How to Use My Workout Log to See Why I Get Injured

Why Your Workout Log Is a Goldmine (If You Know How to Read It)

To use your workout log to see why you get injured, you need to look beyond a single bad workout and instead calculate your 'Acute:Chronic Workload Ratio' from the last 4 weeks. Most non-contact injuries happen when this ratio spikes above 1.5, meaning your training load jumped too fast for your body to handle. You're sitting there, frustrated with another setback-a tweaked shoulder, a sore lower back, a nagging knee. You did the 'right' thing by keeping a workout log, but it feels useless. It's just a list of dates and numbers that don't explain why you're hurting again. The secret isn't in the one rep that caused the pain; it's in the pattern of the 28 days that led up to it. Your log isn't just a diary of what you did; it's a data set waiting to tell you a story. That story is about the relationship between how much work you did recently versus how much work your body is prepared to handle. When those two numbers get too far apart, an injury becomes almost inevitable. The good news is that this is just math. And once you understand the math, you can stop being a victim of random injuries and start controlling your progress.

The Injury Formula: Your Last 7 Days vs. Your Last 28 Days

The reason you keep getting hurt isn't bad luck or bad genetics; it's bad math. Specifically, you're violating the Acute:Chronic Workload Ratio (ACWR). This single metric is the most powerful predictor of non-contact injuries in sports science, and you can calculate it with the data you already have. Here’s how it works:

• Acute Workload: This is the total work you’ve done in the last 7 days. Think of it as your 'fatigue'.
• Chronic Workload: This is your average weekly workload over the last 28 days (4 weeks). Think of it as your 'fitness' or how much stress your body is prepared for.

The Ratio = Acute Workload / Chronic Workload

This number tells you if your recent training was appropriate for your current fitness level.

• The Sweet Spot (0.8 - 1.3): You're progressing safely. Your fitness is growing without adding excessive fatigue.
• The Danger Zone (> 1.5): Your injury risk skyrockets. You've increased your workload too quickly for your body to adapt.

Let's look at an example. Say your main squat workout volume (sets x reps x weight) for the last 4 weeks was:

• Week 1: 15,000 lbs
• Week 2: 16,000 lbs
• Week 3: 17,000 lbs
• Week 4 (This week): You feel good and jump to 22,000 lbs.

Your Chronic Workload is the 4-week average: (15,000 + 16,000 + 17,000 + 22,000) / 4 = 17,500 lbs.

Your Acute Workload is this week's work: 22,000 lbs.

Your ACWR = 22,000 / 17,500 = 1.25. You're in the sweet spot. You pushed it, but you're likely safe.

Now, what if week 3 was a deload at 10,000 lbs?

• Week 1: 15,000 lbs
• Week 2: 16,000 lbs
• Week 3: 10,000 lbs (Deload)
• Week 4 (This week): You feel fresh and jump back to 22,000 lbs.

Your Chronic Workload is now: (15,000 + 16,000 + 10,000 + 22,000) / 4 = 15,750 lbs.

Your Acute Workload is still: 22,000 lbs.

Your ACWR = 22,000 / 15,750 = 1.4. You're on the edge of the danger zone.

One more. What if you took a week off for vacation (0 lbs) and then jumped back in?

• Week 1: 16,000 lbs
• Week 2: 17,000 lbs
• Week 3: 0 lbs (Vacation)
• Week 4 (This week): You try to make up for lost time and hit 20,000 lbs.

Your Chronic Workload: (16,000 + 17,000 + 0 + 20,000) / 4 = 13,250 lbs.

Your Acute Workload: 20,000 lbs.

Your ACWR = 20,000 / 13,250 = 1.51. You are now in the danger zone. This is how people get hurt coming back from a break. It's not the 20,000 lbs that hurt you; it's the fact that your body was only prepared for 13,250 lbs.

That's the formula. Acute workload divided by chronic workload. It explains why you feel fine one week and then suddenly your shoulder gives out on a warm-up set the next. But knowing the formula and actually calculating it are two different things. Can you, right now, calculate your total squat volume for the last 28 days? If the answer is no, you're flying blind.

Stop guessing why you get hurt.

Track your workload automatically. See the injury risks before they happen.

How to Perform a 4-Week Injury Autopsy on Your Log

If you've recently been injured, you can use your workout log to perform an 'autopsy' and find the mathematical cause. This isn't about blame; it's about finding the pattern so you never repeat it. You'll need your log and about 15 minutes.

Step 1: Choose the Culprit Exercise

First, identify the movement that is giving you trouble. If your shoulder hurts, the primary exercise to investigate is likely the bench press or overhead press. If your lower back is the issue, look at your deadlift and squat. You can't analyze everything at once, so pick the one most associated with your pain.

