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The fastest sprinter in 2068 has an artificial limb?
... RSPs emulate the mechanics of biological legs by storing and returning elastic energy during running (13,15,18,21,31,47,70). Since the commercialization of RSPs in the 1980s (58), the athletic achievements of athletes with transtibial amputations have improved remarkably (43). Ensuing prosthetic design iterations, such as the removal of the prosthetic "heel" component, have further enhanced running performance (43,46). ...
... Since the commercialization of RSPs in the 1980s (58), the athletic achievements of athletes with transtibial amputations have improved remarkably (43). Ensuing prosthetic design iterations, such as the removal of the prosthetic "heel" component, have further enhanced running performance (43,46). Yet, despite the improved performance of athletes with transtibial amputations, the prescription of prosthetic model, stiffness, and height are subjective and may not optimize running performance. ...
Running-specific prostheses enable athletes with lower limb amputations to run by emulating the spring-like function of biological legs. Current prosthetic stiffness and height recommendations aim to mitigate kinematic asymmetries for athletes with unilateral transtibial amputations. However, it's unclear how different prosthetic configurations influence the biomechanics and metabolic costs of running. Consequently, we investigated how prosthetic model, stiffness, and height affect the biomechanics and metabolic costs of running. Ten athletes with unilateral transtibial amputations each performed fifteen running trials at 2.5 or 3.0 m/s while we measured ground reaction forces and metabolic rates. Athletes ran using three different prosthetic models with five different stiffness category and height combinations per model. Use of an Ottobock 1E90 Sprinter prosthesis reduced metabolic cost by 4.3% and 3.4% compared to use of Freedom Innovations Catapult (fixed effect (?)=-0.177; p<0.001) and ?ssur Flex-Run (?=-0.139; p=0.002) prostheses, respectively. Neither prosthetic stiffness (p?0.180) nor height (p=0.062) affected the metabolic cost of running. The metabolic cost of running was related to lower peak (?=0.649; p=0.001) and stance average (?=0.772; p=0.018) vertical ground reaction forces, prolonged ground contact times (?=-4.349; p=0.012), and decreased leg stiffness (?=0.071; p<0.001) averaged from both legs. Metabolic cost was reduced with more symmetric peak vertical ground reaction forces (?=0.007; p=0.003), but was unrelated to symmetric stride kinematics (p?0.636). Therefore, prosthetic recommendations based on stride kinematics do not necessarily minimize the metabolic cost of running. Instead, an optimal prosthetic model, which improves overall biomechanics, minimizes the metabolic cost of running for athletes with unilateral transtibial amputations.
... For example, the 100-metre sprint time at the Paralympics for individuals with a lower extremity amputation who wear carbon-fibre running prostheses has been improved with technology. In the future, they could become the fastest sprinters in the world regardless of disability [1]. However, it is not easy to design, as it requires repeated prototyping and trial and error based on experience. ...
In this study, we present a method for estimating the viscoelasticity of a leaf-spring sports prosthesis using advanced energy minimizing inverse kinematics based on the Piece-wise Constant Strain (PCS) model to reconstruct the three-dimensional dynamic behavior. Dynamic motion analysis of the athlete and prosthesis is important to clarify the effect of prosthesis characteristics on foot function. However, three-dimensional deformation calculations of the prosthesis and viscoelasticity have rarely been investigated. In this letter, we apply the PCS model to a prosthesis deformation, which can calculate flexible deformation with low computational cost and handle kinematics and dynamics. In addition, we propose an inverse kinematics calculation method that is consistent with the material properties of the prosthesis by considering the minimization of elastic energy. Furthermore, we propose a method to estimate the viscoelasticity by solving a quadratic programming based on the measured motion capture data. The calculated strains are more reasonable than the results obtained by conventional inverse kinematics calculation. From the result of the viscoelasticity estimation, we simulate the prosthetic motion by forward dynamics calculation and confirm that this result corresponds to the measured motion. These results indicate that our approach adequately models the dynamic phenomena, including the viscoelasticity of the prosthesis.
... For example, the 100-metre sprint time at the Paralympics for individuals with a lower extremity amputation who wear carbon-fibre running prostheses has been improved with technology. In the future, they could become the fastest sprinters in the world regardless of disability [1]. However, it is not easy to design, as it requires repeated prototyping and trial and error based on experience. ...
