The influence of running shoe with different carbon-fiber plate designs on internal foot mechanics: A pilot computational analysis

Effects of plantar fascia stiffness on the internal mechanics of idiopathic pes cavus by finite element analysis: implications for metatarsalgia

Metatarsalgia occurring in individuals with pes cavus is typically associated with abnormal loading patterns in the forefoot resulting from structural alterations. Simultaneously, the frequent overstress of the plantar fascia (PF) caused by the persistence of this foot deformity may further exacerbate the chronic pain induced by metatarsal overload. We aimed to investigate and quantify the effects of PF stiffness on the internal biomechanics of pes cavus using a computational modelling approach. A patient-specific finite element model of the foot-ankle complex using the actual three-dimensional geometry of idiopathic pes cavus bones and soft tissues was reconstructed. A sensitivity study was conducted to evaluate the effects of varying elastic modulus (0-700 MPa) of the PF on the metatarsal stress distribution, and force transmission through the metatarsophalangeal (MTP) and tarsometatarsal (TMT) joints in the pes cavus. The results indicated that variations in PF stiffness led to stress redistribution in the metatarsal region. Peak stress gradually reduced with decreasing stiffness until the PF was released, eventually resulting in a reduction of 22.39% compared to the reference value of 350 MPa. Furthermore, adjusting the PF stiffness to twice the reference value (700 MPa) increased the contact forces through the TMT and MTP joints by up to 23% and 116%, respectively. The reduction of PF stiffness alleviated focal metatarsal loading, and therefore, surgical fascia release can be considered to alleviate metatarsalgia in patients with pes cavus.

Habituation Does Not Change Running Economy in Advanced Footwear Technology

PURPOSE

This study aimed to compare running economy across habituated and nonhabituated advanced footwear technology (AFT) in trained long-distance runners.

METHODS

A total of 16 participants completed up to six 5-minute trials in 1 to 3 pairs of their own habituated shoes and 3 different and standardized AFTs at individual marathon pace. We measured oxygen uptake and carbon dioxide production and expressed running economy as oxygen uptake (in milliliters oxygen per kilogram per minute), oxygen cost of transport (oxygen per kilogram per minute), energetic cost (in watts per kilogram), and energetic cost of transport (in joules per kilogram per kilometer). We used linear mixed-effect models to evaluate differences. Relative shoe weight and shoe mileage (distance worn during running) were covariates.

RESULTS

Forty-eight standardized and 29 individual AFT conditions were measured (mileage 117.0 [128.8] km, range 0-522 km; 25 habituated 135.7 [129.2] km, range 20-522 km; 4 nonhabituated 0 [0] km, range 0-0 km). Rating of perceived exertion, blood [La], and respiratory exchange ratio ranged from 9 to 15, 1.11 to 4.54 mmol/L, and 0.76 to 1.01. There was no effect for habituation on energetic cost of transport (thabituation = -.232, P = .409, b = -0.006; 95% CI, -0.058 to 0.046) or other running economy metrics. Neither shoe weight nor shoe mileage had an effect.

CONCLUSIONS

Our results suggest that habituation to AFTs does not result in greater benefits in the use of AFTs. This means that implementation in training may not be needed, even if we cannot rule out any other possible benefits of habituation at this stage, such as adaptation of the musculoskeletal system.

Curved carbon-plated shoe may further reduce forefoot loads compared to flat plate during running

Using a curved carbon-fiber plate (CFP) in running shoes may offer notable performance benefit over flat plates, yet there is a lack of research exploring the influence of CFP geometry on internal foot loading during running. The objective of this study was to investigate the effects of CFP mechanical characteristics on forefoot biomechanics in terms of plantar pressure, bone stress distribution, and contact force transmission during a simulated impact peak moment in forefoot strike running. We employed a finite element model of the foot-shoe system, wherein various CFP configurations, including three stiffnesses (stiff, stiffer, and stiffest) and two shapes (flat plate (FCFP) and curved plate (CCFP)), were integrated into the shoe sole. Comparing the shoes with no CFP (NCFP) to those with CFP, we consistently observed a reduction in peak forefoot plantar pressure with increasing CFP stiffness. This decrease in pressure was even more notable in a CCFP demonstrating a further reduction in peak pressure ranging from 5.51 to 12.62%, compared to FCFP models. Both FCFP and CCFP designs had a negligible impact on reducing the maximum stress experienced by the 2nd and 3rd metatarsals. However, they greatly influenced the stress distribution in other metatarsal bones. These CFP designs seem to optimize the load transfer pathway, enabling a more uniform force transmission by mainly reducing contact force on the medial columns (the first three rays, measuring 0.333 times body weight for FCFP and 0.335 for CCFP in stiffest condition, compared to 0.373 in NCFP). We concluded that employing a curved CFP in running shoes could be more beneficial from an injury prevention perspective by inducing less peak pressure under the metatarsal heads while not worsening their stress state compared to flat plates.

