RESUMEN

During vertical jump evaluations in which jump height is estimated from flight time (FT), the jumper must maintain the same body posture between vertical takeoff and landing. As maintaining identical posture is rare during takeoff and landing between different jump attempts and in different individuals, we simulated the effect of changes in ankle position from takeoff to landing in vertical jumping to determine the range of errors that might occur in real-life scenarios. Our simulations account for changes in center of mass position during takeoff and landing, changes in ankle position, different subject statures (1.44-1.98 m), and poor to above-average jump heights. Our results show that using FT to estimate jump height without controlling for ankle position (allowing dorsiflexion) during the landing phase of the vertical jump can overestimate jump height by 18% in individuals of average stature and performing an average 30 cm jump or may overestimate by ≤60% for tall individuals performing a poor 10 cm jump, which is common for individuals jumping with added load. Nevertheless, as assessing jump heights based on FT is common practice, we offer a correction equation that can be used to reduce error, improving jump height measurement validity using the FT method allowing between-subject fair comparisons.

Asunto(s)

Postura , Humanos , Fenómenos Biomecánicos/fisiología , Postura/fisiología , Masculino , Tobillo/fisiología , Adulto , Articulación del Tobillo/fisiología , Femenino , Simulación por Computador , Adulto Joven , Movimiento/fisiología

RESUMEN

An abundance of degrees of freedom (DOF) exist when executing a countermovement jump (CMJ). This research aims to simplify the understanding of this complex system by comparing jump performance and independent functional DOF (fDOF) present in CMJs without (CMJNoArms) and with (CMJArms) an arm swing. Principal component analysis was used on 39 muscle forces and 15 3-dimensional joint contact forces obtained from kinematic and kinetic data, analyzed in FreeBody (a segment-based musculoskeletal model). Jump performance was greater in CMJArms with the increased ground contact time resulting in higher external (p = 0.012), hip (p < 0.001) and ankle (p = 0.009) vertical impulses, and slower hip extension enhancing the proximal-to-distal joint extension strategy. This allowed the hip muscles to generate higher forces and greater time-normalized hip vertical impulse (p = 0.006). Three fDOF were found for the muscle forces and 3-dimensional joint contact forces during CMJNoArms, while four fDOF were present for CMJArms. This suggests that the underlying anatomy provides mechanical constraints during a CMJ, reducing the demand on the control system. The additional fDOF present in CMJArms suggests that the arms are not mechanically coupled with the lower extremity, resulting in additional variation within individual motor strategies.

Asunto(s)

Brazo , Músculo Esquelético , Humanos , Fenómenos Biomecánicos , Brazo/fisiología , Masculino , Músculo Esquelético/fisiología , Adulto , Adulto Joven , Articulación de la Cadera/fisiología , Articulación del Tobillo/fisiología , Movimiento/fisiología , Rango del Movimiento Articular/fisiología , Femenino

RESUMEN

A common challenge for exoskeleton control is discerning operator intent to provide seamless actuation of the device with the operator. One way to accomplish this is with joint angle estimation algorithms and multiple sensors on the human-machine system. However, the question remains of what can be accomplished with just one sensor. The objective of this study was to deploy a modular testing approach to test the performance of two joint angle estimation models-a kinematic extrapolation algorithm and a Random Forest machine learning algorithm-when each was informed solely with kinematic gait data from a single potentiometer on an ankle exoskeleton mock-up. This study demonstrates (i) the feasibility of implementing a modular approach to exoskeleton mock-up evaluation to promote continuity between testing configurations and (ii) that a Random Forest algorithm yielded lower realized errors of estimated joint angles and a decreased actuation time than the kinematic model when deployed on the physical device.

Asunto(s)

Algoritmos , Dispositivo Exoesqueleto , Humanos , Fenómenos Biomecánicos/fisiología , Aprendizaje Automático , Marcha/fisiología , Articulación del Tobillo/fisiología , Articulaciones/fisiología

RESUMEN

BACKGROUND AND PURPOSE: Warm-up (WU) is a commonly practiced technique aimed at preparing athletes for physical activity. Although coaches and athletes consider WU essential, there is still an ongoing debate about its effectiveness. This might be due to the fact that WU procedures often rely on experiences rather than scientific research. During WU, athletes may pursue intermediate goals such as ensuring proper ranges of motion in joints, which seem crucial particularly for runners' ankle joints. Hence, the aim of this study was to evaluate influence of whole-body vibration (WBV), drop jump (DJ), and a combination of both (WBV + DJ) in terms of ankle dorsiflexion and running parameters among recreational runners. METHODS: Sixteen runners performed as a WU: five sets of 30 s calf raises without WBV (CTRL), five sets of 30 s calf raises during WBV, five sets of six DJ, five sets of 30 s calf raises during WBV followed by 6 DJ. Range of motion (ROM) of the ankle joint was measured in a prone position using an inclinometer for the soleus and gastrocnemius muscles, separately. Measurements were conducted before and after WU, and after a 3000 m run. RESULTS: There was no interaction for time and WU for left (p = 0.926) and right (p = 0.738) soleus muscle as well as for left (p = 0.748) and right (p = 0.197) gastrocnemius muscles. No difference (p = 0.914) for the running time was found. DISCUSSION: WBV, drop jumps, or a combination of both did not affect ankle dorsiflexion and running time.

