DOES SIDE OF AMPUTATION AFFECT 200- AND 400-M RACE TIME IN SPRINTERS USING RUNNING-SPECIFIC PROSTHESES?

Current Paralympic guidelines for track events are generally based on level of amputation, not side of amputation. Since 200- and 400-m sprint races are performed in a counter clockwise direction, the effects of amputations side on sprint race performance in athletes with unilateral lower limb amputation should be investigated. Forty-five unilateral transtibial amputees participating in elite-level 200- and 400-m races were analysed from publicly available Internet broadcasts. For each athlete, official race time, and amputation side were determined. We found no significant difference in official race time between left and right side amputees during the 200- and 400-m sprint, indicating that sprint performance on a standard track in amputee athletes is not affected by amputation side

LATEST RESEARCHES ON RUNNING-SPECIFIC PROSTHESES: TOWARD SOCIAL IMPLEMENTATIONS OF BIOMECHANICS

Recent developments in running-specific prostheses (RSPs) have allowed individuals with lower extremity amputation (ILEAs) to regain the functional capability of running and jumping. However, the biomechanical characteristics of ILEAs using RSPs remain largely unknown. Understanding the biomechanical adaptations that occur during running and jumping with RSPs will assist clinicians and coaches in making objective decisions regarding the most appropriate prostheses, as well as in the fitting and alignment of these devices, for performance improvements in ILEAs. This presentation introduces our project regarding biomechanics of amputee athletes wearing RSPs, and its applications to athletes, prosthetists, manufacturers, and clinicians for the promotion of activity among amputees

COMPARISONS OF SPATIOTEMPORAL PARAMETERS OF 100-M SPRINT AMONG ELITE-, SUB-ELITE AND NON-ELITE AMPUTEE SPRINTERS

We investigated 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. Average speed, step frequency, and step length were calculated Average speed was greatest in elite sprinters, followed by the sub-elite and non-elite groups. Although there was no significant differences in average step frequency, 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

BRAKING AND PROPULSIVE IMPULSES ACROSS A RANGE OF RUNNING SPEEDS IN UNILATERAL TRANSFEMORAL AMPUTEES

Braking and propulsive ground reaction force impulses (GRIs) are mechanical parameters affecting the running performance. The purpose of this study was to determine the braking and propulsive GRIs across a range of speeds in unilateral transfemoral amputees. Ten unilateral transfemoral amputees ran on an instrumented treadmill at incremental speeds of 30%, 40%, 50%, 60%, and 70% of their maximum speed. At all given speeds, the braking GRI of affected limb was significantly smaller than unaffected limb; however, the propulsive GRIs were similar for both limbs. Consequently, the net anteroposterior GRI was positive in affected limb and negative in unaffected limb. These results suggest that the functional role of braking and propulsion is not the same between the limbs. Training for unilateral transfemoral amputees could focus on reducing the braking GRI of unaffected limb

RUNNING MECHANICS IN UNILATERAL TRANSFEMORAL AMPUTEES ACROSS A RANGE OF SPEEDS

Running-specific prostheses (RSP) allows individuals with lower extremity amputations to participate in running activities. The aim of this study was to investigate the average vertical ground reaction force (Favg), step frequency (Freqstep) and contact length (Lc) between intact and prosthetic limb across a range of running speeds. Nine unilateral transfemoral amputees with RSP performed running on instrumented treadmill at incremental speeds of 30, 40, 50, 60 and 70% of their maximum speed. We found that prosthetic limb generated smaller Favg than intact limb, and had similar Freqstep between limbs. However, prosthetic limb had longer Lc than intact limb at faster speeds. These results suggest that unilateral transfemoral amputees using RSP have asymmetrical running mechanics between limbs to adapt to the increasing running speed

THE REBOUND OF THE BODY USING RUNNING-SPECIFIC PROSTHESES IN UNILATERAL TRANSFEMORAL AMPUTEES

Although the elastic bounce of the body is considered a prerequisite for running, the rebound strategy in individuals with lower extremity amputation is not well known. This study aims to investigate the rebound strategy at different running speeds in unilateral transfemoral amputees (uTFAs) wearing running-specific prostheses (RSPs). On an instrumented treadmill, eight uTFAs ran at incremental speeds (30%, 40%, 50%, 60%, 70%, and 80% of the average speed of their 100-m personal records). The rebound strategy of the unaffected and affected limbs is evaluated using the ratio of the natural frequency of the spring-mass system (fsist) to the step frequency (fstep). At all speeds, fsist/fstep in the unaffected limb is considerably greater than that in the affected one. The interlimb differences in fsist/fstep tended to increase with the speed. These results suggest that the rebound strategy is not the same for the unaffected and affected limbs in uTFAs across a range of speeds, and that uTFAs wearing RSPs perform bouncing steps using the alternate asymmetric rebound strategy (fstep \u3c fsist) through different limbs

LEG AND VERTICAL STIFFNESS OF TRANSFEMORAL AMPUTEES USING RUNNING-SPECIFIC PROSTHESES

Since running-specific prostheses (RSPs) emulate spring-like leg functions, human musculoskeletal system is often modelled as a spring-mass model. In the model, the leg (KM) and vertical stiffness (KM) is known to strongly influence running performance. The purpose of this study was to quantify the asymmetry in stiffness between the intact limbs and prosthetic limbs during sprinting. Eight sprinters with unilateral transfemoral amputation performed overground sprinting at maximum speed. & and Kw,t were calculated from vertical ground reaction force data in both the intact and prosthetic limbs. & was significantly greater in intact limbs than prosthetic limbs. Although there was no significant difference on Kvert, cohen's d of Kvert between legs was 1.28. Therefore KM might have potential significant difference

COMPARISON OF GROUND REACTION FORCES IN TWO RUNNING-SPECIFIC PROSTHESES (SPRINTER 1 E90 AND CHEETAH XTREME): A CASE STUDY

The purpose of this study was to describe the difference in ground reaction forces (GRF) between tvm different running-specific prostheses (RSPs) during maximal sprinting in a transfemoral amputee. One male sprinter performed maximal sprinting with two types of RSP (Sprinter 1E90 and Xtreme) on over 40 m runway with 7 force plates located halfway. Sprint velocity was found to be greater in the trials performed with Sprinter 1 E9O than with Xtreme. The peak VGRF, zero fore-aft shear and impulse of the anteriorposterior component of the GRF with PST limb differed among the two RSPs. These results suggest that the participant in this study would show the differences in variables influencing on the sprint velocity between two types of RSPs

FRONTAL PLANE TAKE-OFF STEP MECHANICS OF LONG JUMPERS WITH AND WITHOUT A BELOW THE KNEE AMPUTATION

Frontal plane mechanics during the long jump take-off step are unknown for athletes with and without a transtibial amputation. This is an issue due to the importance of the knowledge for training and rehabilitation protocols or prosthetic design. In this study the take-off step of three long jumpers with and seven without a below the knee amputation (BKA) were analysed with regard to frontal plane mechanics. Three-dimensional motion capture (Vicon) and a force plate (Kistler) were used to capture kinematic and kinetic data. Inverse dynamic calculations (Dynamicus, Alaska) revealed differences in frontal plane center of mass kinematics and joint kinetics between groups. Specifically, athletes with BKA had lower medio-lateral ground reaction forces, lower frontal plane joint loads and an altered foot position pattern compared to non-amputee athletes