The relative contribution of arm stroke and leg kicking to maximal fully tethered front crawl swimming performance remains to be solved. Twenty-three national level young swimmers (12 male and 11 female) randomly performed 3 bouts of 30 s fully tethered swimming (using the whole body, only the arm stroke, and only the leg kicking). A load-cell system permitted the continuous measurement of the exerted forces, and swimming velocity was calculated from the time taken to complete a 50 m front crawl swim. As expected, with no restrictions swimmers were able to exert higher forces than that using only their arm stroke or leg kicking. Estimated relative contributions of arm stroke and leg kicking were 70.3% versus 29.7% for males and 66.6% versus 33.4% for females, with 15.6% and 13.1% force deficits, respectively. To obtain higher velocities, male swimmers are highly dependent on the maximum forces they can exert with the arm stroke (r = 0.77, P < 0.01), whereas female swimmers swimming velocity is more related to whole-body mean forces (r = 0.81, P < 0.01). The obtained results point that leg kicking plays an important role over short duration high intensity bouts and that the used methodology may be useful to identify strength and/or coordination flaws.

This study aimed at quantifying upper limb kinetic asymmetries in maximal front crawl swimming and to examine if these asymmetries would affect the contribution of force exertion to swimming performance. Eighteen high level male swimmers with unilateral breathing patterns and sprint or middle distance specialists, volunteered as participants. A load-cell was used to quantify the forces exerted in water by completing a 30s maximal front crawl tethered swimming test and a maximal 50 m free swimming was considered as a performance criterion. Individual force-time curves were obtained to calculate the mean and maximum forces per cycle, for each upper limb. Following, symmetry index was estimated and breathing laterality identified by questionnaire. Lastly, the pattern of asymmetries along the test was estimated for each upper limb using linear regression of peak forces per cycle. Asymmetrical force exertion was observed in the majority of the swimmers (66.7%), with a total correspondence of breathing laterality opposite to the side of the force asymmetry. Forces exerted by the dominant upper limb presented a higher decrease than from the non-dominant. Very strong associations were found between exerted forces and swimming performance, when controlling the isolated effect of symmetry index. Results point that force asymmetries occur in the majority of the swimmers, and that these asymmetries are most evident in the first cycles of a maximum bout. Symmetry index stood up as an influencing factor on the contribution of tethered forces over swimming performance. Thus, to some extent, a certain degree of asymmetry is not critical for short swimming performance.

The biomechanical adaptations in front crawl and backstroke swimming, as influenced by the implementation of a concurrent teaching programme were analysed. Sixteen participants (19.75 ± 1.13 years) underwent a 30 weeks intervention characterized by an increasing complexity to accomplish motor skills in the following order: (i) lower limbs propulsion; (ii) lower limbs propulsion synchronized with breathing cycle; (iii) lower limbs propulsion synchronized with one upper limb action; (iv) lower limbs propulsion synchronized with both breathing cycle and one upper limb action; (v) full swimming stroke; (vi) motor trajectory of the arms stroke. Performance and biomechanics were measured at front crawl and backstroke during three time points throughout the programme. There were improvements in performance over time at front crawl (21.49 s to 19.99 s, p<0.01) and backstroke (27.15 s to 24.60 s, p = 0.01). Significant improvements were found for velocity at front crawl (1.13 m/s to 1.22 m/s, p<0.01) and backstroke (0.92 m/s to 1.00 m/s, p<0.01). Stroke frequency increased at backstroke (0.64 to 0.73 Hz, p = 0.01), while the intra-cyclic variation of the velocity decreased at front crawl (0.13 to 0.12%, p = 0.02). There was also a moderate-high inter-subject variability in response to the programme. These findings prove that a programme of 30 weeks teaching concurrently front crawl and backstroke is effective to promote similar biomechanical adaptations in low-tier swimmers. However, each subject shows an individual response to better adapt the biomechanical actions and to reach a higher level of expertise.

