External Moment Research Articles

Is biomechanical loading reduced in individuals with unilateral transtibial amputation during fast-paced walking when using different ankle/foot prostheses? A pragmatic randomized controlled trial.

Sound side loading is a risk factor for osteoarthritis development, which has been noted to reduce when using advanced prostheses during normal-paced walking in individuals with unilateral transtibial amputation (UTTA). However, descriptions of loading during fast-paced walking remain relatively unreported. Therefore, the aim of this study was to describe the biomechanical loading of individuals with UTTA while using different ankle/foot prostheses during fast-paced walking. A blinded, randomized control trial was conducted in a group of K3-K4 ambulators, who used 3 different prosthetic feet (1. a solid ankle cushioned heel foot prosthesis [SACH], 2. a standard energy storage and return foot prosthesis [ESAR], and 3. a novel ESAR foot prosthesis [N-ESAR]) in a 2-week randomized crossover design. The spatiotemporal and kinetic data of the participants' fast walking pace were collected. Data were analyzed using a mixed model and one-way analysis of variances (p < 0.05) and Cohen d. Twenty individuals with UTTA (age: 40 ± 16 years; height: 1.76 ± 0.09 m; and BMI: 24.72 ± 3.63 kg/m2) participated in this study. There were minimal changes in the spatiotemporal data between the different prosthetic feet. When the participants used the N-ESAR feet, they had a lower peak vertical ground reaction force (p = 0.02) and external knee adduction moment (p = 0.02) on the sound side, as well as a higher distal shank power on the prosthetic side (p < 0.01). Overall fast-paced walking resulted in higher sound side loading forces compared with normal-paced walking. However, use of the N-ESAR prosthesis reduced the biomechanical loading on the sound side in individuals with UTTA while walking at a fast pace compared with the ESAR and SACH prostheses. The percentage change in the biomechanical loading from normal- to fast-paced walking of the N-ESAR foot was also larger compared with the other prostheses, perhaps because of the individuals' ability to achieve a faster walking pace when using the N-ESAR prosthesis. Longitudinal intervention studies should be performed to further investigate the possible benefits of using advanced prostheses.

Gait analysis and clinical outcomes of anterior and lateral approach total hip arthroplasty: A prospective randomized study

Objectives: This study compared the lateral and direct anterior approaches (DAAs) for total hip arthroplasty (THA) regarding gait analysis and post-operative outcomes. Methods: Patients undergoing THA for osteonecrosis or primary osteoarthritis were randomized to either the lateral or DAA. Standardized surgical procedures and implants were used. Gait analysis, including temporal distance parameters, kinetics, and kinematics, was conducted at 6 weeks, 3 months, and 18 months. Results: Thirty-four patients (16 lateral, 18 anterior) participated, with comparable demographics. At 6 weeks, the anterior approach group had significantly higher Harris hip scores, improved gait speed, greater hip extension and external rotation moments, higher peak hip abduction angle, and reduced peak hip extension angle. The lateral approach (LA) group showed decreased hip abduction and internal rotation moments. By 3 and 18 months, outcomes were similar between groups. Conclusion: The anterior approach facilitates faster rehabilitation at 6 weeks, but outcomes converge with the LA by 3 and 18 months postoperatively.

Robust integrated control of autonomous vehicles path following with response performance improvement considering lateral stability

In this paper, a robust integrated control scheme is developed for autonomous vehicles path following considering both yaw stability and roll stability. First, a controller with H∞ and optimal guaranteed cost performances is presented, and the poles of the closed-loop system are configured in a given disk region to improve the state response performance. The controller outputs front and rear wheel angles for path following, as well as an external yaw moment and an external roll moment for lateral stability control. Secondly, the braking forces acted on four wheels are optimally distributed by means of quadratic programing. Besides, the steering angles of the four wheels conform to the Ackermann geometry relation. Finally, the proposed control scheme is verified by CarSim/Simulink co-simulation, the results show that the scheme has better performance on path following accuracy and stability of yaw and roll. Meanwhile, constraining the poles in a given disk region can improve the state response performance of the vehicle during operation.

