直立二足歩行前段階モデルとしての垂直木登り説：その現状と展望．
Vertical climbing as the precursor of bipedalism.
Eishi Hirasaki
Laboratory of Biological Anthropology, Graduate School of Human Sciences, Osaka University, Suita, Osaka, Japan.
ABSTRACT
Quadrupedal climbing is seen as an important component of primate locomotor repertoires. Prost(1980) who kinesiologically studied the vertical climbing of chimpanzees, and Fleagle et al.(1980) who reviewed the electromyographic studies and field studies, have specifically proposed that vertical climbing played a crucial role in the phylogeny of bipedalism. Subsequent reseaches also support the vertical climbing hypothesis.
However this hypothesis has some problems unresolved. First, why human became biped and any other primates that climb trees have not? A possible answer is that the climbing patterns of primates are variable, and only a certain type one could influence the evolution of bipedalism, whereas others could not. Hirasaki et al.(1992,1993) showed that the climbing pattern of the antipronograde spider monkey and that of pronograde Japanese macaque are clearly different. They speculated that the patterns of vertical climbing could be divided into at least two types, which are the pronograde primate type and the antipronograde primate one, and the latter has much potential to develop into bipedalism. Further divisions in the among the antipronograde primates are of course expected. Detailed experimental studies and comparisons of those results are urgently needed to look for what type of climbing is best as the precursor of bipedalism.
The second problem is on the definition of the term "climbing". The term used in the field studies and that in the experimental studies are not same. The former includes not only vertical climbing but other miscellaneous arboreal modes of locomotion, whereas the latter only means vertical climbing. To avoid confusion, the term should be used in the restricted sense, like in the experimental studies.
Although climbing is important even in a narrow sense(Cant, 1986), it also is true that extant primates frequently show "climbing in broad sense", such as clambering, bridging, scrambling, horizontal climbing and so on. We have to investigate the evolutionary significance of these types of arboreal locomotion as well as that of vertical climbing.
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人類学輯報 52: 43-57. (C) 1995 人類学輯報
歩行中の頭部と視線の安定は如何にしてなされるか．
Eye-head-trunk coordination strategies during locomotion.
平崎 鋭矢
大阪大学人間科学研究科
ABSTRACT
This article summarizes newly published findings obtained in our recent studies of eye-head-trunk coordination strategies during walking. I attempt to place them within the historical framework of previous studies, and discuss underlying mechanisms that control head and eye movements during walking.
Study of vertical head and trunk movements while walking throughout the range of possible speeds enabled us to obtain quantitative information about translation and rotation of the head and trunk. We also obtained a clearer picture of the motor mechanisms responsible for head movements and their relationship to trunk motion during locomotion. Our results suggest that two mechanisms are used to maintain a stable head fixation distance over the optimal range of walking velocities. The relative contribution of each mechanism to head orientation depends on the frequency of head movement and consequently on walking velocity. Considering the frequency characteristics of the compensatory head pitch, we inferred that the angular vestibulocollic reflex achieves head stability at low walking speeds, while the linear vestibulocollic reflex is predominately responsible for producing compensatory head pitch movement at higher speeds.
We also found that the naso-occipital axis of the head aims approximately at a single point, the head fixation point (HFP), 1 [m] in front of the subject. The HFP position was stable despite changing walking velocity. This led us to design a second set of experiments in which we tested vertical eye and head coordination as a function of viewing distance during locomotion.
The major finding from the second study is that during natural walking the phase of eye velocity relative to head pitch velocity is dependent on the viewing distance, while head translation and rotation are relatively unaffected and tend to maintain the HFP despite changing viewing distance. When viewing a far (2 [m]) target, the vertical eye velocity is 180° out of phase with the head pitch velocity, indicating that the angular vestibuloocular reflex (aVOR) is generating the eye movement response. With a close (0.25 [m]) target, eye velocity is in phase with head pitch and compensates for vertical head translation, suggesting that activation of the linear vestibuloocular reflex (lVOR) contributes to the eye movement response.
