1,456 research outputs found
Vertical- vs. Horizontal-Oriented Drop Jump Training: Chronic Effects on Explosive Performances of Elite Handball Players
No full textDello Iacono, A, Martone, D, Milic, M, and Padulo, J. Vertical- vs. horizontal-oriented drop jump training: chronic effects on explosive performances of elite handball players. J Strength Cond Res 31(4): 921-931, 2017-This study aimed to assess the chronic effects of vertical drop jump (VDJ)- and horizontal drop jump (HDJ)-based protocols on neuromuscular explosive abilities, such as jumping, sprinting, and changes of direction (COD). Eighteen elite male handball players (age 23.4 ± 4.6 years, height 192.5 ± 3.7 cm, weight 87.8 ± 7.4 kg) were assigned to either VDJ or HDJ group training twice a week for 10 weeks. Participants performed 5-8 sets × 6-10 repetitions of vertical alternate (VDJ) or horizontal alternate (HDJ) 1-leg drop jumps, landing from the top of a platform 25 cm in height. Before and after training, several performance, kinetic, and kinematic variables were assessed. The HDJ led to greater improvement of the sprint time (-8.5% vs. -4%, p ≤ 0.05) and COD performance in comparison with the VDJ (-7.9% vs. -1.1%, p ≤ 0.05), whereas the VDJ caused greater improvement in the vertical jump compared with the HDJ (+8.6% vs. +4.1%, p ≤ 0.05). Moreover, the VDJ regimen compared with the HDJ induced greater changes in the kinetic variables associated with vertical jumping performance, such as peak ground reaction forces (+10.3% vs. +4.3%), relative impulse (+12.4% vs. +5.7%), leg spring stiffness (+17.6% vs. +4.6%), contact time (CT) (-10.1% vs. -1.5%), and reactive strength index (+7.2% vs. +2.1%); all comparisons with p ≤ 0.05. Conversely, the HDJ regimen was able to improve the short-distance and COD performances by increasing the step length (+3.5% vs. +1.5% with p ≤ 0.05) and reducing the CT on COD (-12.1% vs. -2.1% with p ≤ 0.05) more than the VDJ. This investigation showed the crucial role that specific plyometric regimens play in optimizing similar biomechanical featured functional performances, such as jumping, sprinting, and COD
Game Profile-Based Training in Soccer: A New Field Approach
No full textDello Iacono, A, Martone, D, Cular, D, Milic, M, and Padulo, J. Game profile-based training in soccer: a new field approach. J Strength Cond Res 31(12): 3333-3342, 2017-The aim of the study was to profile and compare the time-motion, physiological, and neuromuscular responses of both National Youth League (NYL) and UEFA Youth League (UYL) matches with those of an experimental game profile-based training (GPBT) protocol. Time-motion traits and physiological, perceptual, and neuromuscular responses were investigated in 24 male soccer players across 14 matches and 6 GPBT training sessions, for a total of 420 samples. The GPBT had a greater influence on time-motion traits and perceptual responses than the NYL and UYL matches (all p < 0.001). No significant GPBT vs. match differences were found for mean heart rate or blood lactate (F = 1.228, p = 0.304, and F = 0.978, p = 0.385, respectively). Finally, the GPBT protocol led to greater impairment of the neuromuscular explosive performances when compared with those of the postmatch scores (squat jump: F = 19.991, p < 0.001; countermovement jump: F = 61.703, p < 0.001). Results identified the GPBT protocol as characterized by relatively greater high-intensity workloads than official NYL and UYL matches, requiring increased demanding efforts. In light of these outcomes, the GPBT protocol can be considered an advantageous training method for elite soccer players, capable of stimulating the physical effort and physiological capabilities required during a match. This approach is favorable when designing a training intervention according to the principle of sport specificity, as it is based on the specific metabolic demands
Fullerene Unsymmetrical Bis-Adducts as Models for Novel Peptidomimetics
No full textTwo classes of unsymmetrical, orthogonally protected bis-fulleropyrrohdine amino acids have been prepared as models for fullerene-based peptidomimetics with the carbon sphere inserted into the peptide backbone Two successive [3+2] cycloadditions of azomethine ylides (thermally generated from formaldehyde and the corresponding orthogonally protected glycino-amines and -acids) to C(60) afforded NHFmoc/CO(2)tBu and NHBoc/CO(2)Me fulleropyrrolidine couples, offering the possibility of selective deprotection under both acidic and basic conditions In both classes of unsymmetrical bis-adducts, the distribution of all the trans (t(1)-t(4)) and equatorial (e' and e '') isomers was quite similar except. for the t(3) NHBoc/CO(2)Me compound, which rapidly decomposed during chromatography All compounds were characterized by UV/Vis, (1)H and (13)C NMR spectroscopy, and mass spectrometr
The Grey Web: dataveillance vision fulfilled through the evolving Web
No full textOver the past three decades, Web has evolved from an information medium to an intricate economic ecosystem. Initially focused on supporting the transition from traditional business practices to e-commerce, the Web has given rise to new, purely Web based businesses. Aligned with the original vision and expectations of the ‘free Web’, they have provided free services but, over time, developed business models that leverage the user digital footprints and the user generated content to create economic value. With the use of computing technologies to analyze, aggregate, and share such data, individuals’ privacy has been undermined and, with that, the their ability to shape their role in the digital society and beyond. The purpose of this paper is to instigate the dialogue around the critical societal issues that arise from the current Web economy and motivate research initiatives to assist with addressing them. We present three case studies that quantify the extent, rate, and pervasiveness of the user tracking on the Web. We use them to illustrate the determining aspects of the Web that have to be taken into account by the Web Science community. As researchers we aspire to understand the nature of the Web in depth and, based on that, propose designs and policies that are required to ensure that the Web is fit to be the underpinning of our societies and our digital future
