Free Arms Research Articles

Short-Term Effect of Plyometrics and Strength Training With and Without Superimposed Electrical Stimulation on Muscle Strength and Anaerobic Performance: A Randomized Controlled Trial. Part II

The purpose of this study was to compare the effects of combined strength and plyometric training with or without superimposed electromyostimulation (EMS) on muscle strength and anaerobic power. Twenty-nine subjects were randomly assigned to weight+plyometrics+EMS (EP), weight+plyometrics (VP), and control group (CG). Weight+plyometrics+EMS and VP performed 2 plyometric sessions and 2 weight training sessions per week throughout 4 weeks on a knee extension machine. Weight+plyometrics+EMS received EMS throughout the concentric phase of each action (120 Hz, 400 microseconds). Before, after training, and 2 weeks after the end of the training (detraining), maximal voluntary contraction, squat jump, countermovement jump, countermovement jump with free arms, and 20-minute sprint time were analyzed. After the training period, EP and VP increased their muscle strength (28.6 and 22.3%, respectively; p<0.001). After the detraining period, this gain remained above baseline values (28.1 and 18.0%, respectively; p<0.001 and p<0.01). After training and detraining, muscle strength was higher in EP than in VP (p<0.05). Vertical jump height was not modified for whichever group or test, except for the countermovement jump height with free arms, where a decrease for EP was observed after training (-6.3%; p<0.001) and detraining (-5.5%; p<0.001). Sprint performance improved in all groups in the detraining test (-0.8%; p<0.05). If a low number of training sessions are carried out, superimposed EMS leads to a higher strength gain than voluntary training alone. However, if anaerobic power is an important aim of the training, EMS should be applied isometrically instead of superimposed EMS and combined with plyometrics.

Short-Term Effect of Strength Training With and Without Superimposed Electrical Stimulation on Muscle Strength and Anaerobic Performance. A Randomized Controlled Trial. Part I

The purpose of this study was to compare strength training with and without superimposed electromyostimulation (EMS) on muscle strength and anaerobic power. Twenty-eight subjects were assigned to: weight+EMS (ES), weight (VOL), or control group (CG). ES and VOL performed 4 training sessions per week during 4 weeks on a knee extension machine (8 sets; 8 repetitions; 1-second concentric phase from 90 degrees to 0 degrees, 1-second eccentric phase from 0 degrees to 90 degrees , 1-second rest at 90 degrees; 3-minute rest between sets; 70% maximal voluntary contraction). Group ES received EMS in the concentric phase of each action (120 Hz, 400 microseconds). Before training, after training, and 2 weeks after the end of the training (detraining), maximal voluntary contraction, squat jump, countermovement jump (CMJ), countermovement jump with free arms (CMJA), and 20-m sprint time were analyzed. After the training period, ES and VOL increased their muscle strength (40.2% and 31.4%, respectively, p<0.001). After the detraining period, this gain remained above baseline values for ES and VOL (49.1% and 24.5%, respectively, p<0.001). Changes in muscle strength between baseline and detraining were higher in ES than in VOL (p<0.01). Anaerobic performance was not affected by training in any group, but percentage change between baseline and after training suggests that the CMJ and CMJA with free arms performance were impaired in ES with respect to VOL and CG. Superimposed EMS onto voluntary contractions increases strength more than voluntary training alone; nevertheless, a detraining period should be respected to observe this delayed adaptation. To improve anaerobic power with superimposed EMS, a complementary and specific work such as plyometrics should be carried out.

A Comparison of 2 Optical Timing Systems Designed to Measure Flight Time and Contact Time During Jumping and Hopping

