Conference Presentations by Apostolos S Theodorou
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Η έκδοση του παρόντος από την Ελληνική Εταιρία Εμβιομηχανικής δεν υποδηλώνει αποδοχή των γνωμών τ... more Η έκδοση του παρόντος από την Ελληνική Εταιρία Εμβιομηχανικής δεν υποδηλώνει αποδοχή των γνωμών των συγγραφέων (Ν. 5343/1932, άρθρο 202, παρ. 2). Απαγορεύεται η αναδημοσίευση και γενικά η αναπαραγωγή εν όλω ή εν μέρει ή και περιληπτικά, κατά παράφραση ή διασκευή, του παρόντος έργου με οποιοδήποτε μέσο ή τρόπο, μηχανικό, ηλεκτρονικό, φωτοτυπικό και ηχογραφήσεων ή άλλως πως σύμφωνα με τους Ν. 2387/1920, 4301/1229, τα Π.Δ. 3565/56, 4254/62, 4264/75, Ν. 100/74 και λοιπούς εν γένει κανόνες Διεθνούς Δικαίου, χωρίς προηγούμενη γραπτή άδεια της Ελληνικής Εταιρείας Εμβιομηχανικής.
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Research studies and track coaches indicate the importance of the resisted sled sprinting as a cr... more Research studies and track coaches indicate the importance of the resisted sled sprinting as a crucial training aid for sprinters' work outs for developing speed. Various sled loading as a percentage of athlete's body mass (BM) have been under investigation, based on the fact that the larger muscle mass can produce greater muscle output. This study aims to identify the relationship of sprinting acceleration (SA) and maximum velocity (MV) phases with different sled loading to the BM, the maximum strength (MS) and the EMG activity of leg muscles .
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ΛΔΞΔΗ-ΚΛΔΗΓΗΑ: βιοκινηηική ανάλσζη, κινημαηικά ταρακηηριζηικά, κλαζικός αθληηιζμός, ενέργεια, έργ... more ΛΔΞΔΗ-ΚΛΔΗΓΗΑ: βιοκινηηική ανάλσζη, κινημαηικά ταρακηηριζηικά, κλαζικός αθληηιζμός, ενέργεια, έργο. ΔΗΑΓΩΓΖ: Η ηαρύηεηα ηεο θόξαο έρεη αλαθεξζεί πσο απνηειεί ηνλ θαζνξηζηηθόηεξν παξάγνληα επίδνζεο ζην άικα ζε κήθνο (1). Ωζηόζν, ε θπξηόηεξε θάζε ηνπ άικαηνο ζε κήθνο απνηειεί ε θάζε ηεο απνγείσζεο, θαζώο ζηε θάζε απηή ζπληειείηαη ε κεηαηξνπή ηεο θηλεηηθήο ελέξγεηαο ηνπ ζώκαηνο ηνπ άιηε ζε δπλακηθή θαη απαηηείηαη έλαο βέιηηζηνο ζπλδπαζκόο ηνπ πνζνύ ηεο ελέξγεηαο πνπ ράλεηαη θαη ηεο κεηαηξνπήο ηεο ελέξγεηαο από ηε κηα κνξθή ζηελ άιιε (2). Έρεη βξεζεί πσο ε δηαδηθαζία κεηαηξνπήο ησλ δηαθόξσλ κνξθώλ ελέξγεηαο ζην άικα ζε κήθνο είλαη δηαθνξεηηθή ζε άιηεο θαη άιηξηεο (3). Σθνπόο ηεο παξνύζαο κειέηεο ήηαλ λα δηαπηζησζεί εάλ παξαηεξνύληαη δηαθνξέο αλάκεζα ζηα θύια ζηε δηαδηθαζία κεηαηξνπήο ηεο ελέξγεηαο. ΜΔΘΟΓΟΗ ΚΑΗ ΜΔΑ ΔΡΓΑΗΑ: Δμεηάζζεθαλ 10 άιηεο (26.2 ± 4.1 εηώλ, 1.84 ± 0.06 m, 72.8 ± 3.2 kg) θαη 13 άιηξηεο (23.5 ± 3.2 εηώλ, 1.72 ± 0.05 m, 56.8 ± 4.3 kg) πνπ αγσλίζζεθαλ ζηνπο ηειηθνύο ηνπ άικαηνο ζε