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Kinetic and kinematic determinants of shuttlecock speed in the forehand jump smash performed by elite male Malaysian badminton players

Ramasamy Y, Usman J, Sundar V, Towler H, King M

Sports Biomech, 2024 May;23(5):582-597.
PMID: 33663330 DOI: 10.1080/14763141.2021.1877336

Badminton is the fastest racket sport in the world with smash speeds reaching over 111 m/s (400 kph). This study examined the forehand jump smash in badminton using synchronised force plates and full-body motion capture to quantify relationships to shuttlecock speed through correlations. Nineteen elite male Malaysian badminton players were recorded performing forehand jump smashes with the fastest, most accurate jump smash from each player analysed. The fastest smash by each participant was on average 97 m/s with a peak of 105 m/s. A correlational analysis revealed that a faster smash speed was characterised by a more internally rotated shoulder, a less elevated shoulder, and less extended elbow at contact. The positioning of the arm at contact appears to be critical in developing greater shuttlecock smash speeds. Vertical ground reaction force and rate of force development were not correlated with shuttlecock speed, and further investigation is required as to their importance for performance of the jump smash e.g., greater jump height and shuttle angle. It is recommended that players/coaches focus on not over-extending the elbow or excessively elevating the upper arm at contact when trying to maximise smash speed.

Matched MeSH terms: Biomechanical Phenomena
A scoping review of applications of artificial intelligence in kinematics and kinetics of ankle sprains - current state-of-the-art and future prospects

Teoh YX, Alwan JK, Shah DS, Teh YW, Goh SL

Clin Biomech (Bristol, Avon), 2024 Mar;113:106188.
PMID: 38350282 DOI: 10.1016/j.clinbiomech.2024.106188

BACKGROUND: Despite the existence of evidence-based rehabilitation strategies that address biomechanical deficits, the persistence of recurrent ankle problems in 70% of patients with acute ankle sprains highlights the unresolved nature of this issue. Artificial intelligence (AI) emerges as a promising tool to identify definitive predictors for ankle sprains. This paper aims to summarize the use of AI in investigating the ankle biomechanics of healthy and subjects with ankle sprains.
METHODS: Articles published between 2010 and 2023 were searched from five electronic databases. 59 papers were included for analysis with regards to: i). types of motion tested (functional vs. purposeful ankle movement); ii) types of biomechanical parameters measured (kinetic vs kinematic); iii) types of sensor systems used (lab-based vs field-based); and, iv) AI techniques used.
FINDINGS: Most studies (83.1%) examined biomechanics during functional motion. Single kinematic parameter, specifically ankle range of motion, could obtain accuracy up to 100% in identifying injury status. Wearable sensor exhibited high reliability for use in both laboratory and on-field/clinical settings. AI algorithms primarily utilized electromyography and joint angle information as input data. Support vector machine was the most used supervised learning algorithm (18.64%), while artificial neural network demonstrated the highest accuracy in eight studies.
INTERPRETATIONS: The potential for remote patient monitoring is evident with the adoption of field-based devices. Nevertheless, AI-based sensors are underutilized in detecting ankle motions at risk of sprain. We identify three key challenges: sensor designs, the controllability of AI models, and the integration of AI-sensor models, providing valuable insights for future research.

Matched MeSH terms: Biomechanical Phenomena
The inter-laboratory equivalence for lower limb kinematics and kinetics during unplanned sidestepping

Donnelly CJ, Weir G, Jackson C, Alderson J, Rafeeuddin R, Sharir R, et al.

