scholarly journals Profil izokinetickej sily extenzorov a flexorov kolena u mladých futbalových hráčov

2012 ◽  
Vol 6 (1) ◽  
pp. 53-60
Author(s):  
Tomáš Malý ◽  
František Zahálka ◽  
Lucia Malá ◽  
Jaroslav Teplan
Keyword(s):  
Angular Velocity ◽  
Research Group ◽  
Eccentric Contraction ◽  
Baseline Data ◽  
Soccer Players ◽  
Knee Extensors ◽  
Isokinetic Strength ◽  
Concentric Contraction ◽  
Angular Velocities

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.

scholarly journals The relationships between knee extensors/ flexors strength and balance control in elite male soccer players

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12461
Author(s):  
Robert Śliwowski ◽  
Jakub Marynowicz ◽  
Łukasz Jadczak ◽  
Monika Grygorowicz ◽  
Paweł Kalinowski ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Balance Control ◽  
Peak Torque ◽  
Soccer Players ◽  
Knee Extensors ◽  
Measurement Tool ◽  
Strength Performance ◽  
Angular Velocities ◽  
Postural System ◽  
The Relationship

Background Strength and balance are important factors for soccer players to be successful. This study’s aim was to determine the relationship between lower-limb muscle strength and balance control in elite male soccer players (n = 77). Methods Concentric isokinetic strength (peak torque of quadriceps (PT-Q) and hamstrings (PT-H), hamstrings/quadriceps (H/Q) ratio) was measured for the dominant and non-dominant leg at angular velocities of 60°s−1and 240°s−1, as well as the total work for extensors (TW-Q) and flexors (TW-H) for both legs (at an angular velocity of 240°s−1only). Balance score (BAL score) was used for unilateral assessment of balance control using a Delos Postural System Test measurement tool. Hierarchical multiple regression analyses were performed to predict balance control using isokinetic knee strength performance for dominant and non-dominant legs. Results Final modelling included peak torque of hamstrings at 240°s−1 and peak torque of the quadriceps at 240°s−1 for the non-dominant leg (R2 = 19.6%; p ≤ 0.001) and only peak hamstring torque at 240°s−1 for the dominant leg (R2 = 11.3%; p = 0.003) as significant predictors of balance score. Conclusion Findings indicate that balance control is widely influenced by peak hamstring torque and peak quadriceps torque at high angular velocity particularly in the non-dominant leg i.e., the supporting leg in soccer players.

Effect of repeated sprint training on isokinetic strength parameters in youth soccer players

2020 ◽  
pp. 1-9
Author(s):  
Kerem Özgünen ◽  
Çiğdem Özdemir ◽  
Ümüt Adaş ◽  
Abdullah Kilci ◽  
Cumhur Boyraz ◽  
...  
Keyword(s):  
Soccer Players ◽  
Knee Extensors ◽  
Isokinetic Strength ◽  
Sprint Training ◽  
Flexor Muscle ◽  
Strength Parameters ◽  
Youth Soccer ◽  
Repeated Sprint ◽  
Angular Velocities ◽  
Muscle Groups

BACKGROUND: Sprint drills are part of the soccer training routine for their resemblance to match activities. There is a lack of information in the literature about the changes in isokinetic skeletal muscle strength in response to sprint training. OBJECTIVE: This study evaluates the effects of eight weeks, on-season repeated sprint training with a change of direction on isokinetic strength parameters in well-trained youth soccer players. METHODS: Nineteen well-trained youth soccer players volunteered to participate in the study. The training program included three sets of six, 40 m (20 + 20 m) shuttle sprints twice a week for eight weeks. Isokinetic peak moment, work, and power of knee extensors and flexors were measured at angular velocities of 60, 180 and 240∘/s. Pre- and post-training valid isokinetic sector data were compared. RESULTS: Following the training period, dominant and non-dominant legs’ peak moment, work, and power values for both extensor and flexor muscle groups improved significantly at various angular velocities. CONCLUSIONS: Isokinetic strength enhancement may be explained with the induction of muscle hypertrophy following a prolonged period of sprint training.

scholarly journals Isokinetic Strength Responses to Season-long Training and Competition in Turkish Elite Soccer Players