The results of supplementary experiments using fixed-body active head pitch rotation while viewing a head-fixed target indicate that visual suppression modifies both the gain and phase characteristics of the aVOR at frequencies encountered during locomotion. We propose that visual suppression may shift the phase of the aVOR to augment the lVOR when viewing close targets during locomotion.
In this context, we have taken the view that correct transduction and integration of signals from otoliths and canals is essential to maintaining stable vision and head orientation control during natural linear walking.
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Biomechanism 15: 107-118, 2000. (C) 2000 University of Tokyo Press.
歩行中の視線安定を維持する頭部運動と眼球運動．
Eye-Head-Trunk Coordination Strategies for Gaze Stabilization during Locomotion.
Eishi Hirasaki
Laboratory of Biological Anthropology, Graduate School of Human Sciences, Osaka University, Suita, Osaka, Japan.
ABSTRACT
This article summarizes newly published findings of eye-head-trunk coordination strategies during walking. I attempt to place them including our findings within the historical framework of previous studies, and discuss underlying mechanisms that control head and eye movements during walking.
Walking is a natural daily behavior that induces linear and angular head perturbations. The head oscillates vertically and horizontally, and rotates in three planes to compensate for its translations. This "compensatory head rotation" during walking has been considered to be induced by the vestibulo-collic reflexes. The relative contribution of the otolith organs and semicircular canals, however, is not clear. Our study of head and trunk movements while walking throughout the range of possible speeds enabled us to obtain a clearer picture of the motor mechanisms responsible for head movements and their relationship to trunk motion during locomotion. It suggests that two mechanisms are used to maintain a head stability, and the relative contribution of each mechanism to head orientation depends on the frequency of head movement and consequently on walking velocity. Considering the frequency characteristics of the compensatory head rotation, It is postulated that the angular vestibulocollic reflex (aVCR) achieves head stability at low walking speeds, while the linear vestibulocollic (lVCR) reflex is predominately responsible for producing compensatory head pitch movement at higher speeds.
To stabilize the gaze orientation during locomotion coordinated eye and head movements are essential. During natural walking the phase of eye rotation relative to head rotation is dependent on the viewing distance, while head translation and rotation are relatively unaffected and tend to maintain the "head fixation point" despite changing viewing distance. When viewing a far target, the vertical eye pitch rotation is 180 degrees out of phase with the head pitch rotation, indicating that the angular vestibuloocular reflex (aVOR) is generating the eye movement response. With a close target, eye pitch rotation is in phase with head pitch rotation and compensates for vertical head translation, suggesting that activation of the linear vestibuloocular reflex (lVOR) contributes to the eye movement response. The results of our experiments using fixed-body active head pitch rotation while viewing a head-fixed target indicated that visual suppression modifies both the gain and phase characteristics of the aVOR at frequencies encountered during locomotion. We proposed that visual suppression may shift the phase of the aVOR to augment the lVOR when viewing close targets during locomotion.
In this context, I have taken the view that correct transduction and integration of signals from otoliths and canals is essential to maintaining stable vision and head orientation control during natural linear walking. One of the best ways to verify this hypothesis is to investigate head and eye movements during postflight locomotion of the astronauts. Such a study will provide us with the information about the influence of the microgravity environment on the otolith organs, and consequently on the relative contribution of the otoliths and semicircular canals to the head and gaze stability during locomotion, and is one of the major topics of future studies.
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大阪大学大学院人間科学研究科紀要 26: 177-193. (C) 2000 大阪大学大学院人間科学研究科．
木登り運動と直立二足歩行の進化．
Climbing and the Origin of Human Bipedalism.
Eishi Hirasaki
Laboratory of Biological Anthropology, Graduate School of Human Sciences, Osaka University, Suita, Osaka, Japan.