This study was designed to investigate the interchangeability of 2 commercial optical timing systems for measuring flight time and contact time during jumping and hopping. Seventy-three physical education students (33 men and 40 women) participated in this study. They were instructed to perform 3 jump protocols (squat jump, countermovement jump, and countermovement jump free arms) and a hopping test (10 seconds with straight legs at a frequency of 2 Hz). Flight time and contact time were measured with 2 optical timing systems (Optojump, Microgate, Italia and IR-mat, Ergotest, Sweden), consisting of 2 bars placed opposite to each other. Both systems trigger a timer with a precision of 1 millisecond each time the infrared light is interrupted by the feet. Jump height was given by the systems, whereas leg stiffness was computed from contact time and flight time. Flight time was higher when measured with the IR-mat (bias +/- 95% LOA [limits of agreement] = 5 +/- 14 ms, p < 0.001). This difference was trivial (effect size <0.2) and clinically meaningless. The high correlation between sets of data (r = 0.99) together with narrow 95% LOA (3%) support the interchangeability of both systems to measure flight time. Similar results were found with contact time (bias +/- 95% LOA = 8 +/- 23 ms, p < 0.001, effect size <0.2 and r = 0.99), with the exception that it was the Optojump that provided the higher values. These trivial but significant differences between both systems had minor impact on jumping height (bias +/- 95% LOA = 0.6 +/- 1.7 cm, p < 0.001), effect size <0.2 and r = 0.99), and stiffness (bias +/- 95% LOA = 0.8 +/- 1.4 N.m.kg, p < 0.001, effect size <0.2 and r = 0.98). We concluded that both systems can be used interchangeably.

Synthesis, characterisation and coordination chemistry of a new multidentate P2N4 ligand system

A new potentially hexadentate P(2)N(4) ligand has been prepared and its coordination chemistry to Pd(II) and Pt(II) investigated. The ligand bonds in a chelating fashion via the diphosphine backbone to PdCl(2) and PtCl(2) while the appended pyridyl groups remain non-bonding. Abstraction of the chloride ions from the platinum complex results in fluxional exchange of the pyridyl groups in solution at room temperature on the NMR timescale. X-ray crystallographic analysis of this platinum complex revealed a tetracoordinate complex with two bound and two free pyridyl arms.

Synthesis and Characterization of Copper Complexes Containing the Tripodal N7 Ligand Tris{2‐[(pyridin‐2‐ylmethyl)amino]ethyl}amine (=N′‐(Pyridin‐2‐ylmethyl)‐N,N‐bis{2‐[(pyridin‐2‐ylmethyl)amino]ethyl}ethane‐1,2‐diamine): Equilibrium, Spectroscopic Data, and Crystal Structures of Mono‐ and Trinuclear Copper(II) Complexes

AbstractThe stability constants of the CuII chelates with the tripodal heptadentate ligand tris{2‐[(2‐pyridylmethyl)amino]ethyl}amine (=N′‐(pyridin‐2‐ylmethyl)‐N,N‐bis{2‐[(pyridin‐2‐ylmethyl)amino]ethyl}ethane‐1,2‐diamine; tpaa), determined by potentiometry and UV spectrometry, show the formation of [Cu(tpaaH)]3+ and [Cu(tpaa)]2+ species. In the solid state, two mononuclear CuII compounds, [Cu(tpaa)](PF6)2 (1) and [Cu(tpaaH)](ClO4)3⋅H2O (2), and one trinuclear [Cu3(tpaa)2(ClO4)2](ClO4)4⋅2 H2O (3) complex were isolated and characterized by IR, UV/VIS, and EPR spectroscopy. An X‐ray structure of the mononuclear protonated complex 2 shows that the Cu2+ ion has a distorted square‐pyramidal geometry (τ=0.21). and the proton is bound to the secondary‐amine function of one uncoordinated arm of the tripod ligand (Fig. 4). The crystal lattice for 2 is stabilized by the H‐bonds between the N‐atom of the free pyridinyl group with the proton of the free secondary‐amine function of the neighboring molecule. The linear trinuclear complex 3 consists of two entities of the pyramidal mononuclear complex 1 bound to the third central Cu2+ ion by the free unprotonated arms of the ligands in equatorial position (Fig. 5). The octahedral geometry of the third CuII atom is achieved by two perchlorate anions in the axial positions. The redox properties of 1–3 compounds was examined by cyclic voltammetry.