κήθνο ζην Παλειιήλην Πξσηάζιεκα ηνπ 2014. Γηα ηελ πξαγκαηνπνίεζε ηεο 2D-DLT θηλεκαηηθήο αλάιπζεο θαηαγξάθεθε ε θαιύηεξε πξνζπάζεηά ηνπο κε ζπρλόηεηα δεηγκαηνιεςίαο 300fps (θάκεξα Casio EX-FX1, Casio Computer Co. Ltd, Shibuya, Japan). Η αλάιπζε ησλ δεδνκέλσλ πξαγκαηνπνηήζεθε κε ην ινγηζκηθό KAPA-MOTION v.15 (Kapa-Invent, Orsay, France). Η αξρηθή (Δ 1), ηειηθή (E 0), ε δηαθνξά (E Γ) θαη δείθηεο κεηαηξνπήο (T E) ηεο ελέξγεηαο ππνινγίζζεθαλ ζύκθσλα κε ηνπο Arampatzis θαη Brüggemann (2). Τν κέζν ζρεηηθό έξγν ζηελ θάζε απόζβεζεο (W BR) θαη πξνώζεζεο (W PR) ππνινγίζζεθε κε ηε κέζνδν ησλ Lees θαη ζπλ. (3). Οη δηαθνξέο αλάκεζα ζηα θύια ζηελ επίζεκε (S OFF) θαη πξαγκαηηθή (S EFF) επίδνζε, ηελ νξηδόληηα ηαρύηεηα ηνπνζέηεζεο (Vx TD) θαη απνγείσζεο (Vx 0), ηελ θαηαθόξπθε ηαρύηεηα απνγείσζεο (Vy 0),ηελ γσλία απνγείσζεο (α 0), θαζώο επίζεο θαη ζηηο πξναλαθεξόκελεο παξακέηξνπο ελέξγεηαο θαη έξγνπ ειέγρζεθαλ κε T-test γηα αλεμάξηεηα δείγκαηα ρξεζηκνπνηώληαο ην ινγηζκηθό SPSS 10.0.1 (SPSS, Chicago, Il). ΑΠΟΣΔΛΔΜΑΣΑ: Με εμαίξεζε ηελ α 0 , νη ινηπέο θηλεκαηηθέο παξάκεηξνη δηέθεξαλ ζεκαληηθά (p < .05) κεηαμύ αιηώλ θαη αιηξηώλ (Πίλαθαο 1). Γηαθνξέο αλάκεζα ζηα θύια δελ παξαηεξήζεθαλ ζηηο παξακέηξνπο ελέξγεηαο θαη έξγνπ (p > .05), κε εμαίξεζε ηηο Δ 1 θαη E 0. Πίνακας 1: Απνηειέζκαηα ζύγθξηζεο αιηώλ θαη αιηξηώλ (κέζνο όξνο ± ηππηθή απόθιηζε). Παράμετρος Άλτες Άλτριες Παράμετρος Άλτες Άλτριες S OFF (m) 7.57 ± 0.31 5.84 ± 0.27* Δ 1 (J/kg) 55.82 ± 3.79 40.93 ± 2.64* S EFF (m) 7.67 ± 0.35 5.88 ± 0.28* E 0 (J/kg) 48.53 ± 5.57 36.04 ± 1.67* Vx TD (m/s) 9.58 ± 0.40 7.97 ± 0.33* E Γ (J/kg) 7.29 ± 4.84 4.89 ± 1.68 Vx 0 (m/s) 8.51 ± 0.65 7.06 ± 0.25* T E (º/J/kg) 3.75 ± 1.86 5.14 ± 2.77 Vy 0 (m/s) 3.25 ± 0.36 2.77 ± 0.25* W BR (J/kg)-2.66 ± 1.30-2.16 ± 0.86 α 0 (º) 20.92 ± 2.04 21.45 ± 2.12 W PR (J/kg) 8.10 ± 3.74 5.79 ± 1.67 * p < .05 ΤΜΠΔΡΑΜΑΣΑ-ΤΕΖΣΖΖ: Οη δείθηεο κεηαηξνπήο ηεο ελέξγεηαο θαη ηνπ έξγνπ ζηε θάζε ηεο απνγείσζεο ζην άικα ζε κήθνο δε δηαθνξνπνηείηαη αλάκεζα ζηα θύια. Ωζηόζν, νη ηηκέο πνπ παξαηεξήζεθαλ είλαη ρακειόηεξεο από αληίζηνηρεο ηεο δηεζλνύο βηβιηνγξαθίαο (2,3). Έρεη παξαηεξεζεί όηη νη θνξπθαίνη Έιιελεο άιηεο θαη Διιελίδεο άιηξηεο δελ εθκεηαιιεύνληαη απνδνηηθά ηελ ηαρύηεηά ηνπο θαηά ηελ απνγείσζε, παξά ην γεγνλόο όηη δηαθνξνπνηνύληαη κεηαμύ ηνπο ζηηο παξακέηξνπο πνπ θαζνξίδνπλ ηελ απόζηαζε βειελεθνύο ηνπ Κέληξνπ Μάδαο Σώκαηνο (4). Μειινληηθέο κειέηεο ζα πξέπεη λα δηεξεπλήζνπλ ηελ επίδξαζε λεπξνκπτθώλ παξαγόλησλ ζηε δηαδηθαζία κεηαηξνπήο ηεο ελέξγεηαο ζην άικα ζε κήθνο. ησλ ηειεπηαίσλ δηαζθειηζκώλ, ηνπ παηήκαηνο θαη ηεο απνγείσζεο ησλ θνξπθαίσλ Διιήλσλ αζιεηώλ θαη αζιεηξηώλ ηνπ άικαηνο ζε κήθνο, Φσζική Αγωγή και Αθληηιζμός, 29(2):200-218.
