Table 9. Synthesis of the main findings for Achilles tendon.
Study Pain Outcomes Function Outcomes Performance / RTS Tendon Structure / Physiology Safety / Adherence
(Alfredson et al., 1998) VAS0–100 during activity: ECC 81.2→4.8 at 12w (p<0.001); comparator 71.8→21.2 at 24w (p<0.01). Between-group: ECC faster/larger ↓. No VISA. RTS: 100% ECC back to pre-injury running at 12w. Strength deficits at BL resolved after ECC. NR. No AEs with ECC.
(Demir Benli et al., 2022) VAS0–10: at 3m both ≈2.6; NS between groups. At 2y: ECC 1.2 (↑, p<0.001) vs ESWT 5.4 (NS) → long-term benefit only with ECC. VISA-A: both ↑ to ≈80 at 3m (both p<0.001), NS between groups. RTS not direct; “recovery” 81% ECC vs 77% ESWT at EOT. US: thickness ↑ with ECC (4.7→5.2 mm, p=0.002); stiffness ↑ (strain ratio 2.1→3.1, p=0.039); ESWT NS. Neovasc: NS. 63/63 completed; no major AEs.
(Beyer et al., 2015) VAS0–10 (running, heel-rise) ↓ 0–12w, maintained 52w (both p<0.0001); NS between ECC and HSR. VISA-A: ECC 58→84; HSR 54→89 (time p<0.0001); NS between groups. Activity level ↑ modestly; RTS NR. US: thickness ↓ both (p<0.001). Doppler ↓ both (time p<0.005). Satisfaction 12w higher in HSR (100% vs 80%, p=0.052); adherence: ECC 78% vs HSR 92% (p<0.005). No major AEs.
(Habets et al., 2021) VAS0–100 ADL: AG 28.6→5.8; SG 28.6→9.0 (both p=0.004); NS between groups. Sports: AG 44.8→13.1; SG 46.6→12.8 (both p=0.027); NS. VISA-A: AG 60.7→89.4; SG 59.8→83.2 (both p<0.001). NS treatment effect (2.4; 95% CI −8.5 to 13.3; p=0.656). GPE: more “improved” in SG (77% vs 50%, p=0.04). RTS NR. NR. Adherence high (AG 74%, SG 77%). One SG dropout after race.
(Knobloch et al., 2007) VAS0–10: Wrap+ECC 5.1→3.2 (−37%, p=0.0001); ECC 5.5→3.6 (−35%, p=0.0001); NS between groups. FAOS: both ↑; larger % gains with Wrap+ECC (all p≤0.006 vs ECC). RTS NR; FAOS-Sport ↑ more with Wrap+ECC. Microcirculation: Wrap+ECC StO2 ↑, venous pressure ↓ more vs ECC; capillary flow patterns differed. 81% completed; no AEs.
(Knobloch et al., 2008) VAS0–10: Wrap+ECC 5.1→2.9 (−43%, p=0.0001); ECC 5.4→3.6 (−33%, p=0.0001); NS at final. FAOS: ↑ both; no between-group diff at end. RTS NR. Wrap+ECC: StO2 ↑ tendon & paratendon; venous pressure ↓ broadly. ECC alone: limited microvascular change. Safe; no AEs.
(Langberg et al., 2007) VAS0–100: injured 44→13 after 12w ECC (p<0.05). RTS: all 6 injured elite soccer players returned. Microdialysis: collagen synthesis ↑ (PICP 3.9→19.7 μg/L, p<0.05) in injured; no change healthy; degradation (ICTP) unchanged. 100% adherence; no AEs.
(Malliaras et al., 2013) — (no symptoms) Strength: 5RM ↑ all groups; greatest in High-load ECC. Tendon: modulus/stiffness ↑ all at 50–75% MVIC; only High-load ECC ↑ at 75–100% MVIC. CSA unchanged. Training pain ~1.3–2.0% sessions; no consequential AEs.
“center”>(Radovanović et al., 2022) NRS0–10: modest ↓ all (−0.55±0.9, p<0.001); NS between groups. VISA-A: ↑ ≈+20 pts in all (time p<0.001; no interaction). High-load only: MVC ↑7% (p=0.045). CMJ ↓ slightly all. High-load only: stiffness ↑20% (p=0.049), CSA ↑9% (p<0.001), max strain ↓12% (p=0.001); modulus NS. Compliance similar (80–90%); no AEs.
