Injury Biomechanics

Female volleyball athletes incorporate dynamic and static stretching into a warm-up, with evidence generally supporting dynamic stretching to improve performance. However, the effects of these stretching practices on injury risk during subsequent volleyball manoeuvres have yet to be fully elucidated in the warm-up literature. Three-dimensional kinematic data associated with non-contact, lower extremity injury were recorded on 12 female collegiate club volleyball athletes during unilateral landing tasks on the dominant and non-dominant limb. Participants performed landings as part of a volleyball-simulated manoeuvre prior to and post-dynamic (DWU) and combined dynamic-static (CDS) warm-ups. A significant reduction in non-dominant hip adduction angle was found at 15 min post CDS warm-up (p = 0.016; d = 0.38), however, no other warm-up differences were detected. The non-dominant limb demonstrated greater knee abduction (p = 0.006; d = 0.69) and internal rotation angle (p = 0.004; d = 0...

 Football players can receive up to 1400 head impacts per season, averaging 6.3 impacts per practice and 14.3 impacts per game. A decrease in the capacity of a helmet to manage linear acceleration with multiple impacts could increase the risk of traumatic brain injury.  To investigate the ability of football helmets to manage linear acceleration with multiple high-energy impacts.  Descriptive laboratory study.  Laboratory.  We collected linear-acceleration data for 100 impacts at 6 locations on 4 helmets of different models currently used in football. Impacts 11 to 20 were compared with impacts 91 to 100 for each of the 6 locations.  Linear acceleration was greater after multiple impacts (91-100) than after the first few impacts (11-20) for the front, front boss, rear, and top locations. However, these differences are not clinically relevant as they do not affect the risk for head injury.  American football helmet performance deteriorated with multiple impacts, but this is unlikely ...

This study focuses on the analysis of a headband which is called the bandana. Takraw player often used a bandana on the head just for covering their hair and to sweep sweat. Unfortunately, the bandana is much more unprotected compared to headband because it does not have a material that can absorb an impact from the ball thus can cause a severe injury after several times of heading. It is shown that the understanding of the head impact with this bandana wearing by players in a game is imminent to the biomechanics knowledge. The objective of this study is to identify the most suitable material of bandana and fabricate a bandana based on the result of the experiment that has been conducted. This study involved with 2 types of experiment, which the first experiment conducted on the force plate in order to find the most suitable material for bandana among the 3 types of test material. For the second experiment conducted on the skull prototype in order to compare the parameters between b...

Auto insurers use a variety of techniques to control their losses, and one that has been widely employed since the mid-1990's is the Minor Impact Soft Tissue (MIST) segmentation strategy. MIST protocol dictates that all injury claims resulting from collisions producing US dollars 1000 or less in damage be "segmented", or adjusted for minimal compensation. Multiple databases were searched for studies comparing any of three dependent variables (injury risk, injury severity, or duration of symptoms) with structural damage in motor vehicle crashes of under 40 km/h (25 mph). A limited correlation between crash severity and injury claims was found. We could not determine, however, whether this relationship held across all crash severities. Other studies provided conflicting results with regard to acute injury risk, but both found no statistically significant correlation between crash severity and long-term outcome. A substantial number of injuries are reported in crashes of ...

Within the framework of the ShoQR project, Tim Gerbrands is interested in the analysis of human motion with acceleration sensors. In particular, the challenging problem is to infer the knee load during a patient walking. In this report, we investigate ways to extract meaningful information about human gait using the acceleration sensors. Our rst approach is applying frequency domain analysis techniques to the sensor measurements. Secondly, we propose a couple of mathematical models of the leg that captures the quality of the knee. Furthermore, we examine the capabilities of the sensors by performing new experiments. Fontys University of Applied Sciences, The Netherlands Delft University of Technology, The Netherlands Eindhoven University of Technology, The Netherlands Leiden University, The Netherlands University of Oxford, England Norwegian University of Science and Technology, Norway University of Auckland, New Zealand