Human-in-the-loop optimization of rocker shoe to reduce plantar pressure and collision work simultaneously

BACKGROUND

Rocker shoes can be used to reduce foot pressure and adjust lower limb kinetics for various patient population, such as people with diabetic peripheral neuropathy. Selecting adequate properties of the rocker sole is of great importance for its efficacy. This study investigated the capability of human-in-the-loop optimization (HILO) to individually optimize apex position and angle of rocker shoe to reduce peak pressure and collision work simultaneously.

METHODS

Peak pressure, kinetic, and kinematic data were recorded from 10 healthy participants while walking at preferred speed wearing rocker shoes with adjustable apex position and angle. An evolutionary algorithm was used to find optimal apex parameters to reduce both peak pressure in medial forefoot and collision work. The optimized shoe (HILO shoe) was compared with generic optimal rocker settings (Chapman settings) and normal shoe.

FINDINGS

Compared to normal shoe, the HILO shoe had lower plantar pressure (pHILO = 0.007; pChapman = 0.044) and Chapman shoe showed higher collision work (pHILO = 0.025; pChapman = 0.014). Both HILO and Chapman shoe had smaller push-off work than normal shoe (pHILO = 0.001; pChapman < 0.001) with the Chapman shoe exhibited earlier push-off onset (pHILO = 0.257; pChapman = 0.016).

INTERPRETATION

The Human-in-the-loop optimization approach resulted in individualized apex settings which performed on average similar to Chapman settings but, were superior in selected cases. In these cases, medial forefoot could be further offloaded with apex angles larger than generic settings. The larger apex angle might increase the external ankle moment arm and push-off work. However, there is limited room for improvement on collision work compared to generic settings.

Cushioning mechanism of the metatarsals during landing for the skateboarding ollie maneuver

Skateboarding is an Olympic event with frequent jumping and landing, where the cushioning effect by the foot structure (from the arch, metatarsals, etc.) and damping performance by sports equipment (shoes, insoles, etc.) can greatly affect an athlete's sports performance and lower the risk of limb injury. Skateboarding is characterized by the formation of a "man-shoe-skateboard system," which makes its foot cushioning mechanism different from those of other sports maneuvers, such as basketball vertical jump and gymnastics broad jump. Therefore, it is necessary to clarify the cushioning mechanism of the foot structure upon landing on a skateboard. To achieve this, a multibody finite element model of the right foot, shoe, and skateboard was created using Mimics, Geomagic, and ANSYS. Kinetic data from the ollie maneuver were used to determine the plantar pressure and Achilles tendon force at three characteristics (T1, T2, and T3). The stress and strain on the foot and metatarsals (MT1-5) were then simulated. The simulation results had an error of 6.98% compared to actual measurements. During landing, the force exerted on the internal soft tissues tends to increase. The stress and strain variations were highest on MT2, MT3, and MT4. Moreover, the torsion angle of MT1 was greater than those of the other metatarsals. Additionally, the displacements of MT2, MT3, and MT4 were higher than those of the other parts. This research shows that skateboarders need to absorb the ground reaction force through the movements of the MTs for ollie landing. The soft tissues, bones, and ligaments in the front foot may have high risks of injury. The developed model serves as a valuable tool for analyzing the foot mechanisms in skateboarding; furthermore, it is crucial to enhance cushioning for the front foot during the design of skateboard shoes to reduce potential injuries.

A comparison of traditional and net structured intersomatic cages in the lombosacral region: A biomechanical analysis for enhancing discopathy treatment

