Eccentric training has been shown to reduce pain and gain function in patients with chronic Achilles tendinopathy. However, currently no data are available regarding any potential adverse effects of an eccentric training intervention on Achilles tendon microcirculation.
59 patients (49±12years, BMI 27±5, 49 mid-portion, 10 chronic insertional tendinopathy) with 64 symptomatic (54 mid-portion, 10 insertional) Achilles tendons were prospectively enrolled. Baseline tendon microcirculation at four distinct tendon positions from the insertion to the proximal mid-portion area was assessed using a laser Doppler system for capillary blood flow, tissue oxygen saturation and postcapillary venous filling pressure. A 12-week-daily painful home-based eccentric training regimen was initiated (3x15 repetitions per tendon and day).
Achilles tendon capillary blood flow was significantly reduced at the insertion (by 35%, p=0.008) and the distal mid-portion area (by 45%, p=0.015) at 2mm and by 22% (p=0.007) and 13% (p=0.122) at 8mm tissue depths. Achilles tendon oxygen saturation was not decreased after the 12-week-eccentric-training regimen throughout the insertion to the proximal mid-portion area (insertion: 72±13vs.73±10, proximal mid-portion 63±13vs.62±11, both n.s.). Achilles tendon postcapillary venous filling pressures were significantly reduced at the insertion (51±16vs.41±19, p=0.001) and the distal mid-portion (36±13vs.32±12, p=0.037) at 2mm and at the insertion at 8mm (63±19vs.51±13, p=0.0001). Pain was reduced from 5.4±2.1 to 3.6±2.4 (p=0.0001) in mid-portion and from 6.0±2.5 to 3.2±2.7 (p=0.002) in the insertional tendinopathy group. No Achilles tendon rupture nor any interruption during the eccentric training was noted among the 59 patients.
Daily eccentric training for Achilles tendinopathy is a safe and easy measure with beneficial effects on the microcirculatory tendon levels without any evident adverse effects in both, mid-portion and insertional Achilles tendinopathy .
- adverse effect