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This study's aim was to investigate step characteristic reliance and asymmetry during the long ju... more This study's aim was to investigate step characteristic reliance and asymmetry during the long jump approach. Spatiotemporal data of the approach run were collected in national and international athletic competitions of 10 males (age 26.2 ± 4.1 yrs, height 1.84 ± 0.06 m, mass 72.77 ± 3.23 kg, PB 7.96 ± 0.30 m) and 9 females (26.3 ± 2.19 yrs, 1.73 ± 0.05 m, 55.75 ± 3.79 kg, 6.68 ± 0.20 m). Only two males showed step length reliance and only during late approach. Step frequency reliance was demonstrated during total, early and late approach, most prevalently during the latter (7/10 male & 3/9 female). Four males and females displayed step length asymmetry whilst three males and two females were asymmetrical for frequency. No athletes showed step velocity asymmetry. In conclusion, asymmetrical demands of takeoff were not consistently reflected in step characteristics.
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Theodorou A, Ioakimidou E, Kouris P, Panoutsakopoulos V, Smpokos E. Colour contrast and regulatio... more Theodorou A, Ioakimidou E, Kouris P, Panoutsakopoulos V, Smpokos E. Colour contrast and regulation of the long jump approach run. shown that visual perception of the takeoff board and the subsequent regulation of the approach run occur 4-5 strides prior to takeoff. Contrast in visual perception is determined by the difference in colour and occurs when a surface of one colour induces its antagonist colour in an adjoining surface. The aim of the present study was to investigate if colour contrast between the track surface and the board affects the stride regulation pattern at the long jump approach run. Four long jumpers performed long jumps in two different occasions: 6 from a runway track coloured blue, with a white takeoff board and 6 from a modified yellow board. The runway was marked and the approach runs were recorded with a panning camera. Toe-board distance (TBD) for each support phase in every run-up and the percentage distribution of adjustment of the regulated strides was calculated. With the white takeoff board, the average TBD variability reached its peak value (21.74cm) on the 5th stride from the board and at a distance of 9.77m from takeoff point. With the yellow takeoff board the average TBD variability culminated (24.80cm) on the 7th stride from the board and at a distance of 13.40m from takeoff point. With the white board, 80% of the adjustment was distributed during the last two strides as opposed to 61% with the yellow board. When a takeoff board of a colour complementary to the runway's blue track surface is used, athletes initiated their regulation 2 strides earlier. This may be attributed to an enhanced visual perception of the approaching target allowing a more uniform distribution of adjustments during the last two strides of the approach.
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Panoutsakopoulos V, Theodorou A, Kotzamanidou MC, Skordilis E, Kollias IA. Biomechanical analysis... more Panoutsakopoulos V, Theodorou A, Kotzamanidou MC, Skordilis E, Kollias IA. Biomechanical analysis of the final strides of the approach and the takeoff by visually impaired class F12 and F13 long jumpers. J. Hum. Sport Exerc. Vol. 8, No. Proc3, pp. S671-S680, 2013. Despite of the level of visual aquity, European Records in long jumping are greater in class F12 (visual acuity 2/60) than class F13 (visual acuity 6/60) both in males and females. The aim of the present study was to compare the biomechanical parameters of the final strides of the approach and the takeoff in class F12 and F13 long jumpers. 19 class F12 (males: 13, females: 6) and 12 class F13 (males: 4, females: 8) long jumpers participating in the 2009 International Blind Sports Association European Championships were recorded using a stationary digital video camera (sampling frequency: 300 fps). Key biomechanical parameters were extracted with a typical 2D-DLT kinematical analysis. Differences between groups were investigated using Independent samples t-test. Results indicated that the official distance was 6.07 m ± 0.55 and 5.52 m ± 0.91 for F12 and F13 respectively (p<.05). Significant differences were also observed concerning the vertical takeoff velocity (F12: 2.8 m/sec, F13: 2.4 m/sec), the support leg's knee flexion (F12: 18.2 deg, F13: 25.2 deg) and the knee joint flexion velocity (F12: 7.4 rad/sec, F13: 10.2 rad/sec) at the takeoff board and the knee maximum flexion angle at the last stride (F12: 116.8 deg, F13: 125.4 deg). In conclusion, F12 performed better than F13 because of the more advantageus utilization of the factors defining the vertical component in the long-jump takeoff. Additionally, the different last stride maximum knee flexion angle might imply differences concerning the mechanics of the placement of the takeoff leg. It is possible that factors such as the size and surface properties of the 1.22 m x 1.00 m chalked takeoff area used in F12 competition may contribute to the differences observed in the study.
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Conference Presentations by Apostolos S Theodorou