The Rising Tide of UCL Injuries: Why Strong Forearms Matter
⚾️ It’s no secret—UCL injuries are on the rise across all levels of baseball.
➡️ The cause? Multifactorial. There is no single culprit behind elbow injuries, but a combination of factors—including mechanics, workload, and physical preparation.
💪 With advancements in pitching development and strength & conditioning, pitchers are throwing harder than ever. Increased velocity is great for racking up strikeouts, but it also means greater stress on the medial elbow.
So how do we combat this trend and keep arms healthy?
3 Key Strategies to Protect the UCL
1️⃣ Optimize Pitching Mechanics – If mechanical inefficiencies are present, they can increase stress on the UCL and surrounding structures. Proper movement patterns reduce unnecessary strain.
2️⃣ Manage Workloads Effectively – Chronic, acute, and total throwing volume all matter. Proper programming ensures pitchers don’t accumulate more stress than they can recover from.
3️⃣ Increase the Elbow’s Capacity to Handle Stress – This is where forearm strength comes into play. If the elbow can absorb more force, it reduces the reliance on passive structures like the UCL.
🔥 Let’s dive deeper into this third point. In short—the answer is simple: GET STRONG FOREARMS.
How the Elbow Absorbs Valgus Stress: 3 Key Mechanisms
When a pitcher throws, a massive valgus force is placed on the elbow. There are three primary ways this force is dispersed:
✅ 1. Radiocapitellar Joint Compression
When valgus stress is applied, it attempts to open up the medial (inside) portion of the elbow—which is exactly how an orthopedic test for UCL integrity is performed.
However, while the inside of the elbow is being stretched, the outside of the elbow is being compressed. The radius and lateral humerus press together, forming a natural stopping point that helps prevent excessive valgus motion.
✅ 2. Forearm Musculature
The forearm flexor-pronator group acts as the first line of defense against valgus stress. These muscles include:
Pronator Teres
Flexor Carpi Ulnaris (FCU)
Flexor Carpi Radialis (FCR)
Flexor Digitorum Superficialis (FDS)
Palmaris Longus
Because they cross the medial elbow and attach at the medial epicondyle, these muscles act as dynamic stabilizers, helping to absorb and dissipate valgus forces before they reach the UCL.
💡 Research suggests that FCU may be the most effective muscle in resisting valgus stress, but the best approach is to strengthen all of them.
Best Training Strategies:
Finger Flexion Exercises (e.g., grip training, finger curls)
Wrist Flexion Movements (e.g., wrist curls)
Ulnar Deviation Movements (e.g., moving the pinky toward the medial elbow)
Forearm Pronation Movements (e.g., pronation exercises with a weighted bat or hammer)
✅ 3. Ulnar Collateral Ligament (UCL) Itself
What doesn’t get absorbed by joint compression or forearm musculature gets placed directly on the UCL.
💡 The problem? Research shows that an isolated UCL can withstand ~35 Nm of force before failure—but a single pitch produces far more than 35 Nm of valgus stress.
This means the UCL cannot handle the load on its own—it needs help from the radiocapitellar joint and forearm musculature to prevent injury.
The Takeaway: Build Forearm Strength, Protect the UCL
Pitchers will continue throwing harder. The stress on the elbow isn’t going away. The best way to prepare? Train the muscles that protect the UCL.
👉 Stronger forearms = greater force absorption
👉 Greater force absorption = less stress on the UCL
👉 Less stress on the UCL = fewer injuries and greater durability
