Primary vs. Secondary Fault
The primary fault is the swing issue with the highest severity and impact on performance; the secondary fault is the most likely co-existing issue.
In a complex movement like a golf swing or a tennis groundstroke, multiple faults often coexist. An over-the-top swing path may accompany an open clubface; a late unit turn may produce an arm-only swing and an abbreviated follow-through. These faults do not exist on its own — they share a common cause or form a chain where one fault produces another. The primary versus secondary fault framework acknowledges this interconnection and uses it to simplify the training focus. This means fix the primary fault (the root cause or the highest-impact issue). The secondary fault often resolves partially or completely as a consequence.
The primary fault is selected by the advice engine based on severity (how much performance impact it carries) and confidence (how certain the diagnosis is). It is the one issue you are asked to focus on in your current training cycle. The secondary fault is the next highest-ranked issue — present and noted, but not your focus until the primary is addressed and retested. This hierarchy prevents the common coaching failure of assigning multiple simultaneous corrections that compete for attention and produce uneven results.
Understanding the primary-secondary relationship also helps you interpret your results during a retest. If you successfully address the primary fault and the secondary fault improves at the same time without any direct work on it, that is strong evidence that the two faults shared a common cause. This means the primary fix cascaded into the secondary. If the secondary fault persists after the primary is resolved, it is a genuine independent issue that will become the new primary in the next advice cycle. Either outcome is informative and moves the diagnosis forward.
Focus only on the primary fault during your current training cycle. The secondary fault is visible. As a result, you understand the full picture. But working on it at the same time. At the same time, the primary is unresolved is likely to produce conflicting adjustments and slower progress on both.
If you have specific knowledge that the secondary fault is causing more performance impact than the primary in your current competitive context. This means for example, a secondary fault that costs you points in matches. At the same time, the primary fault only affects practice performance. This means you can discuss this with a coach and note it in your session context. The advice engine uses the data available to it, and additional context you provide can refine the prioritization.
Example
An over-the-top path (primary) and an open face (secondary) often share a cause, so fixing the path frequently squares the face too.
How it shows up on video
The primary fault is shown at the top of your report with the highest confidence score and severity rating. Secondary faults appear below it, often with lower confidence scores or lower severity — the report ordering reflects impact priority, not arbitrary sequence.
Common mistakes
- Working on a secondary fault before the primary fault is resolved. This means most secondary faults are compensations for the primary fault and will partially resolve once the primary fault is addressed.
- Treating all faults listed in the report as equally urgent — the primary/secondary ordering reflects biomechanical impact priority; address them in order.
- Not recognizing that a secondary fault can become primary in a future session. This means as you work on the primary fault, the secondary fault may become the most impactful remaining issue and surface as primary in the next analysis.
- Completing only primary fault drills. At the same time, ignoring secondary fault information. This means understanding secondary faults gives you useful context about how your compensations are structured, even when you are not actively drilling them.
In SwingVantage Motion Lab
Your SwingVantage report shows the primary fault prominently at the top of the findings section, with secondary faults listed below it. The relationship between them — whether the secondary is a likely consequence of the primary or an independent co-occurring issue — is noted in the analysis. This context helps you understand whether to expect the secondary to resolve on its own after addressing the primary.
Frequently asked questions
Can there be more than two faults identified?
Yes. The rules engine may identify multiple fault patterns in a single session. SwingVantage presents the top two (primary and secondary) as the actionable focus. This is because research on skill acquisition reliably shows that working on more than two simultaneous changes degrades performance on all of them. Additional identified faults are recorded in your history and will surface as priorities in future cycles after the top issues are resolved.
What if I think the secondary fault is actually more important than the primary?
The ranking is based on the engine's impact and confidence scores from your data. But you have direct knowledge of your performance that the system does not fully capture. If you believe the secondary fault is the more pressing issue, upload additional sessions or context that demonstrate its impact. This means for example, ball flight data showing the performance cost. More evidence may shift the ranking.
Related terms
- SeveritySeverity is how significant a swing fault is expected to be for performance, labeled Critical, High, Moderate, or Low.
- Recommendation EngineThe advice engine ranks possible fixes by impact and confidence so you get one high-leverage priority fix — not twenty competing tips.
- Diagnostic ConfidenceDiagnostic confidence is how certain SwingVantage is about a given finding, based on how much data was available and how reliably the pattern appears.
- Rules EngineThe rules engine is the configuration-driven core that checks your shot data and symptoms against sport-specific target windows to identify the best-fitting pattern.
Put this into your swing
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