The Relationship between Training Intensity and Injury Risk

Oftentimes, gym-goers believe that poor movement is the primary cause of injury. In my clinic, I frequently hear stories like: “I was on my 4th set of 5 reps at 80% of my [insert lift here] when I felt out of position—and suddenly, my back flared up.” Or, “I can’t really pinpoint when it started, but over time, my knee began feeling aggravated. Today, it got bad enough that squatting wasn’t an option.”

These stories don’t reflect recklessness or poor training—they reflect how complex and layered pain and injury can be, even in thoughtful, experienced lifters.

While it may seem logical to assume movement alone causes injury, this perspective is limited. Injury risk isn’t just about movement mechanics—it’s also influenced by factors like training intensity, training volume, sleep, recovery, and nutrition. In this blog, I’ll break down the relationship between training intensity and training volume and explain how understanding these factors can help you reduce your injury risk in training.

Defining the Key Terms

Before we go any further, let’s define a few key terms so we’re on the same page.

Training intensity refers to how hard you’re working—think of it as your maximum output effort. This is different from training volume, which refers to the total amount of work accomplished. For example, 25 reps at 85% of your max would be considered training volume, whereas training at an 8/10 effort would refer to training intensity.

The final term we need to define is injury risk, which refers to the likelihood of exceeding the capacity of your muscles, tendons, or bones.

Now, here’s where these concepts intersect: training intensity and training volume are both directly related to injury risk. The higher your training intensity (max output effort), and the higher your training volume (total work), the more likely you are to push your body past its capacity and increase your injury risk. If that sounds a little abstract, let’s break it down with an analogy.

The Savings Account Analogy

Think of your tissue capacity like a savings account. Your training intensity and training volume? Those are your daily expenses. If your expenses suddenly skyrocket, you start dipping into your savings to cover the extra costs. At first, it’s manageable. But if you keep overspending without adding money back into your account, eventually, you run out of savings—and then you’re in debt.

Now apply this to your body: if your training intensity and training volume exceed your tissue capacity, your body starts borrowing from its reserves to keep up. Without enough time for recovery (aka "depositing money back into your account"), you’ll eventually hit a point where your body can no longer handle the load. This is where injury risk shoots up.

How This Plays Out in Real Life

Let’s look at a common scenario:

Imagine a gym-goer who’s either new to exercise or someone who used to train and play sports 10 years ago. Excited to get back into it, they go from zero workouts to training 5-6 days per week. At first, they’re just really sore—which makes sense since they haven’t moved like this in a while. But they once heard their high school coach say, “No pain, no gain,” so they push harder each day. Soreness? Fatigue? Doesn’t matter—they go 100% every session.

A few weeks in, they notice they’re struggling. Their lifts feel heavier, they can’t push as hard in conditioning workouts, and their energy levels tank. Eventually, nagging joint pain creeps in, or they tweak their back—and suddenly, they’re out of the gym for weeks.

What happened? They trained at high training intensity, with high training volume, beyond their tissue capacity. While stress and challenge are necessary for adaptation and strength gains, failing to regulate training intensity and training volume to allow for recovery leads to breakdown instead of progress. In other words, the dose makes the poison.

So… What’s the Right Dose?

By this point, you’re probably wondering, “Okay, Dr. Coach, then what’s the right dose? How do I balance my training to get the most out of it without increasing my risk of injury?”

Great question. There are a few key things to consider:

Know Your Goal

Most people don’t actually ask themselves: “What is my fitness goal or priority? Why am I doing this?” But this is an important question because it determines where you should focus your effort in training.

• Want to get stronger? Prioritize your strength sessions and ensure you’re recovered enough to push hard on those days.
• Chasing longevity? Training consistently at ~70% effort will help you stay active while minimizing injury risk.
• Competing at a high level? Focus on attacking your weaknesses while modulating training intensity and training volume to ensure adequate recovery.

The BIG 3: Nutrition, Sleep, and Stress

These lifestyle factors are often overlooked but directly impact training training intensity and injury risk.

• Nutrition fuels your body for the demands you place on it—if you’re constantly drained or hungry, you’re likely underfueling.
• Sleep is crucial for recovery—without enough, your body can’t properly adapt and improve.
• Stress affects recovery—if you’re stretched too thin with work, family, or life, your ability to handle more stress in the gym takes a hit.

Sometimes we push too hard without seeing the benefits. If that sounds familiar, it might be time to adjust your training intensity and training volume to a more sustainable level.

Recognizing Overtraining: Central Nervous System Fatigue

One of the biggest signs that your training intensity and training volume are too high is how you feel during your workouts.

• Missing lifts you usually hit with ease
• Struggling to push into a higher gear
• Feeling sluggish, uncoordinated, or mentally drained

These can all be signs of central nervous system (CNS) fatigue.

Your CNS is responsible for sending signals from your brain to your muscles. The harder you train, the more demand you place on it. But just like your muscles, your CNS needs recovery. If you never give it that opportunity, it won’t be able to keep up, leaving you feeling slow, groggy, and worn down.

Final Thoughts

Balancing training intensity and training volume isn’t about avoiding hard training—it’s about applying stress intelligently so your body can adapt and grow without breaking down. Knowing your goals, paying attention to recovery, and listening to your body’s signals will help you get the most out of your training while staying in the game for the long haul.