Instrumentation of sprint and long jump tracks of an indoor athletics field to study athletes’ performances

Introduction: The in-depth study of the performances of athletes is crucial to evaluate and improve their technique. However, collecting representative data is not trivial, as several factors could affect the measurements. Laboratory measurements can lack in realism (artificial environment, athlete’s lack of challenge), whereas data collected in-field using on-board devices can be influenced by the instrumentation itself (weight, encumbrance) [1-2]. The aim of this work is the design of an instrumented track, which will allow to collect kinematic and kinetic data of able bodied and paralimpic athletes in their natural environment, ensuring that the influence of the sensory apparatus is negligible. Methods: The instrumentation set-up of the indoor athletics track of Padova (Padova, 35136, Italy) is represented in the plan view of figure 1a. Seven 60x90 cm and two 40x60 cm force platforms (AMTI, BMS600900 and BMS400600) will be installed following the disposition depicted in figure 1b on the eighth lane of the sprint track, leading to a total of 6.9 metres of force sensing lane. The two smaller force platforms will be installed side-by-side to allow the possibility of mounting one single starting block on each force transducer to collect separate right and left ground reaction forces during the starting phase of sprinting. An additional 60x90 cm force platform will be installed on the long jump track at 1.6 metres from the sand pit in order to collect the last step of the athlete before the flight phase of the long jump (figure 1c). Kinematic data will be collected using 10 optoelectronic motion capture cameras (Vicon, Vantage5), which will be installed on a double portal structure made of aluminium trusses with an overall size of 13 x 7 x 3.5 metres (length x width x height). The structure size allows more than one athlete to run simultanesously, in order to recreate the “challenge effect” typical of official races. Compared to other motion capture mounting solutions, such as using tripods to support each individual camera [3], the use of this single support structure offers the advantage of allowing to rigidly translate the motion capture calibrated volume in different part of the athletics field using wheels. This feature reduces drastically the set-up time of the motion capture system, particularly when the data collection focus has to be moved between the sprint and the long jump area. Moreover, this structure allows to avoid the presence of any cable on the track, as wires will pass through the trusses and descend via the vertical columns. Results and discussion: The design of the sensorized athletics track is complete and the installation of the instrumentation will take place in the next few months. This track will allow to collect insightfull in-field data regarding able bodied and paralimpic athletes performances outside the laboratory environment. Examples of these data will be presented in June at the ISEA 2022 conference

STIFFNESS COMPARISON OF RUNNING PROSTHETIC FEET OF DIFFERENT CATEGORIES AFTER BENCH TESTING

The purpose of the work is the comparison of stiffness properties of Running Prosthetic Feet (RPF) for transtibial amputee athletes after the introduction of test methods to collect and analyse their Load-deflection curves. The study explores the effect of the orientation of the socket (ϑG) with respect to ground during a load cycle.The three Ossur feet Cheetah Xtreme Category 4th, 5th ,6th underwent extensive testing on a multi-component test bench. Results show that the unit interval between categories does not matches with the interval in terms of equivalent stiffness Keq introduced as synthetic stiffness parameter

A Workflow for Studying the Stump-Socket Interface in Persons with Transtibial Amputation through 3D Thermographic Mapping

The design and fitting of prosthetic sockets can significantly affect the acceptance of an artificial limb by persons with lower limb amputations. Clinical fitting is typically an iterative process, which requires patients' feedback and professional assessment. When feedback is unreliable due to the patient's physical or psychological conditions, quantitative measures can support decision-making. Specifically, monitoring the skin temperature of the residual limb can provide valuable information regarding unwanted mechanical stresses and reduced vascularization, which can lead to inflammation, skin sores and ulcerations. Multiple 2D images to examine a real-life 3D limb can be cumbersome and might only offer a partial assessment of critical areas. To overcome these issues, we developed a workflow for integrating thermographic information on the 3D scan of a residual limb, with intrinsic reconstruction quality measures. Specifically, workflow allows us to calculate a 3D thermal map of the skin of the stump at rest and after walking, and summarize this information with a single 3D differential map. The workflow was tested on a person with transtibial amputation, with a reconstruction accuracy lower than 3 mm, which is adequate for socket adaptation. We expect the workflow to improve socket acceptance and patients' quality of life

GRF ANALYSIS OF TWO ELITE PARALYMPIC SPRINTERS IN STEADY AND RESISTED ACCELERATED TREADMILL RUNNING

Analysis of ground reaction forces (GRFs) allows evaluating performances of paralympic runners with transfemoral amputation. Instrumented treadmills are expensive and low-cost solutions to gather GRFs are worth to be studied. This study aimed to use a commercial treadmill placed on four force platforms to evaluate vertical impulse, braking and propulsive horizontal impulses during steady-speed (SSR) and resisted accelerated (RAR) running. The RAR vertical impulses of the unaffected limb (UL) of the two athletes doubled the values of the affected limb (AL) that has, however, on average 23% larger propulsive action than UL in SSR. The horizontal impulse of AL remains positive in the first 10 steps during RAR, as expected. Agreement between present results and literature confirms that the proposed setup gives sufficient confidence in the evaluation of the sprint technique

TOWARDS THE DEVELOPMENT OF BENCH TESTING FOR LOWER-LIMB PROSTHETIC SOCKETS FOR SPORT APPLICATIONS

Prosthetic sockets are the bespoken part of lower-limb prostheses. Knowledge about the mechanical properties of sockets is essential to ensure patient safety and comply with current medical device regulations. This includes sockets designed for sport activities. Unfortunately, the literature is extremely limited and contradictory as described in a recent systematic review. The aim of this study was to initiate a research activity aiming to design a mechanical bench system for socket testing and perform a comparative analysis of the ultimate strength of alternative socket layups. Results highlight substantial differences in the maximum loading at failure, stressing the importance of increasing the knowledge about socket mechanical properties to support prosthetists provide reliable and safe products to patients and athletes

