Limb Joint Angles Research Articles

A mobile brain-body imaging dataset recorded during treadmill walking with a brain-computer interface

We present a mobile brain-body imaging (MoBI) dataset acquired during treadmill walking in a brain-computer interface (BCI) task. The data were collected from eight healthy subjects, each having three identical trials. Each trial consisted of three conditions: standing, treadmill walking, and treadmill walking with a closed-loop BCI. During the BCI condition, subjects used their brain activity to control a virtual avatar on a screen to walk in real-time. Robust procedures were designed to record lower limb joint angles (bilateral hip, knee, and ankle) using goniometers synchronized with 60-channel scalp electroencephalography (EEG). Additionally, electrooculogram (EOG), EEG electrodes impedance, and digitized EEG channel locations were acquired to aid artifact removal and EEG dipole-source localization. This dataset is unique in that it is the first published MoBI dataset recorded during walking. It is useful in addressing several important open research questions, such as how EEG is coupled with gait cycle during closed-loop BCI, how BCI influences neural activity during walking, and how a BCI decoder may be optimized.

Desain Sistem Pengukuran Lower Limb Joint Angles pada Kondisi Dinamik untuk FES

There are two gait parameters on FES used as feedback, namely gait phase and lower limb joint angles. Problems arise when the patient's motion is limited and the psychological factors of the patient are impaired due to the installation of sensors and the complicated wiring connected between the patient and the computer. This can hamper the rehabilitation process, thus a wearable and comfortable sensor system is required. This paper develops a measurement system of two gait parameters that are wearable and comfortable. The system is capable of accurately measuring two gait parameters, which are the lower limb joint angles of hip, knee, and ankle, using inertial sensors: accelerometers and gyroscopes, and gait phase parameter using Force Sensing Resistors (FSRs). The equations of the lower limb joint angles are also derived based on the acceleration vector of the accelerometer. Kalman filters are used to estimate the tilt angle of each lower limb segment based on the inertial sensor output. All processes are performed in real time by a 16-bit microcontroller, dsPIC4013. Measurement data is sent to the PC as a viewer and data storage wirelessly via Bluetooth module. In the test of dynamic subject, the gait parameters have been measured accurately. The required time to process and send all filtered sensor data is only 4.7 ms out of 10ms in maximum time sampling. This system can be further developed into wearable FES closed-loop system for gait restoration, with the addition of stimulus generator circuit and algorithm.

Decoding hind limb kinematics from neuronal activity of the dorsal horn neurons using multiple level learning algorithm

Decoding continuous hind limb joint angles from sensory recordings of neural system provides a feedback for closed-loop control of hind limb movement using functional electrical stimulation. So far, many attempts have been done to extract sensory information from dorsal root ganglia and sensory nerves. In this work, we examine decoding joint angles trajectories from the single-electrode extracellular recording of dorsal horn gray matter of the spinal cord during passive limb movement in anesthetized cats. In this study, a processing framework based on ensemble learning approach is propose to combine firing rate (FR) and interspike interval (ISI) information of the neuronal activity. For this purpose, a stacked generalization approach based on recurrent neural network is proposed to enhance decoding accuracy of the movement kinematics. The results show that the high precision neural decoding of limb movement can be achieved even with a single electrode implanted in the spinal cord gray matter.

Effects of unilateral, bilateral movement and combined exercise using a ski simulator on lower limb joint and muscle activities

Summary Objectives This study was conducted to closely examine the effects of representative types of lower limb flexion and extension exercises (unilateral and bilateral exercises) and the combined exercise using a ski simulator on lower limb joint and muscle activities. Equipment and methods In the experiments of this study performed on 20 participants, lower limb joint angles and muscle activities were measured during unilateral (lunge), bilateral (squat), and combine (ski simulator) using a 3D motion capture and electromyography analysis system. Results Analysis of the measurement results revealed that unilateral exercises required more time and exhibited greater angular displacements of the lower limb joints (P Conclusion Research approaches adopted by such studies are easy to apply and may be applicable in many fields involving rehabilitation and improvement of muscle strength and balance.