Asunto(s)

Articulación del Tobillo , Estudios Cruzados , Rango del Movimiento Articular , Carrera , Vibración , Humanos , Articulación del Tobillo/fisiología , Rango del Movimiento Articular/fisiología , Carrera/fisiología , Masculino , Adulto , Femenino , Adulto Joven , Ejercicio de Calentamiento/fisiología , Músculo Esquelético/fisiología

RESUMEN

The production of triceps surae plantarflexion moment is complex in that the Achilles tendon moment arm affects the Achilles tendon force by determining the muscle length change and shortening velocity during ankle rotation. In addition, there is evidence for associations between the sizes of muscles and their moment arm at the joints they span. These relationships between muscle architecture and tendon moment arm ultimately affect the muscle's force generating capacity and are thus important for understanding the roles played by muscles in producing locomotion. The purpose of this study was to investigate in vivo the relationship between architecture of two plantarflexors and the Achilles tendon moment arm in a healthy adult population. Ultrasound-based measurements were made of the architecture (fascicle length, muscle volume, physiological cross-sectional area, and anatomical cross-sectional area) of the lateral and medial gastrocnemius and the Achilles tendon moment arm was assessed using a technique that combined ultrasound imaging and motion analysis. Positive correlations were observed between the length (r = 0.499, p = 0.049) and size variables (muscle volume r = 0.621, p = 0.010; ACSA r = 0.536, p = 0.032) of the lateral gastrocnemius and the Achilles tendon moment arm, but correlations were only observed for size variables (muscle volume r = 0.638, p = 0.008; PCSA r = 0.525, p = 0.037; ACSA r = 0.544, p = 0.029), and not the length, of the medial gastrocnemius. These findings suggest lateral gastrocnemius adapts to moment arms to maintain force production throughout the range of motion across individuals, while the medial gastrocnemius does not and is thus better suited for static force generation.

Asunto(s)

Tendón Calcáneo , Músculo Esquelético , Ultrasonografía , Humanos , Tendón Calcáneo/fisiología , Tendón Calcáneo/diagnóstico por imagen , Tendón Calcáneo/anatomía & histología , Músculo Esquelético/fisiología , Músculo Esquelético/diagnóstico por imagen , Músculo Esquelético/anatomía & histología , Adulto , Masculino , Femenino , Fenómenos Biomecánicos , Rango del Movimiento Articular/fisiología , Adulto Joven , Articulación del Tobillo/fisiología , Articulación del Tobillo/diagnóstico por imagen , Articulación del Tobillo/anatomía & histología

RESUMEN

Shoes affect the evolved biomechanics of the foot, potentially affecting running kinematics and kinetics that can in turn influence injury and performance. An important feature of conventional running shoes is heel height, whose effects on foot and ankle biomechanics remain understudied. Here, we investigate the effects of 6-26 mm increases in heel height on ankle dynamics in 8 rearfoot strike runners who ran barefoot and in minimal shoes with added heels. We predicted higher heels would lead to greater frontal plane ankle torques due to the increased vertical moment arm of the mediolateral ground reaction force. Surprisingly, the torque increased in minimal shoes with no heel elevation, but then decreased with further increases in heel height due to changes in foot posture. We also found that increasing heel height caused a large increase in the ankle plantarflexion velocity at heel strike, which we explain using a passive collision model. Our results highlight how running in minimal shoes may be significantly different from barefoot running due to complex interactions between proprioception and biomechanics that also permit runners to compensate for modifications to shoe design, more in the frontal than sagittal planes.

