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2. The use of yo-yo intermittent recovery test level 1 for the estimation of maximal oxygen uptake in youth elite soccer players

Author

Michailidis, Y. Chavlis, S. Mitrotasios, M. Ispirlidis, I. Vardakis, L. Margonis, K. Mikikis, D. Mandroukas, A. Mavrommatis, G. Metaxas, T.I.

Subjects
human activities
Abstract

Introduction. Researchers have proposed some equations for the estimation of VO2 max in adults with the use of the total distance or the maximum velocity of the Yo-Yo test. However, the use of these equations for estimating the VO2 max in children may include mistakes. Their physiological adaptations to incremental exercise are different than in adults. Aim of Study. The purpose of this study was to investigate the relationship between a) the predicted VO2 max (by a published equation) with the VO2 max measured in the laboratory and b) the velocity at the last stage of Yo-Yo IR1 (YYIR1) with the vVO2 max measured in the laboratory in elite youth soccer players (U17). Material and Methods. Twenty-seven soccer players completed a laboratory treadmill test (LTT) and the YYIR1 which were conducted in random order. Their VO2 max was measured during LTT and had been predicted by the results of the YYIR1 test from a published equation. Results. The values of VO2 max in LTT and YYIR1 were different (t = –7.652, p < 0.001) (58.9 ± ± 5.3 and 50.8 ± 2.7 ml/kg/min, respectively). There were no differences between the measured values of vVO2 max in LTT and YYIR1 (t = 1.652, p = 0.11). Also, no differences were observed in HRmax values in the two tests (t = –0.185, p = 0.854). The equation derived from the results of the present study did not have prediction power (r = 0.11, r2 = 0.012). Conclusions. The VO2 max which was predicted by the published equation from the performance of YYIR1 was different from VO2 max was measured in the laboratory in elite youth male soccer players (U17). However, YYIR1 could be used for measuring HRmax and VO2 max velocity. © 2020, University School of Physical Education. All rights reserved.

Published
2020

3. Risk transportation via a clique number problem formulation

Author

Mavrommatis, G. and Panayiotopoulos, J.-C.

Subjects
Transportation industry -- Management, Management science -- Models, Company business management, Business, Business, general, Business, international
Abstract

A new approach based on similarity coefficients, clique number and taxonomy theory is proposed to deal with the risk transportation programming problem. It is concluded that a distributed system is needed to solve the clique problem and that it is possible to use this system to share workload among processors and speed up the computation.

Published
2004

4. Political clientelism and social exclusion - The case of Gypsies in the Greek town of Sofades

Author

Marantzidis, N Mavrommatis, G

Abstract

The article relates to two much-discussed concepts in the field of social sciences: clientage relations and social exclusion. Using the city of Sofades in central Greece - where about 2000 Gypsies live - as their empirical research field, the authors attempt the analysis of the following: (1) whether the socially excluded Gypsies of the area form clientage relations, (2) whether their political clientage relations show any particular traits when related to other types of clientage relations and (3) whether political clientage relationships help socially excluded groups surmount their exclusion or not. Even though the dominant theories about clientage relations associate the evolution of those relations with the evolution of a particular society, the study of the clientage relations in Sofades shows that within a society there may coexist more than one type of clientage relationships - from the most traditional to the most modern.