Sports Biomech, 2024 Mar;23(3):324-334.
PMID: 33886425 DOI: 10.1080/14763141.2020.1860254

Much inter-intra-tester kinematic and kinetic repeatability research exists, with a paucity investigating inter-laboratory equivalence. The objective of this research was to evaluate the inter-laboratory equivalence between time varying unplanned kinematics and moments of unplanned sidestepping (UnSS). Eight elite female athletes completed an established UnSS procedure motion capture laboratories in the UK and Australia. Three dimensional time varying unplanned sidestepping joint kinematics and moments were compared. Discrete variables were change of direction angles and velocity. Waveform data were compared using mean differences, 1D 95%CI and RMSE. Discrete variables were compared using 0D 95% CI. The mean differences and 95%CI for UnSS kinematics broadly supported equivalence between laboratories (RMSE≤5.1°). Excluding hip flexion/extension moments (RMSE = 1.04 Nm/kg), equivalence was also supported for time varying joint moments between laboratories (RMSE≤0.40 Nm/kg). Dependent variables typically used to characterise UnSS were also equivalent. When consistent experimental and modelling procedures are employed, consistent time varying UnSS lower limb joint kinematic and moment estimates between laboratories can be obtained. We therefore interpret these results as a support of equivalence, yet highlight the challenges of establishing between-laboratory experiments or data sharing, as well as establishing appropriate ranges of acceptable uncertainty. These findings are important for data sharing and multi-centre trials.

Matched MeSH terms: Biomechanical Phenomena
Fulltext Sit-to-walk strategy classification in healthy adults using hip and knee joint angles at gait initiation

Perera CK, Gopalai AA, Gouwanda D, Ahmad SA, Salim MSB

Sci Rep, 2023 Oct 03;13(1):16640.
PMID: 37789077 DOI: 10.1038/s41598-023-43148-0

Forward continuation, balance, and sit-to-stand-and-walk (STSW) are three common movement strategies during sit-to-walk (STW) executions. Literature identifies these strategies through biomechanical parameters using gold standard laboratory equipment, which is expensive, bulky, and requires significant post-processing. STW strategy becomes apparent at gait-initiation (GI) and the hip/knee are primary contributors in STW, therefore, this study proposes to use the hip/knee joint angles at GI as an alternate method of strategy classification. To achieve this, K-means clustering was implemented using three clusters corresponding to the three STW strategies; and two feature sets corresponding to the hip/knee angles (derived from motion capture data); from an open access online database (age: 21-80 years; n = 10). The results identified forward continuation with the lowest hip/knee extension, followed by balance and then STSW, at GI. Using this classification, strategy biomechanics were investigated by deriving the established biomechanical quantities from literature. The biomechanical parameters that significantly varied between strategies (P

Matched MeSH terms: Biomechanical Phenomena
Fulltext Minimum number of inertial measurement units needed to identify significant variations in walk patterns of overweight individuals walking on irregular surfaces

Sikandar T, Rabbi MF, Ghazali KH, Altwijri O, Almijalli M, Ahamed NU

Sci Rep, 2023 Sep 27;13(1):16177.
PMID: 37758958 DOI: 10.1038/s41598-023-43428-9

Gait data collection from overweight individuals walking on irregular surfaces is a challenging task that can be addressed using inertial measurement unit (IMU) sensors. However, it is unclear how many IMUs are needed, particularly when body attachment locations are not standardized. In this study, we analysed data collected from six body locations, including the torso, upper and lower limbs, to determine which locations exhibit significant variation across different real-world irregular surfaces. We then used deep learning method to verify whether the IMU data recorded from the identified body locations could classify walk patterns across the surfaces. Our results revealed two combinations of body locations, including the thigh and shank (i.e., the left and right shank, and the right thigh and right shank), from which IMU data should be collected to accurately classify walking patterns over real-world irregular surfaces (with classification accuracies of 97.24 and 95.87%, respectively). Our findings suggest that the identified numbers and locations of IMUs could potentially reduce the amount of data recorded and processed to develop a fall prevention system for overweight individuals.

Matched MeSH terms: Biomechanical Phenomena
Fulltext Automated Gait Analysis Based on a Marker-Free Pose Estimation Model

Hii CST, Gan KB, Zainal N, Mohamed Ibrahim N, Azmin S, Mat Desa SH, et al.

