BLADE KINETICS OF A UNILATERAL PROSTHETIC ATHLETE IN CURVE SPRINTING

In athletics sprinting longer than 100 m, athletes will run more than 50% in a curve. No data on ground reaction forces or joint kinetics of prosthetic curve sprinting can be found in the scientific literature. The purpose of this study was to analyze GRFs and moments acting on the prosthesis’ blade using a 3D motion capture system and four force plates. A left sided unilateral amputee athlete (knee exarticulation) of highest international level, ran 30 m straight and curved clockwise and counter clockwise. GRFs show differences between curve and straight running. Results show different loading applied to the blade of a prosthesis when curve running in comparison with straight running. The study gives an inside into the kinetics of amputee curve running and might affect the construction and design of future prosthesis generations as well as performance diagnostics

Associations between long-term exercise participation and lower limb joint and whole-bone geometry in young and older adults

Introduction: Features of lower limb bone geometry are associated with movement kinematics and clinical outcomes including fractures and osteoarthritis. Therefore, it is important to identify their determinants. Lower limb geometry changes dramatically during development, partly due to adaptation to the forces experienced during physical activity. However, the effects of adulthood physical activity on lower limb geometry, and subsequent associations with muscle function are relatively unexplored. Methods: 43 adult males were recruited; 10 young (20–35 years) trained i.e., regional to world-class athletes, 12 young sedentary, 10 older (60–75 years) trained and 11 older sedentary. Skeletal hip and lower limb geometry including acetabular coverage and version angle, total and regional femoral torsion, femoral and tibial lateral and frontal bowing, and frontal plane lower limb alignment were assessed using magnetic resonance imaging. Muscle function was assessed recording peak power and force of jumping and hopping using mechanography. Associations between age, training status and geometry were assessed using multiple linear regression, whilst associations between geometry and muscle function were assessed by linear mixed effects models with adjustment for age and training. Results: Trained individuals had 2° (95% CI:0.6°–3.8°; p = 0.009) higher femoral frontal bowing and older individuals had 2.2° (95% CI:0.8°–3.7°; p = 0.005) greater lateral bowing. An age-by-training interaction indicated 4° (95% CI:1.4°–7.1°; p = 0.005) greater acetabular version angle in younger trained individuals only. Lower limb geometry was not associated with muscle function (p > 0.05). Discussion: The ability to alter skeletal geometry via exercise in adulthood appears limited, especially in epiphyseal regions. Furthermore, lower limb geometry does not appear to be associated with muscle function

Between-Subject and Within-Subject Variation of Muscle Atrophy and Bone Loss in Response to Experimental Bed Rest

To improve quantification of individual responses to bed rest interventions, we analyzed peripheral quantitative computer tomography (pQCT) datasets of the lower leg of 76 participants, who took part in eight different bed rest studies. A newly developed statistical approach differentiated measurement uncertainty UMeas from betweensubject-variation (BSV) and within-subject variation (WSV). The results showed that UMeas decreased 59.3–80% over the two decades of bed rest studies (p < 0.01), and that it was higher for muscles than for bones. The reduction of UMeas could be explained by improved measurement procedures as well as a higher standardization. The vast majority (89.6%) of the individual responses pci exceeded the 95% confidence interval defined by UMeas, indicating significant and substantial BSV, which was greater for bones than for muscles, especially at the epiphyseal measurement sites. Non-significant to small positive inter-site correlations between bone sites, but very large positive inter-site correlation between muscle sites suggests that substantial WSV exists in the tibia bone, but much less so in the calf musculature. Furthermore, endocortical circumference, an indicator of the individual’s bone geometry could partly explain WSV and BSV. These results demonstrate the existence of substantial BSV bone, and that it is partly driven by WSV, and likely also by physical activity and dietary habits prior to bed rest. In addition, genetic and epigenetic variation could potentially explain BSV, but not WSV. As to the latter, differences of bone characteristics and the bone resorption process could offer an explanation for its existence. The study has also demonstrated the importance of duplicate baseline measurements. Finally, we provide here a rationale for worst case scenarios with partly effective countermeasures in long-term space missions

Wie wird weniger genug? Suffizienz als Strategie für eine nachhaltige Stadtentwicklung

Viele Städte sind unter Druck: Der Wohnraumbedarf steigt und mit ihm die Kosten für das Wohnen. Gewerbe und Handel wünschen sich zusätzlich Raum - vor allem am Stadtrand. Jedes Jahr werden mehr und immer größere Autos zugelassen, für die es Verkehrs- und Parkflächen braucht. Bislang reagieren Kommunen auf steigende Anforderungen mit Wachstum, das heißt, Brachen oder Ackerland werden in Siedlungsfläche umgewandelt. Dort aber, wo Flächenkonflikte durch Wachstum gelöst werden, kollidiert dies mit Nachhaltigkeitszielen; mit der Reduktion von Emissionen oder dem schonenden Umgang mit Ressourcen. Wie also wird weniger genug? Wie gelingt es, die Stadt für alle Menschen bezahlbar, lebenswert und alltagstauglich zu machen, ohne immer mehr Ressourcen zu verbrauchen? Die Nachhaltigkeitsstrategie der Suffizienz setzt auf Verhaltensänderung anstelle von Wachstum, um diese Ziele zu erreichen. Suffizienz in der Stadtentwicklung bedeutet, die städtische Infrastruktur so umzubauen, dass ressourcenarmes Leben einfach wird. Suffizienz fördert öffentlichen Wohlstand und schränkt privaten Luxus ein. Konkret heißt das, funktionsgemischte Quartiere, die Stadt der kurzen Wege, gemeinschaftliches Wohnen oder die Innen- vor Außenentwicklung voranzutreiben. Entlang zahlreicher Beispiele aus der Praxis zeigt die Publikation, wie suffizienzorientierte Stadtentwicklung gelingen kann, ohne die Grenzen der Suffizienz in einer wachstumsorientierten Gesellschaft zu verschweigen. Die Publikation ist ein Ergebnis eines transdisziplinären Forschungs- und Entwicklungsvorhabens von Wissenschaftler*innen des Norbert Elias Centers der Europa-Universität Flensburg und der Verwaltung der Stadt Flensburg