Asunto(s)

Tobillo , Talón , Carrera , Zapatos , Carrera/fisiología , Humanos , Fenómenos Biomecánicos , Masculino , Talón/fisiología , Adulto , Tobillo/fisiología , Femenino , Articulación del Tobillo/fisiología , Adulto Joven , Pie/fisiología , Torque , Marcha/fisiología

RESUMEN

BACKGROUND: Anterior cruciate ligament injuries are serious conditions encountered in volleyball players and occur frequently during spike jump landings. During spike jumps, the lower limb kinematics and kinetics during landing may be altered in relation to the ball position. RESEARCH QUESTION: Does the ball position have an effect on lower-limb kinematics and kinetics during spike jumps? METHODS: We measured the lower limb kinematics and kinetics of 20 healthy female college volleyball athletes during a spike jump using a three-dimensional motion analysis system. The ball positions were set to normal, dominant, and non-dominant positions. A repeated analysis of variance was used to compare the lower limb kinematics and kinetics at the initial contact and the maximum knee flexion during jump landing. Additionally, statistical parametric mapping analysis was used to analyze changes over time during the spike jumps. RESULTS: At the initial contact of the spike jump landing, the knee valgus angle, trunk lateral bending angle, and maximum knee valgus moment when the ball was set at the non-dominant position increased compared to those at the dominant position. Statistical parametric mapping analysis showed no significant change in knee valgus angle and moment of jump landing. CONCLUSION: Knee valgus angle, trunk lateral bending angle, and maximum knee valgus moment increased with the non-dominant position; furthermore, the risk of ACL injury may also be increased. SIGNIFICANCE: The posture at ball impact may influence the landing kinematics and kinetics. Therefore, it is necessary to pay close attention to movements during and prior to landing.

Asunto(s)

Articulación del Tobillo , Articulación de la Cadera , Articulación de la Rodilla , Torso , Voleibol , Humanos , Voleibol/fisiología , Fenómenos Biomecánicos , Femenino , Adulto Joven , Articulación de la Rodilla/fisiología , Articulación del Tobillo/fisiología , Articulación de la Cadera/fisiología , Torso/fisiología , Lesiones del Ligamento Cruzado Anterior/fisiopatología , Movimiento/fisiología , Rango del Movimiento Articular/fisiología

RESUMEN

BACKGROUND: Sprint skating is essential for competitive success in hockey. Previous studies have highlighted various measures of lower-body strength and power as key factors influencing sprint performance. However, while these studies have indicated a significant association between the ability to exert greater force and impulse into the ice surface, and the capacity to achieve faster sprint skating speeds, the direct relationship between these factors remains largely inferred. RESEARCH QUESTION: What are the relationships between insole plantar force variables, sprint skating performance, and their association with physical capacity measures, in national-level male hockey athletes? METHODS: Athletes (n=13) performed 25 m sprint skating trials with insole force sensors and completed: ankle dorsiflexion and hip abduction range-of-motion (ROM), countermovement jump (CMJ), seated single-leg jump, and 10-5 repeated-hop test (RHT) assessments. RESULTS: Relationships were assessed using Kendall's Tau rank correlations (τ), with significant relationships identified between mean relative weight acceptance impulse [WAI] and 0-5 m (τ=0.47) and total distance (τ=0.46) times. Additionally, significant associations were observed between mean relative WAI and: CMJ relative eccentric deceleration impulse (τ=0.44), CMJ eccentric peak velocity (τ=-0.46) and RHT concentric impulse (τ=-0.56). Finally, significant relationships were identified between mean relative PI for all strides and the 10-20 m split, with peak velocity (PV) (τ=-0.58 to -0.73); and between ankle dorsiflexion ROM and PV (τ=-0.57). SIGNIFICANCE: Athletes with faster initial acceleration and overall sprint performance times demonstrated lower relative WAI during their strides and employed a jump strategy that optimized concentric impulse with a rapid eccentric phase. To attain a high PV the athletes appeared to require a stride that maximized glide and minimized vertical force, with greater ankle dorsiflexion ROM potentially facilitating this.

Asunto(s)

Rendimiento Atlético , Hockey , Rango del Movimiento Articular , Patinación , Humanos , Hockey/fisiología , Masculino , Rendimiento Atlético/fisiología , Fenómenos Biomecánicos , Adulto Joven , Patinación/fisiología , Rango del Movimiento Articular/fisiología , Atletas , Pie/fisiología , Adulto , Articulación del Tobillo/fisiología , Zapatos

