Can exercise heal Achilles tendon pain?

Short answer

Yes. After 3 months, calf exercise scored 20 points higher on a 100-point scale than waiting it out, and 80% of 34 people treated with exercise alone had fully recovered 5 years later.

Can exercise heal Achilles tendon pain?
'A sore tendon needs rest to heal' — does this formula hold?
A common belief: if the tendon above your heel hurts, stop training and rest. We checked whether resting and waiting or exercising led to better recovery.
Waiting it out did the worst
Calf exercise scored 20 points higher out of 100
An analysis comparing 29 Achilles pain trials found that after 3 months, any treatment beat simply waiting. Calf exercise scored 20 points higher than waiting on a 100-point scale of pain and function. A difference you can actually feel starts at 15 points.
The type of exercise barely mattered
Slow lowering and heavy slow lifting showed no difference
58 people spent 12 weeks either slowly lowering down from a tiptoe or doing heavy, slow calf raises up and down. Both groups improved in pain and function, kept it at 52 weeks, and showed no difference. An analysis of 994 people also found no difference in pain relief between slow lowering and other exercises.
So do you have to stop running?
Those who kept running while tracking pain did no worse
Of 38 people, half kept running and jumping while tracking their pain, and half stopped for 6 weeks. Both groups did the same calf exercises. After 12 months, scores went from 57 to 85 and 91 out of 100, with no difference in how fast they improved.
Added weight beat bodyweight only
Training less than daily worked better
An analysis of 110 tendon pain exercise studies (3,953 people) found bigger improvements when extra weight was added than with bodyweight alone. Training less often than daily beat daily or several-times-a-day programs. 43 Achilles exercise groups were part of this analysis.
Pain where the tendon meets the heel bone was different
Bending the ankle less worked better
In 42 people with pain where the tendon attaches to the heel bone, a program that limited upward ankle bending, dropped calf stretches and used heel lifts did better. Scores on the 100-point scale rose 24.4 points at 12 weeks versus 12.2 with standard exercise, and 29.0 versus 19.3 at 24 weeks.
How well do people recover?
80% of 34 people on exercise alone were fully healed after 5 years
Of 34 people treated with exercise alone, 80% had fully recovered after 5 years and 20% still had symptoms. In 43 people treated without surgery and surveyed 10 years later, 19% still had symptoms.
Bottom line: exercise beat rest
The formula fails at 'you must rest to heal'
Achilles tendon pain improved more with calf exercise than with waiting. The type of exercise made no difference, and adding weight beat bodyweight only. Continuing to run while tracking pain did not slow recovery.