ATHLETIC: Pseudo Anthropometric Exoskeleton with a Semi Passive Actuation System for Countermeasure

This paper presents the ongoing ESA project ATHLETIC (AstronauT HeaLtH EnhancemenT Integrated Countermeasure) which aims to develop a new approach of integrated countermeasure device in the shape of an exoskeleton. It focuses primarily on the training of the lower limbs, which are the most heavily affected body parts while astronauts are exposed to microgravity. The ATHLETIC system enables High Intense Resistive Training exercises (HIRT), as well as plyometric exercises such as hopping and jumping. Development and validation shall give an answer to the question if exoskeleton technology is suitable for countermeasure in zero gravity and how such a system performs compared to existing countermeasure devices for zero gravity applications

Effects of ageing and fitness on hopping biomechanics

Physical exercise promotes healthy aging and is associated with greater functionality and quality of life. Muscle strength and power are established factors in the ability to perform daily tasks and live independently. Stiffness, for mechanical reasons, is another important constituent of running performance and locomotion. This study aims to analyze the impact of age and training status on one-legged hopping biomechanics and to evaluate whether age-related power decline can be reduced with regular physical exercise. Forty-three male subjects were recruited according to their suitability for one of four groups (young athletes, senior athletes, young controls and senior controls) according to their age (young between 21 and 35, vs. older between 59 and 75) and training status (competing athletes vs. non-physically active). The impact of age and training status on one-legged hopping biomechanics were evaluated using the two-way analysis of variance (ANOVA) method. Significant differences among groups were found for hopping height (p &lt; 0.05), ground contact time (p &lt; 0.05), peak ground reaction force (p &lt; 0.05) and peak power (p &lt; 0.01). No differences among groups were found in ground-phase vertical displacement and vertical stiffness (p &gt; 0.05). Young athletes and older non-physically active people achieved the best and worst performance, respectively. Interestingly, there were not any differences found between young non-physically active people and senior athletes, suggesting that chronic training can contribute to partly offset effects that are normally associated with aging

Curvature of gastrocnemius muscle fascicles as function of muscle-tendon complex length and contraction in humans

It has been shown that muscle fascicle curvature increases with increasing contraction level and decreasing muscle–tendon complex length. The analyses were done with limited examination windows concerning contraction level, muscle–tendon complex length, and/or intramuscular position of ultrasound imaging. With this study we aimed to investigate the correlation between fascicle arching and contraction, muscle–tendon complex length and their associated architectural parameters in gastrocnemius muscles to develop hypotheses concerning the fundamental mechanism of fascicle curving. Twelve participants were tested in five different positions (90°/105°*, 90°/90°*, 135°/90°*, 170°/90°*, and 170°/75°*; *knee/ankle angle). They performed isometric contractions at four different contraction levels (5%, 25%, 50%, and 75% of maximum voluntary contraction) in each position. Panoramic ultrasound images of gastrocnemius muscles were collected at rest and during constant contraction. Aponeuroses and fascicles were tracked in all ultrasound images and the parameters fascicle curvature, muscle–tendon complex strain, contraction level, pennation angle, fascicle length, fascicle strain, intramuscular position, sex and age group were analyzed by linear mixed effect models. Mean fascicle curvature of the medial gastrocnemius increased with contraction level (+5 m−1 from 0% to 100%; p = 0.006). Muscle–tendon complex length had no significant impact on mean fascicle curvature. Mean pennation angle (2.2 m−1 per 10°; p < 0.001), inverse mean fascicle length (20 m−1 per cm−1; p = 0.003), and mean fascicle strain (−0.07 m−1 per +10%; p = 0.004) correlated with mean fascicle curvature. Evidence has also been found for intermuscular, intramuscular, and sex-specific intramuscular differences of fascicle curving. Pennation angle and the inverse fascicle length show the highest predictive capacities for fascicle curving. Due to the strong correlations between pennation angle and fascicle curvature and the intramuscular pattern of curving we suggest for future studies to examine correlations between fascicle curvature and intramuscular fluid pressure

NEX4EX: Novel Exercise Hardware for Exploration

This paper presents the NEX4EX project Novel Exercise Hardware for Exploration, which aims to design, build and validate a full-body countermeasure platform that enables high intensive resistive and plyometric exercise as well as postural control training, and strength training. The NEX4EX exerciser herewith addresses neuromuscular and musculoskeletal deconditioning. The intended use is to improve crew health and fitness maintenance for long-duration space missions beyond ISS lifetime. This will require the system to be multi-purpose / versatile in terms of exercises added to a smaller footprint than systems currently used on ISS. NEX4EX is a novel concept for a novel utilization paradigm given future space exploration-class missions

NEX4EX: Novel Exercise Hardware for Exploration

This paper presents the NEX4EX project Novel Exercise Hardware for Exploration, which aims to design, build and validate a full-body countermeasure platform that enables high intensive resistive and plyometric exercise as well as postural control training, and strength training. The NEX4EX exerciser herewith addresses neuromuscular and musculoskeletal deconditioning. The intended use is to improve crew health and fitness maintenance for long-duration space missions beyond ISS lifetime. This will require the system to be multi-purpose / versatile in terms of exercises added to a smaller footprint than systems currently used on ISS. NEX4EX is a novel concept for a novel utilization paradigm given future space exploration-class missions