You see the problem. That’s the first step. The second step is understanding why it’s happening.
A client’s knees cave inward during a squat. Another client’s lower back rounds during a deadlift. A third client’s shoulders shrug up near their ears during a row. Each is a breakdown. Each looks like a form problem. But the reason behind each breakdown is probably different. The reason matters because it determines what you do about it.
Feedback and regression make sense only if you’ve diagnosed correctly. Coaching the wrong problem wastes time for both of you. Feedback tells you something’s wrong. This part is about developing the lens to see not just that something is wrong, but why it’s wrong. Once you know that, the path forward becomes clear.
The Three Types of Capacity
A person’s ability to perform with optimal posture is dependent on their capacity to meet the demand of the exercise. A trainer’s job is to understand the technical, movement, and performance demands of an exercise or routine and match it to the abilities of the client. Improving performance over time requires repeated recoverable bouts of overloading an intended system beyond its capacity. Fatigue needs to be part of the program. However, the ideal scenario is the client having the knowledge and ability to perform the exercise to hit fatigue with perfect form.
This is an obvious unrealistic pipedream.
Coaching movement and performance to be safe and productive requires understanding the integrated relationship between a client’s knowledge, skills, and abilities. Applying progressive overload on a client that doesn’t understand what is expected of them, doesn’t have the skill to execute, and can’t get into or stay in an optimal position produces suboptimal performance and possible increased risk of injury.
Breaking down “capacity” into constituent characteristics allows us to understand the influences on the quality and quantity of movement and make educated decisions to improve the limiting factor.
I call this the Competence Hierarchy: technical, movement, and performance capacity, each dependent on the one beneath it. The quantity of performance is dependent on the quality of movement. The quality of movement is based on knowledge and skill.
The performance of a racecar is dependent on the car’s control. The car’s control is dependent on the driver’s knowledge and skill. I think we all agree that it’s unsafe and unproductive to put someone that doesn’t know how to drive behind the wheel of a formula 1 racecar.Underneath all three levels of the hierarchy sits one simple rule: don’t ask a client to do something they can’t yet do. Every breakdown you’ll see traces back to that rule being violated somewhere: the client didn’t know what to do, couldn’t physically get there, or didn’t have the gas to hold it. Diagnosis is just figuring out which “can’t” you’re looking at.
Does the client have the information and skill necessary to perform the exercise?
A fundamental task of a coach or trainer is to set expectations and convey them to a client in a way that satisfies the coach’s intent. We use a combination of verbal, kinesthetic, and visual instruction, cues, and feedback to teach and refine skill. Asking a client to perform an exercise they don’t understand or can’t control under duress can lead to at the least ineffective output, and at most frustration or potential injury.
Body control > object control, general > specific, simple > complex, slow > fast, frequent feedback > infrequent feedback, known > unknown are all elements that contribute to technical control.
Client experience shapes this more than it gets credit for. A client who’s proprioceptively unfamiliar with their own body (someone who’s never had to scan for position and alignment) has a high likelihood of making errors simply because they don’t know what to pay attention to. Even clients who are familiar with exercise in general may be tracking the wrong reference points: plenty of people know a squat involves going down and up, but aren’t attending to what their feet, knees, or trunk are doing along the way. And new clients may not yet have the habit of internalizing instruction: they’ll nod along to your cues, but nodding isn’t the same as building a reference point they can access mid-rep.
Movement Capacity
Can each joint get into and stay in optimal position for a given movement?
Optimal movement results from the interdependent relationship between actively stable segments that restrict movement in unwanted directions and mobile segments that actively produce movement in an intended direction. Normal movement patterns are the expression of stable and mobile segments moving in concert with coordinated control.
Movement capacity has two dimensions: passive and active.
Passive mobility and stability are determined by the joint’s structural foundation: joint capsule integrity and elasticity, ligament quality and length, bone geometry, cartilage and labrum health, and external compression from clothing or bracing. Some of these are unchangeable: bone structure and genetic predisposition set a baseline for what’s possible. Others can be influenced through training and recovery.
Active mobility and stability depend on the nervous system’s ability to produce and control movement through available range: muscular strength and force production, neuromuscular recruitment patterns, motor control and coordination, proprioceptive awareness, and movement experience. These are trainable through practice and intentional loading.
Your job is understanding which limitation is primary. A client might have excellent passive range but poor active control through that range. Or they might have structural limitations that cap what’s possible, requiring you to work within those constraints. Understanding the difference determines the fix.
