Prediction of Knee Extensor and Flexor Isokinetic Strength in Young Male Soccer Players

2000 ◽  
Vol 30 (11) ◽  
pp. 693-701 ◽  
Author(s):  
Spiros Kellis ◽  
Eleftherios Kellis ◽  
Vasiliki Manou ◽  
Vasilios Gerodimos
2012 ◽  
Vol 31 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Niyazi Eniseler ◽  
Çağatay Şahan ◽  
Hikmet Vurgun ◽  
Hasan Mavi

Isokinetic Strength Responses to Season-long Training and Competition in Turkish Elite Soccer PlayersThere are not enough studies that describe the isokinetic strength of professional soccer players at high angular velocities. The purpose of this study was to evaluate the seasonal changes in isokinetic strength of Turkish professional soccer players (n=14) over the course of a 24-week soccer season. The isokinetic strength of players who underwent usual soccer training and weekly competition throughout the soccer season was assessed by means of the Biodex System 3 dynamometer with the knee attachment. The peak torque of knee extensor and flexor muscles were measured at angular velocities of 60°/s, 300°/s and 500°/s. Players were tested at the beginning and end of the competitive season. While the first- and second-test measurements did not show significant changes at 60°/s and 300°/s angular velocities, at the end of the training period, players' knee strength changed significantly at 500°/s angular velocities. In addition, the H/Q ratio improved significantly for the dominant as well as non-dominant leg at 500°/s. Significant bilateral strength improvements for knee flexors were also observed at 500°/s. The findings of this study suggest that usual daily soccer training (technical, tactical, power, strength, endurance, flexibility, etc.) and weekly competition might produce changes in knee strength at high angular velocities.


Author(s):  
Robert Śliwowski ◽  
Jakub Marynowicz ◽  
Monika Grygorowicz ◽  
Andrzej Wieczorek ◽  
Łukasz Jadczak

The purpose of this study is to evaluate the differences in concentric isokinetic strength characteristics of the knee extensor and knee flexor musculature between international (IL) and non-international level (N-IL) soccer players. The second aim is to establish strength symmetry status in knee muscles for dominant (DL) and non-dominant (NDL) legs for both within and between groups. 100 male top elite soccer players (IL: n = 36, age = 27.5 ± 3.4 years and N-IL: n = 64, age = 27.7 ± 6.4 years) underwent concentric isokinetic strength tests, using a Biodex System 3 dynamometer. Results indicate that statistically significant differences between groups were noted for peak torque of hamstrings (PT-H), hamstrings/quadriceps (H/Q) ratio, and total work of hamstrings (TW-H), where mean values for the IL were similarly higher than for the N-IL group (p = 0.006, p < 0.001, and p = 0.012, respectively). Our results also showed statistically significant differences for peak torque of quadriceps (PT-Q), PT-H, total work of quadriceps (TW-Q) and TW-H between legs, where mean values noted for the DL were higher than for the NDL for both groups (p = 0.021, p < 0.001, p = 0.006, and p = 0.004, respectively). Additional results show that IL players presented more symmetrical strength between legs than N-IL. The results of this study indicate that that the greatest differences in isokinetic strength performance across players at different soccer levels relate to the hamstring muscle. As a result, systematic strength training of these muscle groups is strongly recommended.


2019 ◽  
Vol 14 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Pardis Noormohammadpour ◽  
Shadi Mirzaei ◽  
Navid Moghadam ◽  
Mohammad Ali Mansournia ◽  
Ramin Kordi

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Irene La Fratta ◽  
Sara Franceschelli ◽  
Lorenza Speranza ◽  
Antonia Patruno ◽  
Carlo Michetti ◽  
...  

AbstractIt is well known that soccer sport has the potential for high levels of stress and anxiety and that these are linked to Cortisol (C) variations. To date, much research has been devoted to understanding how Oxytocin (OT) can affect anxiety in response to a challenge. The aim of this study was to investigate, in 56 young male soccer players, the psychophysiological stress response 96 and 24 h before one soccer match of a tournament, in order to establish whether athletes who won or lost, show different levels of C and OT or expressions of competitive state anxiety subcomponents. We found that winners had significantly lower Cognitive anxiety and higher Self-confidence scores than losers. Also, significant differences between winners and losers in C and OT concentrations were observed, with higher OT levels in who has won and higher C levels in who has lost. Our results showed interesting associations between OT, C, anxiety feelings, and the outcome of competition.