RESUMEN

BACKGROUND: Anterior cruciate ligament (ACL) injuries may correlate with lower limb angles and biomechanical factors in both dominant and non-dominant legs at initial contact (IC) post-landing. This study aims to investigate the correlation between ankle angles in three axes at IC and knee and hip joint angles during post-spike landings in professional volleyball players, both pre- and post-fatigue induction. RESEARCH QUESTION: To what extent does fatigue influence lower limb joint angles, and what is the relationship between ankle joint angles and hip and knee angles at IC during the landing phase following a volleyball spike? METHODS: Under conditions involving the peripheral fatiguing protocol, the lower limb joint angles at IC following post-spike landings were measured in 28 professional male volleyball players aged between 19 and 28 years, who executed the Bosco fatigue protocol both before and after inducing fatigue. A paired t-test was utilized to compare the joint angles pre- and post-fatigue in both dominant and non-dominant legs. Furthermore, Pearson's correlation test was conducted to explore the relationship between ankle angles at IC and the corresponding knee and hip joint angles. RESULTS: The findings of the study revealed that fatigue significantly increased hip external rotation and decreased knee joint flexion and external rotation in both the dominant and non-dominant legs (p < 0.05). Additionally, correlation analysis demonstrated that the ankle joint's positioning in the frontal and horizontal planes was significantly associated with hip flexion and external rotation at the IC, as well as with knee flexion and rotation (0.40 < r < 0.80). CONCLUSION: Fatigue increased hip external rotation and ankle internal rotation, weakening the correlation between these joints while strengthening the ankle-knee relationship, indicating a reduced hip control in jumps. This suggests a heightened ACL injury risk in the dominant leg due to the weakened ankle-hip connection, contrasting with the non-dominant leg.

Asunto(s)

Articulación del Tobillo , Lesiones del Ligamento Cruzado Anterior , Articulación de la Cadera , Articulación de la Rodilla , Voleibol , Humanos , Masculino , Articulación de la Cadera/fisiopatología , Articulación de la Cadera/fisiología , Lesiones del Ligamento Cruzado Anterior/fisiopatología , Articulación del Tobillo/fisiopatología , Articulación del Tobillo/fisiología , Adulto Joven , Adulto , Fenómenos Biomecánicos , Articulación de la Rodilla/fisiopatología , Voleibol/fisiología , Rango del Movimiento Articular/fisiología , Fatiga Muscular/fisiología , Rotación

RESUMEN

BACKGROUND: Anterior cruciate ligament (ACL) rehabilitation is a common intervention after ACL reconstruction. Since different types of exercise can influence muscle and kinematic parameters in diverse ways, the training order between the knee and ankle joints may also change gait parameters. PURPOSE: This study aimed to investigate whether the training sequence of the knee and ankle joints (knee followed by ankle training or vice-versa) in an ACL reconstruction (ACLR) rehabilitation program has any effects on knee extension and flexion torques. METHODS: Forty-two men (aged 20-30 years) with ACLR participated in this study. They were randomly allocated to receive one of two interventions: (A) knee joint training followed by ankle training or (B) ankle joint training followed by knee training. After five weeks (four weeks of intervention and one-week washout), participants crossed from one group to another for an additional four weeks. Knee extension and flexion torques were assessed during the stance phase of the gait cycle before and after the intervention program. RESULTS: Two-way Mixed-design MANOVA showed that knee extension torque improved significantly in both groups after training (p = 0.001, Cohen's D = 0.65), while the knee flexion torque increased significantly only in group B (p= 0.001, Cohen's D = 0.97). When comparing both groups, patients of group B presented significant improvements in the post-training mean values of all tested variables compared with group A. CONCLUSION: Starting a post-ACLR rehabilitation program with ankle training followed by knee training is better to improve knee flexion and extension torques during the stance phase of the gait cycle than starting the program by training the knee first, followed by the ankle. Future studies using a mixed-gender sample and different types of ACLR operations are necessary to examine whether similar improvements will happen as well as to test their effects on many sports activities.

Asunto(s)

Articulación del Tobillo , Reconstrucción del Ligamento Cruzado Anterior , Articulación de la Rodilla , Humanos , Masculino , Reconstrucción del Ligamento Cruzado Anterior/rehabilitación , Articulación del Tobillo/fisiopatología , Articulación del Tobillo/fisiología , Adulto , Fenómenos Biomecánicos , Adulto Joven , Articulación de la Rodilla/fisiología , Articulación de la Rodilla/fisiopatología , Estudios Cruzados , Terapia por Ejercicio/métodos , Rango del Movimiento Articular/fisiología , Lesiones del Ligamento Cruzado Anterior/cirugía , Lesiones del Ligamento Cruzado Anterior/rehabilitación , Lesiones del Ligamento Cruzado Anterior/fisiopatología , Marcha/fisiología , Torque

RESUMEN

Individuals with diminished walking performance caused by neuromuscular impairments often lack plantar flexion muscle activity. Robotic devices have been developed to address these issues and increase walking performance. While these devices have shown promise in their ability to increase musculature engagement of the lower limbs when used on a treadmill, most have not been developed or validated for overground walking and community use. Overground walking may limit the effectiveness of robotic devices due to differences in gait characteristics between walking terrains and reduced user engagement. The purpose of this study was to validate our multimodal robotic gait training system for overground walking in individuals with neuromuscular gait impairments. This untethered wearable robotic device can provide an ankle resistive torque proportional to the users' biological ankle torque. The device can also provide audio biofeedback based on users' plantar pressure intending to increase ankle power and muscle activity of the plantar flexors. Seven individuals with cerebral palsy participated. Participants walked overground and on a treadmill with our robotic gait training system in a single testing session. Results showed all seven participants to increase peak plantar flexor muscle activity, 10.3% on average, when walking with the gait trainer overground compared to treadmill. When compared to typical baseline overground walking, overground gait trainer use caused individuals to have slightly less knee joint excursion (3°) and moderately more ankle joint excursion (7°). This work supports our vision of using the wearable robotic device as a gait aid and rehabilitation tool in the home and community settings.