Sensors (Basel), 2023 Jul 18;23(14).
PMID: 37514783 DOI: 10.3390/s23146489

Gait analysis is an essential tool for detecting biomechanical irregularities, designing personalized rehabilitation plans, and enhancing athletic performance. Currently, gait assessment depends on either visual observation, which lacks consistency between raters and requires clinical expertise, or instrumented evaluation, which is costly, invasive, time-consuming, and requires specialized equipment and trained personnel. Markerless gait analysis using 2D pose estimation techniques has emerged as a potential solution, but it still requires significant computational resources and human involvement, making it challenging to use. This research proposes an automated method for temporal gait analysis that employs the MediaPipe Pose, a low-computational-resource pose estimation model. The study validated this approach against the Vicon motion capture system to evaluate its reliability. The findings reveal that this approach demonstrates good (ICC(2,1) > 0.75) to excellent (ICC(2,1) > 0.90) agreement in all temporal gait parameters except for double support time (right leg switched to left leg) and swing time (right), which only exhibit a moderate (ICC(2,1) > 0.50) agreement. Additionally, this approach produces temporal gait parameters with low mean absolute error. It will be useful in monitoring changes in gait and evaluating the effectiveness of interventions such as rehabilitation or training programs in the community.

Matched MeSH terms: Biomechanical Phenomena
Fulltext Effects of powered ankle-foot orthoses mass distribution on lower limb muscle forces-a simulation study

Marconi G, Gopalai AA, Chauhan S

Med Biol Eng Comput, 2023 May;61(5):1167-1182.
PMID: 36689083 DOI: 10.1007/s11517-023-02778-2

This simulation study aimed to explore the effects of mass and mass distribution of powered ankle-foot orthoses, on net joint moments and individual muscle forces throughout the lower limb. Using OpenSim inverse kinematics, dynamics, and static optimization tools, the gait cycles of ten subjects were analyzed. The biomechanical models of these subjects were appended with ideal powered ankle-foot orthoses of different masses and actuator positions, as to determine the effect that these design factors had on the subject's kinetics during normal walking. It was found that when the mass of the device was distributed more distally and posteriorly on the leg, both the net joint moments and overall lower limb muscle forces were more negatively impacted. However, individual muscle forces were found to have varying results which were attributed to the flow-on effect of the orthosis, the antagonistic pairing of muscles, and how the activity of individual muscles affect each other. It was found that mass and mass distribution of powered ankle-foot orthoses could be optimized as to more accurately mimic natural kinetics, reducing net joint moments and overall muscle forces of the lower limb, and must consider individual muscles as to reduce potentially detrimental muscle fatigue or muscular disuse. OpenSim modelling method to explore the effect of mass and mass distribution on muscle forces and joint moments, showing potential mass positioning and the effects of these positions, mass, and actuation on the muscle force integral.

Matched MeSH terms: Biomechanical Phenomena/physiology
A triple compound pendulum model to analyse the effect of an ankle-foot orthosis on swing phase kinematics

Marconi G, Gopalai AA, Chauhan S

Med Eng Phys, 2023 Feb;112:103951.
PMID: 36842774 DOI: 10.1016/j.medengphy.2023.103951

Powered ankle-foot orthoses can be utilised to overcome gait abnormalities such as foot drop; however, normal gait is rarely restored with compensatory gait patterns arising and prevalence of gait asymmetry. Therefore, this study aims to determine the effect of orthosis mass and mass distribution on the swing phase of gait, to understand residual gait asymmetry with orthosis use. Using a triple compound pendulum model, which accounts for mass distribution of the limb and orthosis, the swing phase of gait is simulated in terms of natural dynamics and the effect of an orthosis on kinematic parameters is quantitatively determined. It was found that additional mass causes faster and shorter steps on the affected side due to rapid knee extension and reduced hip flexion, with particular actuator positions and natural cadence causing varying severity of these effects. Our study suggests that this model could be used as a preliminary design tool to identify subject specific optimum orthosis mass distribution of a powered ankle-foot orthosis, without the need for motion data or experimental trials. This optimisation intends to more accurately mimic natural swing phase kinematics, consequently allowing for the reduction in severity of gait asymmetry and the potential to improve rehabilitative outcomes.