Dynamic structure of lower limb joint angles during walking post-stroke

BackgroundVariability in joint kinematics is necessary for adaptability and response to everyday perturbations; however, intrinsic neuromotor changes secondary to stroke often cause abnormal movement patterns. How these abnormal movement patterns relate to joint kinematic variability and its influence on post-stroke walking impairments is not well understood. ObjectiveThe purpose of this study was to evaluate the movement variability at the individual joint level in the paretic and non-paretic limbs of individuals post-stroke. MethodsSeven individuals with hemiparesis post-stroke walked on a treadmill for two minutes at their self-selected speed and the average speed of the six-minute walk test while kinematics were recorded using motion-capture. Variability in hip, knee, and ankle flexion/extension angles during walking were quantified with the Lyapunov exponent (LyE). Interlimb differences were evaluated. ResultsThe paretic side LyE was higher than the non-paretic side at both self-selected speed (Hip: 50%; Knee: 74%), and the average speed of the 6-min walk test (Hip: 15%; Knee: 93%). ConclusionDifferences in joint kinematic variability between limbs of persons post-stroke supports further study of the source of non-paretic limb deviations as well as the clinical implications of joint kinematic variability in persons post-stroke. The development of bilaterally-targeted post-stroke gait interventions to address variability in both limbs may promote improved outcomes.

Reduced vertical displacement of the center of mass is not accompanied by reduced oxygen uptake during walking

The six determinants of gait proposed that the goal of gait is to minimize vertical displacement of the body’s center of mass (CoM) with the objective to optimize energy expenditure. On the contrary, recent investigations suggest that reduced vertical displacement leads to an increase in energy expenditure. However, these investigations had the included subjects deliberately changing their gait, which could bias the endpoint measures. The present study investigated the effect of reduced vertical displacement of the CoM on oxygen uptake and walking economy without imposing altered gait patterns. This was accomplished by having subjects walk on a curved treadmill and on a flat treadmill. Vertical displacement of the CoM (sacrum marker displacement), oxygen uptake, walking economy, stride characteristics and lower limb joint angles were measured. There were significant differences in stride characteristics and phase dependent differences in lower limb movement pattern between the two conditions which in size were comparable to the changes observed between different speeds. The vertical displacement of the CoM was significantly reduced on the curved treadmill. This was accompanied by an increase in oxygen uptake and walking economy. These results support recent assertions that the six determinants of gait do not serve to improve walking economy.

Reliability of upper limb and trunk joint angles in healthy adults during activities of daily living

Assessments of upper limb performance should require participants to perform tasks that challenge the limits of their ability. In order to select appropriate tasks, it is important to know which joints are used to perform the movement and how reliably those movements can be measured. The purpose of this work was to quantify the reliability of upper limb and trunk joint angles in healthy adults during common activities of daily living (ADLs). Nineteen participants performed six ADLs with the right arm (applying deodorant, turning a doorknob, answering a desk telephone, placing a pushpin in a bulletin board, wiping a plate with a towel, and pouring water from a pitcher) during two separate sessions. Within- and between-session reliability was quantified using intraclass correlation coefficients (ICCs) and minimum detectable change values (MDCs). Reliability was generally better within-session than between-session. The ICCs exceeded 0.75 for 88% of the joint angles and exceeded 0.90 for 32% of the angles. All MDCs were less than 25° and 61% were also less than 10°. The MDCs represented a larger percent of the average angles for the trunk (61%) and wrist (62%) compared to the shoulder (18%) and elbow (26%). Although these results show that most angles can be measured reliably for these six ADLs, reliability varied considerably between joints. It is therefore important to select tasks for assessing of upper limb performance based on which specific joints need to be evaluated.