... The original version was distributed over five subscales: reporting (item 1-10), external validity (11)(12)(13), internal validity-bias (item [14][15][16][17][18][19][20], internal validity-confounding (21)(22)(23)(24)(25)(26), and power (item 27). Our modified version included: 1-3, 5-7, 11, 12, 16, 18, 20-22, and 27. ...
The elastic function of Running-Specific Prostheses (RSPs) likely contributes to a lower metabolic cost of running. However, it remains unclear whether RSPs provide advantages concerning the metabolic cost of running in relationship with non-amputee runners. This study aimed to systematically review the scientific literature to examine the peak performance (peak oxygen consumption - VO2peak and peak speed) and the metabolic cost between paired amputees and non-amputees during running, and between amputee runners with traditional prostheses and RSPs. A literature search on 3 databases (MedLine/PubMed, Scopus, and Web of Science) was conducted using the following keywords: (amputation OR amputee) AND (run OR running OR runner) AND (prosthesis OR prosthetics), resulting in 2060 records and 4 studies within the inclusion criteria. A methodological quality assessment was carried out using a modified version of the Downs and Black checklist. VO2peak of the amputees athletes (54 ± 2mLkg-1 min-1) is similar (MD: -0.80mLkg-1 min-1, CI: -4.63 to 3.03) to non-amputees athletes (55 ± 2mLkg-1 min-1). The average metabolic cost of the paired amputee athletes (4.94 ± 1.19Jkg-1 m-1) also does not differ (MD: 0.73Jkg-1 m-1, CI: -0.74 to 2.20) from non-amputee runners (4.21 ± 0.16Jkg-1 m-1). The research on running in amputee and non-amputee athletes is limited. The few existing studies have limited methodological quality. The metabolic cost data from amputee athletes running with RSPs are within the range of non-amputee data.
... Technical developments in carbon-fiber, running-specific prostheses (RSPs) have allowed 87 amputee sprinters to compete at levels never achieved before [1][2]. Theoretically, average 88 forward velocity in a 100-m sprint is the product of mean step frequency (Fstep) and mean step 89 length (Lstep). ...
Study Design: Cross-sectional study
Background: Although anthropometric factors could influence sprint performance in able-bodied sprinters, little is known about the relationships between these anthropometric factors and sprint performance in amputee sprinters.
Objectives: To investigate the relationships between body height and spatiotemporal parameters of 100-m sprints in unilateral transtibial amputee and able-bodied sprinters.
Methods: We analyzed elite-level 100-m races of 14 male unilateral transtibial amputee sprinters and 22 male able-bodied sprinters from publicly available internet broadcasts. For each sprinter’s run, the mean step length and frequency were determined by using the number of steps in conjunction with the official race time. Further, body height data for sprinters in both groups were obtained from publicly available resources.
Results: Linear relationships were found between body height and mean step length and frequency in able-bodied sprinters respectively. On the other hand, there were no significant relationships between body height and spatiotemporal parameters in transtibial amputee sprinters.
Conclusion: The results of the present study suggest that the relationship between body height and spatiotemporal parameters during a 100-m sprint is not the same between unilateral transtibial amputees and able-bodied sprinters.
... Running-specific prostheses (RSPs) with energy storing capabilities have attracted more and more individuals with lower extremity amputations to running as a form of exercise and athletic competition. More recently, RSPs have allowed amputee runners to compete at athletic levels achieved never before [1,2]. Theoretically, the average velocity during a 100-m sprint is the product of the average step frequency and average step length. ...
The aim of this study was to investigate differences of the spatiotemporal parameters in a 100-m sprint among elite, sub-elite, and non-elite sprinters with a unilateral transtibial amputation. Using publicly available Internet broadcasts, we analyzed 125, 19, and 33 records from 30 elite, 12 sub-elite, and 22 non-elite sprinters, respectively. For each sprinter’s run, the average velocity, step frequency, and step length were calculated using the number of steps in conjunction with the official race time. Average velocity was greatest in elite sprinters (8.71±0.32 m/s), followed by the sub-elite (8.09±0.06 m/s) and non-elite groups (7.72±0.27 m/s). Although there was a significant difference in average step frequency between the three groups, the effect size was small and the relative difference among the three groups was 3.1%. Statistical analysis also revealed that the average step length was longest in elite sprinters, followed by the sub-elite and non-elite groups. These results suggest that the differences in sprint performance between the three groups is mainly due to the average step length rather than step frequency.