Background: Prosthesis users perform various compensatory motions to accommodate for the loss of the hand and wrist as well as the reduced functionality of a prosthetic hand. Objectives: Investigate different compensation strategies that are performed by prosthesis users. Study design: Comparative analysis. Methods: A total of 20 able-bodied subjects and 4 prosthesis users performed a set of bimanual activities. Movements of the trunk and head were recorded using a motion capture system and a digital video recorder. Clinical motion angles were calculated to assess the compensatory motions made by the prosthesis users. The video recording also assisted in visually identifying the compensations. Results: Compensatory motions by the prosthesis users were evident in the tasks performed (slicing and stirring activities) as compared to the benchmark of able-bodied subjects. Compensations took the form of a measured increase in range of motion, an observed adoption of a new posture during ...

BackgroundCommon lower limb postures have been found when noncontact anterior cruciate ligament (ACL) injuries occur during sidestep cutting tasks. These same postures have been linked to knee loadings known to stress the ACL.HypothesisWhole body technique modification would reduce knee loading.Study DesignControlled laboratory study.MethodsExperienced team sport athletes were recruited for whole body sidestep cutting technique modification. Before and after a 6-week technique modification training, participants performed sidestep cutting tasks while ground-reaction force and motion data were collected. A kinematic and inverse dynamics model was used to calculate 3-dimensional knee loading during sidestep cutting.ResultsAt initial foot contact, the participants placed their stance foot closer to the body’s midline and held their torso more upright, in line with the aims of the technique modification training. This was accompanied by significantly lower peak valgus moments in the wei...

The football helmet is used to help mitigate the occurrence of impact-related traumatic (TBI) and minor traumatic brain injuries (mTBI) in the game of American football. While the current helmet design methodology may be adequate for reducing linear acceleration of the head and minimizing TBI, it however has had less effect in minimizing mTBI. The objectives of this study are (a) to develop and validate a coupled finite element (FE) model of a football helmet and the human body, and (b) to assess responses of different regions of the brain to two different impact conditions - frontal oblique and crown impact conditions. The FE helmet model was validated using experimental results of drop tests. Subsequently, the integrated helmet-human body FE model was used to assess the responses of different regions of the brain to impact loads. Strain-rate, strain, and stress measures in the corpus callosum, midbrain, and brain stem were assessed. Results show that maximum strain-rates of 27 and...

Kinetic models of human motion rely on boundary conditions which are defined by the interaction of the body with its environment. In the simplest case, this interaction is limited to the foot contact with the ground and is given by the so called ground reaction force (GRF). A major challenge in the reconstruction of GRF from kinematic data is the double support phase, referring to the state with multiple ground contacts. In this case, the GRF prediction is not well defined. In this work we present an approach to reconstruct and distribute vertical GRF (vGRF) to each foot separately, using only kinematic data. We propose the biomechanically inspired force shadow method (FSM) to obtain a unique solution for any contact phase, including double support, of an arbitrary motion. We create a kinematic based function, model an anatomical foot shape and mimic the effect of hip muscle activations. We compare our estimations with the measurements of a Zebris pressure plate and obtain correlati...

Altered movement patterns during single-leg movements in soccer increase the risk of lower-extremity non-contact injuries. The identification of biomechanical parameters associated with lower-extremity injuries can enrich knowledge of injury risks and facilitate injury prevention. Fifty-six elite youth soccer players performed a single-leg drop landing task and an unanticipated side-step cutting task. Three-dimensional ankle, knee and hip kinematic and kinetic data were obtained, and non-contact lower-extremity injuries were documented throughout the season. Risk profiling was assessed using a multivariate approach utilising a decision tree model (classification and regression tree method). The decision tree model indicated peak knee frontal plane angle, peak vertical ground reaction force, ankle frontal plane moment and knee transverse plane angle at initial contact (in this hierarchical order) for the single-leg landing task as important biomechanical parameters to discriminate be...