Matched MeSH terms: Biomechanical Phenomena
Musculoskeletal Gait Simulation to Investigate Biomechanical Effect of Knee Brace

Yap YT, Gouwanda D, Gopalai AA, Chong YZ

J Biomech Eng, 2023 Feb 01;145(2).
PMID: 36082472 DOI: 10.1115/1.4055564

Musculoskeletal modeling and simulation have been an emerging trend in human gait analysis. It allows the user to isolate certain biomechanical conditions and elucidate the dynamics of joints and muscles. This study used an open-source musculoskeletal modeling and simulation tool, opensim to investigate the biomechanical effect of knee brace. It collected gait data from thirty-eight participants and examined the gait spatio-temporal parameters, joint angles, and joint moments. Static optimization was performed to estimate the lower extremity muscle force. Statistical analysis was conducted to identify the difference between normal and braced gaits. The results demonstrated the feasibility of this method to investigate the interaction and coordination of lower extremity joints and muscles. The knee brace constrained the range of the motion of the knee during walking. It also changed the walking speed, step length, and stance-to-swing ratio. Several significant differences were found in the joint moments and muscle forces of the rectus femoris, gastrocnemius, soleus and tibialis anterior. Musculoskeletal modeling and simulation tool offers a less invasive and practical alternative to analyze human motion. It also provides a means to investigate the effect of medical devices such as knee brace, which can be potentially beneficial for the future design and development of such devices and for the derivation of future rehabilitation treatment to improve patient's gait.

Matched MeSH terms: Biomechanical Phenomena
Biomechanical factors associated with non-specific low back pain in adults: A systematic review

Abd Rahman NA, Li S, Schmid S, Shaharudin S

Phys Ther Sport, 2023 Jan;59:60-72.
PMID: 36516512 DOI: 10.1016/j.ptsp.2022.11.011

Low back pain (LBP) can result in increased direct medical and non-medical costs to patients, employers, and health care providers. This systematic review aimed to provide a better understanding of the biomechanical factors associated with chronic non-specific LBP in adults. SCOPUS, ScienceDirect, MEDLINE, and Web of Science databases were searched. In total, 26 studies were included and significant differences were noted between healthy controls and LBP patients in various motion. Biomechanical factors among adults with non-specific LBP were altered and differed as compared to healthy controls in various motion might be to compensate the pain during those motions. This review highlighted the biomechanical differences across those with non-specific LBP and healthy adults. Both groups showed a similar level of pain during functional tasks but LBP patients suffered from a moderate level of disability. Future studies should not rely on questionnaire-based pain scale only. The biomechanical factors summarized in this review can be used to diagnose non-specific LBP accurately, and as modifiable targets for exercise-based intervention.

Matched MeSH terms: Biomechanical Phenomena
The non-sagittal knee moment vector identifies 'at risk' individuals that the knee abduction moment alone does not

Robinson MA, Sharir R, Rafeeuddin R, Vanrenterghem J, Donnelly CJ

Sports Biomech, 2023 Jan;22(1):80-90.
PMID: 33947315 DOI: 10.1080/14763141.2021.1903981

Multi-planar forces and moments are known to injure the anterior cruciate ligament (ACL). In ACL injury risk studies, however, the uni-planar frontal plane external knee abduction moment is frequently studied in isolation. This study aimed to determine if the frontal plane knee moment (KM-Y) could classify all individuals crossing a risk threshold compared to those classified by a multi-planar non-sagittal knee moment vector (KM-YZ). Recreationally active females completed three sports tasks-drop vertical jumps, single-leg drop vertical jumps and planned sidesteps. Peak knee abduction moments and peak non-sagittal resultant knee moments were obtained for each task, and a risk threshold of the sample mean plus 1.6 standard deviations was used for classification. A sensitivity analysis of the threshold from 1-2 standard deviations was also conducted. KM-Y did not identify all participants who crossed the risk threshold as the non-sagittal moment identified unique individuals. This result was consistent across tasks and threshold sensitivities. Analysing the peak uni-planar knee abduction moment alone is therefore likely overly reductionist, as this study demonstrates that a KM-YZ threshold identifies 'at risk' individuals that a KM-Y threshold does not. Multi-planar moment metrics such as KM-YZ may help facilitate the development of screening protocols across multiple tasks.