Asunto(s)

Robótica , Caminata , Humanos , Masculino , Caminata/fisiología , Femenino , Robótica/instrumentación , Robótica/métodos , Biorretroalimentación Psicológica/métodos , Biorretroalimentación Psicológica/instrumentación , Adulto , Articulación del Tobillo/fisiología , Articulación del Tobillo/fisiopatología , Marcha/fisiología , Parálisis Cerebral/fisiopatología , Parálisis Cerebral/rehabilitación , Músculo Esquelético/fisiología , Músculo Esquelético/fisiopatología , Tobillo/fisiología , Adolescente , Trastornos Neurológicos de la Marcha/rehabilitación , Trastornos Neurológicos de la Marcha/fisiopatología , Adulto Joven , Fenómenos Biomecánicos , Prueba de Esfuerzo/métodos

RESUMEN

Texting while walking (TWW) is a dual-task activity that young adults perform in their everyday lives. TWW has been reported to affect gait characteristics such as gait speed, stride length, and cadence. However, the influence of TWW on lower extremity gait function has not been investigated. Therefore, the purpose of this study was to quantify gait function by examining gait symmetry and using a time series analysis. Twenty-eight young adults (14 males, 14 females) walked at their preferred speed for 10 m as a baseline condition and a 10 m TWW task. Three-dimensional segment tracking was achieved utilizing a lower extremity and trunk marker set and the Model Statistic was used to test for statistical differences between the hip, knee, and ankle angular joint positions. The hip yielded the most asymmetries (25 out of 101 points) throughout the gait cycle, while asymmetries for the knee and ankle joints yielded 16 out of 101 points and 11 out of 101 points, respectively. The outcomes of this study suggest there are differences between baseline and TWW gait symmetry, however, the percentage of the gait cycle affected was less than 25 % - indicating gait function is not strongly influenced by texting while walking in young adults.

Asunto(s)

Marcha , Extremidad Inferior , Envío de Mensajes de Texto , Caminata , Humanos , Masculino , Femenino , Adulto Joven , Marcha/fisiología , Caminata/fisiología , Fenómenos Biomecánicos , Adulto , Extremidad Inferior/fisiología , Articulación del Tobillo/fisiología , Velocidad al Caminar/fisiología , Articulación de la Rodilla/fisiología , Articulación de la Cadera/fisiología

RESUMEN

The purpose was to determine the impact of both cognitive constraint and neuromuscular fatigue on landing biomechanics in healthy and chronic ankle instability (CAI) participants. Twenty-three male volunteers (13 Control and 10 CAI) performed a single-leg landing task before and immediately after a fatiguing exercise with and without cognitive constraints. Ground Reaction Force (GRF) and Time to Stabilization (TTS) were determined at landing in vertical, anteroposterior (ap) and mediolateral (ml) axes using a force plate. Three-dimensional movements of the hip, knee and ankle were recorded during landing using a motion capture system. Exercise-induced fatigue decreased ankle plantar flexion and inversion and increased knee flexion. Neuromuscular fatigue decreased vertical GRF and increased ml GRF and ap TTS. Cognitive constraint decreased ankle internal rotation and increased knee and hip flexion during the flight phase of landing. Cognitive constraint increased ml GRF and TTS in all three axes. No interaction between factors (group, fatigue, cognitive) were observed. Fatigue and cognitive constraint induced greater knee and hip flexion, revealing higher proximal control during landing. Ankle kinematic suggests a protective strategy in response to fatigue and cognitive constraints. Finally, these two constraints impair dynamic stability that could increase the risk of ankle sprain.