ABSTRACT
Recently published findings on the origin of human bipedalism, especially those concerned with so-called “vertical climbing hypothesis” are summarized in this short article. Quadrupedal climbing is one of the most important components of primate locomotor repertoires. Prost (1980) who kinesiologically studied the vertical climbing of chimpanzees, and Fleagle et al. (1981) who reviewed the electromyographic studies and field studies, have specifically proposed that vertical climbing played a crucial role in the phylogeny of bipedalism. In particular, Prost proposed the idea that vertical climbing is a precursor for bipedal walking of humans. Subsequent researches also support the vertical climbing hypothesis. This hypothesis, however, has some problems unresolved. First, we do not know why only humans became bipeds and why no other primates that climb trees followed what would appear to be a natural option. A possible answer is that the climbing of primates are variable, and only a certain type of climbing could influence the evolution of bipedalism, whereas others could not. This idea was supported by our results. We tested vertical climbing of the spider monkey and the Japanese macaques, and revealed that the spider monkey-type of climbing has more potential to develop into human bipedalism than does the Japanese macaque-type (Hirasaki et al, 1992, 1993, 2000). These studies partly answered the above-mentioned question, but we should note that kinetic and kinematic data are not enough to fully resolve this problem. Investigations on ecological and environmental factors as well as further detailed experimental studies are needed. Results of our studies raised a new question of why these different types of climbing evolved. Our inference on this issue is that modifications of body proportion associated with suspensory adaptation, for example prolonged forelimb length, could have changed kinesiological characteristics of climbing of the common ancestor of the ape/human clade, although this speculation needs a support from actual data. The second problem of the vertical climbing hypothesis is on the definition of the term "climbing". The term used in the field studies and that in the experimental studies are not the same. The former includes not only vertical climbing but also other miscellaneous arboreal modes of locomotion, whereas the latter only means vertical climbing. To avoid confusion, the term should be used in the restricted sense, like in the experimental studies. Third, some researchers recently intended that knuckle walking is the precursor of human bipedalism. Richmond and Strait (2000) reported that fossil ancestors of the humans retained wrist morphology similar to that of the African apes, and that those characteristics are associated with knuckle walking. Gebo (1996) also questioned about the climbing hypothesis in his review paper, which reexamined the hypothesis in light of recent behavioral, anatomical, and paleontological findings. But, most of their discussions were made on morphology of the forelimb and shoulder portions, and little objection was made to the idea that vertical climbing could develop the hindlimb morphology that is adapted to bipedalism. To sum up, I conclude that vertical climbing played important roles in the phylogeny of bipedalism, especially in development of the hip and hindlimb parts. It is, however, unlikely that shoulder and forelimb morphology of the apes and humans are attributed to an adaptation to climbing behavior. Also, it is unknown whether or not climbing occurred immediately before the advent of bipedalism. Information for discussion on this issue is still scanty and further investigation of arboreal locomotion including vertical climbing, especially that of living African apes are needed.
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大阪大学大学院人間科学研究科紀要 29: 127-143．(C) 2003 大阪大学大学院人間科学研究科．
円周歩行中の頭部と眼球の協調運動．
Head-eye coordination during circular locomotion.
平崎 鋭矢
大阪大学人間科学研究科．
キーワード：視線，姿勢，安定，前庭反射，眼振，円周歩行．
Keywords: Gaze, posture, stability, vestibular reflex, nystagmus, circular.