Matched MeSH terms: Biomechanical Phenomena
Fulltext Biomechanics Analysis of the Firefighters' Thorax Movement on Personal Protective Equipment during Lifting Task Using Inertial Measurement Unit Motion Capture

Yunus MNH, Jaafar MH, Mohamed ASA, Azraai NZ, Amil N, Zein RM

Int J Environ Res Public Health, 2022 Oct 31;19(21).
PMID: 36361112 DOI: 10.3390/ijerph192114232

Back injury is a common musculoskeletal injury reported among firefighters (FFs) due to their nature of work and personal protective equipment (PPE). The nature of the work associated with heavy lifting tasks increases FFs' risk of back injury. This study aimed to assess the biomechanics movement of FFs on personal protective equipment during a lifting task. A set of questionnaires was used to identify the prevalence of musculoskeletal pain experienced by FFs. Inertial measurement unit (IMU) motion capture was used in this study to record the body angle deviation and angular acceleration of FFs' thorax extension. The descriptive analysis was used to analyze the relationship between the FFs' age and body mass index with the FFs' thorax movement during the lifting task with PPE and without PPE. Sixty-three percent of FFs reported lower back pain during work, based on the musculoskeletal pain questionnaire. The biomechanics analysis of thorax angle deviation and angular acceleration has shown that using FFs PPE significantly causes restricted movement and limited mobility for the FFs. As regards human factors, the FFs' age influences the angle deviation while wearing PPE and FFs' BMI influences the angular acceleration without wearing PPE during the lifting activity.

Matched MeSH terms: Biomechanical Phenomena
Biomechanical comparison of new Achilles tendon rupture repair technique the "Giftbox" versus the Krackow technique in New Zealand white rabbits: An experimental animal study

Hashim MH, Teo SH, Al-Fayyadh MZM, Mappiare S, Ng WM, Ali MRM

Injury, 2022 Feb;53(2):393-398.
PMID: 34740441 DOI: 10.1016/j.injury.2021.10.016

INTRODUCTION: To compare the strength between the Achilles tendons repaired with the "Giftbox" and the Krackow techniques in New Zealand white rabbits post six weeks of tendon healing.
MATERIALS AND METHODS: Eight rabbits were randomized into Giftbox and Krackow groups. Tenotomy was performed on the Achilles tendon of one side of the lower limb and repaired with the respective techniques. The contralateral limb served as control. Subjects were euthanized six weeks post-operative, and both repaired and control Achilles tendons were harvested for biomechanical tensile test.
RESULTS: The means of maximum load to rupture and tenacity in the Giftbox group (156.89 ± 38.49 N and 159.98 ± 39.25 gf/tex) were significantly different than Krackow's (103.55 ± 27.48 N and 104.91 ± 26.96 gf/tex, both p = 0.043).
CONCLUSION: The tendons repaired with Giftbox technique were biomechanically stronger than those repaired with Krackow technique after six weeks of tendon healing.