Is the Frequency of a Targeted Neuromuscular Training Program a Factor in Modifying Knee Joint Loading During Typical Netball Landing Tasks?

Unplanned sidestep cutting and forward single-leg jump-landing contribute to non-contact anterior cruciate ligament (ACL) injuries in netball. Neuromuscular training programs (NMTPs) have shown promising results in reducing injury risk in certain populations when compliance is high. Compliance is easier to achieve when NMTPs are effective yet require minimal time for completion. Once- and thrice-weekly intervention groups would be equally effective in reducing knee abduction and internal rotation moments during forward single-leg jump landing and unplanned sidestep cutting. Randomized controlled trial. Level 3. External peak knee abduction and peak knee internal rotation moments during unplanned sidestep cutting and forward single-leg jump-landing were assessed pre- and post-intervention for 17 elite-level female netballers assigned randomly to either a once-weekly or thrice-weekly group. Regular netball training continued throughout the intervention, which lasted 6 weeks (30 minutes/session). One-way analysis of covariance (α = 0.05) was utilized to compare post-intervention peak knee abduction and peak knee internal rotation moments between groups, controlling for pre-intervention knee moments during the forward single-leg jump-landing and unplanned sidestep cut. Paired t tests were used to examine within-group changes in knee moments pre- versus post-intervention. For unplanned sidestep cuts on the right leg, both groups differed significantly, with the once-weekly group displaying a decrease in peak knee internal rotation moments [F(1,14) = 5.23; P = 0.04] whereas the thrice-weekly group did not. No other significant group interactions were found. A condensed NMTP with targeted exercises, performed once-weekly as part of regular training, shows potential to reduce peak knee internal rotation moments that are injurious to the ACL during unplanned sidestep cutting in adult female netballers. A once-weekly targeted NMTP would pose minimal disruption to a high-performing athlete's training schedule and likely increase compliance to ensure the success of the NMTP.

Multi-objective model predictive control for ship roll motion with gyrostabilizers

Ships are prone to significant roll motion while sailing in adverse conditions, posing a serious threat to ship safety and maneuverability. Therefore, effective ship motion control is crucial. Integrating the MPC control algorithm with a gyrostabilizer can effectively achieve this goal. To evaluate and compare control strategies, a multi-objective model predictive control is proposed that integrates considerations of ship motion, safety, and energy consumption to conduct the operation concurrently. By assigning different weights to these factors, the study aims to discern the varying impacts on control effectiveness. The response of ship roll motion in beam waves is evaluated through roll hydrodynamic modelling, accounting for wave memory effects. A state-space model of ship and gyrostabilizers is proposed to represent their dynamic interaction and response to external moment. Subsequently, the influence of different weightings in the multi-objective model predictive control is compared, and the control performances of a frigate under different wave conditions are analyzed respectively. The multi-objective model predictive control, with varied weight assignments, leads to distinct reductions in roll motions. This investigation offers valuable insights into controlling roll motion in beam wave conditions, effectively reducing motion under varying sea conditions, and providing alternative guidance tailored to user preferences.

Residual Performance and Biomechanical Asymmetries During Jumping Tasks in Female Athletes at 9 Months After Anterior Cruciate Ligament Reconstruction.