2012 ◽  
Vol 6 (1) ◽  
pp. 53-60
Author(s):  
Tomáš Malý ◽  
František Zahálka ◽  
Lucia Malá ◽  
Jaroslav Teplan

Th e aim of the study was to present isokinetic strength profi le of knee fl exors and extensors during concentric contraction in young soccer players. Particularly in knee fl exors was evaluated also strength during eccentric contraction. Research group was state from young soccer players U17 category (n=19, age=16,4±0,3 years). All of them are the participant of highest junior soccer league. Isokinetic strength was evaluated by isokinetic dynamometr Cybex Humac Norm in following angular velocities: 30, 60 and 120°/s in eccentric contraction and 60, 180, 240 and 300 °/s in concentric contraction. Th e results did not revealed signifi cant diff erences at three diff erent speed levels of knee fl exors’ strength during eccentric contraction (p>0,05). Regarding the concentric contraction we found signifi cant diff erences for strength production depending on angular velocity for both knee extensors and fl exors (p<0,01). Knee fl exors generated more strength during eccentric contraction compared to concentric contraction. Th e strength profi les developed in the present study can assist in the establishment of baseline data in young soccer players or for comparison values with other researchers.


2021 ◽  
Vol 2 (2021) ◽  
pp. 40-50
Author(s):  
Borislava Petrova ◽  

Soccer is a high-intensity intermittent team sport where both the aerobic and anaerobic energy systems contribute to the physiological demands of the game. The study aims to search and determine relationships between the values of cardiopulmonary and gas exchange indices during frequently used laboratory tests - the CardioPulmonary Exercise Test (CPET) and the Wingate Anaerobic Test (WAnT), exploring the capacity of the energy systems. Forty-seven soccer players (15.06 ± 0.84 years of age) performed both tests as Oxygen uptake (VO2), Oxygen pulse (O2HR), Pulmonary ventilation (VE), Volume of expired air (VTex), and Breath frequency (BF) were measured online using a breathby-breath cardiopulmonary exercise testing system. Ergometric achievements during WAnT: PP (Peak Power) 662.4 ± 121.2 W; AP (Average Power) 494.67 ± 98.5 W; FI (Fatigue Index) 61.2 ± 28.7%. There was no correlation between WAnT PP and AP and maximum power output in CPET. WAnT VE and VTex correlate significantly with CPET VO2max (r = .676 and r = .772, respectively). The main finding was a presence of approximately identical maximal values of cardiopulmonary parameters achieved in the very different in duration and intensity CPET and WАnT: insignificant differences between CPET versus WAnT: VO2max (55.97 ± 2.02 versus 56.02 ± 17.3 ml.kg.min-1); VEmax (133.96 ± 21.77 versus 126.77 ± 24.77 l.min-1); VTex max (2.19 ± 0.37 l versus 2.06 ± 0.43 l); BFmax (62.20 versus 75.43.min-1). We assume that when conducting WAnT with simultaneous registration of respiration, together with the indices of athletes’ power output, reliable information about the magnitude of VO2max and other cardiopulmonary parameters of players could be obtained. This will greatly facilitate the ongoing control of the exercise conditioning status of athletes.


Author(s):  
Hadi Nobari ◽  
Ana Ruivo Alves ◽  
Filipe Manuel Clemente ◽  
Jorge Pérez-Gómez

Abstract Background Digit ratio (2D:4D) characterized by the length of the second digit (2D) divided by the length of the fourth digit (4D), is a powerful marker of athletic performance. Some studies showed a negative correlation between 2D:4D ratio and sports performances. Objectives The purpose of the present study was three-fold: (1) to analyze the influence of anthropometric and 2D:4D ratio on variations of accumulated training load (ATL) and fitness parameters: maximal oxygen uptake (V̇O2max), countermovement jump (CMJ), isometric muscular strength of the knee extensor for hamstring (ISH) and flexor for quadriceps (ISQ) muscles; along three stages of evaluation of soccer players based on playing positions; (2) to analyze the correlations between 2D:4D ratio and aforementioned parameters; and (3) to investigate if variance in fitness levels and ATL can explain the 2D:4D ratio. Methods Twenty-four elite players under 17 years were daily monitored for their rating perceived exertion and ATL across 24 weeks over the season. Soccer players have also measured in three stages for anthropometric traits and fitness parameters. Results Significant differences were observed between playing positions for body mass, goalkeepers had higher body mass compared to centre-midfielder and winger players. Moreover, there were significant differences in ATL between early-season to mid-season in goalkeepers (P = 0.032). The 2D:4D ratio (left and right) shown largely and negatively association with muscular strength (ISQ: r =  − 0.80; r =  − 0.78, P ≤ 0.001, ISH: r =  − 0.63; r =  − 0.62, P = 0.001, respectively) and VO2max changes (r =  − 0.55, P = 0.005; r =  − 0.50, P = 0.013, respectively); lastly, both 2D:4D ratio significantly predicted changes in muscular strength and VO2max in young soccer players. Conclusions Goalkeepers tended to have higher body mass compared to centre-midfielder and winger players; and 2D:4D ratio revealed a mighty predictor of physical fitness changes in soccer players. Evidence should be helpful to professionals to highlight the usefulness of the 2D:4D into the identification of talent, but also to optimize young players' performance.


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