In the past six months, I've had both lingering tennis elbow (from playing a 3 hr match yet do not play very regularly) and also a sore achilles tendon. I've read a few articles for rehab purposes and have come away with the following conclusions. I'm not sure if all are accurate so please correct me if needed. There is a fine line with how you should rest a sore tendon versus continuing to work through it. If you simply rest it, it will lose strength and flexibility. This is different than muscles that need to be rested so that they are fully healed before pushed into action. Tendons are the hidden source of achieving maximum source of power. I always guessed that bodybuilders didn't compete in Olympic power lifting events because they take steroids/PEDs and would be ineligible. One of the articles mentioned that bodybuilders often do not have strong enough tendons to support the strength of their muscles. Therefore, their functional strength is not nearly as impressive as you would expect. Tendons can be maintained much better into old age than muscles but generally do not receive sufficient attention, even from those that exercise regularly (unless they do pilates or yoga). For example, if I were to work on my tendons and perform all of the exercises that focus on strength/flexibility for the next 20 years, they would be stronger at the age of 56 than they are right now at 36.