20) were recruited to evaluate the passive stiffness of gastrocnemius muscle belly and Achilles tendon. Dominant and nondominant legs were randomly divided into an experimental side (20 cases) and a control side (20 cases). The experimental side received 20 minutes of paraffin therapy. RESULTS: The stiffness of muscle and tendon in the experimental side decreased significantly after paraffin therapy (P < .01), whereas no significant differences in stiffness measurements were found in the control side (P > .05). The passive stiffness of muscle and tendon was positively correlated with the ankle from 30° plantar flexion to10° dorsiflexion for dominant legs. Between-days test-retest reliability in stiffness measurements was high or very high (ICCs were above 0.737). CONCLUSION: Paraffin therapy induces a decrease in the passive stiffness of gastrocnemius muscle belly and Achilles tendon. Furthermore, the MyotonPRO can reliably determine stiffness measurements.


Assuntos
Tendão do Calcâneo/efeitos dos fármacos , Hidrocarbonetos/uso terapêutico , Tono Muscular/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Parafina/uso terapêutico , Tendão do Calcâneo/fisiopatologia , Adolescente , Adulto , Articulação do Tornozelo/fisiologia , Feminino , Humanos , Masculino , Músculo Esquelético/fisiopatologia , Modalidades de Fisioterapia/tendências , Amplitude de Movimento Articular/fisiologia , Reprodutibilidade dos Testes , Adulto Jovem
2.
J Sports Sci ; 38(6): 652-657, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32009512

RESUMO

The purpose of this study was to investigate subject- and joint-specific strategies used by male basketball players as they increase their countermovement jump (CMJ) height from sub-maximal to maximal efforts. Lower extremity joint kinematics and kinetics were recorded as 11 male, NCAA Division I basketball players performed 8-10 CMJ across effort levels of approximately 25%, 50%, 75% and 100%. Simple correlation models were used to investigate the associations between effort levels (i.e., CMJ height) and joint mechanics (i.e., negative (eccentric) and positive (concentric) mechanical work performed at the hip, knee, and ankle joints) for each individual player and the entire group. Group-analyses showed that increases in all joint mechanical variables were associated with increases in CMJ height. In contrast, single-subject analyses revealed that players used individualised strategies, and selectively scaled the magnitude of mechanical work at none (n = 2), one (n = 2), two (n = 5), or all three (n = 2) joints as they increased CMJ efforts. In addition, individual players also appeared to selectively scale different combinations of eccentric or concentric joint work as they increased CMJ height. These results highlight that male basketball players use joint-specific strategies to increase CMJ height when progressively increasing CMJ effort.


Assuntos
Articulação do Tornozelo/fisiologia , Basquetebol/fisiologia , Articulação do Quadril/fisiologia , Articulação do Joelho/fisiologia , Exercício Pliométrico , Fenômenos Biomecânicos , Humanos , Cinética , Masculino , Análise e Desempenho de Tarefas , Adulto Jovem
3.
J Sports Sci ; 38(5): 518-527, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31900052

RESUMO

The purpose of this study was to investigate the effects of slope on three-dimensional running kinematics at high speed. Thirteen male sprinters ran at high speed (7.5 m/s) on a motorised treadmill in each a level and a 5.0% slope condition. Three-dimensional motion analysis was conducted to compare centre of mass (CoM) energetics, pelvis segment and lower limb joints kinematics. We found that contact time was not affected by the slope, whereas flight time and step length were significantly shorter in uphill compared to level running. Uphill running reduced negative CoM work and increased positive CoM work compared to level running. Ankle, knee and hip joints were more flexed at initial ground contact, but only the knee was more extended at the end of stance in uphill compared to level running. Additionally, the hip joint was more abducted, and the free leg side of the pelvis was more elevated at the end of stance in uphill running. Our results demonstrate that joint motion must be developed from a more flexed/adducted position at initial contact through a greater range of motion compared to level running in order to meet the greater positive CoM work requirements in uphill running at high speed.


