Three-dimensional Biomechanical Analysis Research Articles

The association between obesity, knee pain, and gait during stair descent in older adults with knee osteoarthritis

BackgroundObesity and knee osteoarthritis adversely affect activities of daily living in older adults. Together, the complexities of their interaction on mobility, including stair negotiation, are unresolved. The purpose of this study was to determine the relationship between obesity, pain, and stair negotiation in older adults with knee osteoarthritis. MethodsOlder adults with symptomatic knee osteoarthritis and overweight or obesity participated in the study (n = 28; age range = 57.0–78.0 yrs.; body mass index range = 26.6–42.8 kg•m−2). The Western Ontario and McMaster Universities Osteoarthritis Index pain subscale was used to measure knee pain. Measurements included a three-dimensional biomechanical analysis during descent on a set of force plate-instrumented stairs and a timed stair descent test. Pearson's r was used to determine associations between body mass index and pain, stair descent weight-acceptance phase vertical ground reaction force (vGRF) variables and lower extremity joint kinematics and kinetics, and timed stair descent performance. FindingsSignificant correlations existed between body mass index and pain (r = 0.41; p = 0.03), peak vGRF (r = 0.39; p = 0.04), vertical impulse (r = 0.49; p = 0.008), and peak ankle plantar flexor moments (r = 0.50; p = 0.007) in older adults with knee osteoarthritis. InterpretationGreater obesity in older adults with knee osteoarthritis was associated with greater knee pain and higher ankle joint loads during stair descent. These results support the recommendations of osteoarthritis treatment guidelines for weight-loss as a first-line of treatment for older adults with obesity and knee osteoarthritis.

Acute effects of footwear on running impact loading in the preschool years

ABSTRACT The aim of this study was to assess acute effects of footwear conditions (barefoot, minimalist and standard running shoes) on running impact loading in the preschool years. Fourty-eight habitually shod preschool children (26 males and 22 females) were divided into four age groups (3-, 4-, 5- and 6-year-old). Children performed a simple running game in three different conditions. Three-dimensional biomechanical analysis was carried out during overground running. Statistical parametric mapping was performed on the vertical ground reaction force profiles during the stance phase and one-way repeated measures ANOVA on the vertical instantaneous loading rate. Three-year-old children displayed significantly lower vertical ground reaction force values in the barefoot condition compared to minimalist (3-7% stance) and standard running shoes (7-11% stance). There were also differences in vertical instantaneous loading rate, where 3-year-olds had lower loading when barefoot than in minimalist (p = 0.010, d = 1.19) or running shoes (p = 0.045, d = 0.98), despite no differences in the footstrike pattern (mostly rearfoot-midfoot strike). No differences were found for the older children. Running in minimalist shoes did not imitate barefoot running in 3-year-old children. On the contrary, increased loading was observed in minimalist shoes in early running developmental stages.

A Three-Dimensional Biomechanical Analysis of the Skeleton in Adolescent Idiopathic Scoliosis

A Three-Dimensional Biomechanical Analysis of the Skeleton in Adolescent Idiopathic Scoliosis

Biomechanics of mini-implants: analysis of the adverse effects of four clinical situations and proposed resolutions

The biomechanical adverse effects generated by our treatments must be considered among the failures of mini-implants, certainly excellent means of anchorage. The aim of this article was to illustrate and comment on mechanical adverse effects and to propose solutions. Four common clinical situations in vestibular technique are analyzed, decomposed three-dimensionally and solved. Maxillary incisor intrusion in direct traction (mini-implant between lateral incisors and canines in direct anchorage) can lead to a disto-labial rotation of the supporting teeth and an incisor flaring. Maxillary incisivo-canine retraction (mini-implant between 5 and 6 in direct anchorage) leads to a canine rotation, a clockwise rotation of the occlusal plane and a version of the adjacent teeth. The maxillary molar two-steps distalization (mini-implant between 5 and 6 with metal ligation to the canine) causes a rotation of the adjacent to the spring teeth, an incisor flaring and a molar disto-version. The protraction of a mandibular molar (mini-implant between 3 and 4 in direct anchorage) causes a disto-labial rotation, a lingual torque and a mesio-version of the molar as well as an incisor flaring and a clockwise rotation of the occlusal plan. The compensation bends on the adjacent teeth, the choice of the location and the type of mini-implant, the use of a power arms to get closer to the center of resistance are among the means of resolution. If mini-implants anchorage allows a significant quantitative effect, adverse effects should be considered individually with a three-dimensional biomechanical analysis.