The vertebral column represents an essential element for support, mobility, and the protection of the central nervous system. Various pathologies can compromise these vital functions, leading to pain and a decrease in the quality of life. Within the scope of this study, a novel redesign of the Intersomatic Cage, traditionally used in the presence of discopathy, was proposed. The adoption of additive manufacturing technology allowed for the creation of highly complex geometries, focusing on the lumbosacral tract, particularly on the L4-L5 and L5-S1 intervertebral discs. In addition to the tensile analysis carried out using Finite Element Analysis (FEA) in static simulations, a parallel study on the range of motion (ROM) of the aforementioned vertebral pairs was conducted. The ROM represents the relative movement range between various vertebral pairs. The introduction of the intersomatic cage between the vertebrae, replacing the pulpy nucleus of the intervertebral disc, could influence the ROM, thus having significant clinical implications. For the analysis, the ligaments were modelled using a 1D approach. Their constraint reaction and deformability upon load application were analysed to better understand the potential biomechanical implications arising from the adoption of the cages. During the FEA simulations, two types of cages were analysed: LLIF for L4-L5 and ALIF for L5-S1, subjecting them to four different loading conditions. The results indicate that the stresses exhibited by cages with a NET structure are generally lower compared to those of traditional cages. This stress reduction in cages with NET structure suggests a more optimal load distribution, but it is essential to assess potential repercussions on the surrounding bone structure.

Mind to move: Differences in running biomechanics between sensing and intuition shod runners

Delving into the complexities of embodied cognition unveils the intertwined influence of mind, body, and environment. The connection of physical activity with cognition sparks a hypothesis linking motion and personality traits. Hence, this study explored whether personality traits could be linked to biomechanical variables characterizing running forms. To do so, 80 runners completed three randomized 50-m running-trials at 3.3, 4.2, and 5m/s during which their running biomechanics [ground contact time (tc), flight time (tf), duty factor (DF), step frequency (SF), leg stiffness (kleg), maximal vertical ground reaction force (Fmax), and maximal leg compression of the spring during stance (ΔL)] was evaluated. In addition, participants' personality traits were assessed through the Myers-Briggs Type Indicator (MBTI) test. The MBTI classifies personality traits into one of two possible categories along four axes: extraversion-introversion; sensing-intuition; thinking-feeling; and judging-perceiving. This exploratory study offers compelling evidence that personality traits, specifically sensing and intuition, are associated with distinct running biomechanics. Individuals classified as sensing demonstrated a more grounded running style characterized by prolonged tc, shorter tf, higher DF, and greater ΔL compared to intuition individuals (p≤0.02). Conversely, intuition runners exhibited a more dynamic and elastic running style with a shorter tc and higher kleg than their sensing counterparts (p≤0.02). Post-hoc tests revealed a significant difference in tc between intuition and sensing runners at all speeds (p≤0.02). According to the definition of each category provided by the MBTI, sensing individuals tend to focus on concrete facts and physical realities while intuition individuals emphasize abstract concepts and patterns of information. These results suggest that runners with sensing and intuition personality traits differ in their ability to use their lower limb structures as springs. Intuition runners appeared to rely more in the stretch-shortening cycle to energetically optimize their running style while sensing runners seemed to optimize running economy by promoting more forward progression than vertical oscillations. This study underscores the intriguing interplay between personality traits of individuals and their preferred movement patterns.

In vivo knee biomechanics during badminton lunges at different distances and different foot positions by using the dual fluoroscopic imaging system

Background: Lunges are common in badminton. Distance and foot position affect knee joint loadings under lunges, which are closely related to knee injury incidence. Investigations involving dynamic knee motion in vivo, kinetics, and muscle activation in lunges, especially during lunges of different distances and foot positions, are instrumental for understanding knee performance and injury risks of players. Methods: A total of 10 experienced badminton athletes (10 females; height, 164.5 ± 5.0 cm; weight, 59.3 ± 6.0 kg; and age, 22 ± 1.0 years) were recruited. By using a high-speed dual fluoroscopic imaging system, Qualisys motion capture system, Kistler force plate, and Delsys electromyography simultaneously, data were collected during players' 1.5 times leg length lunge, the maximum lunge, and the maximum lunge while the foot rotated externally. Magnetic resonance and dual fluoroscopic imaging techniques were used to analyze the in vivo knee kinematics. Results: Compared with the 1.5 times leg length lunge, knee flexion for the maximum lunge increased significantly (p < 0.05). The anterior-posterior ground reaction force (GRF) and vertical GRF of the maximum lunge were significantly higher than those of the 1.5 times leg length lunge. During the two different foot position lunges with the maximum distance, the posterior translation of knee joint was larger (p < 0.05) when the foot rotated externally than the normal maximum lunge. Moreover, the anterior-posterior GRF and vertical GRF increased significantly when the foot rotated externally. Significant differences were observed in valgus-varus rotation torque and internal-external rotation torque of the knee joint under the two distance lunges and two foot position lunges (p < 0.05). No significant difference was found in knee muscle activation during the two distance lunges and during the two foot position lunges. Conclusion: High knee torque and compressive loadings with increasing lunge distance may cause knee injuries in badminton. When lunging in the external foot rotation under the maximum distance, high quadriceps force and posterior tibia translation force could result in knee injuries among badminton players.

