Gender differences in patellofemoral load during the epee fencing lunge

Clinical analyses have shown that injuries and pain linked specifically to fencing training/competition were prevalent in 92.8% of fencers. Patellofemoral pain is the most common chronic injury in athletic populations and females are considered to be more susceptible to this pathology. This study aimed to examine gender differences in patellofemoral contact forces during the fencing lunge. Patellofemoral contact forces were obtained from eight male and eight female club level epee fencers using an eight-camera 3D motion capture system and force platform data as they completed simulated lunges. Independent t-tests were performed on the data to determine whether gender differences in patellofemoral contact forces were present. The results show that females were associated with significantly greater patellofemoral contact force parameters in comparison with males. This suggests that female fencers may be at greater risk from patellofemoral pathology as a function of fencing training/competition.Peer reviewedFinal Accepted Versio

Confirmation of co-denitrification in grazed grassland

peer-reviewedPasture-based livestock systems are often associated with losses of reactive forms of nitrogen (N) to the environment. Research has focused on losses to air and water due to the health, economic and environmental impacts of reactive N. Di-nitrogen (N2) emissions are still poorly characterized, both in terms of the processes involved and their magnitude, due to financial and methodological constraints. Relatively few studies have focused on quantifying N2 losses in vivo and fewer still have examined the relative contribution of the different N2 emission processes, particularly in grazed pastures. We used a combination of a high 15N isotopic enrichment of applied N with a high precision of determination of 15N isotopic enrichment by isotope-ratio mass spectrometry to measure N2 emissions in the field. We report that 55.8 g N m−2 (95%, CI 38 to 77 g m−2) was emitted as N2 by the process of co-denitrification in pastoral soils over 123 days following urine deposition (100 g N m−2), compared to only 1.1 g N m−2 (0.4 to 2.8 g m−2) from denitrification. This study provides strong evidence for co-denitrification as a major N2 production pathway, which has significant implications for understanding the N budgets of pastoral ecosystems.The authors are grateful for the funding that was provided through the Research Stimulus Fund Program administered by the Department of Agriculture & Food under the National Development Plan 2007–2013 RSF 07536. The first author is grateful for the funding provided by Teagasc through the Walsh Fellowship Scheme

THE EVOLUTION OF POSE ESTIMATION ALGORITHMS FOR 3D MOTION CAPTURE DATA: COPING WITH UNCERTAINTY

At the heart of many biomechanical analyses is the estimation of the pose (position and orientation) of a multi-segment model based on recording of 3D motion data. The principle assumption of most pose estimation algorithms is that sensors move rigidly with the body segments to which they are attached. It is accepted, however r, that sensors attached to the skin move e relative to the underlying skeleton and that this idiosyncratic Soft Tissue Artifact (STA A) is challenging to model. Usually pose is estimated with discriminative algorithms that are ill-suited to the uncertainty of STA. Emerging algorithms based on probabilistic inference may mitigate STA by encoding the pose e and any prior knowledge about the pose e probabilistically, and capture the “artifacts” using a generative model

The Book Truly Stops Here: A Lacanian Reinterpretation of Reinaldo Arenas’ Freedom

In his essay, “Reinaldo Arenas, Re-writer Revenant, and the Repatriation of Cuban Homoerotic Desire,” Benigno Sánchez-Eppler puts forth what he terms a “signifying possibility,” an informative yet nondefinitive explanation of what the exiled queer Cuban novelist Reinaldo Arenas meant in his suicide note. Arenas’ suicide note, which served as the conclusion to his autobiography, Before Night Falls: A Memoir, written in 1990 and published posthumously in 1992, has an inconclusive meaning stemming from the novelist’s brief declaration of his own freedom at the end. After encouraging the Cuban people to remain vigilant in their fight for freedom and against the rule of Fidel Castro, Arenas succinctly yet confidently declares that he himself is already free without suggesting the source of his freedom. Citing various works of the novelist, Sánchez-Eppler argues that this individual freedom originates from the exiled novelist’s literary act of self-repatriation, using suicide as an inspired form of return to his homeland. This essay argues against Sánchez-Eppler’s signifying possibility. As expressed in his suicide note, Arenas’ notion of freedom, far from being a literary monumentalization of the writer and his Cuban queerness, destined to be creatively repatriated back to his native Cuba through the vehicle of suicide, is more an example of a successful Lacanian “end-of-analysis,” when the individual subject comes to terms with and accepts his or her own irredeemably divided self in the present. My own “signifying possibility” for interpreting Reinaldo Arenas’ freedom relies on Lacanian psychoanalysis, as interpreted by critical race and Lacanian theorist Antonio Viego in his book, Dead Subjects: Toward A Politics of Loss in Latino Studies