Effects of Orthotic Insoles on Gait Kinematics and Low-Back Pain in Patients with Mild Leg Length Discrepancy.

Mild leg length discrepancy increases biomechanical asymmetry during gait, which leads to low-back pain. Orthotic insoles with a directly integrated heel lift were used to reduce this asymmetry and thus the associated low-back pain. The aim of this study was to analyze the biomechanical adaptations of the locomotor apparatus during gait and the subjective pain ratings before and after the establishment of orthotic insole use. Eight patients with mild leg length discrepancy (≤2.0 cm) underwent three-dimensional biomechanical analysis while walking before and after 3 weeks of orthotic insole use. Low-back pain was assessed separately before both measurement sessions using a visual analog scale. Analysis of the kinematic parameters highlighted individual adaptations. The symmetry index of Dingwell indicated that orthotic insoles had no significant effect on the kinematic gait parameters and an unpredictable effect across patients. Orthotic insole use significantly and systematically (in all of the patients) reduced low-back pain (P < .05), which was correlated with changes in ankle kinematics (P = .02, r = 0.80). The effects of orthotic insoles on gait symmetry are unpredictable and specific to each patient's individual manner of biomechanical compensation. The reduction in low-back pain seems to be associated with the improved ankle kinematics during gait.

Establishment of three-dimensional finite element model and biomechanical analysis of normal metacarpophalangeal joint

Objective To establish a precise three-dimensional finite element model of the second to fifth metacarpophalangeal joints to simulate the stress distribution of the second to fifth metacarpal and phalangeal bones under different loads. Methods A healthy male volunteer was selected to perform 64-slice spiral CT scanning on his right hand. The data were extracted by Mimics 17.0 software. The second to fifth metacarpal and phalangeal bones and cartilage joint models were reconstructed. After the model was modified and assembled, it was imported into Hypermesh 13.0 software in iges format for meshing, and the BDF format file was derived. Finally, the data were put into the MSC. Patran/Nastran2012 software. Ten, twenty, thirty, forty and fifty Newton loads were applied along the longitudinal direction of phalanges to analyze the stress distribution of metacarpal and phalangeal bones. Results A high-precision three-dimensional finite element model of metacarpophalangeal joints was established, with a total of 40 070 nodes and 178 903 tetrahedral elements. The solid element meshes were used for metacarpal and phalangeal bones and cartilage joints. With the increase of load, the peak stress of metacarpal and phalangeal bones ranges from 0.64 to 8.65 MPa, and the overall stress of the fourth metacarpal and phalangeal bone was significantly higher than that of other metacarpal and phalangeal bones, of which the third metacarpal and phalangeal bone suffered the least stress. Conclusion The finite element model established by Mimics and MSC. Patran/Nastran software has higher accuracy and can better simulate the biomechanical properties of metacarpophalangeal joints, which can be used in biomechanical analysis experiments. Key words: Metacarpophalangeal joint; Finite element analysis; Stress; Three-dimensional reconstruction; Digital orthopaedics

Countermovement Jump and Isokinetic Dynamometry as Measures of Rehabilitation Status After Anterior Cruciate Ligament Reconstruction.

Despite an increase in the literature, few definitive guidelines are available to determine when an athlete has been fully rehabilitated after anterior cruciate ligament reconstruction (ACLR). To examine countermovement jump and isokinetic dynamometry measures to (1) identify which measures can best distinguish between ACLR and control participants and (2) provide normative values for identified measures in young adult male multidirectional field-sport athletes. Cross-sectional study. Orthopaedic hospital. Young adult male multidirectional field-sport athletes (n = 118) who had undergone unilateral patellar-tendon graft ACLR at least 6 months earlier and healthy male participants (n = 44) with no previous knee injury. Single-legged countermovement jump (SL CMJ). Three-dimensional biomechanical analysis of the SL CMJ and mean peak concentric knee-extension and -flexion torque using isokinetic dynamometry (ISO) were compared in the 2 groups. A stepwise logistic regression was carried out to identify the best predictors of ACLR- or control-group membership (SL CMJ height, limb symmetry index, peak power, joint power contribution, ISO peak torque, limb symmetry index variables). The control group differed strongly from the ACLR group in isokinetic knee-extension peak torque (d = -1.33), SL CMJ performance (d > 0.4), and limb symmetry measures in both ISO and jump outcomes (d > 1.1). The combination of measures from both ISO and SL CMJ identified group membership with an accuracy of 89%. Rehabilitation of ACLR patients may be complete when they achieve isokinetic knee-extension peak torque of 260% (±40%) body mass, SL CMJ performance of >17 cm (±4 cm), and reach-limb symmetry measures of >90% in both strength and jump outcomes. The outcomes in the control group can inform return-to-play criteria for young adult male multidirectional field-sport athletes after ACLR.