要旨
健常被験者７名が120cmの半径で円周歩行する際の頭部と眼球運動を計測した．横断面内では，頭部は歩行周期と関連するyaw rotation（回旋）を示し，その平均角度位置は歩行軌跡の接線方向よりも円の中心側を向いた．また，位相は歩行軌跡の角度変化に先行していた．眼球には水平眼振が生じ，その緩徐相速度と頭部の動きから求めた視線速度はほぼゼロとなった．これらは，円周歩行中に頭部と眼球運動が協調的・予測的に働き，視線の安定を維持していたことを示す．前額面内においては，頭部平均角度位置は歩行速度の増加に応じて円の中心側に傾いた．この側屈は重力慣性軸（GIA: Gravito-Inertial Acceleration Axis）の傾きによると示唆された．ただし傾きはGIAのそれよりも小さかった．
ABSTRACT
The head and eye movements of seven normal subjects were measured while they walked around the perimeter of a disk-shaped platform (120 cm diameter) in light. During this circular walking, head yaw relative to the body compensated for the intensive modulation in body yaw, resulting in smooth head movement in space. The sum of the angular velocities of the head yaw and the slow phases of eye nystagmus was almost zero, indicating that both of these processes functioned in conjunction to maintain a stable gaze in space. The mean roll position of the head tilted inward. No significant head tilt was observed when the subjects walked on a counter-rotating circular treadmill, suggesting that the head tilts were induced by tilting of the gravito-inertial acceleration vector.
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バイオメカニズム学会誌 28: 34-40, 2004. (C) 2004 バイオメカニズム学会
脳進化の人類学 −覚え書き−．
Notes on human brain evolution from an anthropological perspective.
Eishi Hirasaki
Laboratory of Biological Anthropology, Graduate School of Human Sciences, Osaka University, Suita, Osaka, Japan.
ABSTRACT
This article summarizes recently published findings on the evolution of the human brain. In particular, it focuses on the differences between human and ape brains, and when and how these differences emerged ; some current views on these issues are introduced. The evolution of the human brain has been investigated by comparing it with the brains of various apes. Such studies have revealed that although there are no brain parts or structures that are unique to humans, the organization of the brain in humans and great apes differs. In other words, what occurred in the course of human evolution was "reorganization". This reorganization took place in both the cerebral cortex and in subcortical parts of the brain. For example, in the cerebral cortex, Area 10 of the human brain, the area related to higher cognitive functions, has a greater volume than that of chimpanzees. Another notable finding is that the amount of white matter increased greatly in humans, suggesting the importance of the reorganization in fiber connections. Reorganization in the cytoarchitecture of area Tpt, which is closely related to Wernicke’s language area, has been reported ; the columns in this area are much larger in humans than in apes. As for subcortical structures, the thalamus and cerebellar system, for example, show unique patterns in humans. In particular, the lateral portion of the human cerebellum is much more developed than that of the chimpanzee, reflecting the evolution of humans' unique ability to perform voluntary activities. This area is also considered essential for high?level cognitive activities, such as human language. Debate continues as to how this reorganization proceeded. One hypothesis is that regulatory genes played crucial roles. These genes control the functions of other genes and regulate the timing and duration of mitotic divisions. Consequently, some such genes were responsible for the multiplication of the mini?column in the cortical area during ontogenetic development. A mutation of such genes might have resulted in enlargement of the cerebral cortex or the emergence of new cortical areas. Unraveling these regulatory genes in future studies may lead to a better understanding of human brain evolution. As the fossil record is inadequate, the timing of this reorganization in the course of human evolution is not clear. Only limited information on the primary visual cortex is available. The reduction of this area in hominids implies an increase in the parietal association area. The brain of early hominids probably first underwent reorganization in the occipital lobe, followed by increases in the frontal and temporal association areas and reorganization of the human language area, accompanied by evolution of the lateral cerebellum, and gradually evolved to the modern human brain. The current consensus is that primitive human language existed at least 1.8 million years ago, although this is outright speculation. Postscript : This article is based on a recent discussion with Emeritus Professor S. Matano of Osaka University, and consequently serves as an addendum to the book that Professor Matano published in 1995.
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大阪大学大学 院人間科学研究科紀要 30: 35-46．(C) 2004 大阪大学大学 院人間科学研究科．
サルのロコモーションを調べる.