2012 ◽  
Vol 31 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Niyazi Eniseler ◽  
Çağatay Şahan ◽  
Hikmet Vurgun ◽  
Hasan Mavi
Keyword(s):  
Knee Extensor ◽  
Peak Torque ◽  
Soccer Players ◽  
Isokinetic Strength ◽  
Professional Soccer ◽  
Knee Strength ◽  
Flexor Muscles ◽  
Angular Velocities ◽  
Soccer Training ◽  
Knee Flexors

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.

scholarly journals Changes in Isokinetic Muscle Strength in Adolescent Soccer Players after 10 Weeks of Pre-Season Training

2017 ◽  
Vol 10 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Michal Lehnert ◽  
Petr Stastny ◽  
James J. Tufano ◽  
Pavel Stolfa
Keyword(s):  
Soft Tissue Injuries ◽  
Peak Torque ◽  
Soccer Players ◽  
Knee Extensors ◽  
Future Research ◽  
Isokinetic Strength ◽  
Isokinetic Testing ◽  
Apparent Lack ◽  
Weight Room ◽  
Knee Flexors

Background:During soccer-specific movements, the strength of knee extensors and flexors is of great importance and achieving certain strength ratios between the two has been identified as an important parameter for reducing the risk of soft tissue injuries around the knee.Objective:The aim of the study was to evaluate changes in isokinetic strength of the knee flexors and extensors and their strength ratios in elite adolescent soccer players.Methods:Before and after 10 weeks of standard pre-season soccer training with progressive eccentric hamstring exercises, the players (n=18; age 17.1±0.4 years) participated in isokinetic testing to assess concentric and eccentric peak torque at 60°·s-1.Results:After 10 weeks of training, the peak eccentric torque of the non-dominant quadriceps increased (p=0.018; ω=0.24). Additionally, the average eccentric work increased in the dominant hamstrings (p=0.007; ω=0.23), dominant quadriceps (p=0.02; ω=0.31), non-dominant hamstrings (p=0.003; ω=0.25 and non-dominant quadriceps (p=0.01; ω=0.37). Lastly, the isokinetic functional ratio (eccentric hamstrings-to-concentric quadriceps) increased in favor of eccentric hamstring strength in the non-dominant limb (p=0.04; ω=0.31).Conclusion:The results of the study indicate that pre-season training induced suboptimal changes in the isokinetic strength of the knee flexors and extensors in elite adolescent soccer players. However, the lack of injuries combined with an apparent lack of preparedness explained by slow velocity isokinetic testing indicates that future research should investigate other forms of strength testing to determine soccer-specific preparedness such as isokinetic dynamometry at higher speeds (i.e.180°.s-1or 240°.s-1) and traditional weight-room testing such as 1RM tests.

Effect of Muscular Strength, Asymmetries and Fatigue on Kicking Performance in Soccer Players

2018 ◽  
Vol 39 (04) ◽  
pp. 297-303 ◽  
Author(s):  
Tomas Maly ◽  
Dai Sugimoto ◽  
Jana Izovska ◽  
Frantisek Zahalka ◽  
Lucia Mala
Keyword(s):  
Muscular Strength ◽  
Physical Load ◽  
Soccer Players ◽  
Knee Extensors ◽  
Physical Loading ◽  
Ball Velocity ◽  
Angular Velocities ◽  
Instep Kick ◽  
Strength Asymmetry ◽  
H:Q Ratio

AbstractThe aim of this study was to determine the effect of muscular strength, strength asymmetries, and fatigue on the speed and accuracy of an instep kick in soccer players. We measured ball velocity (BV) and kicking accuracy (KA) in the preferred (PL) and non-preferred leg (NPL) before (PRE) and after (POST) physical load in the PL. Maximum peak muscle torque of the knee extensors and flexors in the PL and NPL as well as ipsilateral knee flexors and knee extensors ratio (H:Q ratio) for both legs were assessed. BV was significantly decreased in POST physical load (5.82%, BVPRE=30.79±1.70 m·s−1, BVPOST=29.00±1.70 m·s−1, t19=3.67, p=0.00, d=1.05). Instep kick accuracy after the physical load worsened by an average of 10% in the most accurate trials. Results revealed a significant decrease in instep kick accuracy after physical loading (KAPRE=2.74±0.70 m, KAPOST=3.85±1.24 m, t19=–3.31, p=0.00, d=1.10). We found an insignificant correlation between H:Q ratio and KA in PRE test value, whereas a lower ipsilateral ratio (higher degree of strength asymmetry) in the POST physical load significantly correlated with KA in all angular velocities (r=–0.63 up to –0.67, p=0.00).

