Acute effect of running exercise on physiological Achilles tendon blood flow

Abstract

Sonographically detectable intratendinous blood flow (IBF) is found in 50%-88% of Achilles tendinopathy patients as well as in up to 35% of asymptomatic Achilles tendons (AT). Although IBF is frequently associated with tendon pathology, it may also represent a physiological regulation, for example, due to increased blood flow in response to exercise. Therefore, this study aimed to investigate the acute effects of a standardized running exercise protocol on IBF assessed with Doppler ultrasound (DU) "Advanced dynamic flow" in healthy ATs. 10 recreationally active adults (5 f, 5 m; 29±3 years, 1.72±0.12 m, 68±16 kg, physical activity 206±145 minute/wk) with no history of AT pain and inconspicious tendon structure performed 3 treadmill running tasks on separate days (M1-3) with DU examinations directly before and 5, 30, 60, and 120 minutes after exercise. At M1, an incremental exercise test was used to determine the individual anaerobic threshold (IAT). At M2 and M3, participants performed 30-minute submaximal constant load tests (CL 1 /CL 2 ) with an intensity 5% below IAT. IBF in each tendon was quantified by counting the number of vessels.IBF increased in five ATs from no vessels at baseline to one to four vessels solely detectable 5 minutes after CL 1 or CL 2 . One AT had persisting IBF (three vessels) throughout all examinations. Fourteen ATs revealed no IBF at all. Prolonged running led to a physiological, temporary appearance of IBF in 25% of asymptomatic ATs.To avoid exercise-induced IBF in clinical practice, DU examinations should be performed after 30 minutes of rest. K E Y W O R D Sadvanced dynamic flow, doppler ultrasound, hyperemia, neovascularization, sonography

The Role of the Vascular and Structural Response to Activity in the Development of Achilles Tendinopathy: A Prospective Study

“…After stepwise, multivariate, Cox proportional hazards model building for the development of AT, the final model included the variables sex, increase in blood flow after running, timing of blood flow measurements, and foot posture. The timing of blood flow measurements and foot posture were included as confounders in the analyses since previous studies showed that the Achilles tendon blood flow after activity had a fast increase followed by a quick recovery to baseline 43 and since recent studies confirmed the relationship between foot pronation and Achilles tendon blood flow. 22,52 The results of the multivariate Cox regression analysis and the strength of the predictive values are presented in Table 2.…”

Doppler Flow Response Following Running Exercise Differs Between Healthy and Tendinopathic Achilles Tendons

“…A small amount of IBF at rest has been suggested to be of physiological nature (Boesen et al, 2006a(Boesen et al, ,b, 2012. Moreover, IBF has been found to increase in response to tendon loading exercise (Boesen et al, 2006a,b;Fahlström and Alfredson, 2010;Sanz-López et al, 2016;Risch et al, 2018a) assuming a physiological metabolic reaction visualized due to increased flow velocity and/or volume in preexisting vessels (Boesen et al, 2006a(Boesen et al, ,b, 2012Risch et al, 2018a). In summary, detectability of IBF itself cannot be considered a pathological finding anymore (Boesen et al, 2006b(Boesen et al, , 2012Risch et al, 2018a).…”

“…Then again, the amount of training hours has also been associated with an increased risk of developing Achilles tendinopathy (Knobloch et al, 2008). An acute increase in amount of sonographic detectable intratendinous vessels following exercise has been suggested to represent elevated blood flow in preexisting vessel beds, rising above the sensitivity threshold of Doppler ultrasound (Boesen et al, 2006b;Risch et al, 2018a). Other studies, however, have found contradictory effects of exercise on detectable IBF in terms of persisting, decreased (Malliaras et al, 2012) or absent blood flow (Pingel et al, 2013b).…”

“…Other studies, however, have found contradictory effects of exercise on detectable IBF in terms of persisting, decreased (Malliaras et al, 2012) or absent blood flow (Pingel et al, 2013b). Due to varying sensitivity and imaging quality of ultrasound devices (Boesen et al, 2012), lacking standardization of exercise and examination protocols as well as inconsistent tendon characterization (healthy, tendinopathy, degenerative changes), comparability of previous studies and interpretation of differing results is limited (Risch et al, 2018a). Consequently, the diagnostic value of sonographic detectable IBF considering a pathological or physiological finding remains inconclusive.…”

The influence of aging on the insertion of the Achilles tendon: A magnetic resonance study

“…Pathologies of the foot and ankle involving the AT are a common orthopedic problem, mostly encountered among athletes and older adults (Beitzel et al, ; Yilmaz et al, ; Gärdin et al, ; Revak et al, ; Docking et al, ; Risch et al, ; Wengler et al, ). Several factors such as age and sex could account for this heterogeneity in the population.…”