... The differences in spatiotemporal parameters between the AS group and two other groups may be explained by the differences in muscle and tendon architectures. L step during sprinting partly depends on the vertical and horizontal ground reaction forces (GRFs) and impulses (Hay 1994). A previous study demonstrated that African runners have longer lower extremities and Achilles tendons than Japanese runners (Kunimasa et al. 2014). ...
Similar to able-bodied sprinters, most of the medals for the 100-m sprint in past Paralympic Games and IPC Athletics World Championships were dominated by West African (WA) and Caucasian (CC) amputee sprinters, not Asian (AS) sprinters. Although these results indicate differences in sprint performance due to ethnicity, little is known about the ethnicity and spatiotemporal parameters of the 100-m sprint for amputee sprinters. The purpose of this study was to investigate the differences in the spatiotemporal parameters of WA, CC and AS sprinters with bilateral and unilateral transtibial amputations during a 100-m sprint. We analyzed 6 WA, 28 CC, and 10 AS amputee sprinters from publicly available Internet broadcasts. For each sprinter’s run, the average speed, average step length, and step frequency were calculated by using the number of steps in conjunction with the official race time. No significant differences were found in the spatiotemporal parameters of the 100-m sprint for the WA and CC groups. On the other hand, the average speed of the AS group was significantly lower because of its shorter step length during the 100-m sprint. The results suggest that WA and CC sprinters would perform similarly during a 100-m sprint, but AS sprinters would not.
Electronic supplementary material
The online version of this article (doi:10.1186/s40064-016-1983-1) contains supplementary material, which is available to authorized users.
Behavioral aspects of organized sports activity for pediatric athletes are considered in a world consumed with winning at all costs. In the first part of this treatise, we deal with a number of themes faced by our children in their sports play. These concepts include the lure of sports, sports attrition, the mental health of pediatric athletes (i.e., effects of stress, anxiety, depression, suicide in athletes, ADHD and stimulants, coping with injuries, drug use, and eating disorders), violence in sports (i.e., concepts of the abused athlete including sexual abuse), dealing with supervisors (i.e., coaches, parents), peers, the talented athlete, early sports specialization and sports clubs.
In the second part of this discussion, we cover ergolytic agents consumed by young athletes in attempts to win at all costs. Sports doping agents covered include anabolic steroids (anabolic-androgenic steroids or AAS), androstenedione, dehydroepiandrostenedione (DHEA), human growth hormone (hGH; also its human recombinant homologue: rhGH), clenbuterol, creatine, gamma hydroxybutyrate (GHB), amphetamines, caffeine and ephedrine. Also considered are blood doping that includes erythropoietin (EPO) and concepts of gene doping.
In the last section of this discussion, we look at disabled pediatric athletes that include such concepts as athletes with spinal cord injuries (SCIs), myelomeningocele, cerebral palsy, wheelchair athletes, and amputee athletes; also covered are pediatric athletes with visual impairment, deafness, and those with intellectual disability including Down syndrome. In addition, concepts of autonomic dysreflexia, boosting and atlantoaxial instability are emphasized.
We conclude that clinicians and society should protect our precious pediatric athletes who face many challenges in their involvement with organized sports in a world obsessed with winning. There is much we can do to help our young athletes find benefit from sports play while avoiding or blunting negative consequences of organized sport activities.
Am Anfang dieses Kapitels steht die Erläuterung grundlegender Mechanismen von Sprungbewegungen. Darauf aufbauend werden Leistungsanalysen im Weitsprung, Dreisprung, Hochsprung und im Stabhochsprung von Topathleten präsentiert. Dabei lernt der Leser, ausgehend vom Messaufbau und der Erfassung und Verarbeitung von Primärdaten, wie Leistungsparameter in den leichtathletischen Sprungdisziplinen erhoben und interpretiert werden. Besondere Aufmerksamkeit wird dabei dem Behindertenleistungssport und hier speziell der Behandlung von Sprung- und Sprintleistungen, die mit Prothesen erbracht werden, gewidmet. Ein Abschnitt dieses Kapitels befasst sich mit der Analyse und Bewertung von Vertikalsprüngen, die oft als Testbasis zur Sprungkraftmessung in verschiedenen Sportarten herangezogen werden.
