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Spinal dynamics during gait have been of interest in research for many decades. Based on respective previous investigations, the pelvis is generally expected to be maximally forward rotated on the side of the reference leg at the beginning of each gait cycle and to reach its maximum counterrotation approximately at the end of the reference leg's stance phase. The pelvic-upper-thoracic-spine coordination converges towards an anti-phase movement pattern in high velocities during ambulation. The vertebral bodies around the seventh thoracic vertebra are considered to be an area of transition during human ambulation where no or at least little rotary motion can be observed. The respective cranial and caudal vertebrae meanwhile are expected to rotate conversely around this spinal point of intersection. However, these previous assumptions are based on scarce existing research, whereby only isolated vertebrae have been analyzed contemporaneously. Due to huge methodological differences in data capturing approaches, the results are additionally hardly comparable to each other and involved measurement procedures are often not implementable in clinical routines. Furthermore, none of the above-mentioned methods provided reference data for spinal motion during gait based on an appropriate number of healthy participants. Hence, the aim of this study was to present such reference data for spinal rotary motion of every vertebral body from C7 down to L4 and the pelvis derived from surface topographic back shape analyses in a cohort of 201 healthy participants walking on a treadmill at a given walking speed of 5 km/h. Additionally, the spine's functional movement behavior during gait should be described in the transverse plane based on data derived from this noninvasive, clinically suitable measurement approach and, in conclusion, the results shall be compared against those of previous research findings derived from other measurement techniques. Contrary to the previous functional understanding, the area of the mid-thoracic spine was found to demonstrate the largest amplitude of rotary motion of all investigated vertebrae and revealed an approximately counterrotated movement behavior compared to the rotary motion of the pelvis. In both directions, spinal rotation during gait seemed to be initiated by the pelvis. The overlying vertebrae followed in succession in the sense of an ongoing movement. Therefore, the point of intersection was not statically located in a specific anatomical section of the spine. Instead, it was found to be dynamic, ascending from one vertebra to the next from caudal to cranial in dependence of the pelvis's rotation initiation.

Truck platoon driving technology uses vehicle-to-vehicle communication to allow one truck to follow another in an automated fashion. The first vehicle is operated manually, the second vehicle is dr...

Objective The aim of the study was to investigate (1) how different gap sizes are perceived by professional truck drivers under real traffic conditions and (2) whether semi-automated platoon driving leads to changes in driving behavior of subsequent manual driving. Background Platoon driving is a current branch in the development of automated driving in which two or more vehicles build a convoy. The lead vehicle is controlled manually while following vehicles are electronically coupled to it and drive semi-automated with small gaps in order to achieve a better traffic flow and potential fuel savings. Method In a real road experiment, 10 trained professional truck drivers completed a total of 33 test drives with a two-truck platoon on the German highway A9 with a gap size of either 15 or 21 m, in the leading and the following vehicle. Results (1) The drivers experienced both gap sizes as comfortable and preferred the smaller gap size of 15 m. (2) Both gap sizes led to significantly higher standard deviation of lane position in post- compared to pre-platoon driving. No significant difference in distance keepings in post- compared to pre-platoon driving occurred. Qualitative data give hints on difficulties, when switching back to regular truck driving. Conclusion The results implicate that small gap sizes are perceived as comfortable by drivers and that platoon driving has an influence on subsequent manual driving. Application Countermeasures to behavioral adaptations should be considered in order to ensure a safe conduction of platoon driving.

Previous studies on factors influencing decision making focused on the effects of additional cognitive load, stress, psychological disorders, and the process of aging. The potential effects of simu...

Bus driving maneuvers are likely to trigger perturbation forces that may cause postural instability in standing passengers and cause tumble. These noncollision incidents are considered a major cause of injuries and may induce passenger discomfort in public transport. Therefore, we analyzed the effects of acceleration and deceleration forces on older passengers in an upright standing position in everyday bus transport situations. We recorded ground reaction and handgrip forces, electromyographic data of the leg muscles, and the acceleration pattern of 8 elderly participants (68.1±5.2 years). The participants were exposed to acceleration and deceleration maneuvers while standing upright in three different positions: in the direction of travel (IT), against the direction of travel (AT), and sideways to the direction of travel (ST). The acceleration pattern of the bus was similar to everyday driving situations (starting and stopping in traffic). Ground reaction forces were higher in free-standing positions, as expected, with peak forces of 135% (ST) to 165% (AT) of individual body weight, than in standing position by grasping a strap, with peak forces of 120% (all conditions). However, when participants grasped the strap, peak forces comprised 65% (ST) to 90% (AT) of individual maximal pulling power. A passenger may experience these forces numerous times during a typical bus transport. Electromyographic analysis revealed a correlation between jerk events and muscle activation and coactivation of antagonistic muscles. This study presents, for the first time, relevant information with regard to the biomechanical demands of older passengers standing upright in bus transportation. On this basis, conceptual solutions may be introduced to improve passenger safety and comfort. Further research studies exploring the relationship between acceleration forces and travel safety of the elderly should be conducted.

Truck platoon driving is a current branch of automated driving, which has the potential to radically change the work routine of professional drivers. In a platoon system, one truck (semi-)automatically follows a lead truck with a reduced distance, which produces significant savings in fuel and enables better traffic flow. In a current application of truck platoon driving, the following vehicle operates at level-2 automation. Thus, the driver of the following truck merely has to supervise the semi-automated system, which takes over steering and speed control when engaged. Level-2 truck platoon driving had not been tested with professional drivers in real traffic before. We hypothesized that user acceptance would improve after the experience of platoon driving. Quantitative questionnaires and qualitative interviews were conducted with 10 drivers before and after an extensive Autobahn experience. The results show a clear increase of acceptance after the experience. Platoon driving was evaluated to be more useful, easier to use, and safer after the experience. Besides perceived driving safety, the prestige of truck platooning, the perceived usefulness of the system, and general technology affinity co-determined user acceptance.

It is well known that dual-tasking is adversely affected by physiological degenerative processes. Furthermore, the completion of a secondary task while walking is frequently discussed as a key contributor for falls in the elderly. Age-related differences in both activated neural structures and human behavior are indicated in numerous previous studies. Besides a general overview of dual-tasking and aging, this article reviews studies aiming at improving gait or postural control in older adults using dual- or multi-task interventions. Approximately, 130 parameters out of 17 illustrated studies presented significant changes after dual-task-specific interventions regarding gait, postural control/balance, and falls. On the one hand, the article at hand shows highly consistent results in all of the dual-task intervention studies analyzed, indicating significant improvements related to postural control, gait, falls, or the performance of a secondary task. On the other hand, the results represent a heterogeneous structure and a gap between theoretical aspects and practical use. To optimize the use of dual-task, a systematization of underlying tasks is inevitable and should be focused on in further research.