Step 2: Calculate Your Weekly Volume

Volume is the universal language of workload. For any given exercise, the formula is simple:

Total Volume = Sets x Reps x Weight

Go back 4 full weeks *before* the week you got injured. For each of those four weeks, calculate the total weekly volume for your chosen exercise. For example, if you benched on Monday and Thursday:

• Monday: 3 sets of 5 reps at 185 lbs = 2,775 lbs
• Thursday: 4 sets of 8 reps at 155 lbs = 4,960 lbs
• Total Weekly Volume: 2,775 + 4,960 = 7,735 lbs

Do this for all four weeks leading up to your injury week.

Step 3: Find Your Chronic and Acute Workloads

Now you have four weekly volume numbers. Let's say they are:

• Week 1 (4 weeks ago): 7,500 lbs
• Week 2 (3 weeks ago): 8,000 lbs
• Week 3 (2 weeks ago): 8,500 lbs
• Week 4 (The week before injury): 13,000 lbs

Your Chronic Workload is the average of these four weeks:

(7,500 + 8,000 + 8,500 + 13,000) / 4 = 9,250 lbs. This is the workload your body was prepared for.

Your Acute Workload is the volume from that last week: 13,000 lbs.

Step 4: Do the Math and Find the Spike

Now, calculate the ratio:

ACWR = 13,000 / 9,250 = 1.41

In this case, you were right on the edge of the danger zone. The jump from an average of 8,000 lbs in the first three weeks to 13,000 lbs in the final week was too much, too soon. Your body sent you the bill in the form of an injury. Look for other clues, too. Did you also add a new exercise? Did you cut your rest times in half? Did you log poor sleep for 3 nights in a row? The volume spike is usually the main suspect, but these other factors are accomplices.

What Your Next 8 Weeks Should Look Like (The 10% Rule)

Finding the cause of your last injury is only half the battle. Now you need a system to prevent the next one. The goal is no longer just to lift more; it's to lift more *sustainably*. This is done by managing your ACWR proactively, and the easiest way to do that is with the 10% rule.

The 10% Rule: Never increase your total weekly volume for a major lift by more than 10% compared to the previous week.

This simple guideline keeps your ACWR from ever spiking into the danger zone. It forces you to make small, manageable jumps that your body can actually adapt to. Progress might feel slower, but it will be infinitely more consistent.

Here’s what an injury-proof 8-week progression for your bench press might look like, starting from a baseline of 10,000 lbs of weekly volume:

• Week 1: 10,000 lbs (Baseline)
• Week 2: 11,000 lbs (+10%)
• Week 3: 12,100 lbs (+10%)
• Week 4: 13,300 lbs (+10%)
• Week 5 (Deload): 6,650 lbs (-50%). This is critical. You intentionally drop the volume to shed fatigue, let your joints recover, and re-sensitize your body to the training stimulus. Your chronic workload average comes down, preparing you for the next push.
• Week 6: 11,500 lbs (Return to a load similar to week 2/3)
• Week 7: 12,650 lbs (+10%)
• Week 8: 13,915 lbs (+10%)

Notice the progress is not a straight line up. It's a series of waves. You build for 3-4 weeks, then pull back to recover, then build again to a new peak. This is how you accumulate months, and then years, of injury-free progress. The person who follows this plan will be dramatically stronger in a year than the person who goes all-out for 3 weeks, gets hurt, and takes 3 weeks off, repeating the cycle endlessly.

So, the plan is simple: track your volume for every major lift, every workout. Calculate your weekly total. Make sure it doesn't jump more than 10% from the week before. And plan a deload every 4-6 weeks. This is the exact system that keeps pro athletes on the field. But it requires tracking every set, rep, and pound. Trying to remember if you did 12,100 lbs or 13,300 lbs last Tuesday is a recipe for failure.

Your training history. In one place.

Every workout logged. Proof you're progressing safely without the guesswork.

Frequently Asked Questions

The Role of RPE in Injury Prediction

Rate of Perceived Exertion (RPE) is a powerful partner to volume tracking. If you notice the RPE for your top set of squats at 225 lbs has crept from a 7 to a 9 over three weeks, that's a major warning sign. It means your body is accumulating fatigue, even if the volume is stable.

How Far Back to Look in Your Log

The 4-week (28-day) window is the standard for calculating the Acute:Chronic Workload Ratio. It's long enough to establish a true 'fitness' baseline but short enough to be sensitive to recent changes in your training. Looking back 6 months is not useful for this specific calculation.

Applying This to Cardio and Conditioning

Yes, this principle applies to more than just lifting. For running, you can calculate volume by multiplying mileage by an intensity factor (e.g., easy run = 1, tempo = 1.5, intervals = 2). The goal remains the same: keep the ratio of this week's work to the last four weeks' average below 1.5.

What to Do After an Injury

Once you are cleared to train again, do not jump back to your old numbers. Use this system in reverse. Start with a very low volume (e.g., 30-40% of your pre-injury workload) and use the 10% rule to slowly and safely build back up over several weeks.

Single-Joint vs. Multi-Joint Volume

Focus your tracking efforts on the big, systemically taxing compound movements: squats, deadlifts, bench presses, overhead presses, and rows. These lifts create the most stress and are the primary drivers of your overall workload. Tracking volume for bicep curls is far less important for injury prevention.