Confirmation of co-denitrification in grazed grassland

Pasture-based livestock systems are often associated with losses of reactive forms of nitrogen (N) to the environment. Research has focused on losses to air and water due to the health, economic and environmental impacts of reactive N. Di-nitrogen (N₂) emissions are still poorly characterized, both in terms of the processes involved and their magnitude, due to financial and methodological constraints. Relatively few studies have focused on quantifying N₂ losses in vivo and fewer still have examined the relative contribution of the different N₂ emission processes, particularly in grazed pastures. We used a combination of a high ¹⁵N isotopic enrichment of applied N with a high precision of determination of ¹⁵N isotopic enrichment by isotope-ratio mass spectrometry to measure N₂ emissions in the field. We report that 55.8 g N m⁻² (95%, CI 38 to 77 g m⁻²) was emitted as N₂ by the process of co-denitrification in pastoral soils over 123 days following urine deposition (100 g N m⁻²), compared to only 1.1 g N m⁻² (0.4 to 2.8 g m⁻²) from denitrification. This study provides strong evidence for co-denitrification as a major N₂ production pathway, which has significant implications for understanding the N budgets of pastoral ecosystems

Inhibition of Y1 receptor signaling improves islet transplant outcome

Failure to secrete sufficient quantities of insulin is a pathological feature of type-1 and type-2 diabetes, and also reduces the success of islet cell transplantation. Here we demonstrate that Y1 receptor signaling inhibits insulin release in β-cells, and show that this can be pharmacologically exploited to boost insulin secretion. Transplanting islets with Y1 receptor deficiency accelerates the normalization of hyperglycemia in chemically induced diabetic recipient mice, which can also be achieved by short-term pharmacological blockade of Y1 receptors in transplanted mouse and human islets. Furthermore, treatment of non-obese diabetic mice with a Y1 receptor antagonist delays the onset of diabetes. Mechanistically, Y1 receptor signaling inhibits the production of cAMP in islets, which via CREB mediated pathways results in the down-regulation of several key enzymes in glycolysis and ATP production. Thus, manipulating Y1 receptor signaling in β-cells offers a unique therapeutic opportunity for correcting insulin deficiency as it occurs in the pathological state of type-1 diabetes as well as during islet transplantation.Islet transplantation is considered one of the potential treatments for T1DM but limited islet survival and their impaired function pose limitations to this approach. Here Loh et al. show that the Y1 receptor is expressed in β- cells and inhibition of its signalling, both genetic and pharmacological, improves mouse and human islet function.info:eu-repo/semantics/publishe

Effects of gluteal kinesio-taping on performance with respect to fatigue in rugby players

Kinesio-tape® has been suggested to increase blood circulation and lymph flow and might influence the muscle's ability to maintain strength during fatigue. Therefore, the aim of this study was to investigate the influence of gluteal Kinesio-tape® on lower limb muscle strength in non-fatigued and fatigued conditions. A total of 10 male rugby union players performed 20-m sprint and vertical jump tests before and after a rugby-specific fatigue protocol. The 20-m sprint time was collected using light gates (SMARTSPEED). A 9-camera motion analysis system (VICON, 100 Hz) and a force plate (Kistler, 1000 Hz) measured the kinematics and kinetics during a counter movement jump and drop-jump. The effect of tape and fatigue on jump height, maximal vertical ground reaction force, reactivity strength index as well as lower limb joint work were analysed via a two-way analysis of variance. The fatigue protocol resulted in significantly decreased performance of sprint time, jump heights and alterations in joint work. No statistical differences were found between the taped and un-taped conditions in non-fatigued and fatigued situation as well as in the interaction with fatigue. Therefore, taping the gluteal muscle does not influence the leg explosive strength after fatiguing in healthy rugby players