Surface EMG based continuous estimation of human lower limb joint angles by using deep belief networks

Abstract Surface electromyography (EMG) signals have been widely used in locomotion studies and human-machine interface applications. In this paper, a regression model which relates the multichannel surface EMG signals to human lower limb flexion/extension (FE) joint angles is constructed. In the experimental paradigm, three dimensional trajectories of 16 external markers on the human lower limbs were recorded by optical motion capture system and surface EMG signals from 10 muscles directly concerned with the lower limb motion were recorded synchronously. With the raw data, the joint angles of hip, knee and ankle were calculated accurately and the time series of intensity for surface EMG signals were extracted. Then, a deep belief networks (DBN) that consists of restricted Boltzmann machines (RBM) was built, by which the multi-channel processed surface EMG signals were encoded in low dimensional space and the optimal features were extracted. Finally, a back propagation (BP) neural network was used to map the optimal surface EMG features to the FE joint angles. The results show that, the features extracted from multichannel surface EMG signals using DBN method proposed in this paper outperform principal components analysis (PCA), and the root mean square error (RMSE) between the estimated joint angles and calculated ones during human walking is reduced by about 50%. The proposed model is expected to develop human-machine interaction interface to achieve continuous bioelectric control and to improve motion stability between human and machine, especially for lower limb wearable intelligent equipment.

A Nonlinear Dynamics-Based Estimator for Functional Electrical Stimulation: Preliminary Results From Lower-Leg Extension Experiments

Miniature inertial measurement units (IMUs) are wearable sensors that measure limb segment or joint angles during dynamic movements. However, IMUs are generally prone to drift, external magnetic interference, and measurement noise. This paper presents a new class of nonlinear state estimation technique called state-dependent coefficient (SDC) estimation to accurately predict joint angles from IMU measurements. The SDC estimation method uses limb dynamics, instead of limb kinematics, to estimate the limb state. Importantly, the nonlinear limb dynamic model is formulated into state-dependent matrices that facilitate the estimator design without performing a Jacobian linearization. The estimation method is experimentally demonstrated to predict knee joint angle measurements during functional electrical stimulation of the quadriceps muscle. The nonlinear knee musculoskeletal model was identified through a series of experiments. The SDC estimator was then compared with an extended kalman filter (EKF), which uses a Jacobian linearization and a rotation matrix method, which uses a kinematic model instead of the dynamic model. Each estimator's performance was evaluated against the true value of the joint angle, which was measured through a rotary encoder. The experimental results showed that the SDC estimator, the rotation matrix method, and EKF had root mean square errors of 2.70°, 2.86°, and 4.42°, respectively. Our preliminary experimental results show the new estimator's advantage over the EKF method but a slight advantage over the rotation matrix method. However, the information from the dynamic model allows the SDC method to use only one IMU to measure the knee angle compared with the rotation matrix method that uses two IMUs to estimate the angle.

Individuals at four months post total knee arthroplasty (TKA) still prefer to perform asymmetrically during sit-to-stand tasks

