Firefighter motion capture data set and biomechanical analysis of task-specific gear effects and loading asymmetries

Movement and loading asymmetry are associated with an increased risk of musculoskeletal injury, disease progression, and suboptimal recovery. Osteopathic structural screening can be utilized to determine areas of somatic dysfunction that could contribute to movement and loading asymmetry. Osteopathic manipulation treatments (OMTs) targeting identified somatic dysfunctions can correct structural asymmetries and malalignment, restoring the ability for proper compensation of stresses throughout the body. Little is currently known about the ability for OMTs to reduce gait asymmetries, thereby reducing the risk of injury, accelerated disease progression, and suboptimal recovery. To demonstrate whether osteopathic screening and treatment could alter movement and loading asymmetry during treadmill walking. Forty-two healthy adults (20 males, 22 females) between the ages of 18 and 35 were recruited for this prospective intervention. Standardized osteopathic screening exams were completed by a single physician for each participant, and osteopathic manipulation was performed targeting somatic dysfunctions identified in the screening exam. Three-dimensional (3-D) biomechanical assessments, including the collection of motion capture and force plate data, were performed prior to and following osteopathic manipulation to quantify gait mechanics. Motion capture and loading data were processed utilizing Qualisys Track Manager and Visual 3D software, respectively. Asymmetry in the following temporal, kinetic, and kinematic measures was quantified utilizing a limb symmetry index (LSI): peak vertical ground reaction force, the impulse of the vertical ground reaction force, peak knee flexion angle, step length, stride length, and stance time. A 2-way repeated-measures analysis of variance model was utilized to evaluate the effectsof time (pre/post manipulation) and sex (male/female) on each measure of gait asymmetry. Gait asymmetry in the peak vertical ground reaction force (-0.6%, p=0.025) and the impulse of the vertical ground reaction force (-0.3%, p=0.026) was reduced in males following osteopathic manipulation. There was no difference in gait asymmetry between time points in females. Osteopathic manipulation did not impact asymmetry in peak knee flexion angle, step length, stride length, or stance time. Among the participants, 59.5% (25) followed the common compensatory pattern, whereas 40.5% (17) followed the uncommon compensatory pattern. One third (33.3%, 14) of the participants showed decompensation at the occipitoatlantal (OA) junction, whereas 26.2% (11), one third (33.3%, 14), and 26.2% (11) showed decompensation at the cervicothoracic (CT), thoracolumbar (TL), and lumbosacral (LS) junctions, respectively. Somatic dysfunction at the sacrum, L5, right innominate, and left innominate occurred in 88.1% (37), 69.0% (29), 97.6% (41), and 97.6% (41) of the participants, respectively. Correcting somatic dysfunction can influence gait asymmetry in males; the sex-specificity of the observed effects of osteopathic manipulation on gait asymmetry is worthy of further investigation. Osteopathic structural examinations and treatment of somatic dysfunctions may improve gait symmetry even in asymptomatic individuals. These findings encourage larger-scale investigations on the use of OMT to optimize gait, prevent injury and the progression of disease, and aid in recovery after surgery.

Reliability quantification and gait loading asymmetry assessment with wearable insoles in transfemoral amputees

PurposeTo determine the effects of asymmetric loads on muscle activity with the bench press.MethodSeventeen resistance-trained men performed one familiarization session including testing one repetition maximum (1RM) and three 5 repetition maximum (RM) lifts; using symmetric loads, 5% asymmetric loads, and 10% asymmetric loads. The asymmetric loading (i.e., reduced load on one side) was calculated as 5% and 10% of the subject`s 1RM load. In the experimental session, the three conditions of 5RM were conducted with electromyographic activity from the pectoralis major, triceps brachii, biceps brachii, anterior deltoid, posterior deltoid, and external oblique on both sides of the body.ResultsOn the loaded side, asymmetric loads reduced triceps brachii activation compared to symmetric loads, whereas the other muscles demonstrated similar muscle activity between the three conditions. On the de-loaded side, 10% asymmetry in loading resulted in lower pectoralis major, anterior deltoid, and biceps brachii activation compared to 5% asymmetric and symmetric loading. On the de-loaded side, only pectoralis major demonstrated lower muscle activation than symmetric loads. Furthermore, asymmetric loads increased external oblique activation on both sides compared to symmetric loads.ConclusionsAsymmetric bench press loads reduced chest and shoulder muscle activity on the de-loaded side while maintaining the muscle activity for the loaded side. The authors recommend resistance-trained participants struggling with strength imbalances between sides, or activities require asymmetric force generation (i.e., alpine skiing or martial arts), to implement asymmetric training as a supplement to the traditional resistance training.

