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

Total arterial revascularization with composite skeletonized gastroepiploic artery graft in off-pump coronary artery bypass grafting

AbstractBackgroundTotal arterial revascularization in coronary artery bypass grafting has recently become of great interest to many surgeons. At the same time, off-pump coronary bypass grafting has also become a popular procedure because of its low morbidity and mortality. Here we report our recent series of off-pump coronary bypass grafting performed with a grafting technique we developed by using the skeletonized gastroepiploic artery and the radial artery composite graft to achieve total arterial revascularization.MethodsFrom September 2000 to April 2003, 98 patients underwent total arterial revascularization with the skeletonized gastroepiploic artery and radial artery composite graft on the beating heart. We used the gastroepiploic artery graft of choice in patients with a right coronary artery lesion. When multiple grafting was required in inferior, posterolateral, or lateral ventricular walls and the gastroepiploic artery graft was too short to cover these areas, we used the composite grafting technique.ResultsThere were no in-hospital deaths and there was no severe morbidity among the study patients. Postoperative angiography showed graft occlusion at the anastomosis site between the gastroepiploic and radial arteries. The patency rate of the gastroepiploic arterial composite graft was 98.3% (118/120 distal anastomoses).ConclusionsA composite graft with the skeletonized gastroepiploic artery and the radial artery ensured sufficient caliber size and length for myocardial revascularization on inferior, posterolateral, and lateral ventricular walls. This composite graft can be used safely and effectively even in off-pump coronary bypass surgery with excellent early clinical and angiographic outcome in selected patients, although longer follow-up periods are necessary to draw definitive conclusions

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

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

Environmental changes in Syowa Station area of Antarctica during the last 2300 years inferred from organic components in lake sediment cores

rganic components in sediment cores from Namazu Ike(lake)(length 40cm) and O-ike(lake)(length 32cm) from Syowa Station area, Antarctica were studied to clarify their features in relation to paleoenvironmental changes, together with carbon-14 dating by Tandetron accelerator mass spectrometry. Namazu Ike sediment core was mainly composed of algal(mainly cyanobacteria) and aquatic moss debris, whereas O-ike sediment core was comprised of coarse and fine sands with the influence of algal(mainly cyanobacteria) debris. The ages of core bottoms of Namazu Ike and O-ike were estimated to be 1550 and 2330 years before present(yBP), respectively. The sedimentation rates of Namazu Ike and O-ike were calculated to be 30 and 59 years/cm, respectively. Very high total organic carbon(TOC) contents(average 24.5%) of Namazu Ike revealed that the sediment core was mainly composed of organic matter. Dramatic increase of TOC/total nitrogen ratios at a depth of 25cm in Namazu Ike strongly suggests that aquatic moss increased from 1100yBP to the core top. Changes in n-alkanes, n-alkanoic and n-alkenoic acids, and sterol compositions in the O-ike sediment core, suggest that microbial composition changed considerably, but their source organisms are not clear and further studies are required