Parameters associated with the performance of countermovement jumps were identified from vertical ground reaction force recordings during fatigue and resting conditions. Fourteen variables were defined, dividing the vertical ground reaction force into negative and positive external working times and times in which the vertical ground reaction force values were lower and higher than the participant's body weight. We attempted to explain parameter variations by considering the relationship between the set of contractile and elastic components of the lower limbs. We determined that jumping performance is based on impulsion optimization and not on instantaneous ground reaction force value: the time in which the ground reaction force was lower than the body weight, and negative external work time was lower under fatigue. The results suggest that, during fatigue, there is less contribution from elastic energy and from overall active state. However, the participation of contractile ele...

OBJECTIVEdThe prevalence of gestational diabetes mellitus (GDM) is rising. There is little evidence to demonstrate the effectiveness of one dietary therapy over another. We aimed to investigate the effect of a low–glycemic index (LGI) versus a conventional high-fiber diet on pregnancy outcomes, neonatal anthropometry, and maternal metabolic profile in GDM. RESEARCHDESIGNANDMETHODSdNinety-nine women (age 26–42 years; mean6 SD prepregnancy BMI 24 6 5 kg/m2) diagnosed with GDM at 20–32 weeks ’ gestation were randomized to follow either an LGI (n = 50; target glycemic index [GI] ~50) or a high-fiber moderate-GI diet (HF) (n = 49; target GI ~60). Dietary intake was assessed by 3-day food records. Pregnancy outcomes were collected from medical records. RESULTSdThe LGI group achieved a modestly lower GI than the HF group (mean 6 SEM 476 1 vs. 536 1; P, 0.001). At birth, there was no significant difference in birth weight (LGI 3.36 0.1 kg vs. HF 3.36 0.1 kg; P = 0.619), birth weight centile...

Bayne et al. (201 6) recently established a direct link between lumbar injury incidence and increased 30 measures of thorax lateral flexion, pelvis rotation and hip extension during the cricket fast bowling action. However, the majority of bowlers are not able to avail themselves to 30 biomechanical analysis. Therefore, we set out to ascertain whether it is appropriate to use 20 measures to assess 3D lumbar injury risk factors in fast bowlers. Nineteen fast-medium bowlers were simultaneously recorded by 30 motion capture and 20 video. Results showed that 2D thorax lateral flexion and pelvis rotation at ball release correlate particularly well with the 3D equivalents. The information presented may be practically applied by coaches to improve field-based lumbar injury risk screening processes.

The anterior cruciate ligament (ACL) plays a key role in the stability of the knee joint restricting the rotation and anterior tibial translation. However, there is a lack of knowledge of the in vivo ACL mechanical behaviour during high impact manoeuvres. The motion of 12 young participants with healthy knees was captured while they performed the following activities: walking, running, cross-over cutting, sidestep cutting, jumping and jumping with one leg. The in vivo ACL length and strain were estimated using experimental kinematic data and three degree of freedom (DOF) knee model. The in vivo ACL tensile forces were determined with a well-established force/strain relationship obtained through ACL tensile tests. Statistical regression models between ACL length with respect to angles for each activity have been performed in order to better understand the ACL failure mechanisms. The maximum ACL tensile force was observed during jumping vertically at maximum effort with two legs (1.07...

This study aimed to analyse how planning time effects peak knee valgus (PKVM) and internal rotation (PKIRM) moments using real-time (RT) and above real-time (ART) gamelike video clips. Twelve male Australian rules football players completed a modified sidestepping (SS) movement assessment. PKVM and PKIRM were measured across the weight acceptance phase of planned (PSS) and four unplanned SS conditions, increasing in video playback speed (UP100, UP125, UP150, UP175). No significant differences were found for PKVM or PKIRM between any SS conditions, however, the coefficient of variation in PKVM increased as the temporal constraints of the unplanned tasks increase. This study suggests that while mean group differences in PKVM may not be obvious, increased trial to trial variability is evident as planning time decreases.