Published
1999

5. WCE 2010 - World Congress on Engineering 2010: Preface

Author

Ahmad, M., Alexandrou, I., Al-Nuaimy, W., Amavasai, B. P., An, Y. -Y, Ariwa, E., Arteche, J., Audrino, F., Ayesh, A., Baber, C., Bailey, C., Balkan, N., Barria, J., Bartosova, J., Benkrid, K., Bleijs, H., Bluck, M., Bose, I., Bouzas, P. R., Braiden, P. M., Brdys, M., Burriesci, G., Cannataro, M., Carvalho, A., Chang, C. -C, Chen, D., Chen, G. G., Chen, Y. -S, Chiclana, F., Cooke, A., Das, D. B., Davis, D. N., Dayoub, I., Deb, S., Demetriou, I. C., Devai, F., Dilmaghani, R. S., Dini, D., Drikakis, D., Durkan, C., Durodola, J., Etebar, K., Fenn, P., Figueiredo, A., Florou, G., Freear, S., Gabrys, B., Galbraith, G. H., Gaskell, P. H., elena gaura, Ge, Z. -Q, Ghafouri-Shiraz, H., Ghavami, M., Giannopoulos, K., Gonzalez, R. E. P., Gracia, A. M., Grecos, C., Guan, L., Gulpinar, N., Guo, R., Guo, Y., Hardalupas, Y., He, L., Herrero, J. R., Hicks, B. J., Hines, E. L., Hodgson, S., Horsfall, A., Hosein, P., Hu, F., Hu, H., Ijomah, W., Ming, J., James, A., Jancovic, P., Jhumka, A., Kamareddine, F., Kannan, R., Karsligil, M. E., Katircioglu, S. T., Khalid, A., Kokossis, A., Kontis, K., Kulekci, M. O., Laukaitis, A., Leeson, M., Limbachiya, M. C., Li, L., Lin, P., Ling, W. -K, Macias Lopez, E. M., Lovas, T., Luglio, M., Mainardi, S., Mahanti, P. K., Marinos, I., Maropoulos, P., Mativenga, P., Mavrommatis, G., Meintanis, S. G., Meisel, Y. D., Mekid, S., Mias, C., Morin, A., Musliu, N., Nabhani, F., Naguib, R., Olatunbosun, O., Olsen, S., Ozalp, A. A., Pang, A. -C, Pao, W. K. -S, Piera, M. A., Pinciroli, F., Popescu, T. D., Power, H., Prewett, P. D., Putrus, G. A., Railton, C., Raja, V., Resta, M., Ristic, M., Roy, R., Russo, A., Sadri, F., Sahinkaya, M. N., Sakata, T., Salous, S., Sazhin, S., Scepi, G., Seneviratne, L., Seng, Q. T., Shammas, N., Shepherd, D. E. T., Short, T., Siddique, M. N. H., Singh, R., Sirlantzis, K., Solanas, A., Stathaki, T., Todd-Pokropek, A., Velez, F. J., Vicent, A. M. P., Virdee, B., Walters, R. J., Wang, C. H. -T, Wang, J., Wang, W., Wang, X. -Z, Ware, M., Webb, P., Wen, D., Wen, J., Wood, A., Woodhead, R., Woods, J., Wu, Q. H., Utyuzhnikov, S. V., Xu, H., Xu, Y., Yan, Y., Yang, G. -C, Yang, W., Yang, X. -S, Yu, H. -F, Zhao, Y., Zharkova, V., Zhong, Q. -C, and Zopounidis, C.

