Tendonitis

Tendonitis refers to an acute inflammatory response in the tendon, often triggered by a sudden spike in workload or an isolated injury. Tendinosis, a very similar term, is part of a broader condition known as tendinopathy—a degenerative process that develops when repeated stress is placed on the tendon without enough recovery time. Instead of healing, the tendon fibers become disorganized, collagen breaks down, and the structure weakens, often without obvious signs of inflammation. This often is a pain that has been present over a long period of time. Identifying where an athlete is on this spectrum of tendonitis vs tendinosis matters, because the rehab approach for inflammation is very different from the progressive loading and rebuilding strategies needed for degeneration.

When tendon pain occurs in the middle of the season, the rehab differs compared to out of season. Research shows Spanish squat, where you lean back against a rigid belt or band placed behind your knees and hold a squat at around 60° of knee flexion, is one of the best exercises to treat tendonitis. Performing 5 sets of 45-second holds, creates a strong analgesic effect in the patellar tendon—meaning it reduces pain—without adding stress to the front of the knee. This allows athletes to push through strength drills while calming the tendon’s pain signal. Another great exercise is the isometric knee extension at 30° of knee flexion. Done using a seated leg-extension machine (or similar setup), this involves holding a static contraction for 45 seconds, for 5 sets, ideally 2–3 times per day. This should cause at max 3/10 pain with 7/10 effort. This loading method typically immediately reduces pain, especially in active athletes.

For out of season athletes, it is important to load the tendon.

Check out this article to learn more: Patellar Tendinopathy: Clinical Diagnosis, Load Management, and Advice for Challenging Case Presentations

The off season is a great time to treat tendinopathy at its root, rather than just manage symptoms. Without the constant stress of games and intense practices, athletes can tolerate the higher mechanical loading needed to stimulate tendon repair. Research supports the use of heavy slow resistance training (HSR)—squats, leg presses, and bulgarian split squats performed at 70–85% of max, 3–4 sets of 6–8 reps—with each repetition lasting 3–4 seconds in both the lowering (eccentric) and lifting (concentric) phases. This slow, heavy loading encourages the tendon’s collagen fibers to realign and thicken, restoring both strength and elasticity. Eccentric training, where the focus is on the lengthening phase, heels elevated squats for the patellar tendon, adds a remodeling stimulus by placing controlled stress on the tendon tissue. Off season rehab also allows integration of isometric holds for pain modulation early on, progressing into plyometric drills only once the tendon shows improved load tolerance.