Assuntos
Articulação do Tornozelo/fisiologia , Articulação do Quadril/fisiologia , Articulação do Joelho/fisiologia , Corrida/fisiologia , Fenômenos Biomecânicos/fisiologia , Teste de Esforço , Marcadores Fiduciais , Marcha , Humanos , Imagem Tridimensional , Masculino , Movimento/fisiologia , Amplitude de Movimento Articular/fisiologia , Adulto Jovem
4.
J Sports Sci ; 38(1): 6-12, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31603027

RESUMO

This study aimed to examine the characteristics of electromyography (EMG) and kinematics of the supporting leg affecting energy cost while running at incline, level, and decline slopes. Twelve male Japanese middle- and long-distance runners volunteered for this study. The subjects were asked to run at 13.5 km·h-1 on a treadmill under three slope conditions. Sagittal plane kinematics and the EMG of the lower limb muscles, respiratory gases were recorded. Energy cost differed significantly between slopes, being the lowest in decline slope and the greatest in incline slope. Integrated EMG (iEMG) of leg extensor muscles was greater in the incline slope than in the decline slope, and iEMG of the gastrocnemius and soleus muscles correlated positively with energy cost. The knee and ankle joint kinematics were associated with energy cost during running. In incline slope, the knee and ankle joints were more extended (plantarflexed) to lift the body. These movements may disturb the coordination between the ankle and knee joints. The gastrocnemius muscle would do greater mechanical work to plantarflex the ankle joint rather than transfer mechanical energy as well as greater mechanical work of mono-articular muscles. These muscular activities would increase energy cost.


Assuntos
Metabolismo Energético/fisiologia , Extremidade Inferior/fisiologia , Corrida/fisiologia , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Eletromiografia , Teste de Esforço/métodos , Articulação do Quadril/fisiologia , Humanos , Articulação do Joelho/fisiologia , Masculino , Movimento/fisiologia , Músculo Esquelético/fisiologia , Troca Gasosa Pulmonar/fisiologia , Adulto Jovem
5.
J Sports Sci ; 38(3): 248-255, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726955

RESUMO

Accelerometers are often placed on the tibia to measure segmental accelerations, and external mechanical load during running. However, in applied sport settings it is sometimes preferable to place accelerometers on the dorsal foot to avoid tibial impact injuries. This study aimed to quantify the differences in accelerations measured at the dorsal foot compared with the distal tibia during running. Sixteen recreationally active participants performed a sprint protocol on a non-motorised treadmill. Accelerometers were positioned bilaterally on the medial tibia (TIBLeft and TIBRight), and bilateral dorsal foot surfaces (DORLeft and DORRight). Continuous acceleration signal waveform analysis was performed using one-dimensional statistical parametric mapping (1DSPM). Resultant accelerations were greater for DORLeft than TIBLeft for 60% of the gait cycle (p < 0.001) and greater for DORRight than TIBRight for 50% of the gait cycle (p < 0.003). The larger accelerations at the dorsal foot than the tibia can be explained by movement at the ankle joint, and the placement location relative to the hip. The dorsal foot location can be used to effectively measure accelerations and external mechanical load when it is not feasible to place the accelerometer on the tibia, however results between the two locations should not be compared.


Assuntos
Acelerometria/instrumentação , Monitores de Aptidão Física , Pé/fisiologia , Corrida/fisiologia , Tíbia/fisiologia , Aceleração , Adulto , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Estudos de Viabilidade , Feminino , Quadril/fisiologia , Humanos , Masculino , Movimento/fisiologia , Percepção/fisiologia , Esforço Físico/fisiologia , Adulto Jovem
6.
Sports Biomech ; 19(2): 189-200, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29768121

RESUMO

Cerebral palsy is known to generally limit range of motion and force producing capability during movement. It also limits sprint performance, but the exact mechanisms underpinning this are not well known. One elite male T36 multiple-Paralympic sprint medallist (T36) and 16 well-trained able-bodied (AB) sprinters each performed 5-6 maximal sprints from starting blocks. Whole-body kinematics (250 Hz) in the block phase and first two steps, and synchronised external forces (1,000 Hz) in the first stance phase after block exit were combined to quantify lower limb joint kinetics. Sprint performance (normalised average horizontal external power in the first stance after block exit) was lower in T36 compared to AB. T36 had lower extensor range of motion and peak extensor angular velocity at all lower limb joints in the first stance after block exit. Positive work produced at the knee and hip joints in the first stance was lower in T36 than AB, and the ratio of positive:negative ankle work produced was lower in T36 than AB. These novel results directly demonstrate the manner in which cerebral palsy limits performance in a competition-specific sprint acceleration movement, thereby improving understanding of the factors that may limit performance in elite sprinters with cerebral palsy.


