Tendon morphological changes after a prolonged ski race can be detected by ultrasound echo intensity

Alessandro Schneebeli,Marco Barbero,Maria Elisabetta Arizzio,Lorenzo Visconti,Ron Clijsen,Corrado Cescon,Guido Giardini

doi:10.1186/s13047-020-00398-9

Abstract

BackgroundUltrasound imaging techniques have been used to assess the characteristics of skeletal muscles and tendons. Such techniques (gray scale analysis) allow qualitative evaluation and have been used recently to assess the internal structure of muscles and tendons by computer-aided gray scale analysis. We hypothesized that changes in the internal structure of the Achilles and patellar tendons after a ski mountaineering race competition could be detected with ultrasound.MethodsTwenty athletes were recruited during the 19th Millet Tour du Rutor extreme, a three-day ski mountaineering competition. Ultrasound measurements of the Achilles and patellar tendons were carried out before the first race and immediately after each of the three competition days. Tendon thickness, cross-sectional area (CSA), and ultrasound gray scale analysis were calculated.ResultsSignificant differences (p < 0.05) were observed between the pre- and post-race measurements for the Achilles tendon thickness and CSA, while no significant differences were noted for the patellar tendon thickness and CSA. However, gray scale analysis of both the Achilles and patellar tendons showed significantly higher post-race values, than the pre-race values (p < 0.05).ConclusionsAchilles and patellar tendons of healthy athletes are highly responsive to an acute increase in mechanical load. Those changes can be detected from classical (thickness and CSA) and innovative (gray scale) ultrasound-based parameters.Trial registrationThis study was approved by the Azienda USL Valle d’Aosta Ethics Committee (protocol no. 23/03/2018.0026243.I).

Highlights

Ultrasound imaging techniques have been used to assess the characteristics of skeletal muscles and tendons
Those adaptations are often due to an increment of mechanical loading applied to the structure that leads to the increased expression of several growth factors [3] and the synthesis of new collagen proteins [2]
In comparison to untrained controls, the Achilles tendon (AT) and its crosssectional area (CSA) in trained endurance and jumping athletes were observed to be larger [4, 5] Kongsgaard et al [6] reported an increase in the CSA of the patellar tendon (PT) after 12 weeks of heavy resistance training

Summary

Introduction

Ultrasound imaging techniques have been used to assess the characteristics of skeletal muscles and tendons. The connective tissue of tendons is not an inert structure, but has considerable capacity to react to external demands by means of dynamic protein turnover [2]. Those adaptations are often due to an increment of mechanical loading applied to the structure that leads to the increased expression of several growth factors [3] and the synthesis of new collagen proteins [2]. The high adaptability of tendon structure to different types of loading and intensity, as well as the morphological and mechanical changes following prolonged training are well known. Seynnes et al [7] reported hypertrophy of the PT following short-term resistance training

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