Biomechanics and anterior cruciate ligament injury mechanisms differ in males and females. There is a need for more data on between-limb biomechanical differences after anterior cruciate ligament reconstruction (ACLR) in females. To explore biomechanical asymmetries throughout the kinetic chain during the single-legged (SL) and double-legged (DL) countermovement jump (CMJ) and drop jump (DJ) in female athletes after ACLR. Descriptive laboratory study. Kinematic and kinetic between-limb differences were analyzed during the SL and DL CMJ and DJ in 67 female athletes 9 months after ACLR. Biomechanical and performance asymmetries between limbs during the jumps and isokinetic strength testing were analyzed with statistical parametric mapping. The entire stance phase was used for the paired t tests of the biomechanical variables, with Cohen d effect sizes of significant portions of the stance phase (reported as % of stance) calculated in a point-by-point manner. Decreased vertical ground-reaction force, internal knee abduction moment, knee internal rotation angle, hip external rotation angle, internal ankle eversion, and external rotation moments were seen in the ACLR limb during all 4 vertical jump tests. The greatest number and highest value of differences were found during the DLDJ, with asymmetries having medium to large effect sizes. They tended to appear more frequently in the concentric phase (50% to 100% of stance) during the SLCMJ and DLCMJ and in the eccentric (0% to 49% of stance) and concentric (50% to 100% of stance) phase during the SLDJ and DLDJ. For the SLCMJ, SLDJ, and quadriceps strength, performance asymmetries of >15% were detected but not for change of direction. The findings suggest that return-to-play testing in female athletes should examine the entire stance phase and include assessments of kinetic and kinematic variables throughout the kinetic chain. Greater deficits were highlighted in the DJ than in the CMJ, and greater performance asymmetries were evident in the SL tasks, with greater kinetic and kinematic and compensatory strategies evident in the DL tests. Biomechanical analysis focusing on contralateral compensation strategies and sex-specific interventions are necessary before return to play.

The effect of prosthetic foot stiffness category on intact limb knee loading associated with osteoarthritis in people with transtibial amputation

Lower limb prosthesis users are at an increased risk of developing osteoarthritis in their intact knee. There is a scarcity of literature examining how the stiffness properties of commercially available prosthetic feet impact gait mechanics, including knee loading biomechanical variables that have been associated with the development of osteoarthritis. This study aimed to isolate the effect of commercial prosthetic foot stiffness on intact knee loading, prosthetic foot–ankle biomechanics, and user perception. Seventeen males with unilateral transtibial amputation were fit with three consecutive foot stiffness categories of a standardized energy-storing prosthetic foot in a randomized order and while blinded to foot condition. Biomechanical and self-report data were collected during level-ground walking in a motion analysis laboratory. As prosthetic foot stiffness increased, contralateral knee external adduction moment significantly decreased between stiff vs. medium and stiff vs. soft foot conditions. Prosthetic foot rollover radius increased as foot stiffness increased. However, prosthetic foot–ankle push-off peak power and work decreased as foot stiffness increased. On average, users favored the medium stiffness condition and were able to correctly identify the foot stiffness condition. Overall, these results raise questions about the relative contributions of foot stiffness and ankle push-off power to changes in contralateral knee loading. The findings contribute to our understanding of the relationships between prosthetic foot mechanical properties and gait biomechanical variables at the contralateral knee when prosthetic foot stiffness is modified without a corresponding alignment adjustment.

The Effectiveness of Massage on Pain, External Knee Adduction Moment, and Muscle Co-contraction in Individuals with Medial Compartment Knee Osteoarthritis

BackgroundThe pain, external knee adduction moment (EKAM), and muscle co-contraction are increased in knee osteoarthritis (KOA). Massage therapy decreases pain in KOA, yet KOA is a mechanical disease and biomechanical changes need to be investigated as well. Therefore, the current study aims to investigate the effectiveness of massage on these outcomes in individuals with medial KOA. MethodsA cohort of fifteen participants with confirmed medial compartment KOA (2 males, 13 females, age: 61.33 (6.16) years; height: 1.62 (0.06) m; mass: 65.39 (4.04) kg; BMI: 24.74 (4.04) kg/m2) was given a six-week massage. Outcomes assessed pre- and post-intervention were: Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, temporal-spatial variables, knee joint kinematics and kinetics in sagittal, frontal, and transverse planes, vertical ground reaction force (GRF), and knee antagonist muscle co-contraction during gait. The paired t-test were used for statistical analysis. ResultsFifteen participants completed the study. Significant improvements were observed in WOMAC scores (pain, stiffness, function, and total), walking speed, step length, 1st peak GRF, sagittal plane knee joint range of motion during stance, and medial muscle co-contraction in early and mid-stance (p<0.05). However, no significant change was found in EKAM and knee adduction angular impulse (KAAI) (p>0.05). ConclusionMassage therapy, as a stand-alone treatment, reduces pain, improves function, and decreases medial muscle co-contraction in individuals with medial KOA. Although EKAM did not change, the results suggest a reduction in medial muscle co-contraction might be a mechanism by which pain is improved.