This is also where coaching alone stops working. No matter how well you instruct or demonstrate, a client whose hips don’t have the passive range for a full squat isn’t going to get there through better cueing. The same way no amount of instruction gets someone into a full pretzel stretch, or makes someone stable walking a tightrope. Mobility and stability are hard limits, not communication problems. Coach clients within their mobility/stability capacity, and build that capacity separately from the coaching itself.
Performance Capacity
Can the client generate the strength, power, or endurance needed right now?
Performance isn’t exclusive to a certain movement, but layered into it. All movements can be done to challenge endurance, strength, or power. Squatting mechanics can be challenged for endurance by climbing 10 flights of stairs, strength with a heavy barbell, and power with a jump. Same pattern, three different performance demands.
The performance profile breaks down into three qualities of force output: strength (the amount of force produced), endurance (the duration force is sustained), and power (the rate of force production). Any movement can be trained to emphasize any of the three.
There is a point where the postural system can no longer support the performance demand placed on it. This is where postural breakdown occurs. The goal of training is to overload performance without sacrificing postural control. Understanding performance capacity helps you recognize when a breakdown is a performance limit (the client simply can’t produce what’s being asked) versus a technical or movement limit.
Before you go looking for a cause, ask two questions:
1. Has this person performed the movement with good technique before?
2. Has this person performed the movement at the intended performance demand with good technique before?
The likelihood of good technique is much higher if they’ve done it well before. These two questions tell you whether you’re looking at a brand-new skill gap or a regression: someone who’s never squatted well is a different problem than someone with a hundred clean reps who suddenly caved their knees. Most of what follows gets interpreted through this context, with one exception noted below.
What Changed Recently Is Probably the Cause
Compensation doesn’t come from nowhere. It shows up when you ask for something new: a new exercise, a new range, a new load. So the fastest diagnostic question isn’t “what capacity is limiting this,” it’s simpler:
What did I just change?
This matters because it also gets you to the simplest fix first. Coaching a skill gap is a quick, in-session correction. Reducing range or load is a small program adjustment. Rebuilding a movement pattern from scratch or overhauling mobility is a much bigger intervention. You want to rule out the cheap fix before reaching for the expensive one, and in most cases, the newest variable you introduced is exactly where the problem lives.
If it’s a new exercise the client hasn’t done with good technique before: Likely cause: technical/awareness gap. They don’t yet know what to pay attention to. Simplest fix: clear, multi-modal instruction. Strip out range, load, and speed demands entirely until basic awareness and competence are established. Build the pattern before adding anything to it.
If it’s a new range of motion or stability demand on a movement they already know: Likely cause: movement capacity gap. This specific range or control requirement exceeds current capacity. Simplest fix: reduce the range of motion and instability back to the point where compensation disappears. Progress gradually as capacity builds.
If it’s a new endurance, strength, or power demand on a movement and range they already own: Likely cause: performance capacity gap. They have the skill and the range, just not the reserve for this specific demand. Simplest fix: reduce only the variable being progressed: duration/reps for endurance, load for strength, speed/load for power. Leave everything else alone.
Performance capacity gaps show up in two forms. The first is what’s above: the demand itself was progressed beyond current capacity. The second is subtler, and it’s the exception to the context questions above, since it can happen even when the client has performed this exact demand well before: nothing was progressed at all. The client performed this same movement under this same load with good technique on an earlier set, but it’s breaking down now. Capacity hasn’t changed. Recovery hasn’t caught up. The fix isn’t a program change; it’s extending inter-set recovery time before the next attempt. Same category, same underlying logic (reduce demand relative to current capacity), just delivered through rest instead of through load.
That endurance/strength/power case is worth dwelling on. Every exercise has a primary stressor: the specific variable the program is actually trying to overload. This is the SAID principle (Specific Adaptation to Imposed Demand): training organizes overload around one system at a time to produce one intended result. When you push that system past what the client can currently hold with good form, you get breakdown.
The fix is to dial back that variable specifically, not everything at once. If the food’s too spicy, reduce the spice. Don’t add sugar. A client breaking down under a heavier squat doesn’t need slower tempo; they need less load. Fixing the wrong variable leaves the real problem untouched.
If none of this fits, if nothing recently changed, fatigue isn’t the explanation, and the breakdown persists even at low demand, the cause is probably outside this framework entirely. See “Where This Approach Falls Short” below.