6. WCE 2010 - World Congress on Engineering 2010: Preface

Author

Korsunsky, A. M., Hunter, A., Hukins, D. W. L., Gelman, L., Hogger, C. J., Ceglarek, D. J., Payne, S., Ao, S. I., Ahmad, M., Alexandrou, I., Al-Nuaimy, W., Amavasai, B. P., An, Y. -Y, Ariwa, E., Arteche, J., Audrino, F., Ayesh, A., Baber, C., Bailey, C., Balkan, N., Barria, J., Bartosova, J., Benkrid, K., Bleijs, H., Bluck, M., Bose, I., Bouzas, P. R., Braiden, P. M., Brdys, M., Burriesci, G., Cannataro, M., Carvalho, A., Chang, C. -C, Chen, D., Chen, G. G., Chen, Y. -S, Chiclana, F., Cooke, A., Das, D. B., Davis, D. N., Dayoub, I., Raman, S. D. C. V., Demetriou, I. C., Devai, F., Dilmaghani, R. S., Dini, D., Drikakis, D., Durkan, C., Durodola, J., Etebar, K., Fenn, P., Figueiredo, A., Florou, G., Freear, S., Gabrys, B., Galbraith, G. H., Gaskell, P. H., Gaura, E., Ge, Z. -Q, Ghafouri-Shiraz, H., Ghavami, M., Giannopoulos, K., Pruneda Gonzalez, R. E., Gracia, A. M., Grecos, C., Guan, L., Gulpinar, N., Guo, R., Guo, Y., Hardalupas, Y., He, L., Herrero, J. R., Hicks, B. J., Hines, E. L., Hodgson, S., Horsfall, A., Hosein, P., Hu, F., Hu, O., Ijomah, W., Ming, J., James, A., Jancovic, P., Jhumka, A., Kamareddine, F., Kannan, R., Karsligil, M. E., Katircioglu, S. T., Khalid, A., Kokossis, A., Kontis, K., Kulekci, M. O., Laukaitis, A., Leeson, M., Limbachiya, M. C., Li, L., Lin, P., Ling, W. -K, Macias Lopez, E. M., Lovas, T., Luglio, M., Mainardi, S., Mahanti, P. K., Marinos, I., Maropoulos, P., Mativenga, P., Mavrommatis, G., Meintanis, S. G., Meisel, Y. D., Mekid, S., Mias, C., Morin, A., Musliu, N., Nabhani, F., Naguib, R., Olatunbosun, O., Olsen, S., Ozalp, A. A., Pang, A. -C, Pao, W. K. -S, Piera, M. A., Pinciroli, F., Popescu, T. D., Power, H., Prewett, P. D., Putrus, G. A., Railton, C., Raja, V., Resta, M., Ristic, M., Roy, R., Alessandra Russo, Sadri, F., Sahinkaya, M. N., Sakata, T., Salous, S., Sazhin, S., Scepi, G., Seneviratne, L., Seng, Q. T., Shammas, N., Shepherd, D. E. T., Short, T., Siddique, M. N. H., Singh, R., Sirlantzis, K., Solanas, A., Stathaki, T., Todd-Pokropek, A., Velez, F. J., Vicent, A. M. P., Virdee, B., Walters, R. J., Wang, C. H. -T, Wang, J., Wang, W., Wang, X. -Z, Ware, M., Webb, P., Wen, D., Wen, J., Wood, A., Woodhead, R., Woods, J., Wu, Q. H., Utyuzhnikov, S. V., Xu, H., Xu, Y., Yan, Y., Yang, G. -C, Yang, W., Yang, X. -S, Yu, H. -F, Zhao, Y., Zharkova, V., Zhong, Q. -C, and Zopounidis, C.

7. IMECS 2011 - International MultiConference of Engineers and Computer Scientists 2011: Preface

Author

Abdelkader, Y. H., Ait-Kadi, D., Al-Najjar, B., Allahverdi, A., Amavasai, B. P., Henggeler, C., Bouchaffra, D., Bose, I., Brabazon, A., Brdys, M., Cacheda, F., Chan, A. H. -S, Chan, F. T. S., Chang, C. -C, Chaudhuri, P., Chen, C. -H, Chen, C. S., Chen, M. -S, Chen, Q., Choy, W., Chung, T. S., Clubb, O. L., Damasio, M. J., Dang, C., Djordjevich, A., Fung, Y. -F, Ganesan, G., Leng, R. G. K., Sing, G. O., Gracia, A. M., Gu, Z., Gulpinar, N., Heaton-Adegbile, P., Herrera-Viedma, E., Herrero, J. R., Huang, X., Hwang, C. -K, Hwang, H. S., Ishihara, S., Jia, L., Kannan, R., Karatzas, G. P., Katagiri, H., Kendall, G., Kikuta, K., Kim, H. K., Kim, S. -I, Kothari, C., Krishnamoorthy, M., Kumamoto, T., Kwan, R., Lee, H. W., Li, L., Li, X., Li, Y., Lin, C. -M, Liu, B., Liu, L., Lopez, E. M. M., Luk, C., Maeda, K., Mahanti, P. K., Mahmoud, Q. H., Matsatsinis, N., Mavrommatis, G., Mcguigan, M., Melin, P., Mikhailov, L., Mineno, H., Monsuur, H., Moon, C., Murua, A., Musliu, N., Nakache, D., Ni, J., Nolle, L., Ozalp, A. A., Pang, W. -K, Papadopoulos, A. N., Piramuthu, S., Premachandra, I. M., Seng, Q. T., Sharma, D., Sheu, J. -B, Sheu, S. -H, Resteanu, C. I. G., Romero, C., Saito, S., Sawik, T., Seva, R. R., Shakshuki, E., Singh, V., Siskos, Y., Stoyan, Y. G., Sun, J., Sun, Z., Rad, A. B., Resta, M., Rodriguez, M. L., Rojas, R., Tiwari, M. K., Tran, D., Triguero, F. H., Tseng, L. -Y, Tsuda, S., Tzeng, G. -H, Utkin, L. V., Vaz, I., Luis, J. V., Wang, H. -F, Wang, L., Wang, S. -H, Watanabe, T., Werner, F., Wojnicki, I., Wu, E. X., Wu, T., Xie, G., Xu, L., Xu, S. H., Yang, G. -C, Yang, X. -S, Yu, K. -M, Zanni, C., Zhang, X., Zhang, Z. G., Zhao, Y., and Zopounidis, C.

