Eccentric and Isometric Exercises in Achilles Tendinopathy Evaluated by the VISA-A Score and Shear Wave Elastography

Abstract

Background: Apart from eccentric exercises (EE), isometric exercises (ISO) might be a treatment option for Achilles tendinopathy. Shear wave elastography (SWE) provides information for diagnosis and for monitoring tissue elasticity, which is altered in symptomatic tendons.

Hypothesis: Isometric exercises will have a beneficial effect on patients' outcome scores. Based on SWE, insertional and midportion tendon parts will differ in their elastic properties according to current symptoms.

Study design: Randomized clinical trial.

Level of evidence: Level 2.

Methods: Group 1 (EE; n = 20; 12 males, 8 females; mean age, 52 ± 8.98 years) and group 2 (EE + ISO; n = 22; 15 males, 7 females; mean age, 47 ± 15.11 years) performed exercises for 3 months. Measurement points were before exercises were initiated as well as after 1 and 3 months using the Victorian Institute of Sports Assessment-Achilles (VISA-A) score, American Orthopaedic Foot & Ankle Society score, and SWE (insertion and midportion).

Results: Both groups improved significantly, but there were no significant interindividual differences (VISA-A; P = 0.362) between group 1 (n = 15; +15 VISA-A) and group 2 (n = 15; +15 VISA-A). The symptomatic insertion (symptomatic, 136.89 kPa; asymptomatic, 174.68 kPa; P = 0.045) and the symptomatic midportion of the Achilles tendon (symptomatic, 184.40 kPa; asymptomatic, 215.41 kPa; P = 0.039) had significantly lower Young modulus compared with the asymptomatic tendons. The midportion location had significantly higher Young modulus than the insertional part of the tendon (P = 0.005).

Conclusion: Isometric exercises do not have additional benefit when combined with eccentric exercises, as assessed over a 3-month intervention period. SWE is able to distinguish between insertional and midportion tendon parts in a symptomatic and asymptomatic state.

Clinical relevance: The present study shows no additional effect of ISO when added to baseline EE in treating Achilles tendinopathy. Different elastic properties of the insertional and midportion tendon have to be taken into consideration when rating a tendon as pathologic.

Keywords: Achilles tendinopathy; eccentric exercises; isometric exercises; muscle; shear wave elastography; tendon.

Figure 1.

Flowchart of the study design. AOFAS, American Orthopaedic Foot & Ankle Society; B-US, B-mode ultrasound; EE, eccentric exercises; ISO, isometric exercises; PD-US, PowerDoppler ultrasound; SWE, Shear wave elastography; VISA-A, Victorian Institute of Sports Assessment–Achilles.

Figure 2.

Isometric exercises: At load level 1 (a), patients were standing 45 seconds on the tip of toes of both legs, whereas at load level 2 (b), they were standing with all their body weight just on the symptomatic leg. At level 3 (c), individuals should add further load by pushing themselves down while standing under a door frame.

Figure 3.

Box plots illustrating increase of VISA-A score. EE group: VISA-A score initial mean = 70.75 (50-80; SD, 8.66; n = 20); VISA-A score after 1 month mean = 76.55 (58-100; SD, 11.24; n = 16), VISA-A score after 3 months mean = 85.26 (75-100; SD, 9.13; n = 15). EE + ISO group: VISA-A score initial mean = 66.18 (40-88; SD, 12.68; n = 22); VISA-A score after 1 month mean = 71.55 (22-100; SD, 18.48; n = 18), VISA-A score after 3 months mean = 81.40 (49-100; SD, 15.38; n = 15). EE, eccentric exercises; ISO, isometric exercises; VISA-A, Victorian Institute of Sports Assessment–Achilles.

Figure 4.

The Likert scales of both groups showed that over 60% of the final cohort rated their actual status as “much improved” or “completely recovered.” In the Roles and Maudsley score, 60% in the EE group and 50% in the EE + ISO group estimated their actual function as “good” or “excellent.” EE, eccentric exercises; ISO, isometric exercises.