Asymmetric Load Transmission Induces Facet Joint Subchondral Sclerosis and Hypertrophy in Patients with Idiopathic Adolescent Scoliosis: Evaluation Using Finite Element Model and Surgical Specimen

Adolescent idiopathic scoliosis (AIS) with thoracic curvature primarily progresses from the thoracolumbar region, causing abnormal twisting and rotation of the spinal column. This results in unbalanced, asymmetric loads on each vertebrae and increased demands on the thoracic facet joints to withstand rotational stress from adjacent vertebrae. However, no studies have focused on the stress distribution on the facet joints of the thoracic spine in patients with AIS. This study aimed to investigate the mechanical loading and its distribution on the thoracic facet joints of AIS patients using finite element (FE) analysis and surgical specimens. FE models of the thoracic spine were created from a total of 13 female AIS patients (Lenke type 1, n = 4; Lenke type 2, n = 4; Lenke type 3, n = 5). A load of 200 N on the T3 vertebrae and 30 N each on the bilateral superior articular processes were applied vertically to quantify the contact force on the facet joints from T3 to T11. In addition, morphological and histological analyses were performed on the inferior articular processes obtained during surgery. FE analysis demonstrated that contact forces of the facet joint progressively increased from the mid to lower thoracic spine of the concave side, reaching a maximum around the apex. More than 91% of the load was transmitted by the facet joints at the concave side, resulting in facet joint subchondral sclerosis and hypertrophy. The apical facet joint in AIS helps counteract rotational stress between vertebrae and transfers most stress through the concave side. In conclusion, this study found that asymmetric load transfer in the facet joints leads to subchondral sclerosis and hypertrophy. These findings can enhance our understanding of the stress loading on facet joints and the resulting biological changes and help clarify the mechanisms involved in scoliosis progression. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Effects of heel apex position, apex angle and rocker radius on plantar pressure in the heel region

Introduction

Rocker shoes and insoles are used to prevent diabetic foot ulcers in persons with diabetes mellitus and loss of protective sensation, by reducing the plantar pressure in regions with high pressure values (>200 kPa) (e.g., hallux, metatarsal heads and heel). However, forefoot rocker shoes that reduce pressure in the forefoot inadvertently increase pressure in the heel. No studies focused on mitigating the negative effects on heel pressure by optimizing the heel rocker midsole, yet. Therefore, we analyze the effect of different heel rocker parameters on the heel plantar pressure.

Methods

In-shoe pressure was measured, while 10 healthy participants walked with control shoe and 10 different heel rocker settings. Peak pressure was determined in 7 heel masks, for all shoes. Generalized estimating equations was performed to test the effect of the different shoes on the peak pressure in the different heel masks.

Results

In the proximal heel, a rocker shoe with distal apex position, small rocker radius and large apex angle (100°), shows the largest significant decrease in peak pressure compared to rocker shoes with more proximally located apex positions. In the midheel and distal heel, the same rocker shoes or any other rocker shoes, analyzed in this study, do not reduce the PP more than 2 % compared to the control shoe. For the midheel and distal heel region with high pressure values (>200 kPa), rocker shoes alone are not the correct option to reduce the pressure to below 200 kPa.

Conclusion

When using rocker shoes to reduce the pressure in the forefoot, a heel rocker midsole with a distal apex position, small rocker radius and apex angle of 100°, mitigates the negative effects on proximal heel pressure. For the midheel and distal heel, other footwear options as an addition or instead of rocker shoes are needed to reduce the pressure.

Biomechanics research on laterality effect between dominant and non-dominant during double roundhouse kick in the competitive taekwondo

Background

The Double Roundhouse Kick (DRK) is one of the major scoring tools and athletes employ the leg of the dominant side (DS) or the non-dominant side (NS) for always attacking in an alternating state. The purpose is to examine the discrepancies in the biomechanical characteristics of the DS and NS of the leg of the DRK skills of sub-elite taekwondo athletes.

Methods

Using the Vicon, Kistler, and Daedo brand Electronic Body Protector (EBP), collection of the DRK data (attack time, joint angle, joint angular velocity, joint moment, ground reaction force, etc.) of 12 sub-elite taekwondo athletes (19.6 ± 2.0 yr, 180 ± 7.3 cm, 70 ± 9.8 kg) with the DS leg and NS leg. The measured data analyses via Visual3D, and statistical methods using nonparametric tests paired with samples based on the Wilcoxon signed-rank test (The significance level is set as significant for P<0.05, and very significant for P<0.01).