Clinical and biomechanical outcomes of rehabilitation targeting intersegmental control in athletic groin pain: prospective cohort of 205 patients

BackgroundClinical assessments and rehabilitation in athletic groin pain (AGP) have focused on specific anatomical structures and uniplanar impairments rather than whole body movement.ObjectiveTo examine the effectiveness of rehabilitation that targeted...

Three-Dimensional Biomechanical Analysis of Rearfoot and Forefoot Running.

Background:In the running community, a forefoot strike (FFS) pattern is increasingly preferred compared with a rearfoot strike (RFS) pattern. However, it has not been fully understood which strike pattern may better reduce adverse joint forces within the different joints of the lower extremity.Purpose:To analyze the 3-dimensional (3D) stress pattern in the ankle, knee, and hip joint in runners with either a FFS or RFS pattern.Study Design:Descriptive laboratory study.Methods:In 22 runners (11 habitual rearfoot strikers, 11 habitual forefoot strikers), RFS and FFS patterns were compared at 3.0 m/s (6.7 mph) on a treadmill with integrated force plates and a 3D motion capture analysis system. This combined analysis allowed characterization of the 3D biomechanical forces differentiated for the ankle, knee, and hip joint. The maximum peak force (MPF) and maximum loading rate (LR) were determined in their 3 ordinal components: vertical, anterior-posterior (AP), and medial-lateral (ML).Results:For both strike patterns, the vertical components of the MPF and LR were significantly greater than their AP or ML components. In the vertical axis, FFS was generally associated with a greater MPF but significantly lower LR in all 3 joints. The AP components of MPF and LR were significantly lower for FFS in the knee joint but significantly greater in the ankle and hip joints. The ML components of MPF and LR tended to be greater for FFS but mostly did not reach a level of significance.Conclusion:FFS and RFS were associated with different 3D stress patterns in the ankle, knee, and hip joint, although there was no global advantage of one strike pattern over the other. The multimodal individual assessment for the different anatomic regions demonstrated that FFS seems favorable for patients with unstable knee joints in the AP axis and RFS may be recommended for runners with unstable ankle joints.Clinical Relevance:Different strike patterns show different 3D stress in joints of the lower extremity. Due to either rehabilitation after injuries or training in running sports, rearfoot or forefoot running should be preferred to prevent further damage or injuries caused by inadequate biomechanical load. Runners with a history of knee joint injuries may benefit from FFS whereas RFS may be favorable for runners with a history of ankle joint injuries.

The Effects of External Jugular Compression Applied during High Intensity Power, Strength and Postural Control Tasks

Introduction Current strategies focused on mitigating concussion in sport have demonstrated limited effectiveness. There is a paucity of research on the optimization of intracranial brain dynamics to mitigate concussion; in the present study, we investigate a novel device that provides mild jugular vein compression and may provide adjunctive protection to protect the brain internally from concussive and sub-concussive impacts. The purpose of this study was to assess the tolerance and acceptance of this device in a population of normal, healthy adults undergoing exertion similar to that is experienced while participating in sports-related competition, while monitoring changes in their biomechanical, strength, power, and postural stability capabilities. Material and Methods A total 18 participants (8 females, 10 males) were tested and included in the final analysis. Laboratory data collection consisted of two separate testing sessions for all participants. During the first testing session, participants were tested while wearing either the mild jugular vein compression neck device or a sham arm device (Sham) that was worn on the upper arm and did not alter venous return; participants exchanged devices for the second session. Participants underwent a battery of physical and neurological tests that included three-dimensional (3-D) biomechanical analysis, dynamic postural control testing using a stabilometer, isokinetic strength testing using a dynamometer, and a maximum vertical jump test. Results Evaluation of vital biomechanics, postural control and dynamic stabilization, isokinetic strength, and power in this population showed no statistically significant effect of wearing a mild jugular vein compression neck device compared with a Sham armband. Conclusions The data evaluated in the current project indicate that the device is safe during high intensity and dynamic postural stabilization exercise and does not alter normal physical or neuromuscular capabilities during physical activity.

