The Effects of Injury Preventive Warm-Up Programs on Knee Strength Ratio in Young Male Professional Soccer Players

Abstract Muscular strength is an important factor which is crucial for performance and injury prevention in most sports. The purpose of this study was to evaluate the effects of the FIFA’s Medical Assessment and Research Centre 11+ and HarmoKnee injury prevention programs on knee strength of young professional male soccer players. Thirty-six soccer players (age: 18.9 ± 1.4 years) were divided equally into three groups; the 11+, HarmoKnee and control groups. The programs were performed for 24 sessions. Hamstring and quadriceps strength was measured using the Biodex System 3 at 30°, 60° and 90° of knee flexion. The 11+ increased quadriceps strength in the dominant leg by 19.7% and 47.8% at 60°and 90° knee flexion, respectively, and in the non-dominant leg by 16%, 35.3% and 78.1 % at 30°, 60° and 90° knee flexion, respectively. The HarmoKnee group, however, showed increased quadriceps strength only at 90° i.e., by 85.7% in the dominant leg and 73.8% in the non-dominant leg. As for hamstring strength, only the 11+ group demonstrated an increment by 24.8% and 19.8% at 30° and 60° knee flexion in the dominant leg, and in the nondominant leg, by 28.7% and 13.7% at 30° and 60° knee flexion, respectively. In conclusion, both warm-up programs improve quadriceps strength. The 11+ demonstrated improvement in hamstring strength while the HarmoKnee program did not indicate any improvement. We suggest adding eccentric hamstring components such as Nordic hamstring exercise to the HarmoKnee program in order to enhance hamstring strength.

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ISOKINETIC PROFILES AND REFERENCE VALUES OF PROFESSIONAL SOCCER PLAYERS

Revista Brasileira de Medicina do Esporte ◽

10.1590/1517-8692202127062021_0073 ◽

2021 ◽

Vol 27 (6) ◽

pp. 610-615

Author(s):

Guillermo Charneco Salguero ◽

Francisco García-Muro San José ◽

Arturo Pérez Gosalvez ◽

Jose Miguel Cárdenas Rebollo ◽

Isabel Brígido Fernández ◽

...

Keyword(s):

Reference Values ◽

Health Professionals ◽

High Speed ◽

Peak Torque ◽

Soccer Players ◽

Level Of Evidence ◽

Warm Up ◽

Professional Soccer ◽

Average Work ◽

Torque Values

ABSTRACT Introduction: Isokinetics is a tool commonly used in professional soccer. There is ongoing debate among researchers as to the isokinetic reference values a player should have. Objectives: To determine the absolute peak torque (PT) and average work of professional soccer players in relation to their positions on the field, and to establish the reference values for these variables. Methods: Purposeful sampling was used to select 289 professional soccer players. The sample included 32 goalkeepers, 100 defenders, 98 midfielders, and 59 strikers. The participants were measured preseason. The players were asked to perform a 10-minute warm-up on an exercise bike, and then to perform 5 repetitions at low speed, 10 at medium speed, and 25 at high speed, with 30 to 40-s of rest between each set of repetitions. The contraction method was concentric-concentric in a dynamometer Isomed 2000. Results: The average age, weight, and height of the players was 21.9 years, 74.3 kilograms, and 1.8 meters, respectively. The goalkeepers presented higher PT at the 3 measured speeds, and the higher average work at 180°/s and 240°/s in relation to defenders and midfielders. The strikers presented higher average work at 240°/s in relation to midfielders, and higher PT in relation to the defenders and midfielders. Absolute values were shown and reference values were established. Conclusions: The goalkeepers and strikers were the players that showed the greatest differences in their favor in relation to the other positions. The peak torque values and average work were described in relation to the player's position on the field. This study resulted in the creation of a tool for health professionals working with professional soccer players, providing reference values for these players in relation to their position on the field that can be used as benchmarks, by health professionals, to optimize soccer players’ performance. Level of evidence II, Prospective comparative study.

