Towards a Simulator Tool for Predicting Sprinting and Long Jump Motions with and without Running-Specific Prostheses: An Optimization-Based Approach

The performances of sprinters and long jumpers with below the knee amputation (BKA) have improved continuously since the development of prostheses specifically for athletic movements. In the last years, a number of athletes with BKA have attempted to compete in non-amputee competitions. Due to the specific shape and material properties of the running-specific prosthesis (RSP), concerns exist that it may give athletes an advantage over non-amputee athletes. In this work, we investigate and compare sprinting and long jump movements of athletes with and without unilateral BKA using accurate computer models. In this context, the aim of the work is to describe similarities and differences between the athletes’ movements and to show that the employed model- and optimization-based computations are useful for this purpose. We created subject-specific multi-body models for five different athletes (four non-amputee athletes, one athlete with unilateral BKA) in order to be able to investigate the different movements. Depending on the research question, the models vary in the number of degrees of freedom (DOFs), from 16 DOFs for a two-dimensional model in the sagittal plane to 31 DOFs for a three-dimensional model. For the athlete with BKA, we created a three-segment model of the RSP with one rotational DOF in the sagittal plane. The respective motion is described by a sequence of several phases, which differ by the type of ground contact. Each of these phases is described by its own set of ordinary differential equations (ODEs) or differential algebraic equations (DAEs). We use multi-phase optimal control problems (OCPs) with discontinuities to generate sprint and long jump motions. Three different formulations of OCPs are adopted in this work. (1) We formulate a least squares OCP to reconstruct the dynamics of sprint and long jump motion capture recordings of the individual athletes. (2) For the generation of realistic motions, which can be used for prediction, we formulate a synthesis OCP; this optimizes an objective function consisting of a weighted combination of chosen optimization criteria. (3) Last, in the study of sprint movements, we use an inverse optimal control problem (IOCP): this consists of an inner loop, in which a synthesis OCP is solved, and an outer loop, which adjusts the weights of the individual optimization criteria such that the distance between the inner loop solution and a reference movement becomes minimal. We have successfully applied these three optimization problem formulations to the computation of two sprint steps of three athletes without and one athlete with unilateral transtibial amputation. Here, the movements of the non-amputee athletes differ from that of the amputee athlete in a large number of variables. In particular, the athletes use different actuation strategies for running with and without a RSP. We have observed lower torques in the amputee athlete in the leg affected by the amputation than in the non-amputee control group. In contrast, significantly larger torques occurred in the joints of the upper extremity in the amputee athlete. Furthermore, the comparison has shown that the asymmetry created by the RSP is reflected throughout the body and affects the entire movement. Using the OCPs for motion reconstruction (1) and synthesis (2), we have successfully computed the last three steps of the approach and the jump of a long jump for an athlete without and an athlete with unilateral amputation. In the reconstructed solutions, the amputee athlete achieves a greater jump distance compared to the non-amputee athlete, despite a slower approach velocity, because his take-off is more efficient. In the synthesis solutions, on the other hand, the non-amputee athlete achieves the greater jump distance because he generates a greater vertical force during the take-off and achieves a better ratio of gain of vertical to loss of horizontal velocity. Finally, we have presented our idea of a simulator tool to compare the amputee athlete with himself without amputation and have demonstrated it using the sprint and long jump movements. For this purpose, we have kept the model of the athlete with unilateral transtibial amputation from the previous studies and have created a non-amputee version of the same model by mirroring the biological leg. We have selected one objective function each for sprinting and for long jump and have solved the OCP for motion synthesis (2) for both model versions. Using the differences to the solutions based on the models of two real athletes, we have highlighted the importance of the simulator tool in the evaluation of advantages and disadvantages due to the use of the RSP

Kinetics in Individuals with Unilateral Transtibial Amputations Using Running-Specific Prostheses