(Rompe et al., 2007) NRS0–10: ECC 7.0→3.6; SWT 6.8→4.0; Wait 7.9→5.9. ECC & SWT > Wait (p<0.001); ECC vs SWT NS. VISA-A: ECC 51→76; SWT 50→70; Wait 48→55. ECC & SWT > Wait (p<0.001); ECC vs SWT NS. Likert recovery 1–2: 60% (ECC), 52% (SWT), 24% (Wait). Tendon diameter: no change. Minor transient effects only; no ruptures.
(Rompe et al., 2009) NRS0–10: ECC 7.0→3.9; ECC+SWT 6.8→2.4; between-group −1.5 (95% CI 0.5–2.5, p=0.0045). VISA-A: ECC 51→73; ECC+SWT 50→87; between-group +13.5 (p=0.0016). Likert 1–2: 56% vs 82% (p=0.001). At 12m, differences diminished due to crossovers/surgeries. NR. Minor transient effects; analgesic use associated with failure.
(Stergioulas et al., 2008) VAS0–100 during activity: LLLT better at 4w (53.6 vs 71.5, p=0.0003), 8w (37.3 vs 62.8, p=0.0002), 12w (33.0 vs 53.0, p=0.007). Secondary function: morning stiffness ↓, dorsiflexion ↑, palpation tenderness/crepitation ↓ more with LLLT (all p<0.05). RTS NR; clinical recovery accelerated (LLLT 4w ≈ placebo 12w). NR. High adherence; 4 transient calf aches resolved; no serious AEs.
ADL: activities of daily living; AE: adverse event; AG: Alfredson group; ALT: alternative therapy; AP: anteroposterior; ACSA: anatomical cross-sectional area; AT: Achilles tendinopathy; BL: baseline; CA: color area (Doppler neovascularity); CMJ: countermovement jump; CODS: change-of-direction speed; CON: conventional therapy; CONC: concentric exercise; CORT: corticosteroid injection; CSA: cross-sectional area; DJ: drop jump; Doppler: power/color Doppler ultrasound; ECC: eccentric exercise; EET: eccentric exercise therapy; EOT: end of treatment; ESWT: extracorporeal shock-wave therapy; FAOS: Foot and Ankle Outcome Score; FU: follow-up; GPE: global perceived effect; GRC: global rating of change; HMB: β-hydroxy β-methylbutyrate; HPLT: high-power laser therapy; HP/LP: hydroxylysyl-/lysyl-pyridinoline ratio; HSR: heavy slow resistance; ICTP: carboxy-terminal telopeptide of type-I collagen; IP: intrapatient; IPT: isokinetic peak torque; IQR: interquartile range; KOOS: Knee injury and Osteoarthritis Outcome Score; LLLT: low-level laser therapy; MD: mean difference; m/M: months; MVC: maximal voluntary contraction; MVIC: maximal voluntary isometric contraction; N/A or NR: not assessed / not reported; NRS or NPRS: numeric (pain) rating scale (0–10); NS: not significant; P-CSA: patellar tendon cross-sectional area; PFP: patellofemoral pain; PICP: procollagen type-I C-terminal propeptide; PP: peak power; PPKG: load at peak power (kg); PPMV: mean velocity at peak power; PPPP: peak power in watts; PT: patellar tendinopathy; PTLE: progressive tendon-loading exercise; PHT: proximal hamstring tendinopathy; QoL: quality of life; rHb: postcapillary venous filling pressure (relative hemoglobin); RTS: return to sport; SG: Silbernagel group; SLDS: single-leg decline squat; StO2: tissue oxygen saturation; SWT: shock-wave treatment; US: ultrasound; USGET: ultrasound-guided electrolysis therapy (as named in Abat 2016); VAS0–10: visual analogue scale 0–10; VAS0–100: visual analogue scale 0–100 mm; VISA-A: Victorian Institute of Sport Assessment—Achilles; wk/w: week(s). Symbols — ↑: increase; ↓: decrease; →: to; ≈: approximately.