Objective Rising from a chair, a demanding task for the lower limbs, is essential to independent living. Biomechanical data collected after knee surgery is relevant for determining the level of residual deficits and compensations during functional tasks and could be used to optimize rehabilitation. The aim of this study was to quantify the kinematics and kinetic differences between the operated and non-operated lower limbs in individuals at 4 months from TKA surgery during sit-to-stand (STS) tasks executed under three foot positions. Material/patients and methods Eighty-one individuals [mean age (standard deviation): 66 (7.5) years] who had received 8 weeks of physiotherapy were assessed 4 months after undergoing knee arthroplasty. Pain, ROM and strength were assessed. Walking endurance (6MWT), stair capacity (timed stair test) and the knee and hip osteoarthritis condition (WOMAC Questionnaire) were also evaluated to determine the participants’ clinical status. For the STS, participants got up from a chair at natural speed under three conditions: spontaneous (SP), symmetrical (SYM) and asymmetrical (ASYM) foot positions (the foot back). 3D lower limb joint angles and moments were obtained using force platforms and a motion analysis system combined with an inverse dynamic approach. Statistical analyses (ANOVAs and paired t-tests) were used to assess the effects of sides and foot positions on the biomechanical data at seat-off. Results Mean values in the WOMAC, 6MWT and stair capacity were 84.7 (14.4), 411.4 m (93.9) and 19.2 (23.5), respectively. Participants had moderate pain at activity and ROM and strength at the knee were inferior on the operated side. The duration of the task was longer for ASYM condition than the two others. Kinematics and kinetic lower limb data generally differed between foot conditions and sides (mainly for joint moments) towards maximizing the use of the non-operated side except for the ASYM condition where the participants increased their weight-bearing on the operated side, resulting in higher knee moments of that side at the knee. Discussion – conclusion These results reveal that the asymmetrical behavior during STS is a preference rather than an inability to perform symmetrically. Further analyses of the data will allow identification of the predicting factors of STS performance at four months post-TKA. The study was financed by the Canadian Institutes of Health Research (CIHR, Trial Number ISRCTN66285945).

New-generation prosthetic feet: Comparative biomechanical evaluation and functional correlation in transtibial traumatic amputee during standing and walking

Even if properly fitted, the posture and gait of amputee people are disturbed, leading to compensations and over-solicitations of the contralateral limb. The recent commercialization of new generation ankle-foot (NG) prosthesis is not covered by French social security insurance. The evaluation of the service delivered by these medical devices was until now a combination of multidisciplinary evaluations and patient assessments, but needs objective evaluation. Several teams reported a benefit of NG feet, mainly in terms of joint mobility, walking speed and reduction in compensations. But the main subjective improvement is in balance, both in static (more comfortable waiting position) as well as in dynamic (quality and fluidity of walking), which was poorly evaluated in amputees with NG feet. The main objective of this research is to evaluate the relevance of these NG feet in terms of static stability, on both flat and inclined surfaces. Six transtibial subjects were included. Three NG feet (Elan ® , Propriofoot ® , Meridium ® ) and the patient's usual foot were successively tested. For each foot type, after socket and alignment validation by an expert prosthetist, an acclimatization period of 15 days at home was observed. After this period, clinical, instrumental (static acquisitions of 20 s on two force platforms, eyes open and closed, on flat ground and on 12% inclined slope uphill and downhill) and functional evaluations (Berg Balance Scale and Activity Specific Balance Scale) were performed. Participants observed a wash out period of 3 weeks with the usual foot before testing each NG foot. The static parameters collected were: lower limb joint angles, Center of Pressure (COP) variation, ground reaction forces (GRF), and functional scores. In static position, a larger prosthetic ankle dorsiflexion, less compensations of the amputed lower limb, better symmetry of the GRF and increase of CoP parameters (as length of trajectory and range) were found with NG feet, compared to ESR. The absence of postural control leads to asymmetrical posture, leading to osteoarticular complications. Ankle mobility of NG feet may allow a better balance and improve destabilizations adaptations, above all on slope, and may reduce sound limb compensations.

Reliability of unipodal and bipodal counter movement jump landings in a recreational male population

Movement patterns during landing have been suggested to be related to injury risk. The purpose of this study was to determine the inter-session reliability of kinematic variables and ground reaction forces during landing in a population of male recreational athletes after a counter movement jump. Both unipodal and bipodal landings were evaluated. Furthermore, the possibility to improve landing reliability with a verbal instruction was also studied. Twenty-four male volunteers with no history of lower extremity trauma were randomly assigned to two groups (with and without verbal landing instruction). An optoelectronic 3D system and force plates were used to measure the lower limb joint angles and the ground reaction forces during landing. Intraclass correlation values show moderate to excellent inter-session reliability for the bipodal task (ICC average: 0.80, range: 0.46–0.97) and poor to excellent reliability for the unipodal task (ICC average: >0.75, range: 0.20–0.95). However, large standard errors of measurement values at the ankle joint at impact (27.6 ± 11.5°) and for the vertical ground reaction forces (394 ± 1091 N) show that some variables may not be usable in practice. The verbal instruction had a negative effect on the reliability of unipodal landing but improved the reliability of bipodal landing. These findings show that the reliability of a landing task is influenced by its motor complexity as well as the instruction given to the subject.