Assuntos
Aceleração , Desempenho Atlético/fisiologia , Paralisia Cerebral/fisiopatologia , Extremidade Inferior/fisiologia , Corrida/fisiologia , Esportes para Pessoas com Deficiência/fisiologia , Adulto , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Articulação do Quadril/fisiologia , Humanos , Articulação do Joelho/fisiologia , Masculino , Amplitude de Movimento Articular , Adulto Jovem
7.
Gait Posture ; 75: 149-154, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31683185

RESUMO

BACKGROUND: Gastrocnemius medialis (GM) and lateralis (GL) act at the ankle complex in the sagittal and frontal planes and there is evidence that their actions can be somewhat uncoupled from each other. Some independence of GM and GL from each other could be advantageous, e.g. to stabilise the ankle complex in unstable walking conditions. Given the compartmentalised structure of the Achilles tendon, the sub-tendons of GM and GL may exhibit different elongation during plantarflexion contractions, particularly with the foot in different frontal plane positions. RESEARCH QUESTIONS: METHODS: Sub-tendon elongation was determined from 18 participants during ramped isometric plantarflexion contractions to 70% of their maximum voluntary contraction (MVC) level with the foot in neutral, inversion and eversion. One-dimensional statistical parametric mapping was applied to determine elongation differences. RESULTS: Elongation within a sub-tendon did not differ in the three foot positions. Elongation was similar between both sub-tendons at very low contraction levels, but GM sub-tendon elongation exceeded GL sub-tendon displacement significantly from 30% MVC. The elongation differences between the sub-tendons were not affected by foot position. SIGNIFICANCE: Greater GM sub-tendon elongation is likely caused by the greater force production capability of GM but may also indicate that the sub-tendons of GM and GL have different mechanical properties, which is currently unknown. Elongation differences were contraction level dependent suggesting that contributions of GM and GL to plantarflexion torque may also be contraction level dependent.


Assuntos
Articulação do Tornozelo/fisiologia , Pé/fisiologia , Músculo Esquelético/fisiologia , Tendões/fisiologia , Tendão do Calcâneo/fisiologia , Adulto , Feminino , Humanos , Contração Isométrica/fisiologia , Masculino , Pessoa de Meia-Idade , Torque
8.
J Sports Sci ; 38(5): 486-493, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31865835

RESUMO

Biomechanical analysis has typically been confined to a laboratory setting. While attempts have been made to take laboratory testing into the field, this study was designed to assess whether augmented reality (AR) could be used to bring the field into the laboratory. This study aimed to measure knee load in volleyball players through a jump task incorporating AR while maintaining the perception-action couplings by replicating the visual features of a volleyball court. Twelve male volleyball athletes completed four tasks: drop landing, hop jump, spike jump, and spike jump while wearing AR smart glasses. Biomechanical variables included patellar tendon force, knee moment and kinematics of the ankle, knee, hip, pelvis and thorax. The drop landing showed differences in patellar tendon force and knee moment when compared to the other conditions. The hop jump did not present differences in kinetics when compared to the spike conditions, instead of displaying the greatest kinematic differences. As a measure of patellar tendon loading the AR condition showed a close approximation to the spike jump, with no differences present when comparing landing forces and mechanics. Thus, AR may be used in a clinical assessment to better replicate information from the competitive environment.


Assuntos
Desempenho Atlético/fisiologia , Realidade Aumentada , Voleibol/fisiologia , Adolescente , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos/fisiologia , Articulação do Quadril/fisiologia , Humanos , Articulação do Joelho/fisiologia , Masculino , Ligamento Patelar/fisiologia , Reprodutibilidade dos Testes , Adulto Jovem
9.
J Sports Sci Med ; 18(4): 663-668, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31827350