Athletic groin pain (part 2): a prospective cohort study on the biomechanical evaluation of change of direction identifies three clusters of movement patterns

BackgroundAthletic groin pain (AGP) is prevalent in sports involving repeated accelerations, decelerations, kicking and change-of-direction movements. Clinical and radiological examinations lack the ability to assess pathomechanics of AGP, but three-dimensional...

A Comparison of an Integrated Three-dimensional Biomechanical Analysis of High-speed Incline and Level Treadmill running in Elite Football Players

ABSTRACT Purpose Recent sprint training regimens have used high-speed incline treadmill running to provide enhanced loading of muscles responsible for increasing forward running speed. The purpose of this study was to determine the standard alterations in the lower-limb joint kinematics and gait parameters resulting from changes in treadmill slope during the use of the treadmill as a medical reference. Subjects The subjects of this study were 20 normal, healthy elite football players without any orthopedic, respiratory, or cardiovascular system problems. Materials and methods The running gait of subjects was analyzed using motion analysis system on an inclined treadmill with three running trials, each for 3 minutes. The gait was measured at incline of 0, 9, and 18%. The speed of the treadmill was fixed at 4.0 m/s in order to maintain a constant running speed. Results The subjects’ gait parameters were observed to change significantly between slopes of 0 and 18%. The results showed greater maximum knee flexion, ankle dorsiflexion, and total hip range of motion (ROM) in incline treadmill running compared to level running. Conclusion The results of this study can be put in as a predesigned rehabilitation program for sprint training on a treadmill, especially for treadmills with adjustable gradients. How to cite this article Singh A, Arvind DN, Sandhu JS. A Comparison of an Integrated Three-dimensional Biomechanical Analysis of High-speed Incline and Level Treadmill running in Elite Football Players. J Postgrad Med Edu Res 2016;50(4):185-189.

Three-dimensional finite element simulation and biomechanical analysis of mandible chin blast injury

Objective To simulate a finite element model for biomechanical analysis of mandible chin blast injury and analyze the mechanism of maxillofacial blast injury. Methods The three-dimensional element model of human mandible blast injury was established to simulate the dynamic process of injury to the mandible chin. Von Mises stress and effective strain were evaluated in biomechanical study of the simulation results. Results The dynamic damage process of human mandible chin blast injury was simulated successfully. In the condition of 1 000 mg and 3 cm, the Von Mises stress and effective were maximum at condylar neck region (9.1×106 Pa, 0.62×10-3e), were second at mandibular angle region (6.1×106 Pa, 0.42×10-3e), and minimum at mental foramen region (6.1×106 Pa, 0.39×10-3e). Blast distance rather than blast equivalent produced more effect on the mechanical parameters and damage degree. Conclusions Von Mises stress and effective strain can be applied to the evaluation of bone tissue damage. The finite element method is effective in simulating mandible blast injury and can provide a new thought and approach to clinical treatment of oral and maxillofacial blast injury. Key words: Mandibular injuries; Finite element analysis; Biomechanics

Integrating biomechanical and motor control principles in elite high jumpers: A transdisciplinary approach to enhancing sport performance

BackgroundIn recent years, there has been a proliferation of technology and sport science utilized within an athlete's training, especially at the elite level. However, the sport science is a broad field, encompassing disciplines such as biomechanics, motor control and learning, exercise physiology, sports medicine, sport psychology to name a few. Rarely are these disciplines applied in an integrated manner. The purpose of this study was to document the effectiveness of an integrated biomechanics and motor control protocol for improving athlete's performance in the high jump. MethodsFour elite high jumpers performed baseline jumps under normal conditions and then jumps using a specific external focus of attention cue designed to improve their running posture. Three-dimensional biomechanical analysis was used to quantify the upright posture throughout the approach as well as horizontal velocity at plant and vertical velocity at takeoff. ResultsThe results showed that when using the external focus of attention cue, the jumpers were significantly more upright during the approach, had significantly higher horizontal velocities at plant, and generated significantly greater vertical velocities during the takeoff. ConclusionThe results of this study lay the foundation for future work examining how integrating sport science disciplines can improve performance of elite level athletes.