Results

(i) There is no statistically significant discrepancy between the DS and NS at the time of hit (P>0.05) and shift of the center of gravity (P>0.05). (ii) Attacking leg (AL): the maximum knee flexion angle (Knee-MFA) (P<0.05) and the peak linear velocity of attack of the foot in the vertical hitting direction (P<0.01) on the DS was greater than that on the NS during the first hit phase (P1). (iii) Supporting leg (SL): the peak hip extension moment (P<0.05) on the DS was reported to be higher than that of the NS during the second hit phase (P2). (iv) Symmetry Index (SI): In the P1, the vertical ground reaction force (vGRF) of the SL leads to SI = 10.19 %, and in the P2, the vGRF of the SL results in SI = 18.48 %.

Conclusions

The DRK requires more and more symmetry between the DS and NS. The Knee-MFA of the AL and the line of attack speed of the foot in the vertical striking direction of the SL exhibited significant discrepancies. The DS has higher striking speed, athletes need to improve the striking speed of the NS leg in training, achieving more scoring opportunities in the game. Both the DS and NS revealed strong symmetry in the peak SI of the ground reaction force of the SL stirrup; however, weak symmetry was attained in the peak SI of the vGRF of the SL landing cushion.

A Data-Driven Approach for Fatigue Detection during Running Using Pedobarographic Measurements

Background

Detecting fatigue at the early stages of a run could aid training programs in making adjustments, thereby reducing the heightened risk of injuries from overuse. The study aimed to investigate the effects of running fatigue on plantar force distribution in the dominant and nondominant feet of amateur runners.

Methods

Thirty amateur runners were recruited for this study. Bilateral time-series plantar forces were employed to facilitate automatic fatigue gait recognition using convolutional neural network (CNN) and CNN-based long short-term memory network (ConvLSTM) models. Plantar force data collection was conducted both before and after a running-induced fatigue protocol using a FootScan force plate. The Keras library in Python 3.8.8 was used to train and tune deep learning models.

Results

The results demonstrated that more mid-forefoot and heel force occurs during bilateral plantar and less midfoot fore force occurs in the dominant limb after fatigue (p < 0.001). The time of peak forces was significantly shortened at the midfoot and sum region of the nondominant foot, while it was delayed at the hallux region of the dominant foot (p < 0.001). In addition, the ConvLSTM model showed higher performance (Accuracy = 0.867, Sensitivity = 0.874, and Specificity = 0.859) in detecting fatigue gait than CNN (Accuracy = 0.800, Sensitivity = 0.874, and Specificity = 0.718).

Conclusions

The findings of this study could offer empirical data for evaluating risk factors linked to overuse injuries in a single limb, as well as facilitate early detection of fatigued gait.

Biomechanical Analysis of Latin Dancers' Lower Limb during Normal Walking

Latin dance involves fundamental walking steps, integral to the dance process. While resembling daily walking, Latin dance demands higher balance levels, necessitating body adjustments by dancers. These adaptations affect dancers' gait biomechanics, prompting our study on gait differences between Latin dancers (LDs) and non-dancers (NDs). We enlisted 21 female Latin dancers and 21 subjects based on specific criteria. Participants executed walking tasks, with an independent sample t-test for 1-dimensional statistical parameter mapping (SPM 1d) analyzing stance phase variations between LDs and NDs. Notably, significant differences in ankle and hip external rotation were evident during the 16.43-29.47% (p = 0.015) and 86.35-100% (p = 0.014) stance phase. Moreover, pronounced distinctions in rectus Achilles tendon force (ATF) (12.83-13.10%, p = 0.049; 15.89-80.19%, p < 0.001) and Patellofemoral joint contact force (PTF) (15.85-18.31%, p = 0.039; 21.14-24.71%, p = 0.030) during stance were noted between LDs (Latin dancers) and NDs (Non-dancers). The study revealed dancers' enhanced balance attributed to external ankle rotation for dance stability, coupled with augmented Achilles tendon and patellofemoral joint strength from prolonged practice. Moreover, integrating suitable Latin dance into rehabilitation may benefit those with internal rotation gait issues.

