Standing, walking, running, and jumping on a force plate

Cross, Rod

doi:10.1119/1.19253

Cited by 110 publications

(54 citation statements)

References 6 publications

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“…They measured horizontal and vertical force from a single footstep using a force plate [31]. The shape of the vertical force with two peaks and a trough of the kind shown in Fig.…”

Section: Single Person Force Measurementsmentioning

confidence: 99%

Vibration serviceability of footbridges under human-induced excitation: a literature review

Živanović

Pavić

Reynolds

2005

Journal of Sound and Vibration

522

315

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Increasing strength of new structural materials and longer spans of new footbridges, accompanied with aesthetic requirements for greater slenderness, are resulting in more lively footbridge structures. In the past few years this issue attracted great public attention. The excessive lateral sway motion caused by crowd walking across the infamous Millennium Bridge in London is the prime example of the vibration serviceability problem of footbridges. In principle, consideration of footbridge vibration serviceability requires a characterisation of the vibration source, path and receiver. This paper is the most comprehensive review published to date of about 200 references which deal with these three key issues.The literature survey identified humans as the most important source of vibration for footbridges. However, modelling of the crowd-induced dynamic force is not clearly defined yet, despite some serious attempts to tackle this issue in the last few years.The vibration path is the mass, damping and stiffness of the footbridge. Of these, damping is the most uncertain but extremely important parameter as the resonant behaviour tends to govern vibration serviceability of footbridges.A typical receiver of footbridge vibrations is a pedestrian who is quite often the source of vibrations as well. Many scales for rating the human perception of vibrations have been found in the published literature. However, few are applicable to footbridges because a receiver is not stationary but is actually moving across the vibrating structure.During footbridge vibration, especially under crowd load, it seems that some form of humanstructure interaction occurs. The problem of influence of walking people on footbridge vibration properties, such as the natural frequency and damping is not well understood, let alone quantified.Finally, there is not a single national or international design guidance which covers all aspects of the problem comprehensively and some form of their combination with other published information is prudent when designing major footbridge structures. The overdue update of the current codes to reflect the recent research achievements is a great challenge for the next 5-10 years. Abbreviations:ASD-auto spectral density; DLF-dynamic load factor; DOF-degree of freedom; FE-finite element;FRF-frequency response function; MDOF-multiple-degree-of-freedom;MTMD-multiple tuned mass damper; RMS-root-mean-square;SDOF-single-degree-of-freedom; TLD-tuned liquid damper; TMD-tuned mass damperThis paper has been published under the following reference:Živanović, S., Vibration serviceability of footbridges under human-induced excitation: a literature review.

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“…They measured horizontal and vertical force from a single footstep using a force plate [31]. The shape of the vertical force with two peaks and a trough of the kind shown in Fig.…”

Section: Single Person Force Measurementsmentioning

confidence: 99%

Vibration serviceability of footbridges under human-induced excitation: a literature review

Živanović

Pavić

Reynolds

2005

Journal of Sound and Vibration

522

315

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“…Т. 59, № 8 датчиков, устанавливаемых на определенные части тела человека [14,15]; специальные платформы для хождения, снабженные силовыми датчиками [16][17][18]; различного рода вос-становительные тренажеры с возможностью контроля движений [19,20] и т.д.…”

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“…1) состоит из условных левой ноги (элементы 2, 3,4,5,7,15), правой ноги (элементы 14,16,17,18,19,21), таза (элементы 6,8,12,13), поддерживающей таз части (элементы 9, 10, 11), ограничителей движения и направляющих пластины-таза (элемен-ты 23, 24,25,26,27,28,29,30) и акселерометров (31), регистрирующих нагрузку (22). Принцип работы экспериментального прототипа следующий: после запуска шаговых двига-телей 1 и 20 левая рейка 2 начинает двигаться вверх.…”

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Mathematical simulation of human lower limbs movements

Zhigailov¹,

Musalimov²,

Aryasov³

et al. 2016

Izv. vysš. učebn. zaved., Priborostr.

