Tendon

A tendon is a tough, fibrous cord of connective tissue that attaches muscle to bone, transmitting the force generated by muscle contraction to move a joint.

What tendons do and why they're vulnerable to injury

Tendons are built for tensile load — the pulling force that travels through them each time a muscle contracts. They're composed primarily of tightly organized collagen fibers aligned to handle this directional stress efficiently. Because of their relatively low blood supply compared to muscle, tendons receive less oxygen and nutrient delivery, which is why they repair more slowly and are more susceptible to cumulative damage from repeated loading. Every time you walk, run, jump, or lift, your tendons absorb and transmit force — and when that load consistently exceeds what the tendon can recover from, the tissue begins to break down. The Achilles, patellar, rotator cuff, and elbow tendons are among the most frequently affected because of the repetitive, high-force demands placed on them. Tendon pain typically develops gradually, worsens with activity, and responds poorly to rest alone without a structured loading program to rebuild tissue capacity.

How Sword Health can help

Tendon rehabilitation requires progressive loading matched to the tissue's current capacity — too little doesn't drive adaptation, too much provokes further breakdown. A physical therapist can assess your tendon and guide that progression precisely. Sword connects you with that expertise from home, so you can build tendon capacity in a way that produces lasting results.