Go slowly getting back into things. I know you know that, but it's worth reiterating. Not because I'm worried you'll hurt yourself, if you've competed you know your body well enough to not to do that, but because I know how frustrating it can be coming back.

I tore one of my left biceps tendons training for an MMA fight about five years ago. When the doctors told me "six month recovery" I didn't understand that they meant six months to start working out like the average person again. That led me to have a lot of frustration during my recovery because I felt like it wasn't happening fast enough. It was closer to 18 months until I was able to perform at the level I did before.

Did you get a graft or just a repair?

Sounds similar to when I tore my ACL. It was ~9 months until I was medically healed, but closer to 18 before I was fully back with strength and confidence in my knee.

I did a patellagraft.

Yeah, I had an anterior tibialis from a cadaver grafted onto my biceps tendon ("grafted" in this case really means stitched onto the remnants of mine with metal thread and then bolted into my radius bone). Recovery was long and brutal, but five years later I don't have any issues.

Been fighting quadriceps tendinitis for 3 years, and there doesn’t seem to be a lot of quality research surrounding tendon regeneration. Living in the US with odd insurance limits for physical therapy has definitely set me back. If you run into issues with that, Martin Koban wrote a book on patellar tendinitis and has an updated online course with a recommended program for tendon strengthening. It’s the only thing that’s helped me so far

I've been struggling with chronic mid-portion Achilles tendinopathy for 13 months. Progressive loading, heavy/slow resistance work and your pick of eccentric, isometric or isotonic exercises are apparenlty the way forward. The biggest surprise has been the amount of quality information on Twitter; finding the people to follow is harder. If you're interested, good starting points are @SethONeill, @UDtendongroup, @kgSilbernagel, @tendonresearch, @TendonGlasgow, @IreneSDavis, @tendonpain, @ProfJillCook, @KFarnqvist, @lorenzo_masci, @sancho_igor and @pdkirwan. HTH!

I have also found success with high repetition (15-30 reps) slow eccentric work for tendinopathy in my fingers and elbow. So far it's really the only thing that helps besides making sure the surrounding areas are not overly tight with soft tissue work. This guide and the linked research have been very helpful. https://stevenlow.org/overcoming-tendonitis/

Thanks for the twitter recommendations. I made great progress with progressive loading with isometric exercises the past 9 months, so I'm transitioning to slow concentric/eccentric movement to increase range of motion and struggling. This stems from an improperly healed ankle injury causing low dorsiflexion ROM so finding the right combination of exercises is tricky.

It really blew my mind how much differently tendons recover and strengthen compared with muscles. I think step one is to consider them differently in terms of rest, loading, and lengthening.

Curious if you’ve tried any supplements?

Mixed viewpoints out there regarding supplements, but I take collagen, fish oil and vitamin C daily. I find that if I skip taking them for a week I notice a bit more pain / less resilience after a strength training session.

Can you recommend a brand of collagen?

I can't recommend any brand. The research is weak regarding oral collagen supplements. I'm planning to switch to vitamin C infused gelatin, as there's some research backing that up. https://www.ncbi.nlm.nih.gov/pubmed/27852613

Possibly placebo, but I felt like bone broth helped during my Achilles tendon recovery.