平崎鋭矢
大阪大学大学院人間科学研究科
Keywords: 霊長類，直立二足歩行，垂直木登り, 二足訓練，進化．
ABSTRACT
サル（霊長類）のロコモーションを調べる実験研究の多くは，直立二足歩行というヒト独自のロコモーション様式の進化と適応に関する手がかりを得ることを目的として行われてきた．研究は大きく２つに分けられ，ひとつは二足歩行へ至る進化と適応を探るもの，もうひとつは二足性獲得後の歩行の進化と適応に関する手がかりを得ようとするものである．筆者は，前者に関連して，直立二足歩行の獲得に大きな影響を与えたとされている木登り運動の分析を，後者に関連して高度に二足訓練されたサルの歩行分析を行っている．それらの具体例を通して，霊長類ロコモーションの実験的研究の実状について簡単に紹介する．
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バイオメカニズム学会誌 28: 2-7, 2004. (C) 2004 バイオメカニズム学会
歩行中に頭部は冠状面内でどのように動くのか．
Head and Body Movements in the Coronal Plane during Straight Walking.
平崎 鋭矢
大阪大学人間科学研究科．
キーワード ： 頭部Roll回転，並進，ロコモーション，安定性，GIA
Keywords: Head roll rotation, head translation, locomotion, stability, GIA
要旨
歩行中の頭部と体幹の冠状面内での動きを運動学的に計測し，歩行中の頭部安定メカニズムを探った．その結果，歩く際に体幹は下肢の動きに合わせて支持脚側へ傾くが，頸部の動きがそれをある程度代償するため，頭部の角度変化の振幅は１度程度に押さえられることが判明した．一方，頭部には重力慣性軸 (GIA)の変化と同調する動きも観察された．これが単に慣性によるものか，あるいは耳石反射を介するものなのかについては今後の課題である．
ABSTRACT
Abstract The purpose of this study was to obtain quantitative information about head movements during linear walking in humans. Subjects (26-33 years old) walked on a motor-driven linear treadmill (Q55, Quinton) at walking velocities of 0.6 to 2.2 m/sec. The head and trunk were modeled as rigid bodies, and their rotation and translation were determined in space coordinates using a video-based motion analysis system (OPTOTRAK 3020, Northern Digital Inc). During walking the trunk rotated in the coronal plane to the supporting limb side. This was compensated by the head roll rotation relative to the trunk over the range of walking speed tested, indicating that the angular VCR (vestibulocollic reflex) functions to produce a compensatory head roll on trunk to maintain head stability in the coronal plane during walking. Head, however, still rotated in space within a range of a few degrees during moderate-to-fast walking. This was almost in phase with change in the GIA (gravito-inertial acceleration vector), suggesting that in the coronal plane the head rotation is orientation response to change in the GIA. A series of our recent studies have revealed that there are considerable well-coordinated head and upper trunk movements in all three planes during locomotion, and have suggested that these compensatory and orienting responses of the head must be considered when modeling human bipedal walking.
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バイオメカニズム 19, 117-124, 2008. (C) 2008 慶應義塾大学出版会
霊長類ロコモーション研究の現状と将来．
Current status and future prospects for primate locomotion studies.
平崎 鋭矢
大阪大学人間科学研究科．
Keywords: bipedalism, evolution, gait, research trends
ABSTRACT
This article summarizes recent findings on the evolution and adaptation of primate locomotor behavior, and discusses the current status and future prospects of this field of study. Japan once led the world in this field of study, but currently the Japanese research community is not very active, partly because of the limited availability of facilities where experimental studies can be conducted. In addition, it has become more difficult to keep and breed primate species in the laboratory, especially in the last five years. By contrast, in the US and Europe, the numbers of researchers and papers in this field are increasing rapidly. This is partly because there are more facilities for experimental studies, but more importantly because they are developing various new approaches. These include sophisticated analyses of limb joint function using computer simulations based on computed tomography images and the statistical shape atlas. Collaboration with researchers in other fields of study, such as physiology, has also begun. In addition, some researchers have taken advanced kinematic apparatus to zoos to collect motion data, since zoos have many species and are now enriching the habitats of their animals. Although it is now more difficult to undertake experiments in the laboratory using living animals, there is still much that we can do. Locomotion is one of the most basic animal behaviors, and reflects both body structure and natural habitat. To discuss primate and human adaptation and evolution, information on locomotor behavior is essential. The various techniques introduced in the studies in this article will make the coming decades exciting and fruitful, and I really hope that this wave of activity spreads to Japan and reverses the recent decline of primate locomotion research.