Sports prosthesis for lower-extremity amputees has a mechanical structure similar to flat springs, and its elastic energy is expected to improve sports performance. However, it is quite challenging to represent the mechanical phenomena during the takeoff action with sports prosthesis because the contact point to the ground moves based on the direction and deformation of the prosthesis. The purpose of this study is to propose a parametric model of sports prosthesis based on the flat spring design formulas to represent the deformation and rolling contact with the ground with a reasonable computational cost. The shape of the prosthesis is modeled as serial elements, and it can easily be changed by using design parameters, such as the curvature and length of each element. The curvature of each element of the prosthesis is modified by the deflection angle of the flat spring model, and the contact point to the ground is calculated by considering the deformation and rolling contact. The spring properties obtained from the proposed model well agreed with the result of a finite element analysis. Moreover, simulation results revealed that the deformed shape of the prosthesis and the takeoff action in the long jump qualitatively agreed with the actual phenomena. As future research, the proposed model, coupled with the human body model, will be applied to a computer simulation system to optimize the shape of the prosthesis in order to improve sports performance.
Although athletes with unilateral below-the-knee amputations (BKAs) generally use their affected leg, including their prosthesis, as their take-off leg for the long jump, little is known about the spring-like leg behavior and stiffness regulation of the affected leg. The purpose of this study was to investigate vertical stiffness during one-legged hopping in an elite-level long jump athlete with a unilateral BKA. We used the spring-mass model to calculate vertical stiffness, which equals the ratio of maximum vertical ground reaction force to maximum center of mass displacement, while the athlete with a BKA hopped on one leg at a range of frequencies. Then, we compared the vertical stiffness of this athlete to seven non-amputee elite-level long-jumpers. We found that from 1.8 to 3.4 Hz, the vertical stiffness of the unaffected leg for an athlete with a BKA increases with faster hopping frequencies, but the vertical stiffness of the affected leg remains nearly constant across frequencies. The athlete with a BKA attained the desired hopping frequencies at 2.2 and 2.6 Hz, but was unable to match the lowest (1.8 Hz) and two highest frequencies (3.0 and 3.4 Hz) using his affected leg. We also found that at 2.5 Hz, unaffected leg vertical stiffness was 15% greater than affected leg vertical stiffness, and the vertical stiffness of non-amputee long-jumpers was 32% greater than the affected leg vertical stiffness of an athlete with a BKA. The results of the present study suggest that the vertical stiffness regulation strategy of an athlete with a unilateral BKA is not the same in the unaffected versus affected legs, and compared to non-amputees.
The purpose of the study was to determine if the kinematics exhibited by skilled runners wearing a unilateral, transtibial prosthesis during the curve section of a 200-m sprint race were influenced by interaction of limb-type (prosthetic limb (PROS-L) vs. nonprosthetic limb (NONPROS-L)) and curve-side (inside and outside limb relative to the centre of the curve). Step kinematics, toe clearance and knee and hip flexion/extension, hip ab/adduction for one stride of each limb were generated from video of 13 males running the curve during an international 200 m transtibial-classified competition. Using planned comparisons (P < 0.05), limb-type and curve-side interactions showed shortest support time and lowest hip abduction displacement by outside-NONPROS-L; shortest step length and longest time to peak knee flexion by the inside-PROS-L. For limb-type, greater maximum knee flexion angle and lower hip extension angles and displacement during support and toe clearance of PROS-Ls occurred. For curve-side, higher hip abduction angles during non-support were displayed by inside-limbs. Therefore, practitioners should consider that, for curve running, these kinematics are affected mostly by PROS-L limitations, with no clear advantage of having the PROS-L on either side of the curve.
