Knee Strength Ratios in Male Judokas: Age-Related Differences

ORIGINAL ARTICLE Knee strength ratios in male judokas: age-related differences Authors’ Contribution: Pavle Malovic1ABD, Dusko Bjelica1DE, Dragan Atanasov2ABE, Tatjana Trivic3BC, A Study Design 4CD 3CD 3CDE B Data Collection Miodrag Drapsin , Nebojsa Trajkovic , Nebojsa Maksimovic , C Statistical Analysis Patrik Drid3ACDE D Manuscript Preparation E Funds Collection 1 Faculty of Sport and Physical Education, University of Montenegro, Montenegro 2 Faculty of Sport, University Union – Nikola Tesla, Belgrade, Serbia 3 Faculty of Sport and Physical Education, University of Novi Sad, Novi Sad, Serbia 4 Medical Faculty, University of Novi Sad, Novi Sad, Serbia Received: 07 November 2019; Accepted: 09 January 2020; Published online: 19 February 2020 AoBID: 13076 Abstract Background and Study Aim: Asymmetries and muscle imbalances are associated with increased risk for lower limb injuries. This study aimed to verify the hypothesis that there is a significant difference between judokas of different age categories in the maximum muscular force, as well as in the functional ratio (H/Qfunc) of thigh muscle for both legs. Materials and Methods: The sample of participants consisted of 25 judo athletes of senior, junior, and cadet age categories, which were roughly equal by body weight. A sample of the variables used in the study was composed of isokinetic indica- tors for estimating the muscular force of the flexors and extensors of knee joint at two angular velocities and two contraction modes. To analyze differences between samples included in this study univariate analysis of variance (ANOVA) and LSD Post Hoc test were used. Results: There were statistically significant differences in the maximum muscular strength between the examined groups and that there were no statistically significant differences in the H/Qfunc ratio of the thigh muscles of the examinees. A trend of growth of muscular force from cadet to senior age category was observed, as well as the decline of muscular symmetry with the increase in the age category of examinees. Conclusions: Although no differences were confirmed in each variable for the assessment of muscle strength, there was an evident trend of increasing muscle strength from cadet to senior age category. In many cases of assessed angular velocities and types of muscle contractions, the symmetry of thigh muscles decreased as the age category increased. Based on the results obtained in this study, it can be concluded that judo does not lead to functional asymmetry of the thigh muscles of athletes who belong to different age categories. Key words: dynamic asymmetry • injury • isokinetic training • velocity Copyright: © 2020, the Authors. Published by Archives of Budo Conflict of interest: Authors have declared that no competing interest exists Ethical approval: The study was approved by the local Institutional Review Board of Faculty of Sport and Physical Education, University of Novi Sad (ref. no 554/2018) Provenance & peer review: Not commissioned; externally peer-reviewed Source of support: This work was supported by the Serbian Ministry of Education, Science and Technological Development under Grant (number179011); Provincial Secretariat for Science and Technological Development under Grant (number142-451-2473); and Faculty of Sport and Physical Education, University of Novi Sad under Grant (2018 Annual Award) Author’s address: Patrik Drid, Faculty of Sport and Physical Education, University of Novi Sad, Lovcenska Str. 16, 21000 Novi Sad, Serbia: e-mail: [email protected] © ARCHIVES OF BUDO | SCIENCE OF MARTIAL ARTS 2020 | VOLUME 16 | 43 This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (http://creativecommons.org/licenses/by-nc/4.0), which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non-commercial and is otherwise in compliance with the license. Original Article INTRODUCTION H/Q ratio – unilateral ratio of relationships within the extremities are easily thigh muscles. This agonist/ Judo is a dynamic, high-intensity intermittent estimated [8]. Unilateral ratio of thigh muscles antagonist ratio is reliable to indicate an insufficiency sport that requires the possession of complex is most commonly referred to as the “H/Q ratio” of particular muscle group skills and the exceptional tactical preparedness in literature. The aforementioned ratio (agonist/ [9, 10]. that is necessary for success [1, 2]. Also, on this antagonist) can very reliably indicate an insuffi- H/Qfunc – represents eccentric topic Franchini et al. [3] stated that competitive ciency of a particular muscle group. H/Q ratio is antagonist to concentric agonist strength ratio [8]. judo can be described as a highly intense sport in particularly significant in acyclic sports as well as which competitors try to throw their opponent on in sports where there is a dominant muscle group H/Q – represents conv the back or control their opponent in a ground bat- in terms of strength [9, 10]. antagonist to agonist strength ratio in the same contraction tle (fight in a horizontal posture – ne waza). Many