The influence of hand positions on biomechanical injury risk factors at the wrist joint during the round-off skills in female gymnastics

The aim of this study was to examine the biomechanical injury risk factors at the wrist, including joint kinetics, kinematics and stiffness in the first and second contact limb for parallel and T-shape round-off (RO) techniques. Seven international-level female gymnasts performed 10 trials of the RO to back handspring with parallel and T-shape hand positions. Synchronised kinematic (3D motion analysis system; 247 Hz) and kinetic (two force plates; 1235 Hz) data were collected for each trial. A two-way repeated measure analysis of variance (ANOVA) assessed differences in the kinematic and kinetic parameters between the techniques for each contact limb. The main findings highlighted that in both the RO techniques, the second contact limb wrist joint is exposed to higher mechanical loads than the first contact limb demonstrated by increased axial compression force and loading rate. In the parallel technique, the second contact limb wrist joint is exposed to higher axial compression load. Differences between wrist joint kinetics highlight that the T-shape technique may potentially lead to reducing these bio-physical loads and consequently protect the second contact limb wrist joint from overload and biological failure. Highlighting the biomechanical risk factors facilitates the process of technique selection making more objective and safe

The Influence of Minimalist Footwear on Knee and Ankle Load during Depth Jumping

Plyometric training is used by athletes to promote strength and explosive power. However plyometric activities such as depth jumping are associated with a high incidence of injuries. This study examined the influence of minimalist and conventional footwear on the loads experienced by the patellofemoral joint and Achilles tendon. Patellofemoral and Achilles tendon forces were obtained from ten male participants using an eight camera 3D motion capture system and force platform data as they completed depth jumps in both footwear conditions. Differences between footwear were calculated using paired t-tests. The results show that the minimalist footwear were associated with significantly lower patellofemoral contact force/ pressure and also knee abduction moment. It is therefore recommended based on these observations that those who are susceptible to knee pain should consider minimalist footwear when performing plyometric training

Simulation Of Human Jumping - Task Alteration

Similar human motions are often grouped together into a single movement class. In jumping, the question of similarity in control and coordination of different tasks within a movement class has been addressed by altering the direction of maximal effort jumps between vertical and horizontal (Jensen & Phillips, 1991). Other researchers have studied vertical jumping using computer simulations (Pandy & Zajac, 1991; van Soest et al., 1993), but have not addressed the issue of modifying the jumping task. The purpose of the present study was to investigate the effect of task alteration on forward .dynamic simulations of jumping. The simulation model was comprised of 4 linked rigid segments (Fig. 1). Segmental motion was controlled by 3 torque generators defined with pre-set magnitudes and activation time constants. All jumps began from a static posture with all torques set to zero. Each jumping performance was dictated by the onset times of each torque generator. The choice of task was specified by one of two objective functions: 1) vertical height, or 2) horizontal distance. The optimization algorithm searched for the pattern of activation onset times for the 3 torque generators which maximized each objective function. A variety of tests were performed to compare the model's optimal vertical and horizontal jumping performance, and the underlying coordination of torque generation. With the set of initial conditions shown in Fig. la (00 = (1.0,-0.7,1.1,-0.8}), the model's maximum height was 1.814 m, with a forward displacement of 0.39 m. For the optimal forward jump the displacement increased to only 0.73 m. However, by changing the initial posture (00 = (0.8,-1.0,0.8,-1.0}) the optimal forward jump was improved to 1.87 m (Fig. lb), but the optimal vertical jump was reduced to 1.465 m. The relative magnitude of onset times varied substantially between the two optimal jumps. For the conditions studied, the order of onset times does not follow the proximo-distal sequence often .proported for humans, and the relative timing of joint torques changes with task. The results illustrate the dependence of the optimal solution on initial conditions. Further work will examine the relations between initial conditions, coordination and perfommance