Individual-based Creatine Kinase Reference Values in Response to Soccer Match-play

Author(s):  
João Ribeiro ◽  
Petrus Gantois ◽  
Vitor Moreira ◽  
Francisco Miranda ◽  
Nuno Romano ◽  
...  

AbstractThe aim of the present study was to determine the creatine kinase reference limits for professional soccer players based on their own normal post-match response. The creatine kinase concentration was analyzed in response to official matches in 25 players throughout a 3-year period. Samples were obtained between 36–43 hours following 70 professional soccer matches and corresponded to 19.1±12.1 [range: 6–49] samples per player. Absolute reference limits were calculated as 2.5th and 97.5th percentile of the samples collected. Creatine kinase values were also represented as a percentage change from the individual’s season mean and represented by 90th, 95th and 97.5th percentiles. The absolute reference limits for creatine kinase concentration calculated as 97.5th and 2.5th percentiles were 1480 U.L−1 and 115.8 U.L−1, respectively. The percentage change from the individual’s season mean was 97.45±35.92% and players were in the 90th, 95th and 97.5th percentiles when the percentages of these differences were 50.01, 66.7, and 71.34% higher than player’s season mean response, respectively. The data allowed us to determine whether the creatine kinase response is typical or if it is indicative of a higher than normal creatine kinase elevation and could be used as a practical guide for detection of muscle overload, following professional soccer match-play.

2009 ◽  
Vol 44 (2) ◽  
pp. 180-184 ◽  
Author(s):  
Matt Greig ◽  
Jason C. Siegler

Abstract Context: Epidemiologic findings of higher incidences of hamstrings muscle strains during the latter stages of soccer match play have been attributed to fatigue. Objective: To investigate the influence of soccer-specific fatigue on the peak eccentric torque of the knee flexor muscles. Design: Descriptive laboratory study. Setting: Controlled laboratory environment. Patients or Other Participants: Ten male professional soccer players (age  =  24.7 ± 4.4 years, mass  =  77.1 ± 8.3 kg, V˙o2max  =  63.0 ± 4.8 mL·kg−1·min−1). Intervention(s): Participants completed an intermittent treadmill protocol replicating the activity profile of soccer match play, with a passive halftime interval. Before exercise and at 15-minute intervals, each player completed isokinetic dynamometer trials. Main Outcome Measure(s): Peak eccentric knee flexor torque was quantified at isokinetic speeds of 180° · s−1, 300° · s−1, and 60° · s−1, with 5 repetitions at each speed. Results: Peak eccentric knee flexor torque at the end of the game (T300eccH105  =  127 ± 25 Nm) and at the end of the passive halftime interval (T300eccH60  =  133 ± 32 Nm) was reduced relative to T300eccH00 (167 ± 35 Nm, P < .01) and T300eccH15 (161 ± 35 Nm, P  =  .02). Conclusions: Eccentric hamstrings strength decreased as a function of time and after the halftime interval. This finding indicates a greater risk of injuries at these specific times, especially for explosive movements, in accordance with epidemiologic observations. Incorporating eccentric knee flexor exercises into resistance training sessions that follow soccer-specific conditioning is warranted to try to reduce the incidence or recurrence of hamstrings strains.


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 ◽  
...  

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.


2018 ◽  
Vol 46 (6) ◽  
pp. 1294-1305 ◽  
Author(s):  
Andrea B. Mosler ◽  
Adam Weir ◽  
Andreas Serner ◽  
Rintje Agricola ◽  
Cristiano Eirale ◽  
...  