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Приведено описание математических моделей движения нижних конечностей человека и представлена конструкция экспериментального прототипа, имити-рующего плоское движение механической системы пятка-таз и предназначен-ного для использования в процессах восстановления моторики. Рассмотрены особенности постановки экспериментов и обработки сигналов, полученных с помощью данного прототипа.Ключевые слова : движение, таз, нижние конечности, ускорение, обработка сигналов, дифференциальные уравнения Введение. Механизмы, имитирующие движения человека [1], могут состоять из разного количества звеньев. Такие механизмы позволяют имитировать как движение нижних конеч-ностей в целом (полная симуляция), так и отдельных их частей (частичная симуляция). В простых механизмах для имитации движений ног и таза используются стандартные стерж-ни и пластины, для имитации мышц -пружины и демпфирующие материалы, для имитации суставов -подшипники, шарниры, тяги и т.д.Сложность конструкции механизма и применимой к нему математической модели зави-сит от задач исследования [2,3].Математические модели. По сложности математические модели движения нижних конечностей человека могут быть разделены на три основные группы [4].1. Модели механизмов, описывающие движение человека очень упрощенно, основанные на принципе действия обратного маятника и использующие в конструкции механизмов до двух пружин или демпфирующих элементов [5][6][7]. Так, метод контроля колебаний таза, представлен-ный в работе [8], предназначен для накопления и передачи энергии посредством использования пружин, имитирующих ноги человека. Здесь предусмотрено управление углом сгибания ноги с помощью усилия пружин. Движения таза смоделированы как плоские перемещения.2. Модели многозвенных механизмов, позволяющие описывать движения нижних ко-нечностей человека и отдельных их частей (пятка, стопа, голень, колено, бедро, тазобедрен-ный сустав и т.д.) с достаточно большой точностью [2]. Действие одного из таких механиз-мов во фронтальной плоскости описано в работе [9]. Механизм имеет 16 степеней свободы и представляет собой робота-гуманоида WABIAN-2LL. Другой многозвенный механизм, пред-ставленный в работе [10], состоит из 11 звеньев стержневого типа. Движение звеньев в сагит-тальной (боковой) области описано с помощью уравнений Лагранжа второго рода.3. Модели, полученные экспериментальным путем. Эти модели, получаемые с помощью измерительных систем различного типа, описывают движение нижних конечностей человека во время ходьбы. Такие математические модели наиболее приближены к реальным движени-ям человека, однако используемое измерительное оборудование, как правило, имеет высокую стоимость, что делает получение экспериментальных моделей не всегда целесообразным.К измерительным системам, применяемым для определения экспериментальных пара-метров человеческой походки, можно отнести оптические системы [11][12][13]; отдельные виды

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“…In search of the 70 kph human: challenging the limits of human muscle contraction time -a pilot investigation Richmond vertically upward (32). For example, a vertical displacement of 1 cm with 20 kg by the subject herein occurring from a vertical velocity produced within 100 ms would equate to a force magnitude of approximately 1400 N; a = √(2gS) / t where S is vertical displacement, g is gravity and t is time of force production (from classical mechanics equations: v2 = u2 + 2gS, a=(v-u)/t).…”

Section: Original Researchmentioning

confidence: 99%

In search of the 70 kph human: challenging the limits of human muscle contraction time, a pilot investigation

Richmond¹

2011

HYP

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ORIGINAL RESEARCHwith the remarkable performances of Usain Bolt in the 100-m sprint, people are speculating about the capacity of humans to run faster. Interest from the population at large with regards to these incredible performances have led some scientist's to propose, through media, that they are attributable to the existence of the super fast-twitch fiber in fast humans (1); which in the absence of published scientific data remains unproven. According to other scientists the faster runners produce more vertical force instead of repositioning their legs faster (2) but humans can already produce 30% more average and 16% more peak vertical force when hopping than they currently choose to use in a maximal sprint which should mean that humans are capable of running much faster already; between 50-and 70 kph (3). Science is now debating whether human sprint performance is instead limited by the capacity to produce force in the smaller and smaller ground contact times as speed increases; as faster muscle fibers would permit the limbs to apply greater forces (3). Without any scientific proof to date of super fast-twitch fiber with distinct properties in humans, maybe the fastest sprinters simply have fast-twitch fiber that has adapted to contract slightly faster through specific training.In the animal kingdom, super fast muscle powers high-frequency sound production and visual tracking which requires low forces (4) but in human sprinters, if the super fast fiber Interest in sprint running has been fueled by the remarkable performance in 100-and 200-metre events at the 2008 Olympic Games. Amid this interest, speculation mounts as to how fast humans can run and to the existence of new types of fast-twitch fibers as the mechanism that realizes faster performances. This paper adopts the view that humans are limited in how fast they can run by how much force they can apply within the muscle contraction times inherent of fast running and proposes a method by which adaptation may be forthcoming to strengthen the locomotive muscles in humans within that required contraction time or shorter contraction times. The proposed method consists of the fast foot drill exercise executed with the intent of increasing the rate of stepping; training with this method was carried out over 16 weeks. The analysis of the post-training stepping rate shows that movement frequencies in human locomotive muscle approaches 7 muscle contractions per second. The analysis also shows that muscle activation times approach 90 milliseconds for the vastus lateralis muscle and 55 milliseconds for the biceps femoris muscle. Furthermore it is speculated that as a result of this training method muscle contraction times may approach and surpass the time limits for humans that are currently accepted in science. The hypothesis is that by combining the fast foot drill with progressive external resistance, runners can increase their force production within the ground contact time inherent of fast running that currently limits how fast humans can run.

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Standing, walking, running, and jumping on a force plate

Cited by 110 publications

References 6 publications

Vibration serviceability of footbridges under human-induced excitation: a literature review

Vibration serviceability of footbridges under human-induced excitation: a literature review

Mathematical simulation of human lower limbs movements

In search of the 70 kph human: challenging the limits of human muscle contraction time, a pilot investigation

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