8. WCE 2010 - World Congress on Engineering 2010: Preface

Author

Korsunsky, A. M., Hunter, A., Hukins, D. W. L., Gelman, L., Hogger, C. J., Ceglarek, D. J., Payne, S., Ao, S. I., Ahmad, M., Alexandrou, I., Al-Nuaimy, W., Amavasai, B. P., An, Y. -Y, Ariwa, E., Arteche, J., Audrino, F., Ayesh, A., Baber, C., Bailey, C., Balkan, N., Barria, J., Bartosova, J., Benkrid, K., Bleijs, H., Bluck, M., Bose, I., Bouzas, P. R., Braiden, P. M., Brdys, M., Burriesci, G., Cannataro, M., Carvalho, A., Chang, C. -C, Chen, D., Chen, G. G., Chen, Y. -S, Chiclana, F., Cooke, A., Das, D. B., Davis, D. N., Dayoub, I., Raman, S. D. C. V., Demetriou, I. C., Devai, F., Dilmaghani, R. S., Dini, D., Drikakis, D., Durkan, C., Durodola, J., Etebar, K., Fenn, P., Figueiredo, A., Florou, G., Freear, S., Gabrys, B., Galbraith, G. H., Gaskell, P. H., Gaura, E., Ge, Z. -Q, Ghafouri-Shiraz, H., Ghavami, M., Giannopoulos, K., Pruneda Gonzalez, R. E., Gracia, A. M., Grecos, C., Guan, L., Gulpinar, N., Guo, R., Guo, Y., Hardalupas, Y., He, L., Herrero, J. R., Hicks, B. J., Hines, E. L., Hodgson, S., Horsfall, A., Hosein, P., Hu, F., Hu, O., Ijomah, W., Ming, J., James, A., Jancovic, P., Jhumka, A., Kamareddine, F., Kannan, R., Karsligil, M. E., Katircioglu, S. T., Khalid, A., Kokossis, A., Kontis, K., Kulekci, M. O., Laukaitis, A., Leeson, M., Limbachiya, M. C., Li, L., Lin, P., Ling, W. -K, Macias Lopez, E. M., Lovas, T., Luglio, M., Mainardi, S., Mahanti, P. K., Marinos, I., Maropoulos, P., Mativenga, P., Mavrommatis, G., Meintanis, S. G., Meisel, Y. D., Mekid, S., Mias, C., Morin, A., Musliu, N., Nabhani, F., Naguib, R., Olatunbosun, O., Olsen, S., Ozalp, A. A., Pang, A. -C, Pao, W. K. -S, Piera, M. A., Pinciroli, F., Popescu, T. D., Power, H., Prewett, P. D., Putrus, G. A., Railton, C., Raja, V., Resta, M., Ristic, M., Roy, R., Alessandra Russo, Sadri, F., Sahinkaya, M. N., Sakata, T., Salous, S., Sazhin, S., Scepi, G., Seneviratne, L., Seng, Q. T., Shammas, N., Shepherd, D. E. T., Short, T., Siddique, M. N. H., Singh, R., Sirlantzis, K., Solanas, A., Stathaki, T., Todd-Pokropek, A., Velez, F. J., Vicent, A. M. P., Virdee, B., Walters, R. J., Wang, C. H. -T, Wang, J., Wang, W., Wang, X. -Z, Ware, M., Webb, P., Wen, D., Wen, J., Wood, A., Woodhead, R., Woods, J., Wu, Q. H., Utyuzhnikov, S. V., Xu, H., Xu, Y., Yan, Y., Yang, G. -C, Yang, W., Yang, X. -S, Yu, H. -F, Zhao, Y., Zharkova, V., Zhong, Q. -C, and Zopounidis, C.

