Search results for "jump"
showing 10 items of 401 documents
Neuromuscular function during drop jumps in young and elderly males
2011
The Hoffman reflex (H-reflex), indicating alpha-motoneuron pool activity, has been shown to be task - and in resting conditions - age dependent. How aging affects H-reflex activity during explosive movements is not clear at present. The purpose of this study was to examine the effects of aging on H-reflexes during drop jumps, and its possible role in drop jump performance. Ten young (26.8 ± 2.7 years) and twenty elderly (64.2 ± 2.7 years) subjects participated in the study. Maximal drop jump performance and soleus H-reflex response (H/M jump) 20 ms after ground contact were measured in a sledge ergometer. Maximal H-reflex, maximal M-wave, Hmax/Mmax-ratio and H-reflex excitability curves wer…
Force-velocity profiling in athletes: Reliability and agreement across methods
2021
The aim of the study was to examine the test-retest reliability and agreement across methods for assessing individual force-velocity (FV) profiles of the lower limbs in athletes. Using a multicenter approach, 27 male athletes completed all measurements for the main analysis, with up to 82 male and female athletes on some measurements. The athletes were tested twice before and twice after a 2- to 6-month period of regular training and sport participation. The double testing sessions were separated by ~1 week. Individual FV-profiles were acquired from incremental loading protocols in squat jump (SJ), countermovement jump (CMJ) and leg press. A force plate, linear encoder and a flight time cal…
L'automobile, la velocità e l'architettura come mantello
2005
L’automobile, la velocità e l’architettura come mantello La tesi di R. Ingersoll denominata Jumpcut Urbanism, costruisce un’analogia fra la composizione cinematografica fatta per tagli e salti e la percezione della città che si registra dall’abitacolo della automobile nel suo scorrere fra gli spazi della città. All’interno dell’articolo l’Autore, utilizzando il cortometraggio Randevouz di C. Lelouch, e il film Collateral, di M. Mann, introduce, progressivamente, un ragionamento che dalla trasformazione delle trame urbane tra la fine del XIX e l’inizio del XX secolo, porta a riconsiderare un ampio percorso dell’architettura che si distende dalla Majolikahaus di O. Wagner, al recente interven…
Segmental contribution to forces in vertical jump.
1978
Performance of a vertical jump was analyzed with respect to the contribution of the different body segments to the forces acting on the whole body center of gravity. Both cinematograph and force-platform techniques were employed. The data disclosed that the take-off velocity in vertical jumps was caused by the different components as follows: knee extension 56%, plantar flexion 22%, trunk extension 10%, arm swing 10%, and head swing 2%. However, the average take-off velocity of the total performance (3.03 m/s) was only 76% from the theoretical maximum calculated from the segmental analyses. Optimal timing of the segmental performances was calculated to increase this “efficiency” to 84%. Gre…
Conditioning hops increase triceps surae muscle force and Achilles tendon strain energy in the stretch-shortening cycle
2018
Postactivation potentiation can improve athletic performance, but the underlying mechanisms are poorly understood. This study investigated the effect of conditioning hops on triceps surae muscle force and tendon strain and its contribution to potentiated stretch-shortening cycle (SSC) performance. Thirty-two subjects participated in two experiments. In both experiments, subjects performed three drop jumps (DJs) after prior conditioning with 10 maximal hops, three unconditioned DJs served as control. Ground reaction forces, kinematics, and triceps surae electromyographic activity were recorded. Ultrasound imaging was used to determine fascicle lengths (FASC) of the gastrocnemius (GM) and sol…
Effect of combined electrostimulation and plyometric training on vertical jump height.
2002
This study investigated the influence of a 4-wk combined electromyostimulation (EMS) and plyometric training program on the vertical jump performance of 10 volleyball players.Training sessions were carried out three times weekly. Each session consisted of three main parts: EMS of the knee extensor muscles (48 contractions), EMS of the plantar flexor muscles (30 contractions), and 50 plyometric jumps. Subjects were tested before (week 0), during (week 2), and after the training program (week 4), as well as once more after 2 wk of normal volleyball training (week 6). Different vertical jumps were carried out, as well as maximal voluntary contraction (MVC) of the knee extensor and plantar flex…
Tipizētās JavaScript valodas izmantošana tīmekļa lietojumprogrammu izstrādei
2015
Pēdējā laikā tīmekļa programmēšanā, precīzāk, tīmekļa lietojumprogrammu izstrādē, pieaug tipizēto JavaScript valodas paveidu popularitāte. Tie iekļauj JavaScript valodā statisko tipizāciju, kā arī vairākas tradicionālu objektorientētu valodu paradigmas. Pašlaik līderi šajā jomā ir Microsoft ar savu TypeScript valodu, bet arī Google un Facebook darbojās šajā virzienā – izstrādā, respektīvi, AtScript un Flow valodas. Maģistra darbā tiek izpētītas šo valodu iespējas, to atšķirības, kā arī tiek novērtēts to potenciāls, perspektivitāte un nozīme tīmekļa izstrādes attīstībai. Lai dziļāk izpētītu izstrādes procesa īpašības, kas ir saistītas ar tipizēto JavaScript valodas paveidu izmantošanu, autor…
Darba laika uzskaites sistēmas izstrāde
2017
Kvalifikācijas darbs apraksta izstrādātu darba laika uzskaites sistēmu, kas pielāgota konkrēta uzņēmuma vajadzībām. Sistēma tiek izstrādāta iekšējām vajadzībām. Lietojumprogrammā iespējams uzzināt detalizētu informāciju par uzņēmuma darbinieku darba laiku, tādējādi atvieglojot saziņu starp uzņēmuma darbiniekiem un darba laika plānošanu. Sistēmai reģistrēt lietotājus var tikai administrators, nereģistrētiem lietotājiem nav piekļuves sistēmas datiem. Izstrāde ir dokumentēta, iekļaujot prasību specifikāciju, projektējumu un testu.
Programma zīmēšanas praksei
2019
Šī kvalifikācijas darba gaitā es izstrādāju lietojumprogrammu “Sketch Practice” Android operētājsistēmai. Lietojumprogramma ir paredzēta cilvēkiem, kuri grib pilnveidot un attīstīt savas zīmēšanas prasmes, pārzīmējot dažādu objektu bildes, kad tas parādas ekrānā uz ierobēžoto laika brīdi.
Muscle strength in male athletes aged 70-81 years and a population sample.
1991
Muscle strength characteristics of different muscle groups were studied in active male strength-trained (ST, n = 14), speed-trained (SP, n = 16), and endurance-trained (EN, n = 67) athletes aged between 70 and 81 years. A population sample of similar age (n = 42) served as a control group. The isometric forces for hand grip, arm flexion, knee extension, trunk extension, and trunk flexion were higher for the athletes than the controls and higher for the ST than EN group. The SP athletes showed higher values in knee extension and trunk flexion than the EN group. When the isometric muscle forces were related to lean body mass, significant differences still existed between the athletes and cont…