scholarly journals Morphological and isokinetic strength differences: bilateral and ipsilateral variation by different sport activity

Open Medicine ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 207-216 ◽  
Author(s):  
Tomas Maly ◽  
Lucia Mala ◽  
David Bujnovsky ◽  
Mikulas Hank ◽  
Frantisek Zahalka
Keyword(s):  
Sport Activity ◽  
Upper Extremities ◽  
Soccer Players ◽  
Knee Extensors ◽  
Isokinetic Strength ◽  
Specific Load ◽  
Young Athletes ◽  
Sport Activities ◽  
Strength Asymmetry ◽  
Male Subjects

AbstractBackgroundThe purpose of this study was to investigate the morphological and isokinetic strength asymmetry and magnitude in young athletes.MethodsOne hundred and thirty nine male subjects (soccer, floorball, non-athletes) were measured for proportion of muscle mass between upper extremities (BADΔ) and lower extremities (BLDΔ). Moreover, the peak muscle torque of knee extensors (PTE) and flexors (PTF), ipsilateral (H:Q) and bilateral strength ratio (Q:Q, H:H) were measured.ResultsWe found significant differences in observed parameters with respect to different sport activities (F = 13.02, p = 0.00, $\eta^2_p$= 0.80). Higher values of BADΔ were observed in the non-active (0.19 ± 0.11 kg) group compared with soccer players (0.10 ± 0.11 kg). We found a lower value of BLDΔ in floorball players (0.32 ± 0.11 kg) compared with soccer players (0.58 ± 0.27 kg) and non-active boys (0.63 ± 0.28 kg). Results revealed significantly higher PTE in soccer players compared with non-active boys and floorball players and higher Q:Q ratio in soccer players (10.99 ± 7.75%) compared with non-active boys (7.47 ± 5.92%).ConclusionsThis study revealed that there are morphological and strength asymmetries in the observed groups, which may have potential maladaptive effects (e.g. uncompensated overload of extremity) in athletes affected by specific load.

scholarly journals Examination of Balance and Isokinetic Strength in Female Volleyball Players

2019 ◽  
Vol 8 (6) ◽  
pp. 31
Author(s):  
Elif Cengizel ◽  
Cagdas Ozgur Cengizel
Keyword(s):  
Angular Velocity ◽  
Significant Relationship ◽  
Knee Flexion ◽  
Isokinetic Strength ◽  
Balance Test ◽  
Significant Difference ◽  
Volleyball Players ◽  
Angular Velocities ◽  
The Relationship ◽  
Flexion And Extension

The purpose of this research is: (a) to compare the dominant and non-dominant leg isokinetic strength and balance, (b) to compare the balance applied on the same side to different directions and isokinetic strength applied to the same side at different angular velocities and (c) to examine the relationship between the balance and isokinetic strength applied at different angular velocities in female volleyball players. Eleven senior female volleyball players voluntarily participated in the research. Isokinetic knee flexion and extension strength were separately obtained on concentric/concentric dominant and non-dominant leg as 5 repetitions at 60˚.s-1 angular velocity, 10 repetitions at 180˚.s-1 and 15 repetitions at 300˚.s-1. The balance test was performed for both sides in anterior (ANT), posterolateral (PL) and posteromedial (PM) directions. In female volleyball players, there is no significant difference between the dominant and non-dominant leg in terms of isokinetic strength and balance. A significant difference was detected between the balance applied in different directions on the same side and isokinetic force applied at different angular velocities. However, there is not any significant relationship between isokinetic strength and balance in female volleyball players. As a result, there is no isokinetic strength and balance asymmetry in volleyball and there is no relationship between them. This may be an indication of the need for both legs in volleyball.