SIAMOC position paper on gait analysis in clinical practice: General requirements, methods and appropriateness. Results of an Italian consensus conference

Gait analysis is recognized as a useful assessment tool in the field of human movement research. However, doubts remain on its real effectiveness as a clinical tool, i.e. on its capability to change the diagnostic-therapeutic practice. In particular, the conditions in which evidence of a favorable cost-benefit ratio is found and the methodology for properly conducting and interpreting the exam are not identified clearly. To provide guidelines for the use of Gait Analysis in the context of rehabilitation medicine, SIAMOC (the Italian Society of Clinical Movement Analysis) promoted a National Consensus Conference which was held in Bologna on September 14th, 2013. The resulting recommendations were the result of a three-stage process entailing i) the preparation of working documents on specific open issues, ii) the holding of the consensus meeting, and iii) the drafting of consensus statements by an external Jury. The statements were formulated based on scientific evidence or experts' opinion, when the quality/quantity of the relevant literature was deemed insufficient. The aim of this work is to disseminate the consensus statements. These are divided into 13 questions grouped in three areas of interest: 1) General requirements and management, 2) Methodological and instrumental issues, and 3) Scientific evidence and clinical appropriateness. SIAMOC hopes that this document will contribute to improve clinical practice and help promoting further research in the field

Structural testing of lower-limb prosthetic sockets: A systematic review

A lower-limb prosthetic socket is the custom-made structural element interfacing the residual limb of a person with an amputation to their prosthetic leg comprising off-the-shelf componentry. The socket can be subject to mechanical failure, especially when new fabrication methods and materials are introduced (e.g. 3D printing). Failures can have severe consequences for patients. A systematic review was conducted to collect information about available socket mechanical testing methods, to support the definition of widely accepted guidelines. To this aim the structural testing methods were reviewed, but not the results of the individual studies. 729 records were retrieved, of which 16 articles were included. No articles addressed transfemoral socket testing, as all focused on transtibial sockets. Thirteen articles used some sort of adaptation of ISO 10328, and all of them simulated the toe-off instant of gait, with load level acceptable for patients from 100 to 125 kg of weight. Ten considered a rigid limb dummy. Overall, ISO 10328 appears as a viable starting point for defining a testing guideline, but a considerable number of details has to be agreed upon, starting from clear definitions of anatomical landmarks and socket axes, which are required to implement a representative and repeatable test method

The Constant score and the assessment of scapula dyskinesis: Proposal and assessment of an integrated outcome measure

The Constant–Murley score (CMS) is a popular measure of shoulder function. However, its ability to monitor the evolution of patients during rehabilitation after rotator-cuff repair is controversial. Moreover, CMS does not account for possible alterations in the scapulo-humeral coordination (SHC, scapula dyskinesis), which are apparent in variety of shoulder pathologies. To address these issues, a new formulation of CMS was firstly proposed, which rates the “affected-to-controlateral side difference in SHC” of a patient with respect to reference values of asymptomatic controls (Scapula-Weighted CMS). Then, 32 patients (53 ± 9 year-old) were evaluated with CMS and SW-CMS at 45, 70, 90-day and >6-month after rotator-cuff repair, to test three hypotheses: (1) CMS and SW-CMS are largely responsive to change; (2) accounting (SW-CMS) or not (CMS) for scapula dyskinesis leads to statistically different scores and SW-CMS cannot be predicted from CMS without clinically relevant differences; (3) 90% of patients recover a side-to-side SHC similar to asymptomatic controls at 90 days. Results supported hypotheses 1 and 2. On the contrary (hypothesis 3), only 10% of patients recovered for SHC alterations at 90 days, and 50% at follow-up. These findings support the use of SW-CMS and the importance of treating scapula dyskinesis after rotator-cuff repair

Energy storing and return prosthetic feet improve step length symmetry while preserving margins of stability in persons with transtibial amputation

Abstract Background Energy storing and return (ESAR) feet are generally preferred over solid ankle cushioned heel (SACH) feet by people with a lower limb amputation. While ESAR feet have been shown to have only limited effect on gait economy, other functional benefits should account for this preference. A simple biomechanical model suggests that enhanced gait stability and gait symmetry could prove to explain part of the difference in the subjective preference between both feet. Aim To investigate whether increased push-off power with ESAR feet increases center of mass velocity at push off and enhance intact step length and step length symmetry while preserving the margin of stability during walking in people with a transtibial prosthesis. Methods Fifteen people with a unilateral transtibial amputation walked with their prescribed ESAR foot and a SACH foot at a fixed walking speed (1.2 m/s) over a level walkway while kinematic and kinetic data were collected. Push-off work generated by the foot, center of mass velocity, step length, step length symmetry and backward margin of stability were assessed and compared between feet. Results Push-off work was significantly higher when using the ESAR foot compared to the SACH foot. Simultaneously, center of mass velocity at toe-off was higher with ESAR compared to SACH, and intact step length and step length symmetry increased without reducing the backward margin of stability. Conclusion Compared to the SACH foot, the ESAR foot allowed an improvement of step length symmetry while preserving the backward margin of stability at community ambulation speed. These benefits may possibly contribute to the subjective preference for ESAR feet in people with a lower limb amputation