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霊長類研究 24: 329-343, 2009. (C) 2009 霊長類学会
Palmar and plantar pressure while walking on a horizontal ladder and single pole in Macaca fuscata.
Yasuo Higurashi, Eishi Hirasaki, Hiroo Kumakura
Laboratory of Biological Anthropology, Graduate School of Human Sciences, Osaka University, Suita, Osaka, Japan.
Keywords: arboreal quadrupedalism, grasping behavior, hand and foot posture, Japanese macaque
ABSTRACT
To investigate biomechanical function in the hand and foot during quadrupedal locomotion in nonhuman primates, physical anthropologists and primatologists measure the pressure under them. We collected hand and foot pressure data while a Japanese macaque (Macaca fuscata), a semiterrestrial anthropoid, walked on 2 different simulated arboreal substrates, a horizontal ladder and a single pole, to explore differences in hand and foot use between the 2 substrates. The ladder rungs were perpendicular to the craniocaudal axis of the subject, and the pole was parallel to the subject’s craniocaudal axis. We tested the hypothesis that the pole was a more challenging substrate for the macaque than the ladder. Focusing on a diagonal sequence, diagonal couplets gait, we calculated gait characteristics and computed mean peak-pressure images of the hand and foot for each substrate from individual peak images via translation registration. We found several substrate differences that supported the hypothesis. The Japanese macaque walked at significantly slower speeds when traveling on the pole than on the ladder. Slower travel speed on the pole suggests that the Japanese macaque needed a wider support base to maintain balance on this substrate. Mean peak-pressure images suggest that the ladder invoked a more stepping-like behavior, but the pole invoked a more grasping-like behavior, especially of the foot. We show that the hand and foot use of the Japanese macaque would be adaptable to biomechanical challenges posed by different substrates.
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International Journal of Primatology 31: 181-190, 2010. (C) Springer Science+Business Media, LLC 2010.
Estimating the functional axis of the primate foot using the distribution of plantar muscles.
Eishi Hirasaki, Hiroo Kumakura
Laboratory of Biological Anthropology, Graduate School of Human Sciences, Osaka University, Suita, Osaka, Japan.
Keywords: bipedal walking, dorsal interossei, functional foot axis, medial shift
ABSTRACT
Morton (American Journal of Physical Anthropology 5, 305-336, 1922) used the longest metatarsal, which he assumed functions as a lever during locomotion, to define the functional axis of the primate foot. In humans and apes, the functional foot axis lies on the second digit, whereas that of nonhominoid anthropoids is mostly on the third digit, suggesting that a medial shift of the functional axis occurred during primate foot evolution. Myological observations support this idea; the dorsal interossei of the human foot are arranged around the second digit, whereas those of nonhominoid anthropoids are around the third digit. However, it is still unclear when, why, and how such a change in foot musculature occurred. In addition, there is inconsistency among the limited number of studies
that have examined foot musculature in apes. We examined modifications in the interosseous muscles of the chimpanzee, gibbon, spider monkey, and Japanese macaque in terms of the shift in the functional foot axis. We found that the dorsal interossei are arranged around the third digit; this is true even in the chimpanzee, whose functional axis based on metatarsal length lies on the second digit. This suggests that the change in the arrangement of the interosseous muscles phylogenetically lagged behind the shift of the osteological axis. Our results also indicate that the dorsal interossei are composite muscles consisting of the deep short flexors and the intermetatarsal abductors. We postulate that changes in the contributions of these 2 components to the formation of dorsal interossei likely occurred in the hominin lineage, resulting in the medial shift of the myological axis. The medial shift of the functional foot axis may have started with the elongation of the second metatarsal in the hominoid ancestors’ lineage, and was completed on the rearrangement of the interosseous muscles.