RESUMO

The purpose of this study was to investigate the mechanical similarity between net joint moments (NJM) of the countermovement jump (CMJ) and the hang power clean (HPC) and jump shrug (JS). Twelve male Lacrosse players performed three maximal effort CMJs and three repetitions of the HPC and JS at 30%, 50%, and 70% of their HPC one repetition maximum (1-RM). Ground reaction forces and motion capture data were used to calculate the NJM of the hip, knee, and ankle joints during each exercise. Statistical comparison of the peak NJM indicated that NJM during the HPC and JS across all loads were equal to or greater than the NJM during the CMJ (all p < 0.025). In addition, correlation analyses indicated that CMJ hip NJM were associated (all p < 0.025) with HPC hip NJM at 30% and 70% (r = 0.611-0.822) and JS hip NJM at 50% and 70% (r = 0.674-0.739), whereas CMJ knee NJM were associated with HPC knee NJM at 70% (r = 0.638) and JS knee NJM at 50% and 70% (r = 0.664-0.732). Further, CMJ ankle NJM were associated with HPC ankle NJM at 30% and 50% (r = 0.615-0.697) and JS ankle NJM at 30%, 50%, and 70% (r = 0.735-0.824). Lastly, knee and ankle NJM during the JS were greater than during the HPC at 30% and 50% of 1-RM (all p < 0.017). The degree of mechanical similarity between the CMJ and the HPC and JS is dependent on the respective load and joint.


Assuntos
Articulação do Tornozelo/fisiologia , Articulação do Quadril/fisiologia , Articulação do Joelho/fisiologia , Exercício Pliométrico , Levantamento de Peso/fisiologia , Estudos Transversais , Humanos , Cinética , Masculino , Esportes com Raquete/fisiologia , Estudos de Tempo e Movimento , Adulto Jovem
10.
Hum Mov Sci ; 68: 102528, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31706119

RESUMO

The objective of this study was to characterize joint angle variation across strides. Specifically, the statistical persistence of variations were quantified using the Hurst exponent. If a time series exhibits statistical persistence, then a parameter which is smaller (or larger) than average will tend to be followed by additional values that are also smaller (or larger) than average. Human walking has statistical persistence between stride durations. Variation in stride duration must arise from variation in the motion of the leg segments during walking. It is unclear, however, if the joint angle variation also exhibits statistical persistence. This study examined kinematic data collected from nine healthy adults walking for 10 min at a self-selected comfortable speed on a treadmill. The joint angle variation in the lower limbs was parameterized using first-order Fourier series which in turn were described by frequency and magnitude coefficients for each stride. To determine if the joint angle variation exhibited statistical persistence, the Hurst exponent was found for each coefficient at each joint. The mean Hurst exponents were 0.54 for the frequency coefficients and 0.61 for the magnitude coefficients. Neither the frequency or magnitude coefficients exhibited statistically significant persistence, although some of the magnitude coefficients were close to reaching statistical significance. This suggests that joint angle variability in healthy adults does not directly produce the statistical persistence observed in stride duration fluctuations.


Assuntos
Articulação do Quadril/fisiologia , Caminhada/fisiologia , Adolescente , Adulto , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos/fisiologia , Teste de Esforço/métodos , Feminino , Marcha/fisiologia , Humanos , Articulação do Joelho/fisiologia , Extremidade Inferior/fisiologia , Masculino , Amplitude de Movimento Articular/fisiologia , Adulto Jovem
11.
J Sports Med Phys Fitness ; 59(10): 1684-1690, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31694362

RESUMO

BACKGROUND: Athletes in jumping and running sports have a high incidence of Achilles tendon (AT) injuries. We compared AT loading during jumping and landing phases in anteroposterior (AP) and mediolateral (ML) directions. METHODS: Sixteen males (age: 21.6±1.8 years, height: 178.4±6.4 cm, weight: 76.4±11.2 kg) performed single leg AP and ML jump-landings during both propulsive (jump) and braking (land) phases. Inverse dynamics and static optimization were used to determine muscle forces. AT cross sectional area was measured with ultrasound. AT force was divided by cross sectional area to determine stress while strain was determined from previous data. Two-way repeated measures analysis of variance (α=0.05) compared several variables (vertical ground reaction force (VGRF), ankle and knee angle, ankle joint muscle moment arm, external ankle moment arm, AT tendon force, stress, and strain) between movements (jump-landings) and directions (AP/ML). RESULTS: AT loading was higher during jump than land in the ML compared to AP direction. VGRF was higher during land versus jump with no direction effect (AP/ML). An interaction showed a higher VGRF during the AP land and ML jump. The ankle joint moment arm was lower in jump and AP direction at peak tendon stress. External ankle moment arm at peak tendon stress was higher in jump and ML direction with an interaction. A larger external ankle moment arm occurred in ML but the change was less in the jump. CONCLUSIONS: Higher tendon loading occurred during the jump and ML direction. This may provide insight into both injuries and rehabilitation efforts.