Interrupter technique for measurement of respiratory mechanics in anesthetized humans
No full textFlow (V), volume (V), and tracheal pressure (Ptr) were measured throughout a series of brief (100 ms) interruptions of expiratory V in six patients during anesthesia (halothane-N2O) and anesthesia-paralysis (succinylcholine). For the latter part of spontaneous expiration and throughout passive deflation during muscle paralysis, a plateau in postinterruption Ptr was observed, indicating respiratory muscle relaxation. Under these conditions, passive elastance of the total respiratory system (Ers) was determined as the plateau in postinterruption Ptr divided by the corresponding V. The pressure-flow relationship of the total system was determined by plotting the plateau in Ptr during interruption against the immediately preceding V. Ers averaged 23.5 +/- 1.9 (SD) cmH2O X l-1 during anesthesia and 25.5 +/- 5.4 cmH2O X l-1 during anesthesia-paralysis. Corresponding values of total respiratory system resistance were 2.0 +/- 0.8 and 1.9 +/- 0.6 cmH2O X l-1 X s, respectively. Respiratory mechanics determined during anesthesia paralysis using the single-breath method (W.A. Zin, L. D. Pengelly, and J. Milic-Emili, J. Appl. Physiol. 52: 1266-1271, 1982) were also similar. Early in spontaneous expiration, however, Ptr increased progressively during the period of interruption, reflecting the presence of gradually decreasing antagonistic (postinspiratory) pressure of the inspiratory muscles. In conclusion, the interrupter technique allows for simultaneous determination of the passive elastic as well as flow-resistive properties of the total respiratory system. The presence of a plateau in postinterruption Ptr may be employed as a useful and simple criterion to confirm the presence of respiratory muscle relaxation
Revisiting revisitation in computer interaction: organic bookmark management
No full textAccording to Milic-Frayling et al. (2004), there are two general ways of user browsing i.e. search (finding a website where the user has never visited before) and revisitation (returning to a website where the user has visited in the past). The issue of search is relevant to search engine technology, whilst revisitation concerns web usage and browser history mechanisms. The support for revisitation is normally through a set of functional built-in icons e.g. History, Back, Forward and Bookmarks. Nevertheless, for returning web users, they normally find it is easier and faster to re-launch an online search again, rather than spending time to find a particular web site from their personal bookmark and history records. Tauscher and Greenberg (1997) showed that revisiting web pages forms up to 58% of the recurrence rate of web browsing. Cockburn and McKenzie (2001) also stated that 81% of web pages have been previously visited by the user. According to Obendorf et al. (2007), revisitation can be divided into four classifications based on time: short-term (72.6% revisits within an hour), medium-term (12% revisits within a day and 7.8% revisits within a week), and long-term (7.6% revisits longer than a week
Synthesis and Water Solubility of Novel Fullerene Bisadduct Derivatives
No full textThe synthesis of four classes of bisadduct derivatives of C-60 is reported. The solubility of the new compounds in aqueous solvents is enhanced and is among the highest ever reported for fullerene derivatives. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003
Pulmonary function is related to success in junior elite Kumite karatekas
No full textSpirometry can be considered a method for measuring lung capacity and speed of air-flow through the airways. Due to its simple application, it is commonly used in sport diagnostics. Aims of this research were to determine the values of ventilation function variables in karatekas competing in kumite discipline and their relationship to result. The sample included 51 junior karate athletes (with defined subgroups of more successful [n=31] and less successful [n=20]), competing in kumite discipline, from nine European countries. Their values of some ventilation function variables were measured. Measurement procedures were chosen and used according to acknowledged literature. By univariate analysis of differences, significant differences between more successful and less successful competitors were determined in the following variables: forced vital capacity (more successful 5.24±0.56 l; less successful 4.27±0.61 l; p=0.00), forced expiratory volume in 1 second (more successful 4.13±0.68 l; less successful 3.69±0.57 l; p=0.02), ratio of forced expiratory volume in 1 second/forced vital capacity (more successful 78.98±10.29%; less successful 86.64±8.37%; p=0.01) and maximal voluntary ventilation (more successful 150.46±31.14 l/min; less successful 125.50±29.49 l/min; p=0.01). More successful contestants showed higher values in some relevant variables compared to less successful ones supporting a relationship to result
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