10. Relative Contribution of Drag and Lift Forces in the Separate Phases of the Front Crawl Swimming.

Author

Gourgoulis, V., Boli, A., Aggeloussis, N., Toubekis, A. G., Vezos, N., Kasimatis, P., and Mavrommatis, G.

Subjects
BODY movement, SWIMMING, SWIMMING techniques, MOTION, UNDERWATER propulsion
Abstract

The purpose of the study was to determine the relative contribution of the drag and lift forces in the separate phases of the underwater stroke in front crawl swimming. Ten female swimmers swam 25 m with maximal intensity. Four camcorders (60 Hz) were used to record the underwater motion of the right hand, and the digitizing of selected points was undertaken manually using the Ariel Performance Analysis System. During the pull phase the drag force was significantly greater than lift force, while during the push phase there was no significant differences. Both drag and lift forces are important for appropriate propulsion. However, the drag force is decisive for the propulsion in both propulsive phases of the underwater motion of the hand, while the contribution of lift force was increased during the push phase. [ABSTRACT FROM AUTHOR]

Published
2010

11. The Acute Effect of Front Crawl Sprint-resisted Swimming on the Direction of the Resultant Force of the Hand.

Author

Gourgoulis, V., Aggeloussis, N., Mavridis, G., Boli, A., Toubekis, A.G., Kasimatis, P., Vezos, N., and Mavrommatis, G.

Subjects
CRAWL stroke (Swimming), SWIMMERS, UNDERWATER propulsion, AQUATIC sports, SWIMMING techniques
Abstract

The aim of the study was to investigate the acute effect of front crawl sprint-resisted swimming on the direction of the resultant force of the hand. Five female swimmers swam 25 m with maximal intensity with and without added resistance. The underwater motion of the hand was recorded using 4 cameras (60 Hz) and the Ariel Performance Analysis System was used for the digitization. The results showed that the magnitude of the drag and lift forces, as well as the magnitude of the resultant force was not modified significantly during resisted swimming. However, the angle formed between the resultant force and the axis of the swimming propulsion was decreased significantly in the pull phase. Thus, it could be speculated that sprint-resisted swimming could contribute to the learning of a more effective application of the propulsive forces. [ABSTRACT FROM AUTHOR]

Published
2010

12. Subject-specific sensitivity of several biomechanical features to fatigue during an exhaustive treadmill run.

Author

Chalitsios C, Nikodelis T, Mavrommatis G, and Kollias I

Subjects
Humans, Cross-Sectional Studies, Kinetics, Machine Learning, Fatigue, Running
Abstract

The aim of the present study was to examine the sensitivity of several movement features during running to exhaustion in a subject-specific setup adopting a cross-sectional design and a machine learning approach. Thirteen recreational runners, that systematically trained and competed, performed an exhaustive running protocol on an instrumented treadmill. Respiratory data were collected to establish the second ventilatory threshold (VT2) in order to obtain a reference point regarding the gradual accumulation of fatigue. A machine learning approach was adopted to analyze kinetic and kinematic data recorded for each participant, using a random forest classifier for the region pre and post the second ventilatory threshold. SHapley Additive exPlanations (SHAP) analysis was used to explain the models' predictions and to provide insight about the most important variables. The classification accuracy value of the models adopted ranged from 0.853 to 0.962. The most important feature in six out of thirteen participants was the angular range in AP axis of upper trunk C7 (RT APu ) followed by maximum loading rate (RFD maxD ) and the angular range in the LT axis of the C7. SHAP dependence plots also showed an increased dispersion of predictions in stages around the second ventilatory threshold which is consistent with feature interactions. These results showed that each runner used the examined features differently to cope with the increase in fatigue and mitigate its effects in order to maintain a proper motor pattern., (© 2024. The Author(s).)

Published
2024
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13. A Comparative Analysis of Symmetry Indices for Spatiotemporal Gait Features in Early Parkinson's Disease.