Assuntos
Tendão do Calcâneo/química , Tendão do Calcâneo/fisiologia , Adulto , Traumatismos do Tornozelo , Articulação do Tornozelo/fisiologia , Atletas , Fenômenos Biomecânicos/fisiologia , Humanos , Articulação do Joelho/fisiologia , Masculino , Movimento , Corrida , Adulto Jovem
12.
Hum Mov Sci ; 68: 102524, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31733429

RESUMO

In computational models of human walking, both magnitude and timing of locomotor propulsion are important for mechanical and metabolic efficiency, suggesting that these are likely tightly controlled by the neuromuscular system. Studies of actual human walking have focused primarily on magnitude-related measures of propulsion, often ignoring its timing. The purpose of this study was to quantify the timing of onset and peak propulsion relative to contralateral heel strike (HS) in healthy, young adults walking at multiple speeds. Propulsion was quantified at the ground-level using the anterior component of the anteroposterior ground reaction force, the limb-level using individual limb power, and the joint-level using ankle power. Contrary to common computational models, most of our timing-related measures indicated that propulsion occurred after contralateral HS. Timing-related measures of propulsion also changed with walking speed - as speed increased, individuals initiated propulsion earlier in the support phase. Timing of locomotor propulsion is theoretically important for walking performance, especially metabolic efficiency, and could therefore provide important clinical information. This study provides a set of relatively simple metrics that can be used to quantify propulsion and benchmark data that can be used for future comparisons with individuals or populations with gait impairments.


Assuntos
Caminhada/fisiologia , Adulto , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos/fisiologia , Teste de Esforço/métodos , Feminino , Calcanhar/fisiologia , Humanos , Masculino , Velocidade de Caminhada/fisiologia , Adulto Jovem
13.
Med Sci Monit ; 25: 7720-7727, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31611547

RESUMO

BACKGROUND Unbalanced standing and gait asymmetry are common in individuals with musculoskeletal disorders. Achieving symmetrical posture and gait is an important goal of rehabilitation. This study investigated the biomechanical differences in the lower extremities observed immediately after an insole was used and without the use of different one-sided insoles. MATERIAL AND METHODS Thirty young, healthy adult males received 3 different insole interventions: experimental group A had a customized 3-dimensional (3D)-printed single-sided lateral wedge insole (CLWI) inserted on the left side, and experimental group B had on the left side, a traditional single insert. The control had unilateral flat insoles; no insole inserted into the socks. Motion mechanics and gait parameters were collected at the 2-time points, after insertion of the insole and after 20 minutes of walking with the insole. RESULTS Asymmetric posture and gait appeared immediately after using the 2 insoles (lower joint moment, P<0.05). Compared with the control group, the abnormal posture and gait of experimental group B after wearing the traditional insole for 20 minutes were not obvious (P>0.05). However, the asymmetrical posture and gait remained in experimental group A after wearing the CLWI for 20 minutes (P<0.05). The center of pressure (COP) trajectory of the left foot of experimental group A was significantly higher than that of experimental group B and the control group at the 2-time points (P<0.05). CONCLUSIONS The asymmetry of posture and gait can be observed in a short time using a customized 3D-printed single-sided lateral wedge insole. This experiment provides guidance for the application of customized 3D-printed single-sided lateral wedge insoles for gait rehabilitation.


Assuntos
Órtoses do Pé/tendências , Marcha/fisiologia , Postura/fisiologia , Adulto , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , China , Pé/fisiologia , Voluntários Saudáveis , Humanos , Articulação do Joelho/fisiologia , Extremidade Inferior/fisiologia , Masculino , Impressão Tridimensional , Caminhada/fisiologia
14.
Sensors (Basel) ; 19(19)2019 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-31569372

