O controle postural é perturbado após a fadiga dos músculos flexores plantares. Por outro lado, o uso do sistema âncora reduz a oscilação postural. Entretanto, não se sabe se o uso dessa ferramenta seria capaz de compensar o aumento da oscilação corporal provocada pela fadiga muscular dos músculos flexores plantares. A informação háptica adicional fornecida pelo toque leve e o taping foi capaz de compensar o efeito perturbador da fadiga em adultos jovens. Porém, não se sabe como os idosos respondem a essa perturbação com o uso da informação háptica adicional. O objetivo desse estudo foi investigar se o uso do sistema âncora é capaz de compensar o aumento da oscilação corporal decorrente da fadiga dos músculos flexores plantares em adultos jovens e idosos. Os grupos de participantes foram testados descalços e com os olhos fechados em quatro condições na postura ereta: com e sem o sistema âncora, antes e depois do protocolo de fadiga. O sistema âncora consiste em dois cabos flexíveis com uma massa leve (125 g) fixada em uma das extremidades de cada cabo. Os participantes devem segurar um cabo em cada mão e manter o cabo esticado, sem retirar as cargas do solo. O protocolo de fadiga consistiu em realizar uma única série de flexão plantar bilateral do tornozelo repetidas vezes de forma constante e ininterrupta. Como esperado, o protocolo de fadiga aumentou a oscilação corporal nos dois grupos. Ambos os grupos se beneficiaram do uso das âncoras com a redução da oscilação corporal. Entretanto, esse efeito foi independente da fadiga. Concluímos que o sistema âncora contribuiu com a redução da oscilação corporal dos adultos jovens e idosos. Contudo, o sistema âncora não foi capaz de compensar o efeito perturbador postural em consequência da fadiga dos músculos flexores plantares. / The fatigue of the planta flexor muscles disturbs postural control. On the other hand, the use of the anchor system reduces postural sway. However, it is unknown whether the use of this tool would compensate for the increase of the body sway caused by muscle fatigue of the plantar flexor muscles. The additional haptic information provided by light touch and taping was able to compensate for the disturbing effect of fatigue in young adults. However, it is unknown how the old adults would respond to this disturbance with the use of additional haptic information. The purpose of this study was to investigate whether the use of the anchor system is able to compensate for the increase of the body sway due to fatigue of the plantar flexor muscles in young and old adults. The groups of participants were tested barefoot and with eyes closed in four conditions in upright posture: with and without the anchor system, before and after the fatigue protocol. The anchor system consists of two flexible cables with a light load (125 g) attached to one end of each cable. Participants should hold one cable in each hand and the keep the cable taut without removing the loads from the ground. The fatigue protocol consisted of performing a single series of bilateral plantar flexion of the ankles repeatedly and continuously and uninterrupted. As expected, the fatigue protocol increased body sway in both groups. Both groups benefited from the use of anchors with reduction of body sway. However, this effect was independent of fatigue. We conclude that the anchor system contributed to the reduction of body sway in young and old adults. However, the anchor system was not able to compensate for the disturbing effect in postural control created by fatigue of the plantar flexor muscles.

Multiline anchors are a novel way to reduce the cost of arrays of floating offshore wind turbines (FOWTs), but their behavior is not yet fully understood. Through metocean characterization and dynamic simulations, this thesis investigates the effects of wind-wave misalignment on multiline anchor systems. Four coastal U.S. sites are characterized in order to develop IEC design load cases (DLCs) and analyze real-world misaligned conditions. Stonewall Bank, Oregon showed the highest 500-year extreme wave height, at 16.6 m, while Virginia Beach, Virginia showed the highest 500-year wind speed, at 56.8 m/s. Misalignment probability distributions, at all sites, are found to converge towards zero (aligned conditions) and become less variable as wind speed increases. This indicates that high misalignment angles are unlikely at high wind speeds. A simulation parameter study, spanning a range of wave directions, misalignment angles, and DLCs, is run in OpenFAST to explore how misalignment affects multiline anchor loading. The simulated anchor is connected to three IEA 15 MW FOWT models via a taut mooring system. The force on the multiline anchor is calculated by summing the three tension vectors from the mooring lines. The mean direction of this force is found to align closely with the wind; each mean is within 5.5° of the wind direction. Higher misalignment angles cause increases to the amount of directional variation about this mean. The magnitude of the multiline force is also examined. Mean force level is found to be nearly unaffected by misalignment. However, maximum force decreases significantly as misalignment angle increases, dropping as much as 23.3% in extreme conditions. This confirms current anchor design practice, which treats aligned metocean conditions as the peak load an anchor experiences. Standard deviation of multiline force also decreases with misalignment. The operational load case, DLC 1.6, shows a slight trend towards this, but the extreme case, SLC, shows a more pronounced drop of 32.4%. This suggests that anchor cyclic loading analyses could benefit from considering misalignment. Doing so could lead to lower estimates of the cyclic loading amplitudes that anchor designs must withstand, thus leading to smaller, cheaper anchors.