Validation du système Optojump en tant qu'outil d'évaluation de la force-vitesse (puissance) des membres inférieurs

Purpose. – The aim of this study was to examine Optojump system efficiency to analyse lower limbs explosive strength. Methods and results. – Twenty untrained subjects were randomly assigned to 2 groups: either an experimental group ( N =10) or a control group ( N =10). They performed vertical jumps using different techniques and sprints. Reproducibility of jumps and sprint, evaluated by Optojump system, was appreciated after correlation analysis . The experimental group took part in a plyometric training for six weeks. Jumps and sprints showed an excellent reproducibility (mean coefficiant of variation =3.6%). Plyometric training increased ( P <0.001) counter movement jump (+19.6%), counter movement jump free arms (+14%) and drop jump (+27.9%) performances. Conclusion. – This study demonstrated the accuracy and validity of the Optojump system to analyse lower limbs explosive strength.

Comparing Strategies for the Synthesis of Polyolefinic Thermoplastic Elastomers via Macromonomer Incorporation

AbstractThe microstructure of polyolefinic thermoplastic elastomers made with a combination of two single‐site catalysts was analyzed by Monte Carlo simulation. The model can be used to describe the crystallizable fraction for both long‐chain branched polypropylene (aPP‐g‐iPP) and long‐chain branched ethylene/α‐olefin copolymers (PEαO‐g‐PE). The simulations showed that at levels of 7.5% of comonomer incorporation, PEαO‐g‐PE samples reach a similar crystallizability level of aPP‐g‐iPP. From a topological point of view, it was demonstrated that the fraction of free arms and inner segments tend to the limit of ½ for highly branched chains and that the fraction of free arms reaches its maximum value when the Y‐type chains are the predominant population. A mathematical correlation between the linear‐ and LCB catalyst probabilities was proposed to ensure the production of symmetrical branched chains.Long‐chain branch architecture of PEαO‐g‐PE.magnified imageLong‐chain branch architecture of PEαO‐g‐PE.

New Zealand’s Nuclear Free Zone Extension Bill

In 1987 the New Zealand Parliament passed the New Zealand Nuclear Free Zone, Disarmament and Arms Control Act 1987 (see Appendix 1). The Act established in New Zealand a Nuclear Free Zone to promot...

High mass clearance of autoantibodies from a murine model of lupus nephritis by immunoadsorption using star-configured polyethylene glycols.

The extracorporeal immunoadsorption of antibodies as part of the therapy for human autoimmune diseases has been limited by technology with inadequate and nonselective mass clearance or problems with bioincompatibility. To overcome these shortcomings, we designed a method utilizing star-configured polyethylene glycols (star-PEGs) having up to 63 free arms with immunoreactive (tresylate ester) end-groups for each arm immobilized to a polymer support substrate. The flexibility and length of the arms are thought to allow optimization of epitope presentation and to permit interaction with immunoligands on adjacent arms. To demonstrate efficacy we used an in vitro murine antibody model of human lupus nephritis, wherein we could study the kinetics and mass clearance of hybridoma derived antihistone antibodies from human plasma. Histones were covalently bound to the star-PEG end-groups and the kinetics of antibody adsorption were assessed using a surface plasmon resonance technique. The equilibrium constants of antihistone antibody binding to histone-star-PEGs that were linked to a support grid demonstrated high affinity with a KA of 3.56E + 07 and a KD of 2.81E - 08. The optimum reaction conditions were determined to accomplish the hydrophilization of polysulfone (PS; by an aqueous nitration method) and polymethylmethacrylate substrates (PMMA; by hydrazine), using sheet casts of both polymer substances. Hollow fiber devices of these polymers (commercial hemodialyzers) were modified so that histone-bound star-PEGs were linked to their intracapillary luminal surfaces, using a process which we have shown retains their immunoadsorption properties for antihistone antibodies. A closed loop recirculating model was constructed to measure mass clearance of antibodies from a reservoir. After optimizing conditions using extraction from saline solutions, the removal of antibody from human plasma by control and surface-modified devices was assessed over 4 h. There was no measurable antibody clearance by the control fibers over this time interval. The 2.1 m2 luminal surface area PMMA devices removed 5.0 +/- 1.1 mg, with a maximum of 7.0 mg. The 1.8 m2 PS device cleared 11.3 +/- 6.2 mg with a maximum of 17.5 mg. In summary, star-PEG immunoadsorption is a promising technique for the treatment of human autoimmune disease because it can achieve very high-mass clearance of autoantibodies using modified biocompatible hollow-fiber polymer devices.