RESUMO

Overweight/obesity is a physical condition that affects daily activities, including walking. The main purpose of this study was to identify if there is a relationship between body mass index (BMI) and gait characteristics in young adults. 12 normal weight (NW) and 10 overweight/obese (OW) individuals walked at a self-selected speed along a 14 m indoor path. H-Gait system, combining seven inertial sensors (fixed on pelvis and lower limbs), was used to record gait data. Walking speed, spatio-temporal parameters and joint kinematics in 3D were analyzed. Differences between NW and OW and correlations between BMI and gait parameters were evaluated. Conventional spatio-temporal parameters did not show statistical differences between the two groups or correlations with the BMI. However, significant results were pointed out for the joint kinematics. OW showed greater hip joint angles in frontal and transverse planes, with respect to NW. In the transverse plane, OW showed a greater knee opening angle and a shorter length of knee and ankle trajectories. Correlations were found between BMI and kinematic parameters in the frontal and transverse planes. Despite some phenomena such as soft tissue artifact and kinematics cross-talk, which have to be more deeply assessed, current results show a relationship between BMI and gait characteristics in young adults that should be looked at in osteoarthritis prevention.


Assuntos
Índice de Massa Corporal , Marcha/fisiologia , Monitorização Fisiológica/instrumentação , Sobrepeso , Adulto , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Humanos , Articulação do Joelho/fisiologia , Masculino , Monitorização Fisiológica/métodos , Sobrepeso/fisiopatologia , Análise Espaço-Temporal , Caminhada/fisiologia
15.
Int J Sports Med ; 40(13): 863-870, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31593991

RESUMO

Previous cross-sectional studies have reported that higher drop heights do not always result in improved performance, and may increase injury risk during drop jumps (DJ). The purpose of this study was to analyze the kinematics and kinetics during the DJ in order to determine the relative drop height that maximize performance without exposing the lower extremity joints to unnecessary loads. Twenty male Division I college volleyball players volunteered. Data were collected using 11 infrared cameras and two force platforms. Participants performed three maximal effort countermovement jumps (CMJ). Subsequently, 50, 75, 100, 125, and 150% CMJ height (CMJH) was used to scale their relative drop height for three DJ trials per height. There was a significant increase in the landing phase impulse when the drop height exceeded 100%CMJH (p<0.05). At 125% and 150%CMJH, the negative work of knee and ankle significantly increased. The incoming velocity, kinetic energy, landing depth, maximum ground reaction force, landing impulse and power absorption of knee and ankle all increased with drop height (p<0.05). DJ height and reactive strength index following the drop landing were not statistically different between any of the drop heights (p>0.05). 50% to 100%CMJH may be the appropriate individual relative drop height for the DJ.


Assuntos
Extremidade Inferior/fisiologia , Exercício Pliométrico , Voleibol/fisiologia , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Estudos Transversais , Articulação do Quadril/fisiologia , Humanos , Cinética , Articulação do Joelho/fisiologia , Masculino , Estudos de Tempo e Movimento , Adulto Jovem
16.
Sensors (Basel) ; 19(20)2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31623248

RESUMO

In this paper, a stride detector algorithm combined with a technique inspired by zero velocity update (ZUPT) is proposed to reconstruct the trajectory of a pedestrian from an ankle-mounted inertial device. This innovative approach is based on sensor alignment and machine learning. It is able to detect 100% of both normal walking strides and more than 97% of atypical strides such as small steps, side steps, and backward walking that existing methods can hardly detect. This approach is also more robust in critical situations, when for example the wearer is sitting and moving the ankle or when the wearer is bicycling (less than two false detected strides per hour on average). As a consequence, the algorithm proposed for trajectory reconstruction achieves much better performances than existing methods for daily life contexts, in particular in narrow areas such as in a house. The computed stride trajectory contains essential information for recognizing the activity (atypical stride, walking, running, and stairs). For this task, we adopt a machine learning approach based on descriptors of these trajectories, which is shown to be robust to a large of variety of gaits. We tested our algorithm on recordings of healthy adults and children, achieving more than 99% success. The algorithm also achieved more than 97% success in challenging situations recorded by children suffering from movement disorders. Compared to most algorithms in the literature, this original method does not use a fixed-size sliding window but infers this last in an adaptive way.