Effects of shoe collar types on ankle and knee biomechanics characteristics when performing the side-step cutting task

This study aimed to examine the effect of football shoes with different collar types on ankle and knee kinematic and kinetics features during 45° and 135° side-step cutting tasks. Fifteen healthy college football players volunteered for the study. Each participant was instructed to perform side-step cutting tasks with high, low, and no collar football shoes. The kinematic and ground reaction force data were measured using a Vicon motion capture system and a Kistler force plate, respectively. Two-way MANOVAs with repeated measures were used to examine the effect of shoe collar type and task conditions. There were no interaction effects. The high collar football shoe showed decreased ankle range of motion in the sagittal plane (p = 0.010) and peak ankle external rotation moment (p = 0.009) compared to the no collar football shoe. The high (p = 0.025) and low (p = 0.029) collar football shoes presented greater peak ankle external rotation angles than the no collar football shoe. These results imply that football shoes with high collars made of high intensity knitted fabric could be used to restrict ankle joint movement, with potential implications for decreasing the risk of ankle sprain injuries in football players.

The Effects of Fatigue on the Lower Limb Biomechanics of Amateur Athletes during a Y-Balance Test

The Y-Balance Test (YBT) is a reliable tool for assessing the dynamic balance of athletes' lower limbs. This study aimed to compare the effects of the YBT on lower limb biomechanics before and after fatigue. Sixteen adult male recreational athletes were recruited for the study, and motion capture in combination with a force plate was used to collect kinematic, dynamics, and center of pressure (COP) data of the dominant leg during YBT testing before and after fatigue. Based on the research findings, there were significant statistical differences in the distances reached during the YBT in three directions before and after fatigue. After fatigue, there is a significant decrease in the ROM of the hip and knee joints in all three directions. Also, there is a significant increase in hip joint torque in the anterior- and posterior-lateral directions, while a significant decrease in hip and ankle joint torque is observed in the posterior-medial direction. Moreover, there is an increasing trend in positive and negative joint work for the hip, knee, and ankle joints in all three directions after fatigue. The range of COP displacement also increases following fatigue. The decline in YBT scores demonstrates the detrimental impact of fatigue on the dynamic balance of the lower limbs of adult male amateur athletes. We hope that these results can provide information for athletes and coaches to better understand the effects of fatigue on the dynamic balance of lower limbs, so as to carry out targeted lower limb balance training and prevent sports injuries.

The biomechanical effects of insoles with different cushioning on the knee joints of people with different body mass index grades

Background: Enhancing knee protection for individuals who are overweight and obese is crucial. Cushioning insoles may improve knee biomechanics and play a significant protective role. However, the impact of insoles with varying cushioning properties on knee joints in individuals with different body mass index (BMI) categories remains unknown. Our aim was to investigate the biomechanical effects of insoles with different cushioning properties on knee joints across different BMI grades. Methods: Gravity-driven impact tests were used to characterize the cushioning properties of three types of Artificial Cartilage Foam (ACF18, 28, and 38) and ethylene-vinyl acetate (EVA) insoles. Knee joint sagittal, coronal, and vertical axis angles and moments were collected from healthy-weight (BMI 18.5-23.9 kg/m2, n = 15), overweight (BMI 24.0-27.9 kg/m2, n = 16), and obese (BMI ≥28.0 kg/m2, n = 15) individuals randomly assigned four different insoles during a drop jump. The Kruskal-Wallis test and mixed model repeated measures analysis of variance were used to compare differences among cushioning and biomechanical data across various insoles, respectively. Results: ACF showed higher cushioning than EVA, and ACF38 was the highest among the three types of ACF (all p < 0.001). During the drop jump, the knee flexion angles and moments of the ACF insoles were lower than those of the EVA insoles, the knee adduction angles of the ACF18 and ACF28 insoles were lower than those of the EVA insoles, and ACF18 insoles increased the first cushion time (all p < 0.05) for all participants in whom biomechanical variables demonstrated no interactions between insoles and BMI. Regarding the BMI-dependent biomechanical variables, compared with the EVA insoles, ACF28 insoles decreased the knee flexion angle and ACF38 insoles decreased the knee adduction and rotation moment in the healthy-weight group; ACF18 insoles decreased the knee flexion angle and ACF38 insoles decreased the knee moment in the overweight group; ACF28 insoles decreased the knee flexion and adduction moment, and ACF38 insoles decreased the knee flexion angle and rotation moment in the obese group (all p < 0.05). Conclusion: Insoles with higher cushioning properties could improve knee biomechanics and provide better knee joint protection in people across different BMI ranges.

Regional plantar forces and surface geometry variations of a chronic ankle instability population described by statistical shape modelling

BACKGROUND

Understanding detailed foot morphology as well as regional plantar forces could provide insight into foot function and provide recommendation for footwear design for chronic ankle instability (CAI) people.

RESEARCH QUESTION

This study presented 3-dimensional statistical shape models of feet from three different populations including CAI, copers and healthy individuals, with regional plantar forces also acquired.