The Impact of Contralateral Cane Placement on the External Knee Adduction Moment

The Impact of Contralateral Cane Placement on the External Knee Adduction Moment

The influence of knee position during static calibration trials on evaluation of knee loading during gait in individual with medial knee osteoarthritis

Quantitative three-dimensional gait analysis has been used to evaluate the loading at the knee (i.e. external knee adduction moment, EKAM) during level ground walking in individuals with knee osteoarthritis (OA). The magnitude of EKAM can be influenced by some factors, such as knee marker position and foot placement angles in static calibration trials, which may lead to inaccurate functional assessments and intervention planning. This study aimed to clarify the effects of knee position during static calibration trials on the evaluation of knee loading during gait in individuals with medial knee OA. Seventeen individuals with medial knee OA completed three different static standing trials; (1) knee flexed at 0 degrees, (2) knee flexed at 15 degrees, and (3) knee flexed at 30 degrees before walking at their self-selected speed. A sixteen-camera three-dimensional VICON gait analysis system with four AMTI force platforms was used to collect the EKAM, knee adduction angular impulse (KAAI), knee joint center (KJC), and other knee kinematic and kinetic variables during gait. A repeated measures ANOVA was used to investigate the differences between conditions. The 1st peak of EKAM, the 1st peak EKAM arm, KAAI, and knee extension moment were significantly increased at the 15-degree and 30-degree conditions in comparison with the 0-degree condition (P < 0.05). Additionally, the knee flexion moment and knee external rotation moment were significantly reduced at the 15-degree and 30-degree conditions in comparison with the 0-degree condition (P < 0.05). All biomechanical variables were influenced by the localization of the KJC during static calibration trials. The changes in knee position during static trials significantly affected the 1st peak EKAM, KAAI, and other knee kinematics and kinetics variables during gait. Therefore, future studies should consider keeping the participants’ knees in a consistent position during static trials between visits, as the variations in knee position could mask or exaggerate the differences between groups and interventions.

The Effect of Static Trial on Knee Adduction Moment During Walking.

Background and aim Sophisticated technologies in rehabilitation, such as three-dimensional gait analysis, allow for measuring kinematic and kinetic variables while performing activities. The first peak external knee adduction moment (EKAM) is considered an important outcome in individuals with knee osteoarthritis (OA) and has been shown to be affected by changes in foot position in static trials. The present study aimed to explore the variables in static trials that may lead to changes in the value of the EKAM while walking. Methods Twelve individuals participated in the current study and were asked to perform three static trials as follows: 20° toe-out, straight (0°), and 20° toe-in. The participants were asked to walk five trials (their own shoes and paces). The first peak EKAM was the main study outcome and was compared between conditions. Linear regression was used to investigate which variables in the static trials significantly predicted the magnitude of change in the EKAM while walking. Results The first peak EKAM significantly decreased by 8.2% while walking when changing the foot position in static trials from 20° toe-in to 20° toe-out. The magnitude of change in the EKAM was significantly (p<0.01) predicted by the magnitude of change in the knee joint frontal plane angle, shank transverse plane angle, ankle joint frontal plane angle, and hip joint frontal plane angle during static trials between 20° toe-in and 20° toe-out. The model was able to predict 94% of the variation in the EKAM due to changes in foot position during static trials. Conclusion Modifications in foot position during static trials led to a change in the first peak EKAM while walking. Researchers should focus on controlling the knee joint frontal plane angle, shank transverse plane angle, ankle joint frontal plane angle, and hip joint frontal plane angle during static trials when conducting longitudinal or crossover studies. Controlling these variables is necessary to reduce the likelihood of the EKAM being affected by static trials and to ensure that the EKAM changes in dynamic trials are not masked or increased by static trials.