Assuntos
Técnicas Biossensoriais , Monitorização Ambulatorial , Caminhada/fisiologia , Algoritmos , Tornozelo/fisiologia , Articulação do Tornozelo/fisiologia , Pé/fisiologia , Marcha/fisiologia , Humanos , Aprendizado de Máquina , Pedestres , Corrida/fisiologia
17.
Gait Posture ; 74: 250-254, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31590046

RESUMO

INTRODUCTION: Simulations suggest that subjects with reduced hip range of motion (ROM) and/or weakness can achieve more normal walking mechanics through compensations at the ankle. The aims of this study were to assess whether subjects with reduced hip ROM (Stiff hip) or hip flexor weakness (Weak hip) exhibit ankle compensations during walking and investigate redistribution of power in the lower extremity joints. METHODS: Retrospective gait data were reviewed (IRB-approved hip registry). Preoperative kinematic/kinetic walking data were collected in patients with: adolescent hip dysplasia (AHD), femoral acetabular impingement (FAI), and Legg-Calvé Perthes disease (Perthes). AHD patients with significantly weak hip flexors on their affected side were included (Weak hip group). The Gait Profile Score (GPS) was calculated on the affected side of the FAI and Perthes groups to identify patients who had a Stiff hip. Patients who had undergone a hip arthrodesis (Fusion) were also included (Stiff hip group). Ankle kinematics/kinetics were compared to healthy participants (Control). The total positive work of sagittal plane hip, knee and ankle power were compared along with the distribution of power. RESULTS: Patients in the Weak/Stiff hip groups did not walk with greater ankle plantarflexion, peak push-off power or positive ankle work on their affected sides compared to Control. Ankle work contribution (percentage of total positive work) on the affected or unaffected sides was greater in the Perthes and Hip Fusion patients compared to Control. Significant gait abnormalities on the unaffected side were observed. CONCLUSIONS: Patients with a weak or stiff hip did exhibit altered ankle mechanics during walking. Greater percent ankle work contribution appeared to correspond with hip stiffness. In patients with hip pathology the redistribution of power among the lower extremity joints can highlight the importance of preserving ankle function.


Assuntos
Articulação do Tornozelo/fisiologia , Impacto Femoroacetabular/fisiopatologia , Marcha/fisiologia , Adolescente , Adulto , Fenômenos Biomecânicos , Estudos de Casos e Controles , Feminino , Humanos , Extremidade Inferior/fisiopatologia , Masculino , Amplitude de Movimento Articular , Estudos Retrospectivos , Caminhada/fisiologia , Adulto Jovem
18.
Gait Posture ; 74: 242-249, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31574408

RESUMO

BACKGROUND: Excessive foot pronation during running in individuals with foot varus alignment may be reduced by medially wedged insoles. RESEARCH QUESTION: This study investigated the effects of a medially wedged insole at the forefoot and at the rearfoot on the lower limbs angles and internal moments of runners with excessive foot pronation and foot varus alignment. METHODS: Kinematic and kinetic data of 19 runners (11 females and 8 males) were collected while they ran wearing flat (control condition) and medially wedged insoles (insole condition). Both insoles had arch support. We used principal component analysis for data reduction and dependent t-test to compare differences between conditions. RESULTS: The insole condition reduced ankle eversion (p = 0.003; effect size = 0.63); reduced knee range of motion in the transverse plane (p = 0.012; effect size = 0.55); increased knee range of motion in the frontal plane in early stance and had earlier knee adduction peak (p = 0.018; effect size = 0.52); reduced hip range of motion in the transverse plane (p = 0.031; effect size = 0.48); reduced hip adduction (p = 0.024; effect size = 0.50); reduced ankle inversion moment (p = 0.012; effect size = 0.55); and increased the difference between the knee internal rotation moment in early stance and midstance (p = 0.012; effect size = 0.55). SIGNIFICANCE: Insoles with 7˚ medial wedges at the forefoot and rearfoot are able to modify motion and moments patterns that are related to lower limb injuries in runners with increased foot pronation and foot varus alignment with some non-desired effects on the knee motion in the frontal plane.