Improvements in rehabilitation and prosthetic design are needed to help promote activities such as running that increase physical activity levels of individuals with lower extremity amputation (ILEA). However, effectively developing these improvements requires a detailed understanding of prosthetic and ILEA running biomechanics. Running-specific prostheses (RSPs) have been developed to improve running performance for ILEA runners, but altered running kinetics may still be necessary to accommodate for the loss of musculoskeletal function caused by lower extremity amputation. The few studies investigating ILEA running with RSPs focus on maximal performance, but our understanding of how ILEA using RSPs modulate kinetics to run at submaximal velocities remains limited. The purpose of this study was to characterize changes in kinetics and mechanical energy across a range of running velocities in ILEA wearing RSPs. This dissertation investigated six specific aims through six corresponding experiments that improve our knowledge of mechanical and anthropometric properties of RSPs and the kinetic profiles of ILEA running at submaximal velocities. Four common RSP designs were tested for mechanical and anthropometric properties. ILEA with unilateral transtibial amputations who wear RSPs and an able-bodied control group participated in the running experiments. Mechanical and anthropometric results indicated that RSP marker placement had little effect on joint kinetic estimations proximal to the prostheses, and trifilar pendulums can measure moments of inertia with <1% error. The running experiments provided the first 3D kinetic descriptions of ILEA running. The prosthetic limb typically generated lower peak kinetic parameters and 50% lower total mechanical work than the intact and control limbs, indicating a greater reliance on the intact limb. To counter the prosthetic limb deficiencies, ILEA increased stride frequencies compared to control subjects. Additionally, the prosthetic limb demonstrated prolonged periods of anterior ground reaction force to increase propulsive impulse and prolonged hip stance phase extension moments that generated increased hip concentric work. The data indicated that ILEA wearing RSPs run differently than able-bodied runners and use several adaptive mechanisms to run at the same velocity and to increase running velocity. These mechanisms are discussed and future directions of research are suggested

A biomechanical comparison of initial sprint acceleration performance and technique in an elite athlete with cerebral palsy and able-bodied sprinters

Cerebral palsy is known to generally limit range of motion and force producing capability during movement. It also limits sprint performance, but the exact mechanisms underpinning this are not well known. One elite male T36 multiple-Paralympic sprint medallist (T36) and 16 well-trained able-bodied (AB) sprinters each performed 5–6 maximal sprints from starting blocks. Whole-body kinematics (250 Hz) in the block phase and first two steps, and synchronised external forces (1,000 Hz) in the first stance phase after block exit were combined to quantify lower limb joint kinetics. Sprint performance (normalised average horizontal external power in the first stance after block exit) was lower in T36 compared to AB. T36 had lower extensor range of motion and peak extensor angular velocity at all lower limb joints in the first stance after block exit. Positive work produced at the knee and hip joints in the first stance was lower in T36 than AB, and the ratio of positive:negative ankle work produced was lower in T36 than AB. These novel results directly demonstrate the manner in which cerebral palsy limits performance in a competition-specific sprint acceleration movement, thereby improving understanding of the factors that may limit performance in elite sprinters with cerebral palsy

Bridging the gap between robotic technology and health care

Although technology and computation power have become more and more present in our daily lives, we have yet to see the same tendency in robotics applied to health care. In this work we focused on the study of four distinct applications of robotic technology to health care, named Robotic Assisted Surgery, Robotics in Rehabilitation, Prosthetics and Companion Robotic Systems. We identified the main roadblocks that are limiting the progress of such applications by an extensive examination of recent reports. Based on the limitations of the practical use of current robotic technology for health care we proposed a general modularization approach for the conception and implementation of specific robotic devices. The main conclusions of this review are: (i) there is a clear need of the adaptation of robotic technology (closed loop) to the user, so that robotics can be widely accepted and used in the context of heath care; (ii) for all studied robotic technologies cost is still prohibitive and limits their wide use. The reduction of costs influences technology acceptability; thus innovation by using cheaper computer systems and sensors is relevant and should be taken into account in the implementation of robotic systems

Investigation of the Effects of Prosthetic Knee Condition on Novice Transfemoral Amputee Runners