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Bilateral and Unilateral Asymmetries of Isokinetic Strength and Flexibility in Male Young Professional Soccer Players

Journal of Human Kinetics ◽

10.2478/hukin-2013-0005 ◽

2013 ◽

Vol 36 (1) ◽

pp. 45-53 ◽

Cited By ~ 57

Author(s):

Abdolhamid Daneshjoo ◽

Nader Rahnama ◽

Abdul Halim Mokhtar ◽

Ashril Yusof

Keyword(s):

Hip Joint ◽

Dynamic Control ◽

Young Male ◽

Movement Pattern ◽

Quadriceps Strength ◽

Soccer Players ◽

Speed Ratio ◽

Joint Flexibility ◽

Young Professional ◽

Professional Soccer

This study investigated bilateral and unilateral asymmetries of strength and flexibility in male young professional soccer players. Thirty-six soccer players (age: 18.9 ± 1.4 years) participated in this study. A Biodex Isokinetic Dynamometer was used to assess the hamstring and quadriceps strength at selected speeds of 60°/s, 180°/s and 300°/s. Hip joint flexibility was measured using a goniometer. No difference was observed in conventional strength ratio, dynamic control ratio and fast/slow speed ratio between the dominant and non-dominant legs (p>0.05). All but one of the players (97.2%) had musculoskeletal abnormality (bilateral imbalance > 10%) in one or more specific muscle groups. The dominant leg had greater hip joint flexibility compared with the non-dominant leg (108.8 ± 10.7° versus 104.6 ± 9.8°, respectively). The findings support the hypothesis that physical performance and movement pattern experienced during soccer playing may negatively change the balance of strength in both legs (bilateral strength balance), but not on the same leg of the young male professional soccer players. The results can be helpful for trainers and coaches to decide whether the players need to improve their balance and strength which in turn may prevent injury. It is suggested that in professional soccer training, quadriceps and hamstrings muscle strength, as well as hip joint flexibility should not be overlooked.

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

Journal of Human Kinetics ◽

10.2478/v10078-012-0017-5 ◽

2012 ◽

Vol 31 (1) ◽

pp. 159-168 ◽

Cited By ~ 14

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.

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Maturity Has a Greater Association than Relative Age with Physical Performance in English Male Academy Soccer Players

Sports ◽

10.3390/sports9120171 ◽

2021 ◽

Vol 9 (12) ◽

pp. 171

Author(s):

John M. Radnor ◽

Jacob Staines ◽

James Bevan ◽

Sean P. Cumming ◽

Adam L. Kelly ◽

...

Keyword(s):

Physical Performance ◽

Performance Measures ◽

Adult Height ◽

Young Male ◽

Sprint Performance ◽

Soccer Players ◽

Countermovement Jump ◽

Sprint Time ◽

Relative Age ◽

Professional Soccer

This study aimed to: (1) examine differences in physical performance across birth-quartiles and maturity-status, and (2) determine the relationships among relative age, maturation and physical performance in young male soccer players. The sample included 199 males aged between 8.1 and 18.9 years, from two professional soccer academies in the English Football League. Data were collected for height, weight, self-reported biological parent heights, 30 m sprint time and countermovement jump (CMJ) height. Relative age was conveyed as a decimal, while maturity status was determined as the percentage of predicted adult height (PAH). There were no significant differences in any measure between birth quartiles, however early maturers outperformed on-time and later maturers in most performance measures. Pearson-product-moment correlations revealed that maturation was inversely associated with 30 m sprint time in U12 to U16 (r = −0.370–0.738; p < 0.05), but only positively associated with CMJ performance in U12 (r = 0.497; p < 0.05). In contrast, relative age was unrelated to sprint performance and only significantly associated with superior CMJ performance in U16. This study indicates that maturity has a greater association with sprint performance than relative age in English male academy soccer players. Practitioners should monitor and assess biological maturation in young soccer players to attempt to control for the influence on physical performance, and avoid biasing selection on absolute performance rather than identifying the most talented player.

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Monitoring Cardiorespiratory Fitness in Professional Soccer Players: Is It Worth the Prick?

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2019-0911 ◽

2020 ◽

Vol 15 (10) ◽

pp. 1437-1441

Author(s):

Martin Buchheit ◽

Ben M. Simpson ◽

Mathieu Lacome

Keyword(s):

Blood Lactate ◽

Labor Cost ◽

Soccer Players ◽

Exercise Heart Rate ◽

Individual Change ◽

Warm Up ◽

Professional Soccer ◽

Starting Speed ◽

Clear Change ◽

Level Of Agreement

Purpose: To compare between-tests changes in submaximal exercise heart rate (HRex, 3 min, 12 km/h) and the speed associated with 4 mmol/L of blood lactate (V4mmol) in soccer players to get insight into their level of agreement and respective sensitivity to changes in players’ fitness. Methods: A total of 19 elite professional players (23 [3] y) performed 2 to 3 graded incremental treadmill tests (3-min stages interspersed with 1 min of passive recovery, starting speed 8 km/h, increment 2 km/h until exhaustion or 18 km/h if exhaustion was not reached before) over 1.5 seasons. The correlation between the changes in HRex and V4mmol was examined. Individual changes in the 2 variables were compared (>2 × typical error considered “clear”). Results: The changes in HRex and V4mmol were largely correlated (r = .82; 90% confidence interval, .65–.91). In more than 90% of the cases, when a clear individual change in HRex was observed, it was associated with a similar clear change in V4mmol (the same direction, improvement, or impairment of fitness) and conversely. Conclusions: When it comes to testing players submaximally, the present results suggest that practitioners can use HRex or V4mmol interchangeably with confidence. However, in comparison with a field-based standardized warm-up run (3–4 min, all players together), the value of a multistage incremental test with repeated blood lactate samplings is questionable for a monitoring purpose given its time, labor, cost, and poorer player buy-in.

