Active Health Performance Lab Dr. Damir Simunac, DC

A Field Guide for the Middle-Age Athlete

Still in the Game

The rules changed. Your body sent the memo. You missed it.

By Dr. Damir Simunac, DC

Small Moves. Big Freedom.

The Field Guide

Introduction

The Conversation

Someone sits down in my office, looks at the floor for a second, and says it. "I used to be athletic." Past tense. Like it's already over.

I hear it every week. From the former college soccer player who now gets winded on the stairs. From the weekend warrior who tweaked his back doing something that used to be easy. From the woman who ran a marathon at 30 and now wonders why her knees talk to her when it rains.

Here's what I tell them: it's not over. But the game changed, and nobody handed you the updated playbook. The body you had at 25 forgave everything. Bad sleep, bad food, no warmup, full send. That body is gone. The body you have now is smarter, more honest, and less interested in your excuses.

Think of it like going back to school for a new degree. You wouldn't walk into advanced coursework without a placement test. Coming back to training after 40, after time off, after injuries, you need that same honest starting point. Where are you now? What can your body actually handle today? Not five years ago. Today.

This guide is the playbook: ten chapters covering everything I've learned in over a decade of treating athletes who refuse to quit. You're not broken. You're just ready to pay attention.

Chapter 01 // The Strategic Pivot

Mindset for the Master Athlete

The first thing that has to change isn't your body. It's the story you tell yourself about what training is for.

In your twenties, training was about performance. How fast, how heavy, how far. You could absorb bad mechanics because your tissues were resilient and your recovery was almost instant. You were a generalist who got away with everything.

In your forties, you need to become a specialist. A specialist in your own body. The goal shifts from performance at all costs to a word I use with every patient: capacity.

Capacity is the ability to show up every single day without the baggage of chronic pain, nagging injuries, or the fear that something is about to give out. That's the real measure. And capacity is built on precision, not intensity.

That means trading ego for intelligence. It means understanding that the guy doing perfect goblet squats three days a week will outlast the guy grinding through heavy back squats with a lumbar spine that's screaming at him. It means accepting that the goal isn't to win the workout. The goal is to still be training at 65.

You stop measuring yourself by the standards of a body you no longer have and start building for the body you want to keep.

You stop measuring yourself by the standards of a body you no longer have and start building for the body you want to keep.

Dr. Damir Simunac
Chapter 02 // The Biology of 40+

What Actually Changes

Let's get honest about what's happening under the hood. After 35, your body starts making different choices about where to spend its resources. Recovery slows, muscle protein synthesis becomes less efficient, hormonal output shifts, and connective tissue loses some of its elasticity. Bone density starts a slow decline if you're not loading the skeleton.

None of this means you're falling apart. It means your biological budget got tighter. You used to be able to overspend on Tuesday and recover by Thursday. Now an overspend on Tuesday might cost you the whole week.

Sarcopenia (age-related muscle loss) is real. After 30, you lose roughly 3-5% of your muscle mass per decade if you do nothing about it. After 50, the rate accelerates. The antidote is resistance training. Not optional. Not "if you feel like it." A biological requirement.

Your body also prioritizes survival over performance as you age. Inflammation becomes less of a temporary repair signal and more of a chronic background noise. Your nervous system gets more protective, tightening muscles not because they're short but because it doesn't trust your joints.

The good news: every single one of these trends is modifiable. You can't stop the clock, but you can absolutely negotiate with it. That's what the next eight chapters are about.

"You can't stop the clock, but you can absolutely negotiate with it."

Every biological trend after 35 is modifiable. That's the whole point of this guide.

Chapter 03 // Joint Health

Earn Your Joints

Your joints are a language. And most people stopped speaking it sometime around their late twenties. They stopped asking their shoulders for full rotation. Stopped requesting their hips to do anything other than sit, stand, and occasionally lunge for a tennis ball.

The result isn't injury, not yet. The result is silence. Joints that used to talk to your brain go quiet, the neural pathways narrow, and the available range shrinks until one day you reach for something overhead and wonder why it feels like your shoulder forgot how to do that.

It didn't forget. You stopped asking.