Inspired by the spring-like action of biological legs, running-specific prostheses are designed to enable athletes with lower-limb amputations to run. Yet, manufacturer recommendations for prosthetic stiffness and height may not optimize running performance. Therefore, we investigated the effects of using different prosthetic configurations on the metabolic cost and biomechanics of running. Five athletes with bilateral transtibial amputations each performed fifteen trials on a force-measuring treadmill at 2.5 or 3.0 m/s. Athletes ran using each of three different prosthetic models (Freedom Catapult FX6, Össur Flex-Run, and Ottobock 1E90 Sprinter) with five combinations of stiffness categories (manufacturer recommended and ± 1) and heights (International Paralympic Committee's maximum competition height and ± 2 cm) while we measured metabolic rates and ground reaction forces. Overall, prosthetic stiffness (fixed effect (β)=0.036; p=0.008) but not height (p≥0.089) affected the net metabolic cost of transport; less stiff prostheses reduced metabolic cost. While controlling for prosthetic stiffness (kN/m), using the Flex-Run (β=-0.139; p=0.044) and 1E90 Sprinter prostheses (β=-0.176; p=0.009) reduced net metabolic costs by 4.3% to 4.9% compared to using the Catapult prostheses, respectively. The metabolic cost of running improved when athletes used prosthetic configurations that decreased peak horizontal braking ground reaction forces (β=2.786; p=0.001), stride frequencies (β=0.911; p<0.001), and leg stiffness values (β=0.053; p=0.009). Remarkably, athletes did not maintain overall leg stiffness across prosthetic stiffness conditions. Rather, the in-series prosthetic stiffness governed overall leg stiffness. The metabolic cost of running in athletes with bilateral transtibial amputations is influenced by prosthetic model and stiffness, but not height.
The 2004 Olympic women's 100-metre sprint champion, Yuliya Nesterenko, is assured of fame and fortune. But we show here that--if current trends continue--it is the winner of the event in the 2156 Olympics whose name will be etched in sporting history forever, because this may be the first occasion on which the race is won in a faster time than the men's event.
For about 15 years, technical advances in prosthetic treatment have been the main factor in the increased performance of athletes with lower-limb amputation. For trans-tibial amputation, the prosthesis for sprinting is composed of a gel liner and a socket joined by a locking or virtual vacuum liner. Because of these dynamic properties, the carbon prosthetic foot equipped with tacks ensures outstanding performance. For trans-femoral amputation, a hydraulic swing and a stance control unit are added to the same prosthesis. In comparison with the able-bodied runner, athletes with amputation have smaller loading times in the prosthetic limb and larger ones in the sound limb. The length of the energy-storing prosthetic foot is determined by the “up-on-the-toes” running gait. The sprinting gait with trans-tibial amputation is almost symmetrical. The hip extensor effort is the main compensation of propulsion reduction with lower-limb amputation. With trans-femoral amputation, the lack of knee increases the asymmetry. The total prosthetic knee extension (early in late-swing phase and lasting during total stance phase) compensates with extension of both hips, especially the opposite one. The amputation and sound limb load transfer with lumbar hyperlordosis concern the pelvis, trunk and shoulders. Because of athletes with amputation, research in prosthetic treatment has progressed. The development of orthotics and prostheses for such athletes has benefited non-athletes with amputation.
For about 15 years, technical advances in prosthetic treatment have been the main factor in the increased performance of athletes with lower-limb amputation. For trans-tibial amputation, the prosthesis for sprinting is composed of a gel liner and a socket joined by a locking or virtual vacuum liner. Because of these dynamic properties, the carbon prosthetic foot equipped with tacks ensures outstanding performance. For trans-femoral amputation, a hydraulic swing and a stance control unit are added to the same prosthesis. In comparison with the able-bodied runner, athletes with amputation have smaller loading times in the prosthetic limb and larger ones in the sound limb. The length of the energy-storing prosthetic foot is determined by the "up-on-the-toes" running gait. The sprinting gait with trans-tibial amputation is almost symmetrical. The hip extensor effort is the main compensation of propulsion reduction with lower-limb amputation. With trans-femoral amputation, the lack of knee increases the asymmetry. The total prosthetic knee extension (early in late-swing phase and lasting during total stance phase) compensates with extension of both hips, especially the opposite one. The amputation and sound limb load transfer with lumbar hyperlordosis concern the pelvis, trunk and shoulders. Because of athletes with amputation, research in prosthetic treatment has progressed. The development of orthotics and prostheses for such athletes has benefited non-athletes with amputation.
Thijs A Heldoorn and Masaaki Mochimaru Digital Human Research Center, National Institute of Advanced Industrial Science and Technology
- Hiroaki Hobara
- Yoshiyuki Kobayashi
Hiroaki Hobara, Yoshiyuki Kobayashi, Thijs A Heldoorn
and Masaaki Mochimaru
Digital Human Research Center, National Institute
of Advanced Industrial Science and
Technology, Tokyo, Japan
Hiroaki Hobara
Email: hobara-hiroaki@aist.go.jp