Biomechanical Demand during 90° and 135° Cutting Manoeuvres: Implications for Anterior Cruciate Ligament Injury

Background: Anterior cruciate ligament (ACL) injuries in athletes have financial and health consequences and are considered career-threatening. The current study aimed to shed light on biomechanical differences between various change of direction (COD) manoeuvres. Understanding such differences is important, given their association with the incidence of non-contact ACL injuries. Methods: Thirty-six male recreational soccer players participated and performed 90° and 135° COD manoeuvres. For gait analysis, the Vicon system was used. The speed and shoe-surface interface were standardized in the COD manoeuvres. Paired sample t-tests were used to compare conditions. Results: A Greater peak external knee abduction moment (PEKAM) (p&lt;0.001) and knee abduction angle at initial contact (IC) (p&lt;0.001) in the 135° COD manoeuvre compared to the 90° COD manoeuvre were observed, highlighting the increased injury risk potential at greater COD angles. In addition, the hip sagittal plane range of motion (RoM) from IC to peak knee valgus angle was higher in the 135° COD manoeuvre than 90° COD manoeuvre (p&lt;0.001). Conclusion: The results of the current study support the idea that ACL biomechanical risk factors are angle-dependent. A sharper cutting angle showed a higher risk of ACL injury due to the increase in the PEKAM and the knee abduction angle at initial contact. Therefore, players should be trained to reduce high PEKAM and the knee abduction angle by using different strategies.

Changes in rotator movement during early gait acquisition in after total hip arthroplasty

BackgroundIn walking in healthy adults, rotation of the hip joint affects stride length and shifts the center of gravity, but these are not seen in hip osteoarthritis which affects gait. In gait of total hip arthroplasty, there are few reports on changes in the horizontal plane. This study clarified the preoperative and early postoperative gait characteristics of patients undergoing total hip arthroplasty. MethodsThe analysis included 12 females who underwent initial total hip arthroplasty using a posterolateral approach. Gait was measured pre and postoperatively using a three-dimensional motion analysis device. Statistics were compared pre and postoperative range of motion, muscle strength, walking speed, stride length, gravity movement distance, trunk angle, hip joint angle, and joint moment. FindingsThe maximum hip abduction moment and trunk flexion angle to the surgical side were lower than in healthy subjects. The angle of internal rotation during the stance phase was significantly higher in the postoperative period. The distance of the center of gravity shift in the left and right directions was significantly decreased postoperatively. InterpretationGait disturbance was seen preoperatively and remained after surgery. Walking after total hip arthroplasty provides the hip joint rotates inward which is closer to normal walking. However, no change was observed in the external rotation moment of the hip joint during walking. We suspect that the invasiveness of the posterolateral approach of total hip arthroplasty affects the muscles for external rotation of the hip joint. This can also cause in gait disturbances.

Pure distortion of symmetric box beams with hinged walls

This paper is concerned with the analysis of the pure torsion and distortion of straight box beams with trapezial cross-sections and hinged walls. A one-dimensional mechanical model for this kind of system subjected to anti-symmetric loads on the end cross-sections and no warping constraints is developed. The distortional stiffness of the system is provided by the torsional rigidity of the wall panels. The cross-sectional kinematic condition for which torsion and distortion are uncoupled has been determined. Novel explicit expressions of the internal and external distortional moments, the distortion constant, and the distortional warping pattern have been deduced; they can be directly translated to the classical distortion theory. Results of representative test cases with different section shapes and loads show excellent agreement with finite element models using shell elements. The model is a first step to analyse bridge decks with a distortionable central cell for wind engineering applications. Finally, an extension of the model, including the distortional stiffness provided by the frame bending stiffness of the cross-section walls, is presented. The extended model is applicable to assess the large-scale torsional–distortional effects in long beams with closed cross sections.