This study investigated the effect of maintaining perception-action coupling during a 4-week perceptual training program aiming to reduce biomechanical risk factors associated with ACL injury. Kinetic (valgus and internal rotation knee moments) and neuromuscular (total knee muscle activation and directed co-contraction ratios) variables were calculated during evasive sidestepping of 3D-projected opponents in 1-on-1, 2-on-2 and 3-on-3 game-based situations pre and post-intervention training. An additional transfer scenario was assessed post-intervention. Twenty-six amateur Australian Rules footballers were allocated to control (C), uncoupled (U) or coupled (PA) groups. Participants completed biweekly perceptual training containing 48 trials requiring a verbal (uncoupled) or running sidestep (coupled) response while counting the number of attentional cues displayed. Training groups showed no reductions in peak valgus and internal rotation moments, however, a small decrease in peak val...

INTRODUCTION Vertical jump is an exercise widely adopted to evaluate some motor characteristics of the athletes. Vertical component of the ground reaction force (VGRF) is often used to gain more information regarding efficiency and motor coordination of the lower limbs. The aim of this study is to evaluate vertical jump performances of subjects afflicted by ACL injury, by means of VGRF patterns. METHODS Ten healthy rugby players (HP) were the sample of this study, together with four subjects who present a ACL pathology (PP), due to a previous injury. At the time of the acquisition all the pathological subjects had been reintegrated in the team training and competitive programs. The subjects were asked to perform 20 two-legged vertical jumps, as high as possible, keeping one foot at a time over a Kistler force platform. Arms were behind their back, in order to minimize the contribution of the upper part of the body to the thrust of the legs. Ground reaction forces were recorded by me...

This diploma thesis analyses in how far currently used crash test dummies are realistic. The analysis primarily focuses on the Žilina Dummy and the Biofidelic Dummy, as those two are used by DEKRA for accident reconstructions. Nine crash tests with the Biofidelic Dummy were conducted by DEKRA and AXA Insurance in June 2018 in Wildhaus, Switzerland, while crash tests with the Žilina Dummy have been conducted in earlier years. Four of those crash tests were chosen for further analysis. The analysis of the dummy trajectories highlights that the Žilina Dummy behaves in an unrealistic way, while the Biofidelic Dummy's trajectory is comparable to those of cadavers. It is also shown that the vehicle damages produced by the Žilina Dummy are too severe, whereas the ones caused by the Biofidelic Dummy are more realistic. The C-ratios obtained with both dummies are good and they only deviate from each other slightly. The analysis of the throw distances further shows that both crash test du...

Introduction: Open simple diaphyseal tibial fracturesare common cases in every hospital and a variety of implants have been used for managing it. We study the results of unreamed solid interlocking nail as a primary treatment in such fractures. Material and Methods: 40 cases of open simple diaphyseal tibial fractureswere followed up for 1 year. All of these cases were treated by undreamed solid interlocking nail at Patna Medical College& Hospital, Patna. All the patients were classified by Gustilo Anderson classification and the primary surgery done by the above method. Coverage was done by plastic team in all demanding cases. At final follow up, outcomes were assessed by ModifiedKetenjian's Criteria and rated as excellent, good, fairand poor based on pain, knee/ankle stiffness, swelling /deformity and gait of patient. Results: We had more cases of male patients than females (82.5% vs. 17.5%) in the age group range of 20 to 46 years (Average 32.17). Road traffic accident was the...

The present work explores some critical aspects of the numerical modeling of a rotorcraft seat and subfloor equipped with energy-absorbing stages, which are paramount in crash landing conditions. To limit the vast complexity of the problem, a purely vertical impact is considered as a reference scenario for an assembly made of a crashworthy helicopter seat and a subfloor section, including an anthropomorphic dummy. A preliminary lumped mass model is used to drive the design of the experimental drop test. Some additional static and dynamic tests are carried out at the coupon and sub-component levels to characterize the seat cushion, the seat pan and the honeycomb elements that were introduced in the structure as energy absorbers. The subfloor section is designed and manufactured with a simplified technique, yet representative of this structural component. Eventually, a finite element model representing the full drop test was created and, together with the original lumped mass model, f...