The fix is something called CARs, short for Controlled Articular Rotations. Think of them as a daily conversation with every joint you own. Slow, intentional, full-range circles at each joint, with tension throughout the entire arc. Not stretching, not yoga. A neurological check-in where your brain asks each joint: "You still have this range? Good. Let's keep it."

I teach every patient the difference between being a tourist and a local in their own body. A tourist visits their end range once in a while, panics when it's tight, stretches aggressively, and leaves. A local lives there. They know the neighborhood. They move through their range every single day with the familiarity of walking to the corner store.

Here's another way to think about it. If it takes you 45 minutes to warm up before you can move well, can you really move well? That's not capacity. That's a loan you're taking out every session. Cold mobility is the real measure. What your body can do when you roll out of bed, no warmup, no foam roller, no twenty minutes on the bike first. That's your actual starting point, and most people have never tested it.

Five minutes a day. Every joint. That's what it costs to stay fluent.

Your body doesn't lose range because you aged. It loses range because you stopped asking for it.

Dr. Damir Simunac
Chapter 04 // The Pre-Flight Check

The Daily Diagnostic

A pilot doesn't take off without a pre-flight check. Every system gets inspected, every gauge gets read. Your body deserves the same respect before you load it.

Most people walk into the gym, do a few arm circles, and start lifting. That's wishful thinking, not a warmup. A real pre-flight check takes five minutes and tells you everything you need to know about what your body is willing to give you today.

When a joint is centrated (positioned in its ideal alignment), the nervous system feels safe. It opens up range, it allows force production, it trusts you. When a joint is off-center, the nervous system puts the brakes on. You feel "tight," but you're not short. You're guarded. The system doesn't trust the position.

The pre-flight check identifies which joints are centered and which ones aren't. Not every day is the same. Your Tuesday body is not your Thursday body. Stress, sleep, yesterday's training, all of it shifts the starting point. A three-minute diagnostic before you train tells you where you are today so you can train smart instead of training blind.

Daily Pre-Flight Protocol

Three to five minutes before every session. Non-negotiable.

  • Segmental Spinal Lead: Move your spine vertebra by vertebra. Flexion, extension, rotation. Identify the "sticky" spots.
  • Hip CARs: Standing circles, both legs. Biggest rotation you can control with tension. This is your pelvic engine check.
  • Shoulder CARs: Full circumduction under tension. Feel every degree of the arc and note any catches or dead spots.
  • 90/90 Hip Flow: Test internal and external rotation. How does today compare to yesterday?
  • Thoracic Extension: Open the upper back to protect the lumbar spine during loading.

What you find in the pre-flight determines how you train that day. No ego. Just data.

Chapter 05 // Structural Armor

Strength Is an Insurance Policy

The guy who used to bench 315 in college now throws his back out picking up a suitcase. Not because he got weak. Because he kept training for a game that ended twenty years ago.

There's a shift that has to happen, and most people resist it. The shift from performance training to durability training. From "how much can I lift?" to "can I still do this when I'm 65?"

That doesn't mean going soft. It means getting honest about the timeline.

You're not training for a season. You're not peaking for a competition (and if you are, God bless, but the other 48 weeks still apply). You're training for the next thirty years of picking up grandchildren, carrying groceries up stairs, getting off the floor without a sound effect, and doing the things that make life feel like yours.

Think of your body like a house. You can renovate a kitchen, add a deck, upgrade the windows. But if the foundation has cracks, if the framing is warped, none of those upgrades matter. The house looks great until a storm hits. Strength training after 40 is foundation work first. Get the structure right, make sure the load-bearing walls can handle what you're asking of them, then build on top of that.

Load is medicine. Your bones need it, your muscles need it, and your nervous system needs the signal that says "we still do hard things." Progressive overload still matters, but the timeline stretches. Adding five pounds every week is a young person's game. Adding five pounds every month, with perfect form, while keeping your joints healthy and your recovery intact? That's the grown-up version, and it works better.

Strength Essentials

  • Frequency: Two to three days a week. Compound movements. Full body or upper/lower split.
  • Patterns: Squat, hinge, push, pull, carry. Master the basics before chasing variety.
  • Tempo: Slow, controlled eccentrics. Time-under-tension builds tendons, not just muscles.
  • Progression: Progressive overload on a longer timeline. Months, not weeks.
  • Ego check: If you can't do it with good form, you can't do it yet. Ego is not a training variable.