Rheology of long‐chain randomly branched polybutadiene

The rheology of a series of long‐chain randomly branched polybutadienes (PBDs) has been investigated. Branched samples were made through a hydrosilation reaction between a small difunctional crosslinker and the 1,2 groups distributed on the backbone of near‐monodisperse PBD (Mw=56 000, 137 000; Mw/Mn=1.04). The resulting samples have both dispersity in molecular weight and architecture. The species distribution has been studied using size exclusion chromatography and has been found to agree with the Flory–Stockmayer distribution for the random branching of monodisperse chains. Sinusoidal oscillation and creep/creep recovery experiments were done to determine dynamic moduli, zero shear viscosity, and equilibrium creep compliance. The observation that branching is random allows structural parameters to be calculated such as weight fractions and average molecular weights of free chains, arms, and interior chains. These parameters are used in existing rheology models whose results are compared to experimental...

Disturbed centromeric meiotic pairing leads to chromosome breaks

In Drosophila females an extended deletion of the second autosome pericentric heterochromatin Df(2R)M-S2-10 under heterozygous conditions results in the loss of autosome 2, formation of autosomal compounds and stable acrocentric chromosomes (free arms). The presence of an inversion in the opposite chromosome suppresses the clastogenic effect of the deletion. This effect is presumed to be due to the formation of the conjugational loop in the region of pericentric heterochromatin which subsequently breaks.

Participatory democracy in peace and security decision making: The Aotearoa/new Zealand experience

Asbstract Amongst other initiatives, New Zealand's Labour Government set up a Public Advisory Committee on Disarmament and Arms Control (PACDAC) to promote greater public accountability in peace and security policy making. The process is illustrated via an examination of the New Zealand Nuclear Free Zone, Disarmament and Arms Control Act, and the apparent inconsistencies in New Zealand's anti‐nuclear stance are highlighted. While PACDAC was a vital conduit for effective transmission of research and peace movement concerns into the decision‐making process, the bureaucracy effectively blocked any real movement on the key issues raised. However, PACDAC may yet serve as a useful model for adoption by other countries within the region in order to facilitate this process.

Radial maze performance in young and aged grey mouse lemurs (Microcebus murinus)

Young and aged grey mouse lemurs have been tested in an eight-arm radial maze out of which four arms were blind. An access to a nesting box was only feasible from the far end of the fourth arm, free to visit (= positive reinforcement). Both age groups memorized the position of the blind arms with an equal efficiency and learned very quickly to avoid them. However, repeated visits to the free arms already explored during the trial were noticed with the aged grey mouse lemurs, while the young group returned much less. These results corroborate the theory that age would preferably deteriorate working memory and less the reference memory.

Selective screen to recover pairs of deletion-tandem duplications

A method of selecting pairs of deletion-tandem duplications in an autosome arm of Drosophila has been developed. Males containing autosome 2 and the right and left free arms of this autosome produce gametes with the metacentric and the free arm through meiotic non-disjunction. Unequal exchanges induced in such gametes give deletions and tandem duplications within the left or right chromosomal arms. This approach removes the necessity of using markers to identify deletions in the chromosome region.

Numerical Simulation of the formation of the Sedimentary Zone of Inclusions in Large Steel Ingots

A mushy zone is formed in the lower part of an ingot by the showering of crystallites from the top and by free dendrite arms fused and broken from dendrites growing from the side mould wall. The zo...

Free left arms as precursor molecules in the evolution of Alu sequences

The dimeric Alu molecule of human and other primates is composed of a left and a right arm that are very similar but show characteristic differences. If the Alu sequence has arisen through the fusion of monomeric precursor molecules, the traces of such precursor genes are expected still to be present in contemporary primate DNA. We report finding seven independent human DNA sequences that qualify as descendants of a left-arm precursor gene. Some characteristics in primary and secondary structures of these sequences are described.