METHODS

Sixty-six males (22 participants per group) were included in this study to capture 3-dimensional foot shapes under a standing condition and regional plantar forces during a cutting maneuver. Principal component analysis was performed to generate a mean foot shape of each group as well as modes of variations. A generalized procrustes analysis was used to achieve rapid registration of mean shapes. Besides, regional plantar forces and contact duration among these three populations were compared.

RESULTS

For 3-dimensional foot shapes, although no significant differences of the average distance between each mode and mean shape were found among three populations, there were subtle variations in mean shapes. The CAI population presented a more bulging of the lateral malleolus; copers were characterized by the flexion of the lesser toes, a more bulging of the medial foot in the sagittal plane; and healthy individuals showed a greater heel width and a more bulging of the heel in the sagittal plane. In terms of plantar forces, healthy individuals had significantly greater summated plantar forces and greater plantar forces in the lateral heel area during the early contact phase compared to copers and CAI participants.

SIGNIFICANCE

Overall, this study suggested that repetitive ankle sprains may lead to the bulging of the lateral malleolus. Further, CAI and copers seem to stabilize the ankle joint by medially shifting the center of pressure compared to healthy individuals under the static and less challenging dynamic conditions.

Biomechanical effects of exercise fatigue on the lower limbs of men during the forward lunge

Background: During competition and training, exercises involving the lungs may occur throughout the sport, and fatigue is a major injury risk factor in sport, before and after fatigue studies of changes in the lungs are relatively sparse. This study is to investigate into how fatigue affects the lower limb's biomechanics during a forward lunge. Methods: 15 healthy young men participate in this study before and after to exposed to a fatigue protocol then we tested the forward lunge to obtain kinematic, kinetic changing during the task, and to estimate the corresponding muscles' strength changes in the hip, knee, and ankle joints. The measurement data before and after the fatigue protocol were compared with paired samples t-test. Results: In the sagittal and horizontal planes of the hip and knee joints, in both, the peak angles and joint range of motion (ROM) increased, whereas the moments in the sagittal plane of the knee joint smaller. The ankle joint's maximum angle smaller after fatigue. Peak vertical ground reaction force (vGRF) and peak contact both significantly smaller after completing the fatigue protocol and the quadriceps mean and maximum muscular strength significantly increased. Conclusion: After completing a fatigue protocol during lunge the hip, knee, and ankle joints become less stable in both sagittal and horizontal planes, hip and knee range of motion becomes greater. The quadriceps muscles are more susceptible to fatigue and reduced muscle force. Trainers should focus more on the thigh muscle groups.

Comparative Efficacy of Vibration foam Rolling and Cold Water Immersion in Amateur Basketball Players after a Simulated Load of Basketball Game

To compare the efficacy of different recovery strategies (sitting; cold water immersion, CWI; vibration foam rolling, VFR) on the lower extremities of amateur basketball players after the simulated load of a basketball game, we assessed the power, agility, and dynamic balance before and after interventions. Ten amateur basketball players alternately underwent 12 min of sitting, 12 min of CWI at 5 °C, and 12 min of VFR. The power, agility, and dynamic balance were measured immediately post-warm-up, immediately post-game, immediately post-intervention, 1 h after interventions, and 24 h after interventions. To simulate the load of a basketball game, specific movements were designed and implemented. Jump height was measured using a Kistler force plate. Reaction time and dynamic balance score were assessed using the Pavigym agility response system and the Y balance test, respectively. The data were analyzed with a two-way repeated measures analysis of variance (ANOVA). The results showed that the vertical jump height significantly decreased after the CWI intervention compared to the CON and VFR groups (p < 0.001). At 1 h after the intervention, the vertical jump height in the CON group showed delayed recovery compared to the CWI and VFR groups (p = 0.007; p < 0.001). At 24 h after the intervention, the vertical jump height in the CWI group further increased and was significantly different from the CON and VFR groups (p < 0.001; p = 0.005). Additionally, reaction times significantly increased immediately after the CWI intervention (p = 0.004) but showed further recovery at 24 h compared to the CON group (p < 0.001). The dynamic balance score significantly rebounded after the CWI intervention compared to the CON group (p = 0.021), with further improvement at 24 h (p < 0.001). CWI initially showed negative effects, but over time, its recovery effect was superior and more long-lasting. VFR had the best immediate effect on lower limb recovery after the game.