"You're not training for a season. You're training for the next thirty years."

The squat you do today is an investment in the version of you that wants to get off the floor at 70 without thinking about it.

Chapter 06 // The Ribcage

Breathe Like You Mean It

I had a patient who couldn't touch her toes. Tight hamstrings, she figured. I didn't touch her hamstrings. I changed how she breathed. Ten minutes later, fingertips on the floor. She looked at me like I'd done a card trick.

No trick. Just physics.

Your ribcage is the center of the whole operation. It's where your diaphragm lives. It's where your spine meets your breath. It's the architectural hub that everything else hangs off of. And when it gets stuck, locked in a position of chronic inflation (which happens to almost everyone who sits at a desk, drives a car, or lives with any ambient stress), everything downstream goes sideways.

Here's the short version: most people are stuck in a state of inhalation. Ribs flared, diaphragm flat, lower back arched, unable to fully exhale. It's a positional pattern. And it affects your hips, your shoulders, your neck, your pelvic floor, and yes, your hamstrings.

Your exhale matters more than your inhale. A full, complete exhale brings the ribs down, restores the diaphragm to a domed position, turns on your deep core, and creates space for everything to move properly. Most people have never experienced a real exhale. They think they breathe fine. They breathe enough to stay alive. That's a low bar.

Breathing Essentials

  • Ribcage position drives everything. Ribs flared out means your system is stuck in overdrive.
  • Practice full exhales. Breathe out until there's nothing left, then pause for two seconds before inhaling.
  • Nasal breathing during exercise. Mouth breathing is for max effort only.
  • Core connection: If you can't exhale fully, you can't stabilize your core. Period.

Most people breathe enough to stay alive. That's a low bar.

Dr. Damir Simunac
Chapter 07 // The Recovery Hierarchy

Recovery Is Not Lazy

The hardest sell in my office isn't "you need to train more." It's "you need to rest better." The middle-age athlete treats rest like a character flaw. Like if they sleep eight hours, they're somehow less committed.

Let me be clear: sleep is the single highest-ROI intervention you have access to. Higher than any supplement. Higher than any training program. Higher than the $200 massage gun collecting dust in your closet.

During deep sleep, your body does the actual work of adaptation. Growth hormone peaks, tissue repairs, your brain consolidates motor patterns (that new squat form you're learning gets rehearsed while you're unconscious), inflammation drops, and immune function resets. All of this happens in hours four through eight, which means the person getting six hours is cutting the line right before the good stuff.

The nervous system doesn't care about your discipline. It cares about your rhythm. Same bedtime, same wake time, a wind-down that doesn't involve a screen three inches from your face, a cool dark room. The boring stuff nobody wants to hear because it doesn't come in a bottle.

Here's the uncomfortable truth about recovery for the over-35 athlete: you don't bounce back like you used to, and pretending otherwise is how injuries happen. The workout doesn't make you stronger. The recovery from the workout makes you stronger. The workout is the stimulus. Sleep, nutrition, and low-level movement (walking, easy mobility) are the response. Skip the response, and the stimulus just becomes stress.

Recovery Essentials

  • Sleep: Seven to nine hours. Non-negotiable. This is where adaptation happens.
  • Consistency: Same sleep and wake times matter more than total hours in bed.
  • Walking: The most underrated recovery tool. Twenty to thirty minutes daily.
  • The test: If you're always sore, always tired, and performance is flat, you don't need a new program. You need rest.

"The workout doesn't make you stronger. The recovery from the workout does."

Skip the response, and the stimulus just becomes stress.

Chapter 08 // Metabolic Fueling

Fuel the Machine

You can't out-train a bad diet. But you also can't out-diet a bad relationship with food. The person eating "clean" while hating every meal is not winning.

I'm not going to give you a meal plan. Meal plans are where good intentions go to die. What I'll give you instead is a framework. Principles that survive holidays, travel, stress, and the reality that you're a grown adult who sometimes wants a beer and a burger.