mode [21]. of the attempts and actions performed during judo There are two described ratios in the literature for Judo – noun a Japanese fight are highly explosive and require strength and the unilateral asymmetry evaluation, namely con- martial art in which opponents coordination to outwit the opponent through ventional (H/Qconv) and functional (H/Qfunc) ratio. use balance and body weight, with minimal physical effort, to quick technical maneuvers [4, 5]. Judokas need Functional ratio which is considered as more rel- throw each other or hold each to perform many tries and techniques during each evant can be calculated by dividing the value of other in a lock [1]. match, which means a physical pressure is placed the maximal strength of the knee flexor muscle Isokinetic training – noun during each match for every judoka. performed in eccentric contraction mode and the weight training in which the value of the maximal strength of the knee exten- muscle contracts at a constant speed, requiring specialized The movement structure in judo is hugely sor muscle performed in concentric contraction equipment [1]. demanding. Therefore, the forces of muscu- mode, thereby assessing the relative ability of the lar contraction play a crucial role in the perfor- hamstring muscles to act with eccentric contrac- Velocity – noun the rate of change of position in given mance of throwing techniques in this martial tion and stabilize the knee in specific actions [8], direction, composed of both art [6]. Accordingly, the strength of the thigh while the conventional ratio can be calculated by speed and direction [1]. muscles, as well as the shoulder muscles, can dividing the value of the maximal strength of the Tactics – plural noun the art make a difference between successful and less knee flexor muscle with the value of the maxi- of finding and implementing means to achieve immediate successful judo competitors. These facts indi- mal strength of the knee extensor muscle and or short-term aims [1]. cate that judo is a complex sport with require- both performed in concentric contraction mode. ments that contain many specific characteristics Furthermore, the assessment of bilateral asym- Technique – noun a way of performing an action [1]. that are necessary to achieve a high competitive metry of the lower extremity musculature is of level. Understanding the characteristics of elite great importance both for the prevention of inju- Tokui-waza – “favourite” or athletes can provide beneficial information about ries and for maximum performance in competi- ”best” technique. It’s the throw that fits naturally to athlete what is necessary to achieve competitive success. tions, and mainly for the dominant use of the left body type. During the techniques training (tokui waza), the or right side of the body in performing techniques Tachi-waza – judo throwing athletes improve their performance and prefer for judo or for example change movement direc- techniques executed from the dominant side, which in turn results in dif- tions in other sport disciplines. a standing position. These include te-waza (hand ferences in strength when testing and comparing techniques), koshi-waza (hip dynamic asymmetry. Of course, top athletes dif- This study aimed is the verification of hypothe- techniques), and ashi-waza (foot and leg techniques) [30]; fer from those who are less successful precisely sis that is there a significant difference between including also sub classification in that they strive to equalize the capabilities and judokas of different age categories in the maxi- sutemi-waza (rear-fall and side- fall judo throws; synonym – abilities of both sides of the body, concerning the mum muscular force, as well as in the functional “dedication throws”). longitudinal axis. The mentioned strength imbal- ratio (H/Qfunc) of thigh muscle for both legs. ance is a risk of injuries, so in many studies, the Tatami – traditional straw mats used in jūdō and aikidō emphasis is on assessing the imbalance and ten- training halls [30]. dency to symmetry, not only muscular but gen- MATERIAL AND METHODS erally the psycho-physical balance of the athlete. Three groups of subjects were involved in this Drid et al. [7] in their study showed that isokinetic study, and the total number of examinees was 25. dynamometry could provide beneficial informa- The first subsample consisted of 8 judokas of the tion regarding the detection of the strength of senior age category, the second subsample con- a particular muscle group as well as the timely sisted of 9 judokas of the junior age category, and detection of imbalance between muscle groups the third subsample consisted of8 judokas of the in judo. Therefore, isokinetic dynamometry is cadet age category. All participants involved in this the optimal way to determine unilateral and study were morphologically similar (Table 1). All par- bilateral asymmetry between the thigh mus- ticipants were active competitors and medal win- cles and thanks to the torque data obtained, ners on national and international competitions.

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