The relationship between myoelectric signal amplitude and muscle strength (EMG-force) has been used as an indirect measure of muscle strength. The aim of this study, in 18 healthy, female, right-handed volunteers, was to assess the influence of arm position on the relationship EMG-force of arm muscles in three different tasks: arm flexion, arm abduction, and neutral arm position. Both myoelectric signals and strength measures were acquired simultaneously, by coupling a load-cell to the electromyograph transducer. Signals from the biceps brachii, braquioradialis, and triceps brachii muscles were analysed, and arm extension and flexion force was estimated. Relationships between these values were statistically analysed, searching for a correlation between myoelectric signal amplitude and muscle strength. Results showed no such correlation could be found during any of the tasks. Arm position did not influence EMG-force of the assessed muscles, to the exception of the triceps brachii muscle, which showed greater activity in the neutral arm task as compared to the other tasks. In isometric contractions, the tasks may be used to activate biceps brachii and braquioradialis; neutral arm position is indicated to activate the triceps brachii muscle.

The purpose of the study was to analyse the effects of a short-term, high-intensity inspiratory muscle training (IMT) on healthy youth maximal respiratory pressures, with and without arm bracing postures. Thirty young women were randomly assigned to three groups: control group (CG); group training with no arm bracing (NAB); and group training with arm bracing (AB). The IMT consisted of three 10-minute daily supervised sessions for three consecutive days. Before, at the end, and one month after the end of training, subjects' maximal inspiratory pressures (MIP) and maximal expiratory pressures (MEP) were assessed. In NAB group a significant increase in MIP was found, from -75±10 to -97±14 cmH2O (p

O objetivo do estudo foi verificar, por meio de termografia, a adaptação à prótese híbrida de extremidade superior de um sujeito do sexo masculino, 42 anos, amputado proximal de braço esquerdo. Imagens termográficas foram captadas por uma câmara de infravermelho imediatamente após a retirada da prótese, que vinha sendo usada por 8 horas ininterruptas, e 20 minutos de repouso mais tarde, quando foi alcançado equilíbrio térmico em ambiente a 21°C. As imagens foram adquiridas nos planos frontal anterior, sagital direito e esquerdo, tendo sido definidas e analisadas regiões de interesse em cada uma. Os resultados mostram que as temperaturas das regiões avaliadas reduziram-se em média 0,79°C (p

Infrared thermal imaging (IRT) has been a target of research for biomedical musculoskeletal applications, due to the possible association of the physiological data that it provides, through skin temperature measurement, with pathological states. The aim of this systematic review is to acquaint the outcomes of the biomedical application of IRT in arm and forearm evaluation and its future perspectives of research. During the literature review, 926 articles were identified using the search engines PubMed and Scopus, and 10 articles were retrieved from other sources. After screening the abstracts and applying the eligibility criteria on those which were fully accessible, 33 articles were included in the review. It can be observed that IRT has the potential to provide physiological information on the arm and forearm, showing potential to serve as an aid in various pathologies and health situations. Future studies and challenges are identified and proposed, facilitating the improvement and acceptance of the application of IRT in the assessment of arm and forearm’ health status.

The relative contribution of arm stroke and leg kicking to maximal fully tethered front crawl swimming performance remains to be solved. Twenty-three national level young swimmers (12 male and 11 female) randomly performed 3 bouts of 30 s fully tethered swimming (using the whole body, only the arm stroke, and only the leg kicking). A load-cell system permitted the continuous measurement of the exerted forces, and swimming velocity was calculated from the time taken to complete a 50 m front crawl swim. As expected, with no restrictions swimmers were able to exert higher forces than that using only their arm stroke or leg kicking.

There is an ongoing trend in several embedded industries to consolidate multiple subsystems onto the same hardware platform. For example, in the automotive industry, network-connected infotainment starts to be deployed alongside safety-critical control systems (e.g., steering, brake, ABS). To guarantee the temporal and spatial isolation of these components with different criticalities/safety integrity levels (ASIL), it is nowadays common to rely on virtualization technology. However, there is an erroneous belief that hypervisors are the new magic bullet, working as transparent layers of software that provide perfect guarantees and have no impact on the overall system. In this paper, we provide a comprehensive picture of the state of affairs concerning the use of virtualization in the context of the so called mixed-criticality systems. While sharing our experience on the development of an open-source static partitioning hypervisor (Bao) and implementing the hardware virtualization support of a novel computer architecture (RISC-V), we will (i) cover the main problems and limitations currently affecting existing hypervisor solutions and (ii) discuss the (research) challenges and opportunities lying ahead of us.