Asunto(s)

Articulación del Tobillo , Cognición , Inestabilidad de la Articulación , Extremidad Inferior , Fatiga Muscular , Humanos , Masculino , Inestabilidad de la Articulación/fisiopatología , Fenómenos Biomecánicos , Adulto Joven , Articulación del Tobillo/fisiopatología , Articulación del Tobillo/fisiología , Fatiga Muscular/fisiología , Extremidad Inferior/fisiología , Extremidad Inferior/fisiopatología , Cognición/fisiología , Rodilla/fisiología , Rodilla/fisiopatología , Adulto , Ejercicio Pliométrico , Tobillo/fisiología , Tobillo/fisiopatología , Estudios de Tiempo y Movimiento , Movimiento/fisiología , Traumatismos del Tobillo/fisiopatología , Articulación de la Rodilla/fisiología , Articulación de la Rodilla/fisiopatología , Articulación de la Cadera/fisiología , Articulación de la Cadera/fisiopatología

RESUMEN

OBJECTIVE: Most biomechanical research on the application of Kinesio taping (KT) to the ankle joint focused on testing anticipated movements. However, ankle sprains frequently occur in real life in unanticipated situations, where individuals are unprepared and face sudden external stimuli. This situation is completely different from the anticipated situation. The aim of the present study was to investigate the effects of ankle KT application on the kinematic and kinetic characteristics of the knee and ankle joints during unanticipated jump tasks in collegiate athletes. METHODS: Eighteen healthy collegiate athletes experienced three taping conditions in a randomized order: no taping (NT), placebo taping (PT), and KT, and performed unanticipated jump tasks. A 9-camera infrared high-speed motion capture system was employed to collect knee and ankle kinematic data, and a 3-dimensional force plate was utilized to collect knee and ankle kinetic data during the tasks. RESULTS: During the right jumps, KT significantly increased peak knee flexion angle (P = 0.031) compared to NT and significantly decreased peak vertical ground reaction force (P < 0.001, P = 0.001) compared to NT and PT. During the left jumps, KT significantly reduced peak ankle inversion angle (P = 0.022, P < 0.001) and peak ankle inversion moment (P = 0.002, P = 0.001) compared to NT and PT. CONCLUSION: During unanticipated jump maneuvers, KT reduced peak ankle inversion angle, peak vertical ground reaction force, and peak ankle inversion moment and increased peak knee flexion angle in collegiate athletes.

Asunto(s)

Articulación del Tobillo , Atletas , Cinta Atlética , Articulación de la Rodilla , Humanos , Articulación del Tobillo/fisiología , Fenómenos Biomecánicos , Masculino , Adulto Joven , Articulación de la Rodilla/fisiología , Femenino , Movimiento/fisiología , Rango del Movimiento Articular/fisiología

RESUMEN

This study examines the effects of limb dominance and lead limb in task initiation on the kinetics and kinematics of step-off drop landings. Nineteen male participants performed drop landings led by the dominant and non-dominant limbs at 45-cm and 60-cm drop heights. Ground reaction force (GRF) and lower body kinematic data were collected. Between-limb time differences at the initial ground contact were calculated to indicate temporal asymmetry. Statistical Parametric Mapping (SPM) was applied for waveform analysis while two-way repeated measures ANOVA was used for discrete parameters. SPM results revealed greater GRF and lesser ankle dorsiflexion in the lead limb compared to the trail limb in 3 out of 4 landing conditions. The dominant limb displayed a greater forefoot loading rate (45 cm: p=.009, ηp2 = 0.438; 60 cm: p=.035, ηp2 = 0.225) and greater ankle joint quasi-stiffness (45 cm: p < .001, ηp2 = 0.360; 60 cm: p < .001, ηp2 = 0.597) than the non-dominant limb. Not all 380 trials were lead-limb first landings, with a smaller between-limb time difference (p=.009, d = 0.60) at 60 cm (4.1 ± 2.3 ms) than 45 cm (5.6 ± 2.7 ms). In conclusion, the step-off drop landing is not an ideal protocol for examining bilateral asymmetry in lower limb biomechanics due to potential biases introduced by limb dominance and the step-off limb.

Asunto(s)

Articulación del Tobillo , Humanos , Masculino , Fenómenos Biomecánicos , Adulto Joven , Articulación del Tobillo/fisiología , Lateralidad Funcional/fisiología , Extremidad Inferior/fisiología , Adulto , Ejercicio Pliométrico

RESUMEN

Boots are widely used by many people for various purposes, but their impact on gait biomechanics and injury risk is not well understood. This study investigated the effects of boots on walking biomechanics, compared to casual footwear. The lower limb joint kinematics and kinetics of 20 healthy male participants aged 20 to 30 years old were compared during self-paced walking with boots and shoes. The results showed that walking with boots is associated with greater hip extensor (P = 0.009) and ankle dorsiflexor (P < 0.001) moments in early stance, hip power generation (P < 0.001) and knee power absorption (P < 0.001) in early swing phase, hip abductor (P < 0.001) and knee adduction (P < 0.001) moments in the entire stance, net concentric work for the hip joint in sagittal (13.9%, P = 0.001) and frontal (21.7%, P = 0.002) planes. In contrast, the subtalar supinator moment in the entire stance (P < 0.001), ankle angular velocity in late stance (P < 0.001), and net concentric (- 42.7%, P < 0.001) and eccentric (- 44.6%, P = 0.004) works of subtalar joint were significantly lower in the boot condition. The compensatory adjustments in the hip and knee joints may result from ankle restrictions. While boots may aid those with ankle disorders, lower limb loading and the risk of musculoskeletal injuries and osteoarthritis could be increased. This study offers new perspectives on the biomechanical impact of boots on gait, potential prevention and treatment strategies of related injuries, and advancing footwear design.