Matched MeSH terms: Biomechanical Phenomena
Biomechanics analysis on Jejag kick of pencak silat

Doewes RI, Elumalai G, Azmi SH

J Popul Ther Clin Pharmacol, 2022;29(4):e116-e125.
PMID: 36441049 DOI: 10.47750/jptcp.2022.989

The force in the pencak silat jejag kick is called the moment of force or torque. The force moment is a measure of the force that can cause an object to rotate around the axis where the axis of rotation is located at the knee joint with the length of the calf as the length of the arm (the radius of the rotation axis). This research was conducted using laboratory biomechanical analysis. The research sample consisted of three male athletes of pencak silat. Previously, anthropometric measurements were carried out in the form of measuring calf length and calf muscle mass, then taking videos of athletes doing jejag kick movements in a static state with targets, which were then analyzed by kinovea. Research results showed that the technique of the jejag kick pencak silat produces a force called the moment of force or torque. Sample 1 produces a force moment of -12.00 Nm, sample 2 produces -5.53 Nm, and sample 3 produces -8.73 (negative sign means the direction of the pencak silat jejag kick is counterclockwise). The magnitude of the force moment is influenced by the angle of knee extension and the radius of the rotation axis. The amount of force moment affects the kick speed. In the speed of a movement, there is a tendency to keep moving, which is called the moment of inertia. The fasterthe movement, the greater the moment of inertia. The result is a force moment, influenced by the rotational kinetic energy that is owned and requires effort. Every effort is made to produce a force moment; it takes power to drive the effort. This means that the greater the angle of extension and the longer the calf, the greater the force moment, the faster the kick speed, and the greater the moment of inertia. This requires a large amount of rotational kinetic energy, effort, and power.

Matched MeSH terms: Biomechanical Phenomena*
Fulltext Quantification of Gait Stability During Incline and Decline Walking: The Responses of Required Coefficient of Friction and Dynamic Postural Index

Abdul Yamin NAA, Basaruddin KS, Abu Bakar S, Salleh AF, Mat Som MH, Yazid H, et al.

J Healthc Eng, 2022;2022:7716821.
PMID: 36275397 DOI: 10.1155/2022/7716821

This study aims to investigate the gait stability response during incline and decline walking for various surface inclination angles in terms of the required coefficient of friction (RCOF), postural stability index (PSI), and center of pressure (COP)-center of mass (COM) distance. A customized platform with different surface inclinations (0°, 5°, 7.5°, and 10°) was designed. Twenty-three male volunteers participated by walking on an inclined platform for each inclination. The process was then repeated for declined platform as well. Qualysis motion capture system was used to capture and collect the trajectories motion of ten reflective markers that attached to the subjects before being exported to a visual three-dimensional (3D) software and executed in Matlab to obtain the RCOF, PSI, as well as dynamic PSI (DPSI) and COP-COM distance parameters. According to the result for incline walking, during initial contact, the RCOF was not affected to inclination. However, it was affected during peak ground reaction force (GRF) starting at 7.5° towards 10° for both walking conditions. The most affected PSI was found at anterior-posterior PSI (APSI) even as low as 5° inclination during both incline and decline walking. On the other hand, DPSI was not affected during both walking conditions. Furthermore, COP-COM distance was most affected during decline walking in anterior-posterior direction. The findings of this research indicate that in order to decrease the risk of falling and manage the inclination demand, a suitable walking strategy and improved safety measures should be applied during slope walking, particularly for decline and anterior-posterior orientations. This study also provides additional understanding on the best incline walking technique for secure and practical incline locomotion.

Matched MeSH terms: Biomechanical Phenomena
Fulltext Instantaneous, Dual-Frequency, Multi-GNSS Precise RTK Positioning Using Google Pixel 4 and Samsung Galaxy S20 Smartphones for Zero and Short Baselines

Yong CZ, Odolinski R, Zaminpardaz S, Moore M, Rubinov E, Er J, et al.