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International Journal of Primatology 31: 239-261, 2010. (C) Springer Science+Business Media, LLC 2010
Experimental and computational studies of bipedal locomotion in the bipedally-trained Japanese macaque.
Naomichi Ogihara (1), Eishi Hirasaki (2), Masato Nakatsukasa (1)
(1) Laboratory of Physical Anthropology, Graduate School of Science, Kyoto University, Kyoto, Kyoto, Japan.
(2)Laboratory of Biological Anthropology, Graduate School of Human Sciences, Osaka University, Suita, Osaka, Japan.
ABSTRACT
Japanese macaques trained as performing monkeys have a remarkable ability to walk bipedally. This shift towards bipedalism in an inherently quadrupedal primate could be regarded as a modern analogue for the evolution of bipedal locomotion and offers an interesting model for understanding the emergence of human bipedalism. Here, we review the results of our recent experimental studies of bipedal locomotion in trained Japanese macaques to explore the unique characteristics of their bipedal locomotion. We then describe the development of an anatomically-based, whole-body musculoskeletal model of the Japanese macaque for biomechanical analyses and predictive simulations of locomotion. Such constructive studies of locomotion based on a mathematical model of the musculoskeletal system allow computational investigation of mechanisms of bipedal walking, providing profound insights on the origin and evolution of human bipedalism.
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(C) 2010 Springer Science+Business Media, Inc.
支持基体の傾斜角度によるニホンザル運動様式の変化について．
The change of the locomotor pattern caused by the inclination of the substrata in a Japanese macaque
中野良彦(1), 石田英實(2), 平崎鋭矢(1)
(1)大阪大学人間科学部生物人類学教室
(2)京都大学理学部自然人類学研究室
ABSTRACT
In order to clarify the condition of the change from the horizontal quadrupedal walking to the vertical climbing in a Japanese macaque, we made an experiment on the inclined substrata. The subject was an adult male Japanese macaque. It freely moved on the substrata, a bamboo pole (8cm diameter). The inclination of the substrata was changed from 15 degrees to 65 degrees with each 5 degrees and the number of the steps was eleven. We put the surface extrodes and telemetry transmitters on the subject to record the activity of the triceps brachii and the biceps brachii. The patterns of the electromyography were clearly different between the horizontal quadrupedal walking and the vertical climbing. The palm of the Japanese macaque touched the substrata on the behind side in the vertical climbing. It was found that this type of forelimb use was observed in the inclination of 50 degrees or more. The cycle duration also decreased at the inclination of 50 degrees or more. The relative duration of stance phase of the forelimb decreased at the inclination of 65 degrees and that of the hindlimb increased at the inclination of 55 degrees or more. The electromyography study showed three stages. The first stage was similar to the horizontal quadrupedal walking and it was seen at the inclination of 15 degrees or less. The second stage was the intermediate type and it was observed between the inclination of 20 degrees and 50 degrees. The last stage was similar to the pattern of vertical climbing at the inclination of 55 degrees or more. These results of electromyography were related to the difference in the locomotor function of
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霊長類研究 12: 79-87, 1996. (C) 1996 日本霊長類学会
三次元解析システムを用いたヒト歩行の研究．
Three dimensional analysis of human locomotion with on-line computer system.