Assuntos
Órtoses do Pé , Pé/fisiologia , Extremidade Inferior/fisiologia , Pronação/fisiologia , Corrida/fisiologia , Sapatos , Adulto , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Feminino , Articulação do Quadril/fisiologia , Humanos , Cinética , Articulação do Joelho/fisiologia , Masculino , Pessoa de Meia-Idade , Análise de Componente Principal , Amplitude de Movimento Articular
19.
Gait Posture ; 74: 76-82, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31479852

RESUMO

BACKGROUND: Ankle push-off drives forward progression during gait. Reduced peak ankle moment and peak ankle power may contribute to the increased metabolic cost of walking observed in certain clinical populations. Biofeedback is an effective gait training tool, however biofeedback targeting ankle moment has not been previously studied. RESEARCH QUESTION: Does haptic biofeedback directly targeting ankle moment enable able-bodied adults to modulate peak ankle moment during gait? METHODS: 20 able-bodied adults participated in the study. Participants completed a 90-second baseline walking trial, followed by two 2-minute trials with haptic biofeedback. Haptic biofeedback guided participants to either increase peak ankle moment (Feedback High), or decrease peak ankle moment (Feedback Low). Ten participants received haptic biofeedback alone; the other ten participants additionally received verbal suggestions of movement strategies they could adopt during the biofeedback trials. Two-way analysis of variance was used to determine the effect of walking condition and verbal instruction on key gait parameters. RESULTS: A main effect of walking condition on peak ankle moment and peak ankle power was observed (all P < 0.001). Peak ankle moment did not change from baseline during Feedback High, however peak ankle power was increased (P < 0.001). A decrease in peak ankle moment and peak ankle power was observed during Feedback Low (all P < 0.001). Verbal instruction had a significant interaction effect with walking condition in only a limited number of parameters (all P < 0.05). SIGNIFICANCE: This study demonstrates the effects of haptic biofeedback targeting peak ankle moment during gait. While this study demonstrates that able-bodied individuals have some capacity to modulate their gait pattern in response to direct biofeedback on ankle moment, further investigation is required to develop a biofeedback paradigm that can increase peak ankle moment.


Assuntos
Articulação do Tornozelo/fisiologia , Retroalimentação Sensorial/fisiologia , Marcha/fisiologia , Caminhada/fisiologia , Adulto , Análise de Variância , Feminino , Humanos , Masculino , Adulto Jovem
20.
J Athl Train ; 54(11): 1171-1178, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31483150

RESUMO

CONTEXT: Foam-rolling exercises are frequently included in warmups due to their benefits for increasing range of motion (ROM). However, their effects on proprioception and vertical jump have not been analyzed and therefore remain unclear. Moreover, the effects of performing practical-duration foam-rolling exercises after typical warmup exercises such as jogging are unknown. OBJECTIVE: To analyze the effects of jogging and practical-duration foam-rolling exercises on the ROM, knee proprioception, and vertical jump of athletes. DESIGN: Randomized controlled study. SETTING: Sports laboratory and university track. PATIENTS OR OTHER PARTICIPANTS: Thirty athletes were randomly classified into an experimental group (EG) or control group (CG). INTERVENTION(S): The EG performed 8-minute jogging and foam-rolling exercises. The CG performed 8-minute jogging. MAIN OUTCOME MEASURE(S): Knee flexion, hip extension, active knee extension, ankle dorsiflexion (ADF), knee-joint position sense, and countermovement jump (CMJ) were evaluated before the intervention (baseline), after (post 0 min), and 10 minutes later. RESULTS: The EG exhibited higher values for ADF and CMJ at post 0 min (ADF: P < .001, d = 0.88; CMJ: P < .001, d = 0.52) and 10 minutes later (ADF: P = .014, d = 0.41; CMJ: P = .006, d = 0.22) compared with baseline. Although the CG also showed increased CMJ at post 0 min (P = .044, d = 0.21), the EG demonstrated a greater increase (P = .021, d = 0.97). No differences were found in the remaining ROM variables (knee flexion, hip extension, active knee extension: P values > .05). For knee-joint position sense, no differences were found (P > .05). CONCLUSIONS: Combining jogging and practical-duration foam rolling may increase ADF and CMJ without affecting knee proprioception and hip or knee ROM. Jogging by itself may slightly increase ADF and CMJ, but the results were better and were maintained after 10 minutes when foam rolling was added.


Assuntos
Atletas , Desempenho Atlético/fisiologia , Articulação do Quadril/fisiologia , Corrida Moderada/fisiologia , Propriocepção/fisiologia , Amplitude de Movimento Articular/fisiologia , Adolescente , Adulto , Articulação do Tornozelo/fisiologia , Feminino , Humanos , Articulação do Joelho/fisiologia , Masculino , Adulto Jovem
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