Alfredson et al. 1998, Heavy-load eccentric calf muscle training for chronic Achilles tendinosis

Prospective study (Alfredson H, Pietilä T, Jonsson P, Lorentzon R), American Journal of Sports Medicine 26(3):360-6. Fifteen recreational athletes (mean age 44.3) with chronic midportion Achilles tendinosis performed a high-volume eccentric heel-drop programme (3×15 reps twice daily, seven days a week, for 12 weeks), lowering the heel below the level of the step into full dorsiflexion. All 15 returned to pre-injury running, with significant falls in pain and recovered calf strength; a conventionally treated comparison group of 15 all went on to surgery. This is the origin of the ‘Alfredson protocol’. Strong for midportion disease (landmark study, since replicated and pooled), but note the protocol was developed and tested on midportion, not insertional, tendinopathy.