Effects of tendon viscoelasticity in Achilles tendinosis on explosive performance and clinical severity in athletes

Abstract

The aim was to compare viscoelastic properties of Achilles tendons between legs in elite athletes with unilateral tendinosis, and to investigate relationships between the properties and explosive performance and clinical severity. Seventeen male athletes (mean ± standard deviation age, 27.3 ± 2.0 years) who had unilateral, chronic middle-portion tendinopathy of the Achilles tendon were assessed by the Victorian Institute of Sport Assessment questionnaire, measurements of tendon viscoelastic properties, voluntary electromechanical delay (EMD), normalized rate of force development (RFD), and one-leg hopping distance. Compared with the non-injured leg, the tendinopathic leg showed reduced tendon stiffness (-19.2%. P < 0.001), greater mechanical hysteresis (+21.2%, P = 0.004), lower elastic energy storage and release (-14.2%, P = 0.002 and -19.1%, P < 0.001), lower normalized RFD at one-fourth (-16.3%, P = 0.02), 2/4 (-17.3%, P = 0.006), and three-fourths maximal voluntary contraction (-13.7%, P = 0.02), longer soleus and medial gastrocnemius voluntary EMD (+26.9%, P = 0.009 and +24.0%, P = 0.004), and shorter hopping distances (-34.1%, P < 0.001). Tendon stiffness was correlated with normalized RFD, voluntary EMD in the medial gastrocnemius, and hopping distances (r ranged from -0.35 to 0.64, P < 0.05). Hysteresis was correlated to the soleus voluntary EMD and hopping distances (r = 0.42 and -0.39, P < 0.05). We concluded that altered tendon viscoelastic properties in Achilles tendinosis affect explosive performance in athletes.

Increased Patellar Tendon Microcirculation and Reduction of Tendon Stiffness Following Knee Extension Eccentric Exercises

“…11,13 Tendon mechanical properties determine stress and strain distribution within the tendon. 37,38,40 Tendon microcirculation reflects intratendinous metabolic demands and includes the distribution of blood flow and oxygen consumption in the arteriolar, capillary, and venular segments. …”

“…11,13 Tendon mechanical properties determine stress and strain distribution within the tendon. 37,38,40 Tendon microcirculation reflects intratendinous metabolic demands and includes the distribution of blood flow and oxygen consumption in the arteriolar, capillary, and venular segments. 22,31 Local blood flow is controlled by autoregulation (myogenic responses and metabolism) and shearing stress stimulation of the endothelium and neurohormones, 31 and is partially influenced by vessel radius and length (Poiseuille's equation).…”

“…27 The real-time images, recorded at 30 Hz, were stored on a disc. The software described previously 37,38,40 was used to synchronize concurrent ultrasonic and other measurements. Images corresponding to each 5% increment of MVIC between 0% and 100% were used to measure tendon elongation.…”

Relationship between Muscle Strength and Tendon Stiffness of the Ankle Plantarflexors and Its functional Consequence

“…대표적인 외부자극인 저항성 운동, 순발력 운동 등 다양한 외력이 지속적으로 가해지면 근력과 함께 건의 경도가 증가하며 이러한 자극이 중단 될 경우 운동 전의 수준으로 감소한다는 여러 선행연구가 보 고되고 있다 (Alexander, 2002;Foure, Nordez, McNair, & Cornu, 2011;Kubo, Ikebukuro, Maki, Yata, & Tsunoda, 2012;Kubo, Kanehisa, Ito, & Fukunaga, 2001;Kubo et al, 2006;Reeves, Maganaris, & Narici, 2003). 근력과 건의 경도 간 상관성에서 나아가 건의 경도는 폭 발적인 운동에 중요한 부분을 차지하고 (Wang, Lin, Su, Shih, & Huang, 2012), 건의 경도가 상대적으로 낮은 수 준인 장거리 달리기 선수가 그렇지 않은 선수에 비해 그 기록이 더 좋은 것으로 나타나는 등 (Kubo et al, 2010) 운동 수행에 있어 간과할 수 없는 요소이므로 경도 수준 에 따른 기능적 차이를 확인하는 것이 중요하다. 아킬레스 건의 경도가 직접적으로 운동 수행에 기여하는 동작인 수 직반동점프를 (Kawakami et al, 2002) 반동이 없는 수직점 프와 비교하였을 때 건에서 생성되는 탄성에너지를 측정 함으로써 경도와 기능적 동작 사이의 상관관계도 정량화 할 수 있다.…”

Side-to-side differences in Achilles tendon geometry and mechanical properties following achilles tendon rupture

“…However, assessment of mechanical properties of tendon tissue has not been without its challenges. Techniques to measure mechanical properties often require loading of the tendon with muscle contraction 14 or invasive techniques 9 , limiting their clinical application particularly early post-injury. To overcome these obstacles, non-invasive ultrasound techniques have been proposed to measure tendon mechanical properties in vivo.…”