Multi-Trial Gait Adaptation of Healthy Individuals during Visual Kinematic Perturbations.

Optimizing rehabilitation strategies requires understanding the effects of contextual cues on adaptation learning. Prior studies have examined these effects on the specificity of split-belt walking adaptation, showing that contextual visual cues can be manipulated to modulate the magnitude, transfer, and washout of split-belt-induced learning in humans. Specifically, manipulating the availability of vision during training or testing phases of learning resulted in differences in adaptive mechanisms for temporal and spatial features of walking. However, multi-trial locomotor training has been rarely explored when using visual kinematic gait perturbations. In this study, we investigated multi-trial locomotor adaptation in ten healthy individuals while applying visual kinematic perturbations. Subjects were instructed to control a moving cursor, which represented the position of their heel, to follow a prescribed heel path profile displayed on a monitor. The perturbations were introduced by scaling all of the lower limb joint angles by a factor of 0.7 (i.e., a gain change), resulting in visual feedback errors between subjects' heel trajectories and the prescribed path profiles. Our findings suggest that, with practice, the subjects learned, albeit with different strategies, to reduce the tracking errors and showed faster response time in later trials. Moreover, the gait symmetry indices, in both the spatial and temporal domains, changed significantly during gait adaptation (P < 0.001). After-effects were present in the temporal gait symmetry index whens the visual perturbations were removed in the post-exposure period (P < 0.001), suggesting adaptation learning. These findings may have implications for developing novel gait rehabilitation interventions.

Comparison in three dimensional gait kinematics between young and older adults on land and in shallow water

This study investigated in three-dimensional space, firstly whether the aquatic medium and secondly ageing, had any effect on the lower limb's joint angles during aquatic-based gait. Three-dimensional joint kinematics of the lower limb of 51 healthy male participants [25 young group (24.6±4.9 years, 172.1±5.5cm, 69.8±10.3kg) and 26 older group (58.5±5.1 years, 167.9±5.1cm, 70.8±12.1kg)] were quantified during land and shallow water walking. Participants walked at their self-selected comfortable speed in both mediums. The results suggested that the properties of water – hydrodynamic drag, and buoyancy – affected the gait kinematics for both groups. Both age groups used more of their hip flexion in the aquatic environment to help them propel forward instead of using the ankle plantarflexion. The effect of age during the aquatic-based gait was identified in ankle adduction angle and knee abduction/adduction angle at initial contact. Only the older group elicited a significantly smaller ankle adduction angle during the aquatic-based gait when compared to the land-based gait. Only the young group elicited a significantly larger knee abduction/adduction angle at initial contact during the aquatic-based gait when compared to the land-based gait. These findings can facilitate professionals in the area of aquatic rehabilitation to better customise aquatic-based walking exercise programmes to suit their client's specific needs.