Calculation of lift-curve slope using a wing tip biased vortex distribution

equal to one-quarter the width of the bound portion of the preceding horseshoe vortex, and the bound portion of each vortex lies along the quarter-chord of the wing. The control point associated with each horseshoe, which is required for the application of the normal flow boundary condition, is placed on the three-quarter-chord line halfway between its infinitely extending free vortex arms. In total, there are seven horseshoe vortices in the model and, a core vortex that is acted upon by two pairs of wing tip cascades that are each composed of three elements. Also, the cascade geometry is similar to that of the Cantor sets described by Mandelbrot.2 The geometric structure of the model is based on two fundamental flow concepts, which were first put forward by Lanchester3 and later refined by Prandtl, 4 that are generally accepted as accounting for the nature of the flow in the vicinity of a wing. On a global scale, as illustrated by Prandtl, the finite wing is aerodynamically similar to the core horseshoe vortex. However, on a local scale, the spanwise flow in the region of the wing tips is not adequately represented by the basic core vortex. The wing tips allow more fluid to circulate to the upper surface than can be accommodated by this model, and therefore the core vortex by itself would tend to not correctly predict the lift generated by the wing. Introduction of the wing tip cascades, as first described in qualitative terms by Lanchester, accounts for the more elaborate local spanwise distribution of circulation over the wing that is created by the tips. Classically, the variation in circulation along the wing is accounted for by allowing the vortex strength to be a continuous function of the spanwise coordinate. This naturally leads to discretized computational methods like that outlined in the introductory discussion. The present model is an attempt to shift the emphasis from viewing the finite wing as an aerodynamic structure composed of many geometrically similar elemental structures of varying strength to viewing it as a fundamentally two-dimensional aerodynamic structure that is explicitly modified by vortex creation at the wing tips.

THE EARLY RADIATION AND PHYLOGENY OF ECHINODERMS

THE EARLY RADIATION AND PHYLOGENY OF ECHINODERMS

Neutron scattering studies of the H2a-H2b and (H3-H4)2 histone complexes.

Neutron scattering experiments have shown that both the (H3-H4)2 and H2a-H2b histone complexes are quite asymmetric in solution. The (H3-H4)2 tetramer is an oblate or flattened structure, with a radius of gyration almost as large as that of the core octamer. If the tetramer is primarily globular, it must have an axial ratio of about 1:5. It is more likely, however, that this asymmetry results in part from N-terminal arms that extend outward approximately within the major plane of the particle. If this is the case, less asymmetric models for the globular part of the tetramer, including a dislocated disk of the type proposed by Klug et al. (23), can be made consistent with the scattering data. The H2a-H2b dimer, on the other hand, is an elongated structure. The low resolution data are in good agreement with those calculated for a cylindrical model 64 X 27 A, but other elongated models fit those data almost as well, including one that approximates free N-terminal arms at each end. Free arms are not necessary, but they must extend from the ends if they exist. A contrast matching experiment done with 50% deuterated H2b and undeuterated H2a in the reconstituted dimer showed that these two histones must each be rather elongated within the complex and are not just confined to one end. The amount of scattering contrast between the undeuterated and 50% deuterated histones was sufficient to suggest further experiments using complexes reconstituted from mixtures of undeuterated and partially deuterated histones which will help elucidate their arrangement within the histone complexes and within the octamer core of the nucleosome core particle.

One-armed brachiation in gibbons (Hylobates lar).

The locomotor and postural behavior of Hylobates lar was studied in a seminaturalistic environment at the New York Zoological Park. A particular locomotor pattern, one-armed brachiation, was observed and filmed. Analysis indicated that the occurrence of one-armed brachiation as a preferred locomotor pattern was rare and was limited to the carrying of food. The limb and joint movements of one-armed brachiation closely resembled those of two-armed brachiation with differences occurring in the angular rotations of the support and the free arms. Analysis showed how a gibbon could maximize its forward momentum during one-armed brachiation. The adaptive value of one-armed brachiation is discussed in reference to brachiating while carrying food and to brachiating with a fracture of a forelimb. Finally, one-armed brachiation is discussed as an example of the concepts of locomotor totipotentiality and locomotor habit.