197,614 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
Sequence analysis and characterisation of virally induced viperin in the saltwater crocodile (Crocodylus porosus)
No full textAbstract not availableNatalie L. Milic, Steven Davis, Jillian M. Carr, Sally Isberg, Michael R. Beard, Karla J. Helbi
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
Moving from the prediction of fractures to the prediction of falls in an aging HIV scenario
No full textSmith Machine exercise: the key points
No full textDuring the past two decades, sports scientists, coaches, therapeutic specialists, and other professionals are using the Smith Machine exercise (SME) to improve lower limb muscle strength. By overviewing the literature, the position of the bar, load, training volume (repetitions and sets), recovery (resting time), power, muscular work, and one repetition maximum (1-RM) are characteristics describing the SME and presented as variables on which the resistance training (RT) program periodization is focused. Therefore, the aim of the present brief review is to clarify this crucial point and to simplify the SME approach for the strength and condition trainers as well as for all other scientist involved in sports or therapeutic work. This brief review offers an insight into several recommendations on the key points, firmly based on relevant literature
Metric characteristics of the step hop test in young female volleyball players [Metrijske karakteristike step hop testa kod mladih odbojkašica]
No full textThe main goal of the study was to analyse the metric characteristics of a specific volleyball agility test (SHT: Step-hop test) on a sample of 204 youth Croatian female volleyball players whose mean chronological age was 14.11±0.84 years with a training experience of 42.14±16.76 months. High values of the Cronbach’s alpha coefficient (0.93) and low values (0.97 – 0.87 to include the values) of the coefficient of variation (0.004) confirmed good reliability of the step-hop test. Significant differences were found between the measured items by using the F-test,i.e.,there was a noticeable trend of result improvement over the three consecutive test performances. The obtained value of the KS test and the values of coefficients of distribution Skewness (Skew) and Kurtosis (Kurt) indicated good sensitivity of the step-hop test. It was determined by factor analysis (principal components analysis) and correlation analysis that the step-hop test had the same object of measurement as the two tests for assessing agility in volleyball (side steps and 9-3-6-3-9) with validated metric characteristics. Univariate analysis of variance showed no significant inter-positional differences in the SHT performance. By applying an independent samples t-test significant differences were found between more successful and less successful young volleyball players at passer-hitter position. Based on the obtained results,the SHT can be recommended in the process of identification and selection of young female volleyball players at passer-hitter position. To improve the homogeneity of the test,subjects should be allowed more trials and the test should be modified so that every change of movement direction is initiated by the foot opposite from that which was last put on the floor in the previous movement
Pathophysiology of chronic obstructive pulmonary disease
No full textIn normal animals, cyclic airway closure and reopening during prolonged mechanical ventilation at low lung volumes causes histological damage of small airways, characterized by epithelial sloughing and lesion and/or rupture of alveolar-bronchiolar attachments, with a concurrent increase in airway resistance that persists after restoration of physiological end-expiratory lung volume. Peripheral airway injury should be therefore expected to occur when the closing capacity exceeds the functional residual capacity and tidal airway closure is regularly present during spontaneous breathing. On these basis, it is proposed that in smokers the transition from peripheral airway disease to chronic obstructive pulmonary disease is characterized by three sequential stages: Stage I, during which the closing capacity eventually exceeds the functional residual capacity, i.e. airway closure and reopening occur cyclically with breathing; Stage II, during which tidal expiratory flow limitation is eventually exhibited; and Stage III, during which dynamic hyperinflation progressively increases leading to dyspnea and exercise limitation. In this perspective, it is tidal airway closure and, probably, tidal expiratory flow limitation that promote peripheral airway injury, accelerate the abnormalities of lung function, and may determine which smoker is destined to develop chronic obstructive pulmonary disease
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
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