Inertial Sensor Technologies-Their Role in Equine Gait Analysis, a Review

Objective gait analysis provides valuable information about the locomotion characteristics of sound and lame horses. Due to their high accuracy and sensitivity, inertial measurement units (IMUs) have gained popularity over objective measurement techniques such as force plates and optical motion capture (OMC) systems. IMUs are wearable sensors that measure acceleration forces and angular velocities, providing the possibility of a non-invasive and continuous monitoring of horse gait during walk, trot, or canter during field conditions. The present narrative review aimed to describe the inertial sensor technologies and summarize their role in equine gait analysis. The literature was searched using general terms related to inertial sensors and their applicability, gait analysis methods, and lameness evaluation. The efficacy and performance of IMU-based methods for the assessment of normal gait, detection of lameness, analysis of horse-rider interaction, as well as the influence of sedative drugs, are discussed and compared with force plate and OMC techniques. The collected evidence indicated that IMU-based sensor systems can monitor and quantify horse locomotion with high accuracy and precision, having comparable or superior performance to objective measurement techniques. IMUs are reliable tools for the evaluation of horse-rider interactions. The observed efficacy and performance of IMU systems in equine gait analysis warrant further research in this population, with special focus on the potential implementation of novel techniques described and validated in humans.

The effect of foot posture on static balance, ankle and knee proprioception in 18-to-25-year-old female student: a cross-sectional study

BACKGROUND & PURPOSE

Afferent input from the sole affects postural stability. Cutaneous reflexes from the foot are important to posture and gait. Lower-limb afferents alone provide enough information to maintain upright stance and are critical in perceiving postural sway. Altered feedback from propreoceptive receptors alters gait and patterns of muscle activation. The position and posture of the foot and ankle may also play an important role in proprioceptive input.Therefore, the current research aims to compare static balance and ankle and knee proprioception in people with and without flexible flatfeet.

METHODOLOGY

91 female students between the ages of 18 and 25 voluntarily participated in this study, of which 24 were in the flexible flatfoot group and 67 were in the regular foot group after evaluating the longitudinal arch of the foot. The position sense of ankle and knee joints were measured using the active reconstruction test of the ankle and knee angle; Static balance was measured using the Sharpened Romberg test. Data were non-normally distributed. Accordingly, non-parametric tests were applied. The Kruskal-Wallis test was applied to compare differences between groups in variables.

RESULT

Kruskal-Wallis test showed a significant difference between two groups of flat feet and normal feet in the variables of static balance and position sense of ankle plantarflexion, ankle dorsiflexion, and knee flexion (p ≤ 0.05). A significant correlation was found between static balance and sense of ankle and knee position in the group with normal feet. The analysis of the regression line also showed that ankle and knee position sense could predict the static balance score in the regular foot group (ankle dorsiflexion position sense 17% (R² = 0.17), ankle plantarflexion position sense 17% (R² = 0.17) and knee flexion position sense 46% (R² = 0.46) explain of changes in static balance).

DISCUSSION & CONCLUSION

Flexible flatfoot soles can cause loss of balance and sense of joint position; therefore, according to this preliminary study, clinicians must be aware and should take into account this possible deficit in the management of these patients.

Low Correlation between Gait and Quality of Life in Advanced Knee Osteoarthritis

Advanced knee osteoarthritis patients' gait usually undergoes alterations leading to decreased mobility and lower functional performance, which can result in a worsening of their quality of life (QoL). While several authors have reported a moderate correlation between gait parameters and QoL assessed by generic questionnaires, the literature is scarce. This study aimed to explore the relationship between gait and QoL parameters assessed by a generic and a disease-specific questionnaire in patients with advanced knee osteoarthritis. In this single-centre, prospective, observational study, 129 patients with advanced knee osteoarthritis scheduled for elective total knee replacement were selected. The patients' gait was evaluated by means of a validated wireless device while they walked 30 m at a comfortable speed. Patient function was also analysed using the Knee Society Score (KSS). QoL was measured with the EQ-5D and the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaires. Patients showed a mean walking speed of 0.95 ± 0.19 m/s, a mean cadence of 105.6 ± 9.9 steps/min, and a mean stride length of 1.25 ± 0.17 m on both legs. They presented poor knee status (KSS < 60) and poor QoL, with an EQ-5D of 0.44 ± 0.24 and a total KOOS of 29.77 ± 13.99. Positive low correlations (r <0.5, p <0.5) were found only between the speed, propulsion and stride length of both legs, and the overall and ADLs subscale scores of the total KOOS questionnaire. In conclusion, several gait parameters have a significant low correlation with the QoL of patients with advanced knee osteoarthritis, as assessed by an osteoarthritis-specific questionnaire.