Most desk shoulder pain and neck pain at a computer aren’t caused by “wrong desk height” or “wrong chair height.” They’re caused by repeated reach cycles—typing to mousing, clicking small targets, and reaching past the desk edge—that quietly lift the shoulders and add small forward leans. Over time, those repeats create fatigue even when your ergonomic heights look correct.
“Why do my shoulders hurt even when my desk height is correct?” Because repeated reaches push devices outside a comfortable band, so your shoulders lift to compensate.
“Is my typing posture the issue?” Posture usually collapses after the shoulders get tired from reaching too far, too often.
Desk height and chair height adjustments often fail to stop shoulder pain because they don’t change how work actually happens. During typing‑to‑mousing transitions, even small distance errors force shoulder lift and a subtle forward lean. Over hundreds of repetitions, that reach cycle—not “bad posture”—creates fatigue.
- Core Engineering (I–IX)
- System Context — Where This Layer Fits
- I. Concept Reframe
- II. Why Reach Distance Matters More Than Desk or Chair Height
- III. Geometry / Fit Variable
- IV. Stability / Reserve Variable
- V. Transition Event
- VI. Asymmetry & Real-World Distortions
- VII. Downstream Propagation
- VIII. Metrics Feeding Transition Risk
- IX. Risk Diagnostic
- Engineering Decisions (X–XVIII)
- X. Engineering Criteria
- XI. VBU Matrix
- XII. VBU Audit Card
- XIII. Cross-System Intelligence
- XIV. Common Mistakes & Engineered Fixes
- XV. The Engineered Standard
- XVI. People Also Ask (PAA)
- XVII. FAQ
- XVIII. Conclusion
- Glossary
“If my heights look fine, why am I still tired?”
Because reach creeps outside your neutral band during quick switches. That increases shoulder effort and adds small forward leans to land precise clicks. Reduce reach first; once the device is inside the band, desk and chair height usually become “good enough.”
System Context — Where This Layer Fits
This article builds directly on the foundation established in the Chair–Desk Interface Engineering layer. In that earlier article, the focus was on how the body connects to the desk: grounding, arm support, stability, and the conditions that make ergonomic heights meaningful in the first place.
This layer moves one step deeper into the mechanics of desk work. Once the chair–desk interface is stable, the next determinant of comfort is reach geometry — specifically how device distance converts into leverage at the shoulder. Here we show how even small increases in reach amplify shoulder load, trigger forward‑lean events, and create the fatigue patterns most people mislabel as “wrong desk height.”
In the Home Office stack, this layer controls reach bands so shoulder effort stays low and forward‑lean events stay rare, creating stable visual targeting and smooth task movement above it.
This is why adjusting desk height alone rarely solves shoulder pain at a computer workstation.
I. Concept Reframe
The main reason desk sessions feel heavy isn’t desk vs chair height—it’s repeated reach cycles. As reach grows, the shoulder abducts and leverage increases, raising effort. The torso then leans to close distance, and those small leans add up over hundreds of targets—classic “mouse too far shoulder pain.”
| Common Belief | Why It Misses the Cause | What’s Actually Happening |
|---|---|---|
| “My desk is too high.” | Shoulders lift because reach is long or arm support is missing—not height alone. | Long reach increases effort; missing support forces shoulder lift during transitions. |
| “I just have bad posture.” | Posture often collapses after fatigue builds from repeated reaching. | Reach cycles tire stabilizers first; posture degrades later in the session. |
| “I need perfect ergonomic chair height vs desk height.” | Numbers don’t fix distance or desk‑edge interference. | Keep devices inside the reach band and preserve forearm glide; heights become secondary. |
II. Why Reach Distance Matters More Than Desk or Chair Height