The Idea Behind All of This
Every branch above traces back to the Competence Hierarchy: technical, movement, and performance capacity, each dependent on the one beneath it. You can’t have good performance without movement quality, and you can’t have movement quality without technical understanding. That’s also why the newest thing you introduced is the most likely place to look. It’s usually asking for a level of the hierarchy the client hasn’t built yet.
Don’t ask a client to do something they can’t yet do. Finding the cause is just figuring out which “can’t” you’re looking at, and coaching is giving them the smallest step back toward “can.”
Where This Approach Falls Short
addresses movement breakdowns that stem from capacity limitations. It works well when one bottleneck is primary: when you can isolate the root cause to technical, movement, or performance capacity.
But real clients are messier than the framework. Here’s where this breaks down:
Multiple simultaneous limitations: Sometimes a client has poor mobility and poor proprioceptive awareness and is under-recovered. The model tells you to address them sequentially, but in practice, some improvement in all three happens together. You might start with mobility work while also building awareness and ensuring better recovery. The framework doesn’t prescribe the exact sequencing of overlapping issues.
Psychological and emotional barriers: Some movement avoidance isn’t about capacity. It’s about fear, past injury trauma, or body image. A client might have full mobility and strength but unconsciously resist certain ranges of motion because they feel unsafe. This framework doesn’t account for those non-physical constraints. You’ll need to recognize when to bring in other expertise.
Variability across contexts: A client might nail perfect form in a controlled environment but break down in a high-pressure or high-distraction setting. This is partly a technical/awareness issue but also reflects how context-dependent movement control is. The framework works best in consistent training environments.
Genetic and anatomical differences: Some limitations aren’t addressable through training. A client’s bone structure, limb length ratios, or genetic mobility ceiling will always constrain certain positions. The framework can help you work within those constraints, but it won’t overcome structural reality.
In a Nutshell
• Form breakdowns fall into three categories: technical capacity (knowledge/awareness), movement capacity (mobility/stability), and performance capacity (strength/endurance/power), a Competence Hierarchy where each level depends on the one beneath it
• Start by checking whether the client has done the movement, and this specific demand, with good technique before: that context shapes everything else
• The newest thing you changed is usually the cause: a new exercise points to a technical gap, a new range points to a movement gap, a new load/speed/duration points to a performance gap
• When it’s a performance issue, dial back the specific stressor the exercise is meant to overload (SAID), not every variable at once
• Underneath all of it: every breakdown traces back to asking for something the client can’t yet do
FAQ
How do I know if a breakdown is a technical problem or a capacity problem?
Start with what changed. If you just introduced a new exercise the client hasn’t done with good technique before, look at technical capacity first. They may not know what to pay attention to yet. If the exercise is familiar but you just progressed the range of motion, stability demand, load, speed, or duration, the breakdown is probably tied to whichever variable you changed. Matching the diagnosis to the newest change lets you pick the right fix instead of guessing.
What if a client has mobility but still can’t do the movement?
They probably have a stability or complexity issue instead. They can access the range (mobility is there) but can’t control it or coordinate it with other body parts. The fix isn’t more stretching. It’s a simpler variation where they learn to control the range, then progress gradually. And if range itself is genuinely missing, remember that’s a hard limit: no amount of cueing gets a client into a range their joints don’t have.
Should I always fix the limitation before progressing?
Not always. Sometimes addressing a limitation takes weeks, and the client benefits from working around it while you address it separately. For example, a client with ankle mobility restriction can deadlift from an elevated surface while you work on ankle mobility. It respects their capacity while building strength.
A client did the same exercise and load well last set, but broke down this set. What’s going on?
Probably not a new capacity gap at all. It’s likely accumulated fatigue within the session. Capacity hasn’t changed, but recovery hasn’t caught up yet. Extend inter-set recovery before the next attempt rather than changing load, range, or instruction.
How long does it take to build movement capacity?
Depends on the limitation. Stability and coordination can improve within 1-2 weeks with consistent practice. Mobility typically takes 4-12 weeks depending on how restricted the range is and how consistently they work on it. Performance capacity responds faster to training stimulus but is also quicker to lose with detraining.
Next Steps
Now that you can diagnose the problem, the real coaching work begins. Diagnosis tells you which capacity is missing. Actually building it, and coaching a client through the moment-to-moment feedback loop, is its own skill covered next in this series.