Flywheel or free weight training for improvement of lower limbs strength?

2021 ◽  
pp. 1-7
Author(s):  
S. Arsenis ◽  
A. Gioftsidou ◽  
I. Smilios ◽  
P. Malliou ◽  
A. Chatzinikolaou ◽  
...  
Keyword(s):  
Training Program ◽  
Weight Training ◽  
Training Group ◽  
Lower Limbs ◽  
Soccer Players ◽  
Knee Extensors ◽  
Control Group ◽  
Training Methods ◽  
Free Weight ◽  
Angular Velocities

BACKROUND: New training methods are constantly used to improve the ability of skeletal muscles to develop strength. OBJECTIVE: The aim of the present study was to investigate the effect of half-squat training with free weights and flywheel device on isokinetic knee muscle strength for well-trained amateur soccer players. METHODS: Forty eight players were randomly divided into three groups (n= 16 each): Desmotech Training group (DT), Free Weight Training group (WT) and one Control Group (CON). DT and WT performed an eight-week half-squat training program, with two sessions per week. The DT group performed training with a flywheel device. Isokinetic concentric-eccentric strength assessments of the knee extensors-flexors muscle groups were performed at different angular velocities (60, 180 and 240∘/s). RESULTS: The eight-week training program improved all the isokinetic joint moment indicators examined in the DT and WT groups (p< 0.01). The DT group achieved higher performances at all the isokinetic parameters examined, however, without statistically significant differences to the WT group. CONCLUSIONS: Flywheel-based exercise is an effective training method and is suggested to be used to strengthen the lower limbs of soccer players.

The Analysis of Proprioception Alteration during First Five Months after Anterior Cruciate Ligament Reconstruction

2018 ◽  
Vol 1 (84) ◽  
Author(s):  
Vilma Jurevičienė ◽  
Albertas Skurvydas ◽  
Juozas Belickas ◽  
Giedra Bušmanienė ◽  
Dovilė Kielė ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Angular Velocity ◽  
Knee Joint ◽  
Cruciate Ligament ◽  
Position Sense ◽  
Joint Position Sense ◽  
Joint Position ◽  
Starting Position ◽  
Angular Velocities ◽  
Anterior Cruciate

Research  background  and  hypothesis.  Proprioception  is  important  in  the  prevention  of  injuries  as  reduced proprioception  is  one  of  the  factors  contributing  to  injury  in  the  knee  joint,  particularly  the  ACL.  Therefore, proprioception appears not only important for the prevention of ACL injuries, but also for regaining full function after ACL reconstruction.Research aim. The aim of this study was to understand how proprioception is recovered four and five months after anterior cruciate ligament (ACL) reconstruction.Research methods. The study included 15 male subjects (age – 33.7 ± 2.49 years) who had undergone unilateral ACL reconstruction with a semitendinosus/gracilis (STG) graft in Kaunas Clinical Hospital. For proprioceptive assessment, joint position sense (JPS) was measured on both legs using an isokinetic dynamometer (Biodex), at knee flexion of 60° and 70°, and at different knee angular velocities of 2°/s and 10°/s. The patients were assessed preoperatively and after 4 and 5 months, postoperatively.Research results. Our study has shown that the JPS’s (joint position sense) error scores  to a controlled active movement is significantly higher in injured ACL-deficient knee than in the contralateral knee (normal knee) before surgery and after four and five months of rehabilitation.  After 4 and 5 months of rehabilitation we found significantly lower values in injured knees compared to the preoperative data. Our study has shown that in injured knee active angle reproduction errors after 4 and 5 months of rehabilitation were higher compared with the ones of the uninjured knee. Proprioceptive ability on the both legs was  independent of all differences angles for target and starting position for movement. The knee joint position sense on both legs depends upon the rate of two different angular velocities and the mean active angle reproduction errors at the test of angular velocity slow speed was the highest compared with the fast angular velocity. Discussion and conclusions. In conclusion, our study shows that there was improvement in mean JPS 4 and 5 months after ACL reconstruction, but it did not return to normal indices.Keywords: knee joint, joint position sense, angular velocity, starting position for movement.

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