Oxidative Stress and Abnormal Tendon Sonographic Features in Elite Soccer Players (A Pilot Study) / Estresse oxidativo e características ultrassonográficas do tendão anormal em jogadores de futebol de elite (um estudo piloto)

Abstract Objective Sound experimental data suggest that oxidative stress plays an important role in the pathogenesis of tendinopathies. However, this hypothesis in humans remains speculative given that clinical data are lacking to confirm it. Recently, a new methodology has allowed to quantify the oxidative stress in vivo by measuring the concentration of hydroperoxides of organic compounds, which have been utilized as an oxidative stressrelated marker in several pathologic and physiologic conditions. Given the reliability of this test and the lack of information in subjects with tendinopathies, the aim of the present study was to assess the oxidative stress status in elite professional soccer players with and without ultrasonographic features of tendon damage. Methods In 73 elite players, blood metabolic parameters were evaluated and oxidative stress was measured by means of a specific test (expressed as U-Carr units). Therefore, an ultrasonographic evaluation of the Achilles and patellar tendons was performed. Results No significant relationships were observed between metabolic parameters and oxidative stress biomarkers. The Achilles and patellar tendons showed a normal echographic pattern in 58 athletes, and sonographic abnormalities in 15. The athletes with ultrasonographic alterations, compared to those with normal US picture, showed significantly higher U-Carr levels (p = 0.000), body mass index (BMI) values (p = 0.03) and were older (p = 0.005). The difference in U-Carr values among the subjects remained significant also after adjustment for age and BMI. Conclusion The results of the present study support the hypothesis that oxidative substances, also increasedat systemicand notonlyat local level, mayfavor tendon damage. Level of Evidence IV (pilot study).

Resumo Objetivo Dados experimentais ultrassonográficos sugerem que o estresse oxidativo desempenha um papel importante na patogênese das tendinopatias. No entanto, essa hipótese permanece especulativa em humanos, dado que faltam dados clínicos para comprová-la. Recentemente, uma nova metodologia permitiu quantificar o estresse oxidativo in vivo medindo a concentração de hidroperóxidos de compostos orgânicos, que tem sido utilizada como um marcador relacionado ao estresse oxidativo em várias condições patológicas e fisiológicas. Dada a confiabilidade desse teste e a falta de informação em sujeitos com tendinopatias, o objetivo do presente estudo foi avaliar o status de estresse oxidativo em jogadores profissionais de elite com e sem características ultrassonográficas de dano tendinoso. Métodos Em 73 jogadores de elite foram avaliados parâmetros metabólicos e o estresse oxidativo foi medido por meio de um teste específico (expresso como unidades U-Carr). Por isso, foi realizada uma avaliação ultrassonográfica dos tendões de Aquiles e patelar. Resultados Não foram observadas relações significativas entre parâmetros metabólicos e biomarcadores de estresse oxidativo. Os tendões de Aquiles e patelar mostraram um padrão ecográfico normal em 58 atletas, e anormalidades ultrassonográficas em 15. Os atletas com alterações, em comparação com aqueles com quadro normal, apresentaram níveis significativamente mais elevados de U-Carr (p = 0,000), índice de massa corporal (IMC) (p = 0,03) e eram mais velhos (p = 0,005). A diferença nos valores de U-Carr entre os sujeitos permaneceu significativa também após ajuste por idade e IMC. Conclusão Os resultados deste estudo corroboram a hipótese de que as substâncias oxidativas, também aumentadas a nível sistêmico e não apenas a nível local, podem favorecer danos no tendão. Nível de Evidência IV (estudo piloto).

Postural adjustment in experimental leg length difference evaluated by means of thermal infrared imaging.

Limb length discrepancy (LLD) is defined as a condition in which limbs are unequal. The asymmetric load of body segments secondary to LLD may cause a tonic contraction of back and lower limb muscles, thus resulting in subtle cutaneous temperature variations. The aim of this study was to test the capability of high-resolution thermal infrared (IR) imaging to measure the cutaneous temperature short-term adaptation, potentially associated with 'forced' LLD conditions. An experimental LLD, obtained by placing a 20 mm foot support under the dominant foot, was used. IR imaging on 18 male healthy volunteers was performed in three experimental conditions of standing position: (T(0)) neutral posture; (T(1)) experimental LLD; (T(2)) neutral posture as in T(0). Temperature variations were evaluated on the cutaneous projection of postural muscles bellies. Significant and specific temperature variations among conditions were ipsilaterally observed on the tibialis anterior, gastrocnemius, quadriceps and latissimus dorsi muscles. Specific patterns characterized the cutaneous temperature as a consequence of the muscle activity associated with the posture variation. IR imaging was able to highlight specific functional activations. The method is non-invasive and it can be repeated without any discomfort for the physiopathological and clinical evaluation of LLD patients.