山川純至(1), 野沢真司(1), 平崎鋭矢(2)，熊倉博雄(2)，久保武(1)
(1)大阪大学医学部耳鼻咽喉科学教室
(2)大阪大学人間科学
Key words: 3-D analysis, elite system, human, head and body movements, locomotion
ABSTRACT
Head and body movements during walking on a treadmill were analyzed with a 3-D motion assessment system (ELITE system), which enabled real time analysis of target movement in each subject. Head roll in counter action to body motion in the coronal plane and pitch rotation in the sagittal plane were noted in the control data. Head movement became small due to compensatory counter motion, though lateral sway became larger in the upper part of the body than in the lower. After the recording of control data, ice water was irrigated into the ear canal for vestibular stimulation in six healthy subjects. Walking immediately after caloric stimulation showed that step length and gait cycle time became shorter than before caloric stimulation. Lateral sway and vertical translation of the head also increased. Head counter roll in the coronal plane and pitch rotation in the sagittal plane became indistinct after caloric stimulation. Behavioral changes in human locomotion after vestibular stimulation are described in this report.
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Equilibrium Research, Supplement 10: 54-57, 1994. (C) 1994 日本平衡神経学会
圧力分布センサーを用いたケータイ文字入力動作解析の試み．
An attempt to analyze the action of Japanese text-input on a mobile phone using a pressure mat.
平崎鋭矢，熊倉博雄
大阪大学大学院人間科学研究科
Keywords: Mobile phone, text-input time, pressure mat, repeat-press time, movement time
キーワード：ケータイ，文字入力時間，圧力分布センサー，同一キー連打時間，キー間移動時間
ABSTRACT
In this study we examined performance of Japanese text-input on a mobile phone. A pressure mat instrumented on a mobile phone enabled us to measure "repeat-press time", "movement time" and force of press, which had not accurately been estimated with previous methods using video images. Spatial effects of key positions on text-input performance were also studied. Results showed that skilled users shortened their text-input time by shortening "movement time" rather than "repeat press time". Movement time of skilled subjects was relatively stable over the key positions and different tasks. No significant difference was found in pressing force between groups. A spatial effect analysis revealed that both groups seemed to have difficulties to press keys at right corners (3, 9) and left-top key (1). In contrast, left keys at 2nd and 3rd rows seemed to be easy to be pressed.
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モバイル学会編 モバイル2007 研究論文集，pp 109-114, 1994. (C) 1994 モバイル学会
ニホンザルの二足歩行訓練効果 −キネマティクスと足圧分布からみて−．
Effects of training on bipedal locomotion in Japanese macaques −From the viewpoint of kinematics and plantar pressure distribution−.
平崎鋭矢(1)，中務 真人(2)，荻原直道(2)
(1)大阪大学大学院人間科学研究科
(2)京都大学大学院理学研究科
キーワード Macaca fuscata，倒立振子，後肢関節，足圧中心点
Keyword Macaca fuscata，inverted pendulum，hindlimb joint，center of pressure
ABSTRACT
ヒトの直立二足歩行に見られる特徴は，効率の良い歩行に欠かせないとされている．しかし，そう考えられてきた理由は，ヒトがそれらの特徴でもって歩いているからというもので，これは一種の循環論法である．キネマティクスと足圧分布を調べた我々の実験的研究は，高度に二足訓練されたニホンザルの二足歩行が，通常のニホンザルのそれとは明らかに異なり，ある程度ではあるがヒト歩行に近い特徴を持つようになることを示した．ヒトと系統的に遠く二足歩行に適した形態を持たないニホンザルが，訓練によってヒト歩行に近い特徴をある程度持つようになることは，ヒト歩行の特徴が効率的な歩行に欠かせないものだという考えを支持する具体的な証拠と言える．
The locomotor characteristics of human walking are considered essential to efficient bipedal walking, but they are considered thus because humans walk bipedally using those characteristics. This constitutes circular reasoning. The results of our study prove that the characteristics of human walking are adaptations to bipedalism. We examined the kinematics and plantar pressure distribution of bipedal walking by Japanese macaques that had been intensively trained to stand and walk bipedally, and compared the results with those for ordinary monkeys. The results show that intensive training could develop human-like features of walking even in monkeys, which are phylogenetically distant from humans and whose bipedal walking is unlike human walking.
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電子情報通信学会技術研究報告 106 (330): 29-32, 2007. (C) 2007 電子情報通信学会