Asunto(s)

Articulación del Tobillo , Marcha , Articulación de la Cadera , Zapatos , Caminata , Humanos , Masculino , Adulto , Fenómenos Biomecánicos , Caminata/fisiología , Adulto Joven , Marcha/fisiología , Articulación de la Cadera/fisiología , Cinética , Articulación del Tobillo/fisiología , Articulación de la Rodilla/fisiología , Extremidad Inferior/fisiología

RESUMEN

BACKGROUND: Gait kinematics differ between settings and among young and older adults with and without knee osteoarthritis. Out-of-lab data has a variety of walking bout characteristics compared to controlled in-lab settings. The effect of walking bout duration on gait analysis results is unclear, and there is no standardized procedure for segmenting or selecting out-of-lab data for analysis. RESEARCH QUESTION: Do gait kinematics differ by bout duration or setting in young and older adults with and without knee osteoarthritis? METHODS: Ten young (28.1±3.5 yrs), ten older adults (60.8±3.3 yrs), and ten older adults with knee osteoarthritis (64.1±3.6 yrs) performed a standard in-lab gait analysis followed by a prescribed walking route outside the lab at a comfortable speed with four IMUs. Walking speed, stride length, and sagittal hip, knee, and ankle angular excursion (ROM) were calculated for each identified stride. Out-of-lab strides included straight-line, level walking divided into strides that occurred during long (>60 s) or short (≤60 s) bouts. Gait kinematics were compared between in-lab and both out-of-lab bout durations among groups. RESULTS: Significant main effects of setting or duration were found for walking speed and stride length, but there were no significant differences in hip, knee, or ankle joint ROM. Walking speed and stride length were greater in-lab followed by long and short bout out-of-lab. No significant interaction was observed between group and setting or bout duration for any spatiotemporal variables or joint ROMs. SIGNIFICANCE: Out-of-lab gait data can be beneficial in identifying gait characteristics that individuals may not encounter in the traditional lab setting. Setting has an impact on walking kinematics, so comparisons of in-lab and free-living gait may be impacted by the duration of walking bouts. A standardized approach for to analyzing out-of-lab gait data is important for comparing studies and populations.

Asunto(s)

Análisis de la Marcha , Marcha , Osteoartritis de la Rodilla , Humanos , Fenómenos Biomecánicos , Marcha/fisiología , Masculino , Femenino , Persona de Mediana Edad , Adulto , Osteoartritis de la Rodilla/fisiopatología , Anciano , Rango del Movimiento Articular/fisiología , Caminata/fisiología , Articulación de la Rodilla/fisiología , Factores de Tiempo , Velocidad al Caminar/fisiología , Adulto Joven , Articulación del Tobillo/fisiología

RESUMEN

BACKGROUND: Technological running shoes have become increasingly popular, leading to improvements in performance. However, their long-term effects on foot musculature and joint mobility have not been thoroughly studied. OBJECTIVE: To compare the activation of the intrinsic foot muscles between runners wearing technological footwear and barefoot runners. Secondary objectives included assessing ankle dorsiflexion (DF) range of motion (ROM) and dynamic postural control in both groups. METHODS: A cross-sectional study was conducted involving 22 technological footwear runners and 22 barefoot runners. Ultrasonography was used to measure the thickness of the plantar fascia (PF) and the quadratus plantae (QP), abductor digiti minimus (ADM), abductor hallucis (AH), and flexor hallucis longus (FHL) muscles. Ankle mobility and dynamic postural control were also recorded. RESULTS: Ultrasonography measurements showed statistically significant differences for PF thickness (mean difference [MD]: -0.10 cm; 95% CI: -0.13, -0.05 cm), QP cross-sectional area (CSA) (MD: -0.45 cm2; 95% CI: -0.77, -0.12 cm2), ADM CSA (MD: -0.49 cm2; 95% CI: -0.70, -0.17 cm2), and FHL thickness (MD: 0.82 cm; 95% CI: 0.53, 1.09 cm), with all measurements being lower in the group wearing technological footwear compared to the barefoot runners. Ankle DF ROM was also significantly greater for the barefoot runners (MD: -5.1°; 95% CI: -8.6, -1.7°). CONCLUSIONS: These findings suggest potential implications for the foot musculature and ankle mobility in runners using technological footwear.