Robot-assisted gait training improves the walking ability of hemiplegic patients

Objective To evaluate the effect of robot-assisted gait training on the walking ability of hemiplegic patients. Methods Sixty hemiplegic patients were randomly divided into a control group and a treatment group, each of 30. Both groups were given traditional rehabilitation and drug therapy. The control group was additionally provided with the traditional gait training, while the treatment group additionally received robot-assisted gait training. The gait training lasted 30 minutes a day, 5 days per week. Before and after 8 weeks of training, the time parameters, phase parameters, the joint angles of the lower limbs, and the peak ground reaction forces of both groups were evaluated using a three-dimensional gait analysis system. Results After the intervention, the walking velocity, stride frequency and stride length had increased in the treatment group, while stride width had decreased. Significant improvement was observed in the treatment group in terms of the percentage of swing phase on the paretic side, the percentage of stance phase on the paretic side, the single support time ratio, the percentage of double support phase, the range of motion of the hip and knee joints, and the peak vertical and forward ground reaction force as a percentage of body weight. The improvements were significantly greater than those observed in the control group. Conclusions Compared with traditional walking training, robot-assisted gait training can be more effective in improving the walking ability of hemiplegic patients. Key words: Robots; Gait training; Walking ability; Gait analysis

ORIGINAL Lower Extremities' Joint Stability during the Elderly Woman's Walking

Objective: The aim of this study was to investigate the periodicity of the lower extremity joint flexion/extension angle to compare the local stability between young and elderly women during walking on a treadmill. Method: Eighteen young women (mean <TEX>$age=21.2{\pm}1.6y$</TEX>; mean <TEX>$mass=57.1{\pm}6.1kg$</TEX>; mean <TEX>$height=1.61{\pm}0.04m$</TEX>) and 18 elderly women (mean <TEX>$age=66.4{\pm}1.2y$</TEX>; mean <TEX>$mass=55.4{\pm}8.3kg$</TEX>; mean <TEX>$height=1.56{\pm}0.04m$</TEX>) participated in this study. Approximate entropy (ApEn) was used to determine the periodicity in the lower limb joint angles. Results: The ApEn values of the two groups were statistically greater in the surrogate data test than in the original time series data (p<.05). The periodicity of the hip and ankle flexion/extension angles decreased in the elderly women group compared with the young women group (p<.05). The periodicity of the lower extremity joint flexion/extension angle showed that the ankle joint increased dominatingly in both groups (p<.05); the hip joint decreased compared with the knee joint in the young women group; and the knee joint decreased compared with the hip joint in the elderly women group (p<.05). Conclusion: These results suggest that the lower extremity joint flexion/extension angles of the young and elderly women during walking contained random noises as well as biological signals. In addition, the differences in the periodicity in the lower extremity joint between the young and elderly women may provide some insight in predicting potential falls and be used as a characteristic indicator for determining local stability in elderly women during walking.

野球の打撃動作における打撃条件の違いが上肢のキネマティクスに及ぼす影響：ティーおよび飛来球打撃条件による比較

The purpose of this study was to compare the kinematic characteristics of the upper body between baseball tee batting and pitched ball batting in order to gain basic knowledge for improvement of batting skill. Ten male collegiate baseball players (age: 20.7±1.1 yr; height: 1.75±0.05 m; body mass: 76.3±7.1 kg; athletic career: 12.7±2.7 yr) participated. They performed 2 kinds of batting: tee batting (TB) and machine-pitch batting (MB) using a pitching machine (approximate ball speed 33.3 m/s), which were set at middle ball height for the strike zone. Three-dimensional coordinate data were acquired with a motion capture system. Kinematic variables such as maximum bat-head speed, swing time, bat angle, joint angles of the upper limbs, and segment angle of the upper trunk were calculated. Differences between TB and MB were analyzed statistically using paired t-test (p<0.05). The maximum bat-head speed was significantly greater in TB than in MB, but swing times divided into 2 phases showed no significant differences between MB and TB. In the first half of the swing, the bat inclination angle was significantly larger in MB than in TB. The joint angles of the barrel-side shoulder abduction, knob-side shoulder adduction and internal rotation were significantly larger in MB than in TB, and those of the barrel-side shoulder internal rotation and individual elbow pronations were significantly larger in TB than in MB. The clockwise rotational angle of the upper trunk was significantly larger in TB than in MB. In the last half of the swing, the joint angles of the barrel-side shoulder abduction, knob-side shoulder flexion and adduction were significantly larger in MB than in TB, and that of the knob-side elbow pronation was significantly larger in TB than in MB. The changes in upper body movement in MB affected the radius of rotation of the bat about the vertical axis to control the bat easily. The movements in the last half of the swing largely resulted from those in the first half of the swing, and did not contribute to timing adjustment. These results indicate that the initial configuration of the bat and upper limbs, and movements at the beginning of the bat swing contribute to the timing adjustment of the bat for a pitched ball. The results of the present study suggest that it could be useful to pay attention to the movement of the bat and upper body in the first half of the swing as TB practice in order to improve timing adjustment.