Are 7 MM neoprene knee sleeves capable of modifying the knee kinematics and kinetics during box jump and front squat exercises in healthy CrossFit practitioners? An exploratory cross-sectional study

ObjectiveInvestigate whether wearing 7 mm neoprene knee sleeves during the front squat and box jump CrossFit exercises change the biomechanics of the knee joint. Designa cross-sectional exploratory study. SettingLaboratory-based. ParticipantsSeventeen male healthy CrossFit participants completed front squats and box jumps with knee sleeves (KS) and without knee sleeves (WKS). Main outcomes measuresKinematic and kinetic data of the knee in the sagittal, frontal and transverse planes were obtained for the two tasks and under the two experimental situations. The maximum load lifted on 1 MR test was recorded under KS and WKS conditions. The GROC scales were applied after each exercise and condition to assess participants' self-reported perception of stability. ResultsThe KS reduced the knee range of motion in the transverse plane during box jump (p = 0.029) and the peak knee external adduction moment (p = 0.047) during front squat compared to WKS. The 1RM during front squat increased in KS compared to WKS (p < 0.001). Most participants (94%) reported that they felt better stability using KS and all participants (100%) believed that knee sleeves would avoid knee pain. Conclusionneoprene knee sleeves have little impact on the biomechanics of the knee joint during CrossFit. However, participants reported improved knee stability.

Impact of step width on trunk motion and gait adaptation in elderly women with knee osteoarthritis.

Step width during walking can provide important information about aging and pathology. Although knee osteoarthritis (OA) is a common disease in elderly women, little is known about how different step widths influence gait parameters in patients with knee OA. To address this, we investigated the differences between narrower and wider step width on the center of mass (CoM) and gait biomechanics of elderly women with knee OA. Gait and CoM data were measured using a three-dimensional motion capture system and anthropometric data were acquired via standing full-limb radiography. Thirty elderly women with knee OA were divided into two groups depending on the average step width value (0.16 m). Specifically, the narrower step width group included those with a below average step width (n= 15) and the wider step width group included those with an above average step width (n= 15). The differences between the two groups were analyzed using an independentt-test. Walking speed, step length, knee and ankle sagittal excursion, and medial-lateral CoM range were significantly greater in the narrower group. In contrast, the medial-lateral CoM velocity, medial-lateral ground reaction force (GRF), and foot progression angle were significantly higher in wider group. The external knee adduction moment, vertical GRF, and vertical CoM did not differ between the groups. Our data indicate that step width in women with knee OA is associated with trunk motion and gait patterns. People with a narrower step might improve their gait function by increasing trunk frontal control to maintain gait stability. In contrast, in those with a wider step, greater toe out angle and shorter step length might be a compensatory adaptation to reduce knee loading.

Trunk and Lower Extremity Biomechanics in Female Athletes With and Without a Concussion History.

Athletes with a history of concussion are at a greater risk for lower extremity musculoskeletal injury. Female athletes may be at an even greater risk than male athletes. Previous researchers on postconcussion landing biomechanics have focused on the lower extremities, but the trunk plays a crucial role as an injury risk factor. To compare lower extremity and trunk biomechanics during jump-landing and cutting maneuvers between female athletes with and those without a concussion history. Cross-sectional study. Biomechanics laboratory. A total of 26 athletes (mean ± SD age = 19.0 ± 1.3 years, height = 1.68 ± 0.07 m, mass = 64.02 ± 6.76 kg, body mass index = 22.58 ± 1.97 kg/m2; median [interquartile range] time since most recent concussion = 37.5 months [25.0 months, 65.8 months]) with a concussion history and 38 athletes (age = 19.0 ± 1.1 years, height = 1.71 ± 0.08 m, mass = 64.72 ± 9.45 kg, body mass index = 22.14 ± 1.80 kg/m2) without a concussion history. Peak kinetics (vertical ground reaction force, vertical loading rate, external knee-abduction moment, and external knee-flexion moment) and kinematics (trunk-flexion angle, trunk lateral-bending angle, ankle-dorsiflexion angle, knee-flexion angle, knee-abduction angle, and hip-flexion angle) were obtained during the eccentric portion of jump-landing and cutting tasks. Separate 2 (group) × 2 (limb) between- and within-factors analyses of covariance were used to compare outcomes between groups. We covaried for time since the most recent concussion and the limb that had a history of musculoskeletal injury. Athletes with a concussion history displayed a greater peak knee-abduction angle in their nondominant limb than their dominant limb (P = .01, ηp2 = 0.107) and the nondominant limb of athletes without a concussion history (P = .02, ηp2 = 0.083) during jump landing. They also had less trunk lateral bending during cutting compared with athletes without a concussion history (P = .005, ηp2 = 0.126). Our results indicated landing biomechanics are different between female athletes with and those without a concussion history. This finding may be due to impairments in neuromuscular control postconcussion that may ultimately increase the risk of subsequent lower extremity injury, although further research is warranted given the cross-sectional nature of our study.