Vestibular, visual, and proprioceptive influences on muscle activity correcting for backwards body tilt were investigated in normals and patients with bilateral peripheral vestibular deficits. Body tilt was induced by a dorsi-flexion rotation of the feet about the ankle joints while the subject stood on a force measuring platform. Ankle muscle activity and torque were monitored as upright stance was reestablished, and correlated with head angular accelerations and neck muscle activity. In normals with eyes closed, soleus stretch reflex activity at 50-80 ms was followed by two bursts of tibialis anterior (TA) EMG activity at ca 80 and 125 ms from the onset of 36 deg/s, 3 deg amplitude platform rotations. Neck muscle activity rotated the head backwards at the same time as TA activity rotated the body forwards about the ankle joints. Under the influence of vision, i.e. eyes open, slight increases in the second burst of TA activity, and ankle torque were observed. When the subjects sat, and were instructed to activate TA rapidly on onset of the platform movement, TA EMG activity increased gradually at ca. 150 ms and not as a burst. In patients with long-lasting bilateral vestibular deficits, both bursts of TA activity were significantly less than normal with eyes closed. Consequently sway correcting torques were abnormally low and all but one of the patients fell over backwards. With eyes open, TA activity was slightly less than, and ankle torques were approximately equal to normal values. In contrast to normals, TA responses obtained in standing and sitting positions were not significantly different. Neck EMG activity varied from normal, consisting of a long burst 100 ms in duration. The present data indicate that a coordinated pattern of ankle, and neck muscle activity occurs during the first 150 ms following induced backward tilt. Ankle muscle activity corrects for the body sway, and neck muscle activity attempts to stabilise the head with respect to earth fixed coordinates. It is proposed that the vestibulo-spinal reflex system predominantly underlies the genesis and coordination of this muscle activity.

Simulation-based biomechanical assessment of a passive back support exoskeleton: Comparison of various support levels during a sustained forward bending task.

Calibrationless monocular vision musculoskeletal simulation during gait

Amputee gait is known to be asymmetrical, especially during loading of the lower limb. Monitoring asymmetry could be useful in quantifying patient performance during rehabilitation. Wearable insoles can provide normal ground reaction force asymmetry in real-life conditions. To characterize the validity of Loadsol® insoles versus force plates in quantifying normal ground reaction force and gait asymmetry. To determine the influence walking speed has on loading asymmetry in transfemoral amputees. This is a prospective study. Six transfemoral amputees, wearing Loadsol® insoles, walked at three self-selected speeds on force plates. Validity was assessed by comparing normal ground reaction force data from the insoles and force plates. The Absolute Symmetry Index was used to calculate gait loading asymmetry at each speed. Normalized root mean square errors for the normal ground reaction forces were 6.6% (standard deviation = 2.3%) and 8.9% (standard deviation = 3.8%); correlation coefficients were 0.91 and 0.95 for the prosthetic and intact limb, respectively. The mean error for Absolute Symmetry Index parameters ranged from -2.67% to 4.35%. Loading asymmetry increased with walking speed. This study quantified the validity of Loadsol® insoles in assessing loading asymmetry during gait in transfemoral amputees. The calibration protocol could be improved to better integrate it into a clinical setting. However, our results support the relevance of using such insoles during the clinical follow-up of transfemoral amputees. This is the first study to validate Loadsol® insoles versus force plates and report on loading asymmetry during gait at three different speeds in transfemoral amputees. Loadsol® insoles, which provide visual and audio feedback, are clinically easy to use and could have beneficial application in the amputee's rehabilitation and follow-up.

This study evaluated the effects of target sizes on biomechanical and cognitive load and the performance of virtual reality (VR) interactions. In a repeated-measures laboratory study, each of the twenty participants performed standardised VR tasks with three different target sizes: small, medium, and large. During the VR tasks, biomechanical load in the neck and shoulders (joint angles, joint moments, and muscle activity), cognitive load (perceived workload and cognitive stress), and task performance (completion time) were collected. The neck and shoulder joint angles, joint moments, and muscle activities were greater with the large targets compared to the medium and small targets. Moreover, the larger VR targets caused greater temporal demand and longer task completion time compared to the other target sizes. These findings indicate that target sizes in VR interfaces play important roles in biomechanical and cognitive load as well as task performance.