Efecto del ejercicio acuático sobre la cinemática del patrón de marcha en pacientes con enfermedad de Parkinson: un estudio piloto

AIM. To determine the effects of an aquatic-based physical exercise program on gait parameters of patients with Parkinson's disease (PD). PATIENTS AND METHODS. A total of nine patients diagnosed with idiopathic PD (stages I-III according to the Hoehn and Yahr scale) carried out an aquatic physical exercise program which lasted for five months, with one session per week. A three-dimensional biomechanical analysis was used to determine the effects of the program on several kinematic variables (walking speed, cadence, stride length, step time, single and double support time, angles of the hip, knee and ankle joints) which were assessed by a treadmill-walking test. RESULTS. At the end of the program, significant improvement in walking speed, stride length and on the relationship between single and double support time (p < 0,05). Although improvements in all tested ranges of motion were obtained, these did not reach statistical significance. CONCLUSIONS. Aquatic-based physical exercise seems to have positive effects in some aspects of the gait kinematics parameters present in the typical gait pattern of patients with PD.

The relationships between muscle strength, biomechanical functional moments and health-related quality of life in non-elite older adults

to investigate the association between muscle strength, biomechanical functional moments during everyday tasks and health-related quality of life (HRQoL) in older adults. eighty-four healthy adults aged 60-88 years were tested. A torque dynamometer was utilised to measure muscle moments at the knee and hip joints. Functional assessment involved three-dimensional biomechanical analysis of gait, chair rise and sit-down, stair ascent and descent using an 8-camera VICON® system with Kistler force plates. HRQoL was assessed using the Short Form-36 (SF-36) questionnaire. Spearman's correlation coefficient showed significant correlation (P<0.001) between isometric strength and functional moments (r=0.24-0.67). Muscle strength was significantly correlated with SF-36 scores, including physical functioning, bodily pain, vitality, social functioning and role emotional scores. Knee flexion moment was correlated with role physical, vitality, social functioning, role emotional, mental health and mental component scores (r=0.24-0.40). loss of muscle strength is associated with poorer functional ability and both are associated with reduced HRQoL. The reduction in HRQoL is considerable in the physical functioning domain. Cause and effect was not established but studies need to be undertaken to evaluate the benefits of strength training, functional activity training or increased participation in life.

Impact of Resistance Training on Balance and Gait in Multiple Sclerosis

Multiple sclerosis (MS) is an incurable neurodegenerative disease whose symptoms are only partially relieved by pharmaceutical intervention. Disability due to this disease process can impede activities of daily living and decrease quality of life, both for MS patients and for their care partners and families. A nonrandomized, nonblinded prospective cohort study of 45 patients with MS was undertaken to investigate the impact of an exercise program emphasizing resistance training on balance and gait. This article presents data for the first 33 participants to complete the study protocol. The exercise program consisted of twice-weekly 50-minute sessions for 6 months. At 3 months and 6 months, statistically significant improvements (P &amp;lt; .05) from baseline were observed for the following measures: Nine-Hole Peg Test, 2- and 3-second Paced Auditory Serial Addition Test, Modified Fatigue Impact Scale, NeuroCom Balance Master (NeuroCom International, Inc, Clackamas, OR), Timed Up and Go test, and Berg Balance Scale. Three-dimensional biomechanical gait analysis showed increased knee power generation during midstance and increased hip power generation during terminal stance. To determine whether individuals with varying levels of disability responded to exercise in a similar fashion, participants were divided into two subgroups based on Expanded Disability Status Scale score: little or no disability (EDSS score 1.0–4.0) and mild-to-moderate disability (EDSS score 4.5–6.5). No statistically significant differences in results were found. The results of this study indicate that participation in a resistance training program improves MS patients' ability to walk and to generate muscular forces during locomotion.

