Can exercise fix tennis elbow?

Short answer

Exercise sped up recovery in the first few weeks. But after 1 year about 90% got better even without it, so there was no difference, and over the long run exercise beat steroid shots.

Can exercise fix tennis elbow?
'Elbow pain → exercise → recovery' — does this formula hold?
Many say exercise is the cure for tennis elbow, pain on the outside of the elbow. But do people heal because of exercise, or just because time passes? We started with what happens when you do nothing.
What happens if you do nothing?
89% were better after 1 year
An analysis of 1,085 people who got no treatment or a fake treatment found that after 1 year, 89% said they were 'much better' or 'fully recovered'. Every 2.5 to 3 months, half of those still in pain got better. People who had pain for longer improved at the same speed.
So is exercise useless?
The first 4 weeks were clearly faster
In a trial of 165 people, 39% of those who got physiotherapy (including exercise) were 'much better' at 4 weeks, versus 10% without it. In a trial of 198 people, exercise plus joint therapy also beat simply waiting through week 6.
And after 1 year?
The gap between exercisers and non-exercisers disappeared
In the same 165-person trial, the 1-year recovery rate was 91% with physiotherapy and 88% without it, no difference. An analysis of 1,023 people found exercise lowered pain at 4 weeks to 3 months by only 0.53 points from 5.1 on a 10-point scale, and the gap did not last.
Aren't shots faster?
They were, but the pain came back
Steroid shots gave the fastest relief up to 6 weeks. But in the 198-person trial, 47 of the 65 people who improved after a shot got worse again. In the 165-person trial, the 1-year recovery rate after a shot was 83%, lower than with a fake shot (96%), and relapse was 54% vs 12%.
Exercise vs shots over the long run?
Exercise came out ahead
An analysis of 2,123 people in 30 studies found exercise beat shots on every outcome except pain in the first few weeks. Pain-free grip strength was higher with exercise in the short run and in the long run.
Which exercise worked best?
Added weight, not done every day
An analysis of 110 tendon-pain studies (3,953 people, including 29 elbow groups) found exercise with added weight beat bodyweight only, and every-other-day training beat several times a day. Still, of 19 people on a very heavy, slow program, only 6 stuck with it, and 8 stopped because pain got worse.
Bottom line: exercise made recovery faster
Most people got better on their own within a year
About 90% of tennis elbow cases improved within 1 year. Exercise sped up the first few weeks and did not cause the relapses seen with shots. What worked best was exercise with added weight, not done every day, kept at a level that does not make the pain worse.