Following an engine failure, a turbojet multi-engine aircraft experiences the yawing moment generated by the thrust asymmetry, whereas a wing-mounted turboprop airplane will also face a significant rolling moment due to aerodynamic wing loading asymmetry. The one-engine-inoperative (OEI) condition of a propeller-driven multi-engine aircraft, critical for directional control, may also be critical to the lateral control concept definition. Therefore, in early design phases, the wing loading asymmetry evaluation is mandatory to properly assess the OEI condition and its possible impact on lateral control sizing. The proposed work aims at modeling the lateral aerodynamic asymmetry in OEI using a modified lifting-line theory coupled with an independent propeller model that provides the slipstream induced velocities in the wing. The result obtained using the methodology was compared with wind tunnel data to validate that the low-fidelity formulation captures satisfactorily the lateral aerodynamic asymmetry phenomenon in OEI. The analysis of the wing aerodynamic loading asymmetry also provided physical insights in order to identify the dominant contribution regarding the propeller slipstream components. Finally, a straightforward calculation was performed for a conventional turboprop aircraft in OEI and the lateral aerodynamic asymmetry was compared with typical aileron rolling moment coefficient to address the possible impact on lateral control sizing. The proposed modeling provided sufficient information to initially address the lateral control sizing of turboprop multi-engine aircraft without requiring detailed information about airfoil and propeller geometry.

Visual gait analysis pocket-sized tool for rehabilitation of lower limb amputees

Most machines utilize mechanical couplings between the drive and load. A common malfunction that happens after load unbalance in rotating machines is the shaft misalignment, which might be because of incorrect assembling of machine, thermal distortion together with asymmetry in load. However, during assembly, care must be taken to keep it inside a tolerable limit. The alignment condition of the machines varies because of the asymmetry in loads, thermal distortion, unequal foundation settlement, and various other static loading. It leads to the development of reactive forces in the coupling and often a major cause of vibration and brings about poor efficiency of the rotating machines, which in turn culminates to failure. It will be helpful during diagnosis to have a meticulous study about the vibration characteristics on misalignments. To study the misaligned rotors dynamics, a set up is modelled and constructed. An investigation is carried out to study the effect of provoked misalignments and also steady-state vibration reaction on integer fraction of the initial bending Natural Frequency (NF). Additionally, the effects on Parallel Misalignments (PM), Angular Misalignments (AM), and combination of AM and PM both are analysed.KeywordsMisalignmentNatural frequencyFFT analyzerFlexible coupling

In women’s artistic gymnastics, the balance beam belongs among the disciplines with the heaviest lower limbs load. The aim of our research was to disclose a lower limbs weekly load volume regarding load asymmetry, and to determine the take-off and landing reaction forces between landing ground and foot in selected gymnastic elements. In 9 female artistic gymnasts of junior and senior category one training week was video-recorded and analysed. The reaction forces were measured using 5 Bertec force plates in one female Czech nation-al team member. Based on the training video recordings 12 jump and acrobatic elements were analysed. Among the total of 422 recorded take-offs and landings 41% were performed from both legs, (BL), 44.5% from one lower limb (HL) and 14.5% from the other lower limb (LL). The maximum reaction force of the landing ground during take-offs was 2.4 BW in av-erage, 3.1 BW in landings. In asymmetrical elements, one leg was loaded three times more (538.3 BW) than the other (174.1 BW) in one training day in total. We recommend to record the load asymmetry in the course of the gymnastic trainings in order to choose and person-alise the appropriate regeneration process and compensational exercise.

Measurement and biomechanical analysis of human movement are important in diverse fields, such as rehabilitation, sports science, ergonomics, and human-robot interaction. However, the accessibility of conventional motion analysis systems - typically based on optical motion capture (Mocap) and force plates - is limited by their high cost and spatial constraints. Recent studies have increasingly exploited the application of wearable sensors, such as inertial measurement units (IMUs) and pressure insoles, to assess human movements. However, the integration of multiple sensor types for estimating internal biomechanical parameters, such as joint torques and muscle activations, remains underdeveloped and insufficiently validated. In this study, we combined wearable sensors with musculoskeletal simulation to enhance a full-chain biomechanical analysis of human movement. Data were simultaneously collected from an integrated wearable sensor system including IMUs and pressure insoles and a laboratory-based Mocap system on five able-bodied participants performing three daily movements: walking, squat and sit-to-stand. Joint angles, joint torques, and muscle activations were estimated with musculoskeletal simulation framework OpenSim. The results demonstrated that the wearable system could provide a sufficiently accurate biomechanical analysis, particularly in sagittal plane joint angles and ankle joint torque. However, the lack of shear force measurement from pressure insoles limited the accuracy in the knee and hip joint estimation. The estimated muscle activation from static optimization showed a similar on-off trend as measured EMG data. These findings highlighted the potential of wearable sensor-based motion analysis as a viable alternative to the conventional lab-based systems, particularly for out-of-lab applications.

An optimization model of tractor clutch pedal design parameters based on lower limb biomechanical characteristics

Kinematic, kinetic and EMG patterns during downward squatting