Author

Giannakou E, Fotiadou S, Gourgoulis V, Mavrommatis G, and Aggelousis N

Abstract

This study compared the five most commonly used equations for calculating gait symmetry in discrete variables among Parkinson's disease patients. Twelve patients (five women and seven men) performed ten consecutive gait trials on a 10 m walkway. Gait data were collected using eight optoelectronic cameras (100 fr/s). The analysis focused on various spatiotemporal parameters, including cadence, step time, stride time, single support, double support, walking speed, step length, stride length, step width, and foot angle. Five symmetry indices were calculated for each trial rather than averaging the ten recorded trials. The variability in and reliability of each symmetry equation were assessed using the coefficient of variation (CV) and intraclass correlation coefficient (ICC), respectively. Additionally, Bland-Altman plots were produced to visualize the agreement between each pair of methods for each spatiotemporal parameter. The results revealed that the symmetry ratio method exhibited lower variability and higher reliability compared with the other four indices across all spatiotemporal gait parameters. However, it was found that the reliability of a single trial was generally poor, regardless of the symmetry calculation formula used. Therefore, we recommend basing measurements of gait asymmetry in Parkinson's disease on multiple trials.

Published
2023
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14. Inter-arm coordination and intra-cyclic variation of the hip velocity during front crawl resisted swimming.

Author

Gourgoulis V, Aggeloussis N, Boli A, Michalopoulou M, Toubekis A, Kasimatis P, Vezos N, Mavridis G, Antoniou P, and Mavrommatis G

Subjects
Adolescent, Biomechanical Phenomena, Female, Humans, Hip Joint physiology, Movement physiology, Swimming physiology
Abstract

Aim: The aim of the study was to assess the acute effect of front crawl sprint resisted swimming on the inter-arm coordination and the fluctuation of the swimming velocity., Methods: Nine female swimmers swam four all-out trials of 25 m, without and with low, moderate and high added resistance. Four camcorders were used to record the underwater movement. The inter-arm coordination was quantified using the index of coordination and the hip intra-cyclic velocity variation was analysed by calculating the coefficient of variation and the difference between the maximum and minimum velocities normalized for the mean stroke cycle velocity., Results: One-way repeated measures analyses of variance showed that swimmers change their inter-arm coordination from a "catch up" toward an "opposition" mode. Concerning the hip horizontal intra-cyclic velocity variation, it was increased significantly during resisted swimming., Conclusion: These findings indicate that although resisted swimming cause an increase in the index of coordination and consequently it could be speculated a better propulsive continuity, the velocity fluctuations of the hip within a stroke cycle are not decreased, probably due to the inability of the swimmers to overcome effectively the concrete added resistances used in this study. Thus, at least concerning its acute effect, the hypothesis that the sprint resisted swimming could led to a technical improvement can not be satisfied.

Published
2013

15. Acute effect of front crawl sprint resisted swimming on the propulsive forces of the hand.

Author

Gourgoulis V, Aggeloussis N, Mavridis G, Boli A, Kasimatis P, Vezos N, Toubekis A, Antoniou P, and Mavrommatis G

Subjects
Adolescent, Computer Simulation, Female, Friction physiology, Humans, Stress, Mechanical, Athletic Performance physiology, Hand physiology, Models, Biological, Physical Exertion physiology, Posture physiology, Resistance Training methods
Abstract

The purpose of the current study was to investigate the acute effect of sprint resisted front crawl swimming on the propulsive forces of the hand. Eight female swimmers swam 25 m with maximal intensity, with and without added resistance. A bowl with a capacity of 2.2, 4 and 6 L was used as low, moderate and high added resistance, respectively. The underwater motion of the swimmer's right hand was recorded using 4 cameras (60 Hz) and the digitization was undertaken using the Ariel Performance Analysis System. Repeated-measures ANOVA revealed that the velocity of the hand, the pitch and the sweepback angles of the hand, as well as the magnitude and the relative contribution of the drag and lift forces were not significantly modified and thus the magnitude of the resultant force did not change. Moreover, the magnitude of the effective force, as well as the angle formed between the resultant force and the axis of the swimming propulsion were not significantly affected. Thus, it could be concluded that resistance added as in this study did not alter the pattern of the propulsive hand forces associated with front crawl sprinting.

Published
2013
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