Hydrodynamic mechanism for dynamical structure formation of a system of rotating particles

Based on the hydrodynamic mechanism, which takes into account the interaction of all particles, a numerical simulation of the formation of a dynamical structure in a viscous fluid was carried out. This structure is a result of the collective dynamics of rotating particles in the fluid. It is supposed that the particles have a magnetic moment and are driven into rotation by an external variable uniform magnetic field. The results of numerical modeling of collective dynamics are presented for three initial structures that can be formed by interacting dipole particles in the absence of an external magnetic field. Such equilibrium structures are a straight chain, a closed chain, and a periodic structure in the form of a flat system of particle chains. The rotation of particles sets the surrounding fluid in motion, whose flow creates hydrodynamic forces and moments that move the particles. The collective dynamics of a system of rotating particles leads to the formation of a new dynamical structure from the original one, and this new structure has its own characteristic features for each case considered. A qualitative comparison of the results of the dynamics for a particles’ system set in motion due to the action of an external moment or an external force is carried out. The proposed hydrodynamic mechanism for the formation of a dynamical structure as a result of the collective dynamics of a rotating particles’ system can be used to control structure formation in a liquid-particle system.

Bidirectional tuned liquid dampers for stabilizing floating offshore wind turbine substructures

Tuned sloshing dampers have long been used to stabilize tall and thin buildings and are now being applied to marine structures. In this study, the effectiveness of two new passive control devices at stabilizing floating offshore wind turbine substructures was investigated: the bidirectional tuned liquid damper and bidirectional tuned liquid column damper. Numerical simulations were performed to consider the sloshing effect on the passive control devices and the pitch-induced external moment brought about by wave action. The effects of adding baffles and orifices to the passive control devices were explored to optimize the geometric design. The results showed that the optimal combination of substructure geometry and passive control device type could reduce the pitch motion by 20%–40%.

Knee contact forces of individuals with osteoarthritis and those with lower limb amputation: A systematic review.

Osteoarthritis (OA) is a major cause of impairment. Research has shown that individuals with unilateral lower limb amputation (ULLA) are 17 times more likely to develop OA on their sound side limb. Therefore, this review aimed to describe similarities and differences in the biomechanical loading variables of individuals with OA and those with ULLA. Researchers systematically searched PubMed-Medline, EBSCOhost and Web of Science for articles published between January 1990 and February 2022. Included studies investigated the biomechanical profiles (peak external knee adduction moment (KAM); peak external knee flexion moment (KFM); ground reaction force; external knee adduction moment loading rate; external knee adduction moment impulse) of both population groups. A total of 31 articles were included in this review. Only KAM and KFM presented similar profiles in both groups, whilst all other variables were dissimilar. The use of advanced prostheses reduced the loading on the sound side of individuals with ULLA. As both KAM and KFM are surrogate measures for knee contact forces, interventions need to target these variables to help manage and prevent the development of OA. Interventions, particularly for addressing these variables in individuals with ULLA, should be further investigated in future research.