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Knee Flexor Eccentric Strength, Hamstring Muscle Volume and Sprinting in Elite Professional Soccer Players with a Prior Strained Hamstring

Biology ◽

10.3390/biology11010069 ◽

2022 ◽

Vol 11 (1) ◽

pp. 69

Author(s):

Alberto Mendez-Villanueva ◽

Francisco Javier Nuñez ◽

Jose Luis Lazaro-Ramirez ◽

Pablo Rodriguez-Sanchez ◽

Marc Guitart ◽

...

Keyword(s):

Biceps Femoris ◽

Muscle Volume ◽

Soccer Players ◽

Hamstring Muscle ◽

Knee Flexor ◽

Hamstring Strain ◽

Professional Soccer ◽

Knee Strength ◽

History Of ◽

Flexor Strength

The aim was to determine if players with a prior hamstring strain injury (HSI) exhibit bilateral deficits in knee flexor eccentric strength and hamstring muscle volume and differences in sprinting performance compared with players without a history of HSIs. Forty-six male professional soccer players participated in this study. Eccentric knee flexor strength, hamstring muscle volume (MRI), and a 20-m running sprint test (5- and 10-m split time) were assessed at the start of the preseason. Eccentric knee strength of the previously injured limbs of injured players was greater (ES: 1.18–1.36) than the uninjured limbs in uninjured players. Previously injured limbs showed possibly larger biceps femoris short heads (BFSh) and likely semitendinosus (ST) muscle volumes than the contralateral uninjured limbs among the injured players (ES: 0.36) and the limbs of the uninjured players (ES: 0.56), respectively. Players who had experienced a previous HSI were possibly slower in the 5-m (small ES: 0.46), while unclear differences were found in both the 10-m and 20-m times. Players with a prior HSI displayed greater eccentric knee flexor strength, possibly relatively hypertrophied ST and BFSh muscles, and possibly reduced 5-m sprinting performances than previously uninjured players. This can have implication for the design of secondary hamstring muscle injury prevention strategies.

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Characterization of Warm-Up in Soccer: Report from Portuguese Elite Soccer Coaches

The Open Sports Sciences Journal ◽

10.2174/1875399x02114010114 ◽

2021 ◽

Vol 14 (1) ◽

pp. 114-123

Author(s):

Ricardo Ferraz ◽

Paulo Ribeiro ◽

Henrique P. Neiva ◽

Pedro Forte ◽

Luís Branquinho ◽

...

Keyword(s):

Training Session ◽

Point Of View ◽

Soccer Players ◽

Specific Information ◽

Cross Sectional ◽

Warm Up ◽

Professional Soccer ◽

Psychological Point ◽

Observational Study Design ◽

And Performance

Background: Warm-up before competition and training is a strategy that is widely acknowledged to improve players’ physical condition and performance. However, the importance of warm-up is not well understood and so there is a research gap into this topic. Objective: This study aimed to characterize the warm-up of professional soccer players by differences and similarities between different coaches’ methodologies. Methods: A group of thirty-two Portuguese elite soccer coaches participated in this study An observational study design was conducted through a cross-sectional descriptive questionnaire with nineteen questions. During the questionnaire, coaches were asked to provide specific information about the warm-ups prescribed for soccer players, about their importance from a technical, physical and psychological point of view and the importance they attached to the warm-up / reheating of substitute players. The questionnaire was administered to the coaches at the end of a training session. Results: The results indicated that there is no consensus regarding the type of warm-up that should be prescribed. There are different opinions between elite coaches regarding the warm-up components that must be emphasized in order to prepare players for the game demands. Moreover, considering the tactical, technical, physical, and psychological dimensions, the coaches have different perspectives of the warm-up. Conclusion: This study allowed to conclude that there is no standard regarding the prescription of warm-up in professional soccer players, in the opinion of coaches. This is mainly due to the fact that there is a distinct appreciation in relation to the importance and influence of warm-up for performance.

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