Objective: Prophylactic ankle taping is considered as one of the most effective treatment strategy following inversion ankle sprains. In the last few decades, several studies have established that centre of pressure (COP) of the ankle and foot complex plays an important role in estimating abnormal mechanics following inversion ankle sprains. The main purpose of this study was to evaluate the effect of ankle taping on the centre of pressure (COP) of the ankle and foot complex at heel strike in participants with a history of inversion ankle sprain. Methods: In this study, secondary analysis of the data recorded from a well designed cohort study was conducted. The study participants were grouped as cases (n = 14) with a mean age of 26.9 (± 11.3) years and controls (n = 14) with a mean age of 34.9 (± 10.0) years. The cases represented the participants having functional ankle instability (FAI) following inversion ankle sprains and the controls represented non ankle sprain (NAS) participa...

Lower extremities are the most affected areas of injuries in indoor team handball, especially for female youth player. The mechanics of such injuries are well-known, however little is known about the influence of fatigue injury on risk factors. This study addresses fatigueinduced changes of movements that are associated lower extremity injuries in female youth handball players. Kinematics and kinetic data of 15 elite youth female team handball players were recorded for doubleand single-leg landings as well as sidecutting maneuvers before, in the middle of and after a simulated handball specific load protocol. The protocol consisted of exercises typical for handball match activity. RPE was used as measure of fatigability and showed values ranging from 13 to 18 at the end of the treatment. ANOVA revealed fatigue related changes in initial knee flexion angle of the non-dominant leg in all tasks. For the cutting task, significant changes of the initial knee angle of the dominant leg, th...

Altered movement patterns during single-leg movements in soccer increase the risk of lower-extremity non-contact injuries. The identification of biomechanical parameters associated with lower-extremity injuries can enrich knowledge of injury risks and facilitate injury prevention. Fifty-six elite youth soccer players performed a single-leg drop landing task and an unanticipated side-step cutting task. Three-dimensional ankle, knee and hip kinematic and kinetic data were obtained, and non-contact lower-extremity injuries were documented throughout the season. Risk profiling was assessed using a multivariate approach utilising a decision tree model (classification and regression tree method). The decision tree model indicated peak knee frontal plane angle, peak vertical ground reaction force, ankle frontal plane moment and knee transverse plane angle at initial contact (in this hierarchical order) for the single-leg landing task as important biomechanical parameters to discriminate be...

Inertial sensors (IS) enable the kinematic analysis of human motion with fewer logistical limitations than the silver standard optoelectronic motion capture (MOCAP) system. However, there are no data on the validity of IS for perturbation training and during the performance of dance. The aim of this present study was to determine the concurrent validity of IS in the analysis of kinematic data during slip and trip-like perturbations and during the performance of dance. Seven IS and the MOCAP system were simultaneously used to capture the reactive response and dance movements of fifteen healthy young participants (Age: 18–35 years). Bland Altman (BA) plots, root mean square errors (RMSE), Pearson’s correlation coefficients (R), and intraclass correlation coefficients (ICC) were used to compare kinematic variables of interest between the two systems for absolute equivalency and accuracy. Limits of agreements (LOA) of the BA plots ranged from −0.23 to 0.56 and −0.21 to 0.43 for slip and...

Muscle activation and movements performed during occupational work can lead to musculoskeletal disorders, one of the nursing profession's most significant health hazards. However, physical activity like exercise training tailored to the exposure and physical ability offers health prevention and rehabilitation. Professional nursing associations have advised squat training to promote occupational health because it strengthens lower limb and back muscles. Given that squatting is a fundamental part of many daily activities and various actions in caregiving processes, we hypothesized that chair squat performance is a potential predictor of nurses’ physical capabilities to perform occupational tasks. We conducted kinetic and electromyographic assessments of 289 chair squat repetitions and compared them to ergonomic patient transfer tasks. In this task, nurses transferred a supine patient to a lateral position in a care bed using similar movement characteristics of the squat task. This...