Protein is the non-negotiable. After 35, your body gets worse at using protein for muscle synthesis. The science calls it anabolic resistance. The practical translation: you need more than you think. Somewhere between 0.7 and 1 gram per pound of body weight, spread across your meals. Not crammed into one chicken breast at dinner. Distributed. Breakfast, lunch, dinner, each one anchored by a real protein source.

Hydration is the thing everyone thinks they're good at. They're not. Most people are chronically under-hydrated and compensating with caffeine, which is a diuretic. Drink water before you drink coffee. Aim for half your body weight in ounces, minimum. If your urine isn't light yellow, you're behind.

Eat things that came from the ground or had a mother. That's the simplest filter I know. Vegetables, fruits, quality meats, fish, eggs, nuts, legumes, whole grains. If it has a nutrition label longer than three lines, it's probably not food. It's a product. You can eat products sometimes. But the foundation should be food.

Anti-inflammatory eating doesn't require a manifesto. Colorful vegetables, olive oil, fish a couple times a week, and less (not zero, less) sugar, alcohol, and heavily processed food. You don't need to become a person who talks about inflammation at dinner parties. Just eat like an adult who's paying attention.

Eat like an adult who's paying attention. That's the whole plan.

Dr. Damir Simunac
Chapter 09 // Tactical Programming

Logic Over Ego

The biggest mistake middle-age athletes make with programming is treating every day like game day, every session a max effort, every workout supposed to leave you on the floor. They confuse feeling destroyed with making progress.

That approach works when you're 22 and your recovery runs on autopilot. At 40, it's a one-way ticket to overtraining, chronic inflammation, and the kind of nagging injuries that never fully resolve because you never let them.

Load management is the concept that separates smart programming from ego programming. Not every day should be hard. Your week needs a rhythm: high-intensity days balanced with low-intensity days, power sessions balanced with mobility resets. The nervous system needs variation, not just the muscles.

A sample week for the middle-age athlete might look like this: two strength sessions (one heavier, one moderate), one conditioning session that doesn't trash your joints (rowing, biking, loaded carries), one dedicated mobility session, and the rest is walking and living your life. That's not lazy. That's tactical.

The 1% habit matters here too. Improving your joint hygiene by just 1% every day creates a compound effect that's staggering over a decade. The five-minute CARs routine you do on the days you don't feel like it? Those are the reps that buy you freedom on the days that count.

Weekly Template

  • Day 1: Strength (heavier, compound focus). Pre-flight check first.
  • Day 2: Mobility and breathing work. CARs, breathing drills, soft tissue. Active recovery.
  • Day 3: Strength (moderate load, tempo work, accessory movements).
  • Day 4: Conditioning (joint-friendly: row, bike, carry, sled). Keep the heart rate up without beating up the joints.
  • Day 5: Joint circles only. Walk. Rest. Let the system consolidate.
  • Weekends: Play. Hike, bike, practice your sport. Earn it through the week, enjoy it on the weekend.

Adjust based on your pre-flight check. Some weeks you push. Some weeks you pull back. Both are correct.

"The five-minute routine you do when you don't feel like it? Those are the reps that buy you freedom."

Consistency compounds. One percent better every day is a different body in a year.

Chapter 10 // The Vision

Capability Is the Victory

You don't need a dramatic overhaul. You don't need to quit your job and become a monk who does yoga at sunrise. You don't need a $3,000 biohacking stack or a personal chef or a recovery pod in your basement.

You need five minutes of joint circles in the morning, heavy things in your hands two or three times a week, breathing that actually does something, sleep you protect like your job depends on it, and food that looks like it came from a kitchen and not a factory.

That's the game. Simpler than the internet wants you to believe and harder than anyone wants to admit. The hard part isn't physical. It's showing up on Tuesday when nobody's watching and nothing hurts yet.

But you knew that already. You've always known how to do hard things. You just forgot that the hard thing changed.

Success for the middle-age athlete isn't defined by a single scoreboard. It's defined by the decades you spend in the game. By the fact that you can still get on the floor and play with your kids. By the hike you take at 60 without thinking about your knees. By the barbell you pick up at 70 because you never stopped.

You're still in the game.