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      Patellar and Achilles Tendon Stiffness in Elite Soccer Players Assessed Using Myotonometric Measurements

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          Abstract

          Background:

          Tendon overuse injuries are an issue in elite footballers (soccer players) and may affect tendon function. Achilles and patellar tendinopathy are the most frequent pathologies. Tendon stiffness, the relationship between the force applied to a tendon and the displacement exerted, may help represent tendon function. Stiffness is affected by training and pathology. Nevertheless, information regarding this mechanical property is lacking for elite soccer athletes.

          Hypothesis:

          Achilles and patellar tendon stiffness assessed using myotonometric measurements will be greater in elite soccer athletes than in control participants.

          Study Design:

          Cross-sectional study.

          Level of Evidence:

          Level 4.

          Methods:

          Forty-nine elite soccer athletes and 49 control participants were evaluated during the 2017 preseason. A handheld device was used to measure Achilles and patellar tendon stiffness. Dominant and nondominant limbs were assessed for both groups.

          Results:

          A significantly stiffer patellar tendon was found for both the dominant and the nondominant limb in the elite soccer athletes compared with the control group. Nevertheless, no differences were found in Achilles tendon stiffness between groups. When comparing between playing positions in soccer athletes, no significant differences were found for both tendons.

          Conclusion:

          Greater patellar tendon stiffness may be related to an improvement in force transmission during muscle contraction. On the other hand, it seems that after years of professional training, Achilles tendon stiffness does not change, conserving the storing-releasing function of elastic energy. The nonsignificant differences between positions may be attributable to the years of homogeneous training that the players underwent.

          Clinical Relevance:

          The present study shows another technique for measuring mechanical properties of tendons in soccer athletes that could be used in clinical settings. In the future, this technique may help clinicians choose the best exercise protocol to address impairments in tendon stiffness.

          Related collections

          Most cited references 40

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          Performance characteristics according to playing position in elite soccer.

          The paper provides a large-scale study into the motion characteristics of top class soccer players, during match play, according to playing position. Three hundred top-class outfield soccer players were monitored during 20 Spanish Premier League and 10 Champions League games using a computerized match analysis system (Amisco Pro, Nice, France). Total distance covered in five selected categories of intensity, and the mean percentage of playing time spent in each activity were analyzed according to playing position. Midfield players covered a significantly greater total distance (p < 0.0001) than the groups of defenders and forwards did. Analyzing the different work rates showed significant differences (p < 0.5 - 0.0001) between the different playing positions. There were no significant differences between halves in the total distance covered, or in distances covered at submaximal and maximal intensities. However, significantly more distance was covered in the first half compared to the second in medium intensities (11.1 - 19 km/h). The current findings provide a detailed description of the demands placed on elite soccer players, according to their positional role at different work intensities, which may be helpful in the development of individualized training programs.
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            Prevalence of jumper's knee among elite athletes from different sports: a cross-sectional study.

            The prevalence of jumper's knee across different sports has not been examined, and it is not known if there is a gender difference. Data from surgical case series indicate that there may be a high prevalence in sports with high speed and power demands. The aim of this study was to estimate the prevalence of jumper's knee in different sports among female and male athletes and to correlate the prevalence to the loading characteristics of the extensor mechanism in these sports. Cross-sectional study; Level of evidence, 4. The authors examined approximately 50 Norwegian male and female athletes at the national elite level from each of the following 9 sports: athletics (male athletes: high jump, 100- and 200-m sprint), basketball (male athletes), ice hockey (male athletes), volleyball (male athletes), orienteering (male athletes), road cycling (male athletes), soccer (male and female athletes), team handball (male and female athletes), and wrestling (male athletes). The examination included an interview on individual characteristics (weight, age, height, and training background), a clinical examination, and self-recorded Victorian Institute of Sport Assessment score from 0 (worst) to 100 (best). The overall prevalence of current jumper's knee was 14.2% (87 of 613 athletes), with a significant difference between sports with different performance characteristics (range, 0%-45%). In addition, 51 athletes (8%) reported previous symptoms. The prevalence of current symptoms was highest in volleyball (44.6%+/-6.6%) and basketball (31.9%+/-6.8%), whereas there were no cases in cycling or orienteering. The prevalence of current jumper's knee was lower among women (5.6%+/-2.2%) compared with men (13.5%+/-3.0%; chi2 test, P=.042). The duration of symptoms among athletes with current jumper's knee (n=87) was 32+/-25 (standard deviation) months, with a Victorian Institute of Sport Assessment score of 64+/-19. The prevalence of jumper's knee is high in sports characterized by high demands on speed and power for the leg extensors. The symptoms are often serious, resulting in long-standing impairment of athletic performance.
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              Muscle fascicle and series elastic element length changes along the length of the human gastrocnemius during walking and running.

              Ultrasound imaging has recently been used to distinguish the length changes of muscle fascicles from those of the whole muscle tendon complex during real life movements. The complicated three-dimensional architecture of pennate muscles can however cause heterogeneity in the length changes along the length of a muscle. Here we use ultrasonography to examine muscle fascicle length and pennation angle changes at proximal, distal and midbelly sites of the human gastrocnemius medialis (GM) muscle during walking (4.5 km/h) and running (7.5 km/h) on a treadmill. The results of this study have shown that muscle fascicles perform the same actions along the length of the human GM muscle during locomotion. However the distal fascicles tend to shorten more and act at greater pennation angles than the more proximal fascicles. Muscle fascicles acted relatively isometrically during the stance phase during walking, however during running the fascicles shortened throughout the stance phase, which corresponded to an increase in the strain of the series elastic elements (SEEs) (consisting of the Achilles tendon and aponeurosis). Measurement of the fascicle length changes at the midbelly level provided a good approximation of the average fascicle length changes across the length of the muscle. The compliance of the SEE allows the muscle fascicles to shorten at a much slower speed, more concomitant with their optimal speed for maximal power output and efficiency, with high velocity shortening during take off in both walking and running achieved by recoil of the SEE.
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                Author and article information

                Journal
                Sports Health
                Sports Health
                SPH
                spsph
                Sports Health
                SAGE Publications (Sage CA: Los Angeles, CA )
                1941-7381
                1941-0921
                02 January 2019
                Mar-Apr 2019
                02 January 2020
                : 11
                : 2
                : 157-162
                Affiliations
                []Escuela de Kinesiología, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
                []Laboratorio Integrativo de Biomecánica y Fisiología del Esfuerzo, Escuela de Kinesiología, Facultad de Medicina, Universidad de los Andes, Santiago, Chile
                [§ ]Clínica MEDS, Santiago, Chile
                Author notes
                [* ]Iver Cristi-Sánchez, PT, Universidad Mayor, Chile, Camino La Piramide 5750, Huechuraba, Santiago, Chile 8580000 (email: iver.cristi@ 123456mayor.cl ).
                Article
                10.1177_1941738118820517
                10.1177/1941738118820517
                6391548
                30601077
                © 2019 The Author(s)
                Categories
                Current Research
                Custom metadata
                March/April 2019

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