Asunto(s)

Articulación del Tobillo , Pie , Rango del Movimiento Articular , Carrera , Zapatos , Humanos , Estudios Transversales , Carrera/fisiología , Pie/fisiología , Articulación del Tobillo/fisiología , Tobillo/fisiología , Ultrasonografía , Músculo Esquelético/fisiología

RESUMEN

BACKGROUND: Impairments in unilateral ankle propulsion may result from restriction by an external device or pathology such as lower limb amputation. Models of gait suggest this reduction may lead to increased collisional force on the contralateral side, potentially increasing force through the knee and increasing the risk of knee pain or osteoarthritis. RESEARCH QUESTION: How do restrictions in unilateral ankle propulsive force affect contralateral knee joint loading in otherwise healthy individuals? METHODS: 18 individuals without impairment walked on a treadmill at 1.5 m/s for two conditions: one free of restrictions, and one where a randomized limb's ankle propulsive force was restricted using an off-the-shelf ankle-foot orthosis (AFO). Ankle propulsive power, lower extremity joint work, and ground reaction force variables were calculated for the final 3 gait cycles of each condition. Tibiofemoral joint contact force (TJCF) for the limb contralateral to the AFO was calculated through a standard OpenSim workflow utilizing the gait2392 model. Intra-limb pair-wise comparisons were made between conditions. RESULTS: Compared to walking unrestricted, the limb wearing the AFO demonstrated a significant reduction in peak ankle propulsive power and positive ankle work by approximately 50 % each (p<0.01). With ankle restriction, the ipsilateral knee significantly increased positive work (p<0.01). The overall propulsion produced by that limb did not change between conditions, demonstrated by a lack of change in anterior ground reaction force impulse (p=0.11). The knee of the limb contralateral to the AFO did not display differences in any TJCF variable between conditions (all p>0.07). SIGNIFICANCE: These results suggest a unilateral deficit in ankle propulsion will not increase contralateral knee joint forces in individuals who are able to use other joints of the limb to compensate for the loss of ankle function. However, further research should investigate this relationship in those who display pathologies that may prevent more proximal compensations.

Asunto(s)

Articulación del Tobillo , Marcha , Articulación de la Rodilla , Humanos , Masculino , Articulación de la Rodilla/fisiología , Articulación del Tobillo/fisiología , Articulación del Tobillo/fisiopatología , Adulto , Fenómenos Biomecánicos , Femenino , Marcha/fisiología , Adulto Joven , Soporte de Peso/fisiología , Ortesis del Pié , Caminata/fisiología , Prueba de Esfuerzo

RESUMEN

BACKGROUND: The metabolic cost of locomotion is a key factor in walking and running performance. It has been studied by analysing the activation and co-activation of the muscles of the lower limbs. However, these measures do not comprehensively address muscle mechanics, in contrast to approaches using muscle moments and co-contraction. RESEARCH QUESTION: What is the effect of speed and type of locomotion on muscle moments and co-contraction, and their relationship with metabolic cost during walking and running? METHODS: Eleven recreational athletes (60.5 ± 7.1 kg; 169.0 ± 6.6 cm; 23.6 ± 3.3 years) walked and ran on a treadmill at different speeds, including a similar speed of 1.75 m.s-1. Metabolic cost was estimated from gas exchange measurements. Muscle moments and co-contraction of ankle and knee flexors and extensors during the stance and swing phases were estimated using an electromyographic-driven model. RESULTS: Both the slowest and fastest walking speeds had significantly higher metabolic costs than intermediate ones (p < 0.05). The metabolic cost of walking was correlated with plantarflexors moment during swing phase (r = 0.62 at 0.5 m.s-1, r = 0.67 at 1,25 m.s-1), dorsiflexors moment during stance phase (r = 0.65 at 1.25 m.s-1, r = 0.67 at 1.5 and 1.75 m.s-1), and ankle co-contraction during the stance phase (r = 0.63 at 1.25 and 1.75 m.s-1). The metabolic cost of running at 3.25 m.s-1 during the swing phase was correlated with the dorsiflexors moment (r = 0.63), plantarflexors moment (r = 0.61) and ankle co-contraction (r = 0.60). DISCUSSION AND CONCLUSION: Fluctuations in metabolic cost of walking and running could be explained, at least in part, by increased ankle antagonist moments and co-contraction.

Asunto(s)

Electromiografía , Metabolismo Energético , Contracción Muscular , Músculo Esquelético , Carrera , Caminata , Humanos , Carrera/fisiología , Caminata/fisiología , Músculo Esquelético/fisiología , Masculino , Metabolismo Energético/fisiología , Adulto Joven , Fenómenos Biomecánicos , Adulto , Contracción Muscular/fisiología , Femenino , Articulación del Tobillo/fisiología