Some unilateral transfemoral amputees (TFAs) run in a prosthesis with an articulating prosthetic knee, others choose to run without a knee (prosthetic socket and foot are linked via a straight, non-articulating pylon) to increase stability. Research regarding unilateral TFA running with an unlocked versus locked prosthetic knee (approximately equivalent to the no-knee condition) with respect to energy cost and temporal metrics is limited; no studies have investigated the impact of knee condition on kinematic metrics. The purpose of this study was to investigate whether the prosthetic knee of a running-specific prosthesis (RSP) should be unlocked or locked for unilateral TFAs during recreational treadmill distance running. Five male TFA novice runners, aged 52-59 years, completed one training and one testing session running with the knee of a RSP in the unlocked and locked conditions. The testing session included two three-minute self-selected running speed (SSRS) trials (one trial for each knee condition) as well as six peak speed trials (three trials per knee condition). Temporal, kinematic, and oxygen consumption data were acquired during the SSRS trials. Paired t-tests and Wilcoxon signed-rank tests were conducted to identify significant differences between knee conditions. Statistically significant differences were observed between knee conditions for running economy (RE); mean RE was lower (suggesting greater efficiency) for the unlocked knee condition. Peak running speed did not differ significantly between knee conditions. Significant differences between knee conditions were also observed for peak hip flexion and abduction of the prosthetic limb during swing; maximum prosthetic limb hip flexion increased and prosthetic limb hip abduction was reduced for the unlocked knee condition. These differences contributed to reduced kinematic asymmetry at the hip for the unlocked knee condition; the unlocked knee condition also resulted in less asymmetry in hip range of motion. These differences in RE and hip kinematics between knee conditions may be attributed to circumduction of the prosthetic limb during swing to provide foot clearance with the locked knee condition. For novice recreational runners, the unlocked knee condition may be advantageous for TFAs during treadmill running, provided the individuals have sufficient endurance and cognitive focus to prevent knee buckling

Recent trends in assistive technology for mobility

Loss of physical mobility makes maximal participation in desired activities more difficult and in the worst case fully prevents participation. This paper surveys recent work in assistive technology to improve mobility for persons with a disability, drawing on examples observed during a tour of academic and industrial research sites in Europe. The underlying theme of this recent work is a more seamless integration of the capabilities of the user and the assistive technology. This improved integration spans diverse technologies, including powered wheelchairs, prosthetic limbs, functional electrical stimulation, and wearable exoskeletons. Improved integration is being accomplished in three ways: 1) improving the assistive technology mechanics; 2) improving the user-technology physical interface; and 3) sharing of control between the user and the technology. We provide an overview of these improvements in user-technology integration and discuss whether such improvements have the potential to be transformative for people with mobility impairments. © 2012 Cowan et al.; licensee BioMed Central Ltd

The potential for emulating the human footstrike using a Six Degrees-of-Freedom industrial robot

Part of the testing process for athletic footwear is exposing the shoes to realistic wear conditions; this can be in the form of user trials or, as is becoming more common place, the use of mechanical test devices. However, current mechanical test devices tend to be somewhat simplistic and fail to expose the footwear to the realistic loading environment. Thus, the aim of this thesis was to investigate the potential of using an off the shelf 6 Degrees-of-Freedom industrial robot to emulate the ground contact phase of human gait. This was achieved through addressing four research questions. The first research question aimed to outline the biomechanical features that were to be emulated and what their typical values were. Kinematics and kinetics of the real human gait were then collected, for use in programming the robot and evaluating its outputted movements. This was complemented by a comprehensive review of relevant literature. Previous investigations had highlighted the need for understanding of the robot s capabilities. This was taken further and input parameters such as level of robotic smoothing, programme velocity and the number of three dimensional co-ordinate points used were found to have an effect on the output kinematics of the robot. These features were also found to be part of the accompanying programme software (RoboGuide). Despite this, the differences were not identical and it was concluded that the software could only have a limited use in supporting the wider thesis aim. Prior to emulation, there was a need for robot set-up and its environment to be optimised. A new robot end-effector, with improved biofidelity, was developed which incorporated a new way of generating the robot motion that intended to aid kinetic and kinematic emulation. Further to this, analysis on robot movements in various locations identified the optimal location for the ground contact phase to be achieved. Using all of the gathered knowledge the robot was programmed to complete a footstrike for human walking using two types of programming method. When the robot is programmed directly with the human kinematic data the emulation of the footstrike is relatively poor; ground contact time is too long with an increased footprint size and poor ground reaction force profiles replication. Using a rotation about a fixed point on the footform led to improved, although not complete, emulation of the human gait parameters. The developed system has been shown to improve on previous work at Loughborough University and is also comparable with what is being used in industry and developed within academia. The concept remains in the early phases but the current study indicates that future work can move the robot further towards being able to produce a more biofidelic emulation that can be used in the footwear testing industry

Analysis of the backpack loading efects on the human gait

Gait is a simple activity of daily life and one of the main abilities of the human being. Often during leisure, labour and sports activities, loads are carried over (e.g. backpack) during gait. These circumstantial loads can generate instability and increase biomechanicalstress over the human tissues and systems, especially on the locomotor, balance and postural regulation systems. According to Wearing (2006), subjects that carry a transitory or intermittent load will be able to find relatively efficient solutions to compensate its effects.info:eu-repo/semantics/publishedVersio

