countermovement jump – The Sport Journal

An evaluation of professional regional soccer goalkeepers using three different choice reaction times and vertical jumps

Authors: Rıdvan Çolak¹, Eda Ağaşcıoğlu²

¹ Department of Physical Education and Sports, Ardahan University, Ardahan, Turkey.
²Department of Sports Training, Galata University, İstanbul, Turkey.

Corresponding Author:
Rıdvan Çolak, Ph. D., Assistant Professor
E-mail: colak.ridvan@gmail.com
GSM: +905556229421, Fax: +904782117514
Orcid ID: https://orcid.org/0000-0002 -7998-5847

Rıdvan Çolak, Ph. D., is an Assistant Professor of Physical Education and Sports at Ardahan University in Ardahan, Turkey. His research interests focus on free radicals and protein oxidation markers associated with exercise, exercise at altitude, physical activity and performance related measurements.

Eda Ağaşcıoğlu, Ph. D., is an Assistant Professor of Training at Galata University in İstanbul, Turkey. Her research interests focus on free radicals and protein oxidation markers associated with exercise, exercise and ageing, hypoxia, physical activity and performance related measurements.

An evaluation of professional regional soccer goalkeepers using three different choice reaction times and vertical jumps

ABSTRACT

Soccer goalkeepers’ (GKs) role in a team is important, but they are either disregarded or considered like fielders in current literature. This study aims to evaluate 1) soccer GKs’ reaction times with tree different decision making visual reaction time tests (shapes, directions and number), 2) relationship between reaction times and vertical jumps (Countermovement Jump (CMJ) and Squad Jump (SJ)). Turkish professional male soccer players were classified into four groups: GKs, defenders (DFs), midfielders (MFs) and attackers (ATs) (n = 10 for each). Reaction times and vertical jumps tests were done using Sport Expert TM-MPS-501. One-way ANOVA and Pearson Correlation of SPSS V.22 were used for data analysis. GKs were taller and heavier than fielders. GKs were fast in number reaction time (NumRT) and shape reaction time (ShaRT) than fielders, but they had no difference in direction reaction time (DirRT). GKs had higher scores in both vertical jumps than MFs and DFs, but not ATs. In general, the high negative correlations were observed between vertical jumps, and ShaRT and NumRT in GKs. The results illustrate that professional GKs are as talented as ATs; however, considering their height and body mass, they may be the best in motor abilities.

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Effects of 6-Week Plyometric Training on Vertical Jump Performance and Muscle Activation of Lower Extremity Muscles

Author: Kerim SOZBIR*(1)

(1)Kerim SOZBIR is an Assistant Professor and lectures Human Anatomy and Physiology, Speed Training, and Track and Field in the Department of Coaching Education at the University of Abant Izzet Baysal in TURKEY. He is also Head Coach of University Table Tennis, and Track and Field Teams.

*Corresponding Author:
Kerim SOZBIR, Ph.D
Department of Coaching Education, School of Physical Education and Sports,
University of Abant Izzet Baysal, Golkoy Kampusu, 14030, Bolu/TURKEY
Office Phone: +903742541000 (ext. 2027)
Fax: +90 374 2534636
Email: sozbir_k@ibu.edu.tr

ABSTRACT
The purpose of this study was to determine the effects of 6-week plyometric training on vertical jump performance and electromyography (EMG) activities of vastus lateralis (VL), vastus medialis (VM), and gastrocnemius (GAS) muscles during countermovement jump (CMJ). Twenty-four highly physically active physical education students were randomly assigned either to a plyometric (PLY) group or a control group. The experimental group performed plyometric exercises 2 times a week for 6 weeks, whereas the control group participated only in their lectures. The results revealed that there were no significant changes in either vertical jump height or EMG activities of selected muscles for the control group (p greater than 0.05). However, after 6 weeks of plyometric training, significant improvements (p less than 0.05) were observed in EMG activities of VL (13.25%), VM (9.60%), and GAS (13.93%) muscles, and no significant increase (p greater than 0.05) was found in CMJ (2.77%) in the PLY group. In conclusion, the findings of the this study suggest that 6 weeks of PLY training, in addition to the regular academic program, induced significant improvements in EMG activities of lower extremity muscles but no significant increases in vertical jump height. Accordingly, PLY exercises are recommended as part of a regular academic program in order to increase important components of athletic performance for physical education students.

KEYWORDS: Stretch-shortening cycle, electromyography, root mean square, countermovement jump, knee extensor muscles.
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