재활운동에 참가한 뇌졸중 환자들의 걷기형태 비교 연구

뇌졸중 환 6명을 대상으로 발병후 3개월 지난 시기에 1차 실험을 실시하였고, 6개월 지난 시기에 2차 실험을 하여 뇌졸중환자들을 대상으로 운동학적변인, 각운동학적변인 그리고 지면반력과 발바닥의 압력분포를 알아보았다. 운동학적변인의 결과 통계적으로 유의한 차이는 나타나지 않았으나 6개월간 꾸준히 재활운동에 참가한 환자는 3개월 때 보다 훨씬 보폭(step length)이 크게 나타났으며(11.18 cm, 12.25 cm, p=0.58), 보폭의 빈도(step time) 또한 빠르게 나타났다(1.20 sec, 1.18 sec, p=0.53). 환측의 발만 지지면에 닿아 있는 시간(single support time)의 연구에서는 재활운동에 꾸준히 참가한 환자가 발을 지면으로부터 빨리 떼는 것으로 나타났다(34.97%, 29.02%, p=0.74). 환측다리 움직임의 빠르기를 나타내는 변인(cadence)에서는 1분당 움직임의 회수가 6개월 운동에 참가한 사람의 보폭회수가 3개월 운동에 참가한 사람의 보폭회수 보다 훨씬 빠르게 나타났다(21.04 step/min, 28.89 step/min, 0.27). 각 운동학변인에서는 통계적으로 모든 변인에서 유의한 차이는 나타나지 않았으나 평균의 비교에서 꾸준하게 6개월 동안 재활운동에 참가한 환자는 발목관절, 무릎관절 그리고 엉덩관절 모두의 가동범위가 크게 나타났다. 걷기동작에서 상해의 원인이되는 최초 접촉 순간의 충격력(impact force)의 비교에서는 6개월간 꾸준히 재활운동에 참가한 환자는 충격력이 작게 나타났다(1.20 N/kg, 1.13 N/kg, p=0.45). 전방으로의 추진력(anterior propulsion force)과 후방으로의 감속력(posterior braking force)은 통계적으로 유의한 차이(p=0.28, p=0.39)를 나타내지 않았으나 재활운동에 꾸준히 참가한 환자들은 전후방의 힘(0.10 N/kg, 0.15 N/kg; -0.12 N/kg, -0.18 N/kg)이 좋아지는 것을 볼 수 있었다. 걷기 동작 시 환측발의 최대 압력분포값은 통계적으로 유의한 차이(p=0.24)는 없었으나 6개월 재활훈련참가자(15.51 N/<TEX>$cm^2$</TEX>)가 3개월 재활훈련참가자(13.99 N/<TEX>$cm^2$</TEX>) 보다 지면을 더욱 가볍게 밟고 지나가는 것으로 나타났다. 위의 연구결과들을 바탕으로 볼 때 뇌졸중 환자들은 꾸준하게 재활운동에 참가하여야 하며 주위 사람들의 관심이 항상 필요하다고 사료된다. The purpose of this study was to analyse the gait characteristics of stroke patients walking on a Zebris system, through quantitative three-dimensional biomechanical analysis. They underwent a continuous rehabilitation training program (RTP). A comparison was made between 3 month and 6 month RTP participants. Their ages were between 60 and 65. The data were analyzed by t-test. The result of comparative analysis of the two groups can be summarized as below. Temporal-spatial data, sagittal plane angular kinematics data, and peak ground reaction force and max pressure data showed that there were no significant differences between the 3 month RTP group and the 6month RTP group (Table 2, Table3, Table 4). It can be suggested that patients with hemiplegia after stroke can improve their walking function through continuous RTP participation.

Effects of educational intervention on joint angles of the trunk and lower extremity and on muscle activities during patient-handling tasks

The objective of this study was to examine the effects of educational intervention on joint angles of the trunk and lower extremity and on muscle activities during patient-handling task. Thirty-two subjects (17 males and 15 females) volunteered for the study. They were classified into three groups: intervention group 1, comprised of first grade physical therapist students; control group, which included first grade occupational therapist students; intervention group 2, which comprised third grade physical therapist students. The educational intervention during the experimental period consisted of: (1) 12 regular classes and short-term clinical practice for the students of intervention group 1; (2) long-term clinical practice, relating to patient-handling task, for the students of intervention group 2. The following experiments were repeated before and after the educational intervention. Each subject was asked to transfer a male (55 kg) from one chair to a second chair (left to right) and then back again to the original chair (right to left). The flexion angles of the trunk, hip and knee joints were quantified by means of the dynamic three-dimensional biomechanical analysis. Muscle activities (% maximum voluntary contraction, %MVC) of biceps brachii, trapezius, rectus femoris and erector spinae muscles were measured using surface electromyography (EMG). The effects of group, gender, measurement time and side on joint angles of trunk and lower extremity, %MVC of four muscle activities and transfer time were assessed. Although the EMG analysis could not clearly demonstrate any reduction of physical load to the low back, the flexion angles of the hip and knee joints of student subjects during the patient-handling task became larger and that of the trunk became smaller in the group given the educational intervention. The finding of this study suggests that the posture of the study subjects changed to the squat lifting method, which is preferable for reducing the physical load to the lower back, as a result of the educational intervention.

Why it is difficult to detect an illegally bowled cricket delivery with either the naked eye or usual two-dimensional video analysis

ObjectiveIn this study, the influence of various anatomical and biomechanical factors on the ability to detect the magnitude of elbow extension during the cricket bowling action, with either the naked...