Background: Musculoskeletal hip/groin screening tests are commonly performed to detect at-risk individuals. Bony hip morphology is considered a potential intrinsic risk factor but has not been examined prospectively. Purpose: To evaluate the association between intrinsic risk factors identified from musculoskeletal and radiographic screening tests and hip/groin injuries leading to time loss from training and/or match play in professional male soccer players. Study Design: Prospective cohort study; Level of evidence, 2. Methods: Male professional soccer players, aged ≥18 years, underwent screening specific for hip/groin pain during 2 consecutive seasons of the Qatar Stars League. The screening battery included pain provocation, range of motion, and strength tests as well as a hip radiographic examination. The radiographic examination included an anteroposterior pelvic view and 45° Dunn view, with bony hip morphology determined using quantitative methods. Time-loss (≥1 day) hip/groin injuries and individual player exposure (training and match play) were recorded prospectively, and injuries were categorized as adductor-related, inguinal-related, iliopsoas-related, pubic-related, or hip-related groin pain, or “other,” as recommended in the Doha agreement. We calculated hazard ratios (HRs) from univariate and multivariate Cox regression models to assess the relationship between potential risk factors and hip/groin injuries. Results: There were 438 players, completing 609 player seasons, and 113 hip/groin injuries that met the criteria for inclusion, with 85 injuries categorized as adductor-related. The proportion of players with bony morphological variants was the following: cam, 71%; pincer, 5%; and acetabular dysplasia, 13%. Previous hip/groin injuries (HR, 1.8; 95% CI, 1.2-2.7) and eccentric adduction strength were associated with the risk of hip/groin injuries. Higher (>1 SD above the mean) than normal eccentric adduction strength was associated with an increased risk for all hip/groin injuries (HR, 1.6; 95% CI, 1.0-2.5). Lower (<1 SD below the mean) than normal eccentric adduction strength was associated with an increased risk for adductor-related injuries (HR, 1.7; 95% CI, 1.0-3.0). No other musculoskeletal screening test or bony hip morphology variables were associated with the injury risk. Conclusion: Previous groin injuries and eccentric adduction strength were associated with the risk of groin injuries. However, these associations were not strong enough to identify an “at-risk” individual, and therefore, musculoskeletal screening tests were not useful to dictate individualized prevention strategies. Bony hip morphology was not associated with the risk of groin injuries.


Author(s):  
José M. Oliva-Lozano ◽  
Daniel Rojas-Valverde ◽  
Carlos D. Gómez-Carmona ◽  
Víctor Fortes ◽  
José Pino-Ortega

PLoS ONE ◽  
2014 ◽  
Vol 9 (10) ◽  
pp. e110995 ◽  
Author(s):  
Liam D. Harper ◽  
Daniel J. West ◽  
Emma Stevenson ◽  
Mark Russell

2014 ◽  
Vol 49 (4) ◽  
pp. 447-453 ◽  
Author(s):  
Mark Russell ◽  
David Benton ◽  
Michael Kingsley

Context: The ingestion of carbohydrate (CHO) before and during exercise and at halftime is commonly recommended to soccer players for maintaining blood glucose concentrations throughout match play. However, an exercise-induced rebound glycemic response has been observed in the early stages of the second half of simulated soccer-specific exercise when CHO-electrolyte beverages were consumed regularly. Therefore, the metabolic effects of CHO beverage consumption throughout soccer match play remain unclear. Objective: To investigate the blood glucose and blood lactate responses to CHOs ingested before and during soccer match play. Design: Crossover study. Setting: Applied research study. Patients or Other Participants: Ten male outfield academy soccer players (age = 15.6 ± 0.2 years, height = 1.74 ± 0.02 m, mass = 65.3 ± 1.9 kg, estimated maximal oxygen consumption = 58.4 ± 0.8 mL·kg−1·min−1). Intervention(s): Players received a 6% CHO-electrolyte solution or an electrolyte (placebo) solution 2 hours before kickoff, before each half (within 10 minutes), and every 15 minutes throughout exercise. Blood samples were obtained at rest, every 15 minutes during the match (first half: 0–15, 15–30, and 30–45 minutes; second half: 45–60, 60–75, and 75–90 minutes) and 10 minutes into the halftime break. Main Outcome Measure(s): Metabolic responses (blood glucose and blood lactate concentrations) and markers of exercise intensity (heart rate) were recorded. Results: Supplementation influenced the blood glucose response to exercise (time × treatment interaction effect: P ≤ .05), such that glucose concentrations were higher at 30 to 45 minutes in the CHO than in the placebo condition. However, in the second half, blood glucose concentrations were similar between conditions because of transient reductions from peak values occurring in both trials at halftime. Blood lactate concentrations were elevated above those at rest in the first 15 minutes of exercise (time-of-sample effect: P &lt; .001) and remained elevated throughout exercise. Supplementation did not influence the pattern of response (time × treatment interaction effect: P = .49). Conclusions: Ingestion of a 6% CHO-electrolyte beverage before and during soccer match play did not benefit blood glucose concentrations throughout the second half of exercise.


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