Sensors (Basel), 2021 Dec 13;21(24).
PMID: 34960412 DOI: 10.3390/s21248318

The recent development of the smartphone Global Navigation Satellite System (GNSS) chipsets, such as Broadcom BCM47755 and Qualcomm Snapdragon 855 embedded, makes instantaneous and cm level real-time kinematic (RTK) positioning possible with Android-based smartphones. In this contribution we investigate the instantaneous single-baseline RTK performance of Samsung Galaxy S20 and Google Pixel 4 (GP4) smartphones with such chipsets, while making use of dual-frequency L1 + L5 Global Positioning System (GPS), E1 + E5a Galileo, L1 + L5 Quasi-Zenith Satellite System (QZSS) and B1 BeiDou Navigation Satellite System (BDS) code and phase observations in Dunedin, New Zealand. The effects of locating the smartphones in an upright and lying down position were evaluated, and we show that the choice of smartphone configuration can affect the positioning performance even in a zero-baseline setup. In particular, we found non-zero mean and linear trends in the double-differenced carrier-phase residuals for one of the smartphone models when lying down, which become absent when in an upright position. This implies that the two assessed smartphones have different antenna gain pattern and antenna sensitivity to interferences. Finally, we demonstrate, for the first time, a near hundred percent (98.7% to 99.9%) instantaneous RTK integer least-squares success rate for one of the smartphone models and cm level positioning precision while using short-baseline experiments with internal and external antennas, respectively.

Matched MeSH terms: Biomechanical Phenomena
Jumping in lantern bugs (Hemiptera, Fulgoridae)

Burrows M, Ghosh A, Sutton GP, Yeshwanth HM, Rogers SM, Sane SP

J Exp Biol, 2021 12 01;224(23).
PMID: 34755862 DOI: 10.1242/jeb.243361

Lantern bugs are amongst the largest of the jumping hemipteran bugs, with body lengths reaching 44 mm and masses reaching 0.7 g. They are up to 600 times heavier than smaller hemipterans that jump powerfully using catapult mechanisms to store energy. Does a similar mechanism also propel jumping in these much larger insects? The jumping performance of two species of lantern bugs (Hemiptera, Auchenorrhyncha, family Fulgoridae) from India and Malaysia was therefore analysed from high-speed videos. The kinematics showed that jumps were propelled by rapid and synchronous movements of both hind legs, with their trochantera moving first. The hind legs were 20-40% longer than the front legs, which was attributable to longer tibiae. It took 5-6 ms to accelerate to take-off velocities reaching 4.65 m s-1 in the best jumps by female Kalidasa lanata. During these jumps, adults experienced an acceleration of 77 g, required an energy expenditure of 4800 μJ and a power output of 900 mW, and exerted a force of 400 mN. The required power output of the thoracic jumping muscles was 21,000 W kg-1, 40 times greater than the maximum active contractile limit of muscle. Such a jumping performance therefore required a power amplification mechanism with energy storage in advance of the movement, as in their smaller relatives. These large lantern bugs are near isometrically scaled-up versions of their smaller relatives, still achieve comparable, if not higher, take-off velocities, and outperform other large jumping insects such as grasshoppers.

Matched MeSH terms: Biomechanical Phenomena
A preliminary investigation on upper limb exoskeleton assistance for simulated agricultural tasks

Harith HH, Mohd MF, Nai Sowat S

Appl Ergon, 2021 Sep;95:103455.
PMID: 33991852 DOI: 10.1016/j.apergo.2021.103455

Manual harvesting is still prevalent in the agricultural industry. Accordingly, it is one of the largest contributors toward work-related musculoskeletal disorder. The cutting task in oil palm harvesting uses a long pole and involves repetitive and forceful motion of the upper limbs. Exoskeleton technology is increasingly explored to assist manual tasks performance in manufacturing and heavy industries, mainly for reducing discomfort and injuries, and improving productivity. This paper reports an initial investigation on the feasibility of using an upper limb exoskeleton to assist oil palm harvesting tasks. Previous studies highlighted that exoskeletons for agricultural activities should be adaptable to changing field tasks, tools and equipment. The immediate difference in the activity of three muscles were analyzed for a range of harvesting-simulated tasks. Lower activities were observed for tasks involving overhead work when using the prototype. Nevertheless, users' feedback highlighted that its design should be optimized for better acceptance.