A Mechanical Sensor Designed for Dynamic Joint Angle Measurement.

Background. The measurement of the functional range of motion (FROM) of lower limb joints is an essential parameter for gait analysis especially in evaluating rehabilitation programs. Aim. To develop a simple, reliable, and affordable mechanical goniometer (MGR) for gait analysis, with six-degree freedom to dynamically assess lower limb joint angles. Design. Randomized control trials, in which a new MGR was developed for the measurements of FROM of lower limb joints. Setting. Reliability of the designed MGR was evaluated and validated by a motion analysis system (MAS). Population. Thirty healthy subjects participated in this study. Methods. Reliability and validity of the new MGR were tested by intraclass correlation coefficient (ICC), Bland-Altman plots, and linear correlation analysis. Results. The MGR has good inter- and intrarater reliability and validity with ICC ≥ 0.93 (for both). Moreover, measurements made by MGR and MAS were comparable and repeatable with each other, as confirmed by Bland-Altman plots. Furthermore, a very high degree of linear correlation (R ≥ 0.92 for all joint angle measurements) was found between the lower limb joint angles measured by MGR and MAS. Conclusion. A simple, reliable, and affordable MGR has been designed and developed to aid clinical assessment and treatment evaluation of gait disorders.

Development of algorithm for different programmable modes for a prototype of orthotic ambulatory device for gait rehabilitation

Presently available orthotic devices have many limitations in their mechanical design, sensor mechanism and real-time control to achieve stable, efficient and human like bipedal walking. User adaptive control algorithm with different programmable modes for developed prototype of an orthotic device is implemented. Gait postures like sit, stand, walk, stair walk, user defined exercise mode, etc., are basic human mobility functions. These activities are part of rehabilitation therapy for a locomotive disabled. With emerging trend of robotic rehabilitation, orthotic devices with good control strategy that helps in early recovery and more effective in gait rehabilitation are required. Control strategy is based on gait parameters like lower limb joint angles and ground reaction force. Software algorithm is developed in LabVIEW platform for different modes like sit, stand, walk and stair climbing. Implemented control strategy is verified based on the trajectory error estimated of hip, knee and ankle of the device are analysed. These trajectories are compared with the standard available data.

ハンマー投における高重量ハンマーを使用したトレーニングが投てき距離および技術に及ぼす影響の検討

The purpose of this study was to investigate the cumulative effect of training with the heavier hammer (8.0 kg). Sixteen male hammer throwers were divided into a TR group (n=8) and a CT group (n=8). The TR group trained with the heavier hammer (8.0 kg) for 4 weeks. In order to investigate the effect of the training, tests were conducted before and after training. Utilizing 3 high-speed video cameras (300 fps), the 3-dimensional coordinates of the hammer head and 25 landmarks on the body were obtained by the direct linear transformation method. The results showed that in the TR group, the throwing record was increased and the release velocity increased due to an increase of velocity increment during the turn. The maximum centrifugal force was increased in the all double support phase after training in the TR group. With regard to the lower limb joint angles, bending motion of the hip and the knee joint was emphasized after training in the TR group. These results suggest that throwing with the heavier hammer is an effective training method for improving the throwing distance, and for throwing action against the increased load during the turn phase.