Shear Wave Elastography Measures of the Achilles Tendon: Influence of Time of Day, Leg Dominance and the Impact of an Acute 30-Minute Bout of Running

Abstract

The mechanical properties of human tendons are likely to be influenced by factors known to affect elastic structures, including patterns of loading and unloading during the day. However, the exact scale and relevance of these variables to tendon stiffness remains unclear. The aim of this study was to (1) measure Achilles tendon (AT) stiffness over the course of the day, (2) examine AT stiffness between dominant and non-dominant standing leg tendons and (3) assess the impact of previous activity on AT stiffness. To assess the impact of time of day and leg dominance, 15 healthy participants (6 females, 9 males; mean age 28 ± 4 year, mean VISA-A score 99.0 ± 1.2) had shear wave elastography (SWE) measures taken at 08:00 h, 12:30 h and 17:00 h on both dominant and non-dominant legs. To assess the impact of exercise, 24 tendons were analysed (7 females, 5 males; mean age 27 ± 4 year, mean VISA-A Score 99.1 ± 1.1) with participants randomly assigned to either a control (CONT) group or a running (RUN) group. The RUN group performed a 30-min run at a subjective intensity of 13–15 on rating of perceived exertion (RPE) scale and had SWE measures taken before, immediately after, 6 h 24 h, 48 h and 72 h following the run. There were no significant differences in AT stiffness over the course of a day or between dominant and non-dominant leg. Significant increases in AT stiffness were noted pre-post run (0.27 m/s, 2.95%, p = 0.037). Leg dominance does not affect SWE values from asymptomatic ATs or change throughout a day, but a 30-min run significantly increases AT stiffness. Leg dominance and timing of clinical appointments are unlikely to affect SWE results, however a prior bout of physical activity may cause changes within the AT resulting in a significantly different SWE measure. Clinicians and researchers should be cautious of interpreting SWE results if weight bearing exercise has been performed beforehand.

Changes of Material Elastic Properties during Healing of Ruptured Achilles Tendons Measured with Shear Wave Elastography: A Pilot Study

“…That degenerative process most likely goes along with the loss of capacity of resistance to stress, which is reflected in the decrease of the Young's modulus slope [12]. A relation of shortage of load and decrease of elastographic stiffness was shown before [52,53]. This supports the hypothesis, that a tensile load is necessary to maintain the biomechanical properties [16].…”

“…Most likely this is due to the general reduced mobility. An increase in elastographic stiffness was shown for short-term load (already after 30 min of running) [52] and also between physically active people (six or more hours of weight-bearing exercise per week) and a normal population [53].…”

Three-Dimensional Mapping of Shear Wave Velocity in Human Tendon: A Proof of Concept Study

“…In our experiment, all three tendon structures behaved consistently with an increase in SWV in response to 15 s maximum voluntary isometric contraction, with statistical significance only for the patellar and the Achilles tendon. Data from the literature on the matter are sparse but support our findings in that variable modes of loading resulted in an increase in Achilles tendon SWV [ 39 , 44 , 45 ]. Contrary to these findings, the global tendon stiffness assessed by measuring force-controlled tendon elongation was reduced following isometric contractions [ 58 ] and static stretching [ 59 ] in the Achilles tendon, as well as following eccentric knee extension exercises in the patellar tendon [ 60 ].…”

“…Tendon SWV is position-dependent [ 33 , 35 , 38 ], which may explain the lower reproducibility in the case of 2D SWE. Furthermore, tendon elasticity undergoes natural fluctuations in relation to loading history [ 39 ] and hydration state [ 40 ].…”

Elastography in the assessment of the Achilles tendon: a systematic review of measurement properties

“… Intra rater same day Adequate ICC = 0.93 ICC = 0.87 + Schneebeli et al, 2016 [ 35 ] 24 bilateral Intra rater same day Adequate ICC relaxed = 0.87 ICC contracted = 0.94 + NA NA NA Payne et al, 2017 [ 32 ] 8 right Intra rater same day Intra rater different days Adequate ICC T = 0.00–0.11, L = 0.01–0.11 both foot position - Adequate CV L = 80.8%-111.5% T = 53.6—112.4% ? Shear wave elastography—velocity Aubry et al, 2013 [ 38 ] 30 bilateral Inter-rater same day Doubtful ICC L = -0.011–0.46, T-0.062–0.29 NA NA NA NA DeWall et al, 2014 [ 39 ] 10 feet side not reported Inter-rater Doubtful CV = 0.156 NA NA NA NA Fu et al, 2016 [ 40 ] 326 bilateral Inter-rater same day Adequate ICC L = 0.923, T = 0.870 + NA NA NA Payne et al, 2018 [ 47 , 48 ] …”