Early Development of Total Hip Replacement

Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone. First published by the Wellcome Trust Centre for the History of Medicine at UCL, 2007. ©The Trustee of the Wellcome Trust, London, 2007. All volumes are freely available online at: www.history.qmul.ac.uk/research/modbiomed/wellcome_witnesses/Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Annotated and edited transcript of a Witness Seminar held on 14 March 2006. Introduction by Dr Francis Neary and Professor John Pickstone,Total hip replacement effectively began in the UK in 1938 and has led to widely used, commercially successful, mass-produced devices that relieve pain for an ever increasing period. The Witness Seminar, chaired by Mr Alan Lettin, discussed the remarkable postwar collaboration of British surgeons, engineers and manufacturing firms in the development of efficient alloys, surgical procedures, instruments and the implementation of clean, bacteria-reduced air in enclosed operating theatres, as illustrated by successful prostheses and techniques developed in Norwich (Kenneth McKee), Wrightington (Sir John Charnley), Stanmore (John Scales), Redhill (Peter Ring), and Exeter (Robin Ling and Clive Lee). Early failures - such as loosening from infection, osteolysis, and wear debris - stimulated the search for improved materials and fixation methods, as well as the addition of antibiotics to bone cement to reduce infection. National hip registers that record the survival of different implants were adopted in Europe in the 1970s (2003 in the UK), and they pinpoint the successful devices, as measured by survival and low rates of revision. An introduction to the volume by Dr Francis Neary and Professor John Pickstone, and appendices on materials by Professor Alan Swanson; on international standards by Mr Victor Wheble; and of details of selected prosthesis supplement the transcript. Contributors include: Lady Charnley, the late Mr Harry Craven, Mr Graham Deane, Professor Duncan Dowson, Mr Reg Elson, Dr Alex Faulkner, Professor Michael Freeman, Mrs Phyllis Hampson, Mr Kevin Hardinge, Mr Mike Heywood-Waddington, Mr John Kirkup, Mr Krishna (Ravi) Kunzru, Miss Betty Lee, Mr Alan Lettin (chair), Mr John Older, Mr John Read, Mr Peter Ring, Mr Ian Stephen, Mr Malcolm Swann, Professor Alan Swanson, Sir Rodney Sweetnam, Mr Keith Tucker, Mr Victor Wheble and Professor Michael Wroblewski. Reynolds L A, Tansey E M. (eds) (2007) Early development of total hip replacement, Wellcome Witnesses to Twentieth Century Medicine, vol. 29. London: The Wellcome Trust Centre for the History of Medicine at UCL.The Wellcome Trust Centre for the History of Medicine at UCL is funded by the Wellcome Trust, which is a registered charity, no. 210183

Development of an Optimal Control Framework to Predict Human Motion

Motion prediction is a field of great interest in sports and rehabilitation because it can help to determine the best way to perform a sport movement, to choose the optimal treatment for a specific patient, or to personalize an assistive device. The main objective of this bachelor’s thesis is to develop an optimal control framework to predict human motion. The iomechanical simulation software OpenSim has been used to develop the biomechanical model and perform inverse dynamics analysis, and the direct collocation optimal control software Moco has been used to formulate and solve the optimal control simulations. Once the optimal control framework is developed, it has been used to predict human motions, in this thesis, the squat-to-stand and the walking 2D motion. Their cost functions have been modified to predict the most accurate motion.This project includes a theoretical background, a description of what is human motion, the two target motions, the analysis types and the optimal control techniques for human motion prediction. We explain the models used, the reference data and the framework of OpenSim Moco. For every motion, the biomechanical model and the problem formulation are presented in detail, with their results and discussion. Finally, we exposed the environmental, social and economic impact of the project. Regarding the results of this thesis, the most accurate motion is reached by implementing the state tracking goal. It also has been appreciated that the kinetic energy goal improves convergence but it needs some kinematic constraints for a correct motion execution. Moreover, the control goal complemented with tracking does not bring any extra help but it could be a useful cost term for prediction without or little tracking. Regarding the reality of the motion predictions, the squat-to-stand one has been executed as a real one, whereas the gait has not been real since a contact model was missing and, besides, the model used is not a full-body on