Matched MeSH terms: Biomechanical Phenomena
Biomechanical analysis of three different types of fixators for anterior cruciate ligament reconstruction via finite element method: a patient-specific study

Zainal Abidin NA, Abdul Wahab AH, Abdul Rahim RA, Abdul Kadir MR, Ramlee MH

Med Biol Eng Comput, 2021 Sep;59(9):1945-1960.
PMID: 34392448 DOI: 10.1007/s11517-021-02419-6

Complication rates of anterior cruciate ligament reconstruction (ACL-R) were reported to be around 15% although it is a common arthroscopic procedure with good outcomes. Breakage and migration of fixators are still possible even months after surgery. A fixator with optimum stability can minimise those two complications. Factors that affect the stability of a fixator are its configuration, material, and design. Thus, this paper aims to analyse the biomechanical effects of different types of fixators (cross-pin, interference screw, and cortical button) towards the stability of the knee joint after ACL-R. In this study, finite element modelling and analyses of a knee joint attached with double semitendinosus graft and fixators were carried out. Mimics and 3-Matic softwares were used in the development of the knee joint models. Meanwhile, the graft and fixators were designed by using SolidWorks software. Once the meshes of all models were finished in 3-Matic, simulation of the configurations was done using MSC Marc Mentat software. A 100-N anterior tibial load was applied onto the tibia to simulate the anterior drawer test. Based on the findings, cross-pin was found to have optimum stability in terms of stress and strain at the femoral fixation site for better treatment of ACL-R.

Matched MeSH terms: Biomechanical Phenomena
Fulltext Impact of Bone Cement Augmentation on the Fixation Strength of TFNA Blades and Screws

Sermon A, Hofmann-Fliri L, Zderic I, Agarwal Y, Scherrer S, Weber A, et al.

Medicina (Kaunas), 2021 Aug 28;57(9).
PMID: 34577822 DOI: 10.3390/medicina57090899

Background and Objectives: Hip fractures constitute the most debilitating complication of osteoporosis with steadily increasing incidences in the aging population. Their intramedullary nailing can be challenging because of poor anchorage in the osteoporotic femoral head. Cement augmentation of Proximal Femoral Nail Antirotation (PFNA) blades demonstrated promising results by enhancing cut-out resistance in proximal femoral fractures. The aim of this study was to assess the impact of augmentation on the fixation strength of TFN-ADVANCEDTM Proximal Femoral Nailing System (TFNA) blades and screws within the femoral head and compare its effect when they are implanted in centre or anteroposterior off-centre position. Materials and Methods: Eight groups were formed out of 96 polyurethane low-density foam specimens simulating isolated femoral heads with poor bone quality. The specimens in each group were implanted with either non-augmented or cement-augmented TFNA blades or screws in centre or anteroposterior off-centre positions, 7 mm anterior or posterior. Mechanical testing was performed under progressively increasing cyclic loading until failure, in setup simulating an unstable pertrochanteric fracture with a lack of posteromedial support and load sharing at the fracture gap. Varus-valgus and head rotation angles were monitored. A varus collapse of 5° or 10° head rotation was defined as a clinically relevant failure. Results: Failure load (N) for specimens with augmented TFNA head elements (screw/blade centre: 3799 ± 326/3228 ± 478; screw/blade off-centre: 2680 ± 182/2591 ± 244) was significantly higher compared with respective non-augmented specimens (screw/blade centre: 1593 ± 120/1489 ± 41; screw/blade off-centre: 515 ± 73/1018 ± 48), p < 0.001. For both non-augmented and augmented specimens failure load in the centre position was significantly higher compared with the respective off-centre positions, regardless of the head element type, p < 0.001. Augmented off-centre TFNA head elements had significantly higher failure load compared with non-augmented centrally placed implants, p < 0.001. Conclusions: Cement augmentation clearly enhances the fixation stability of TFNA blades and screws. Non-augmented blades outperformed screws in the anteroposterior off-centre position. Positioning of TFNA blades in the femoral head is more forgiving than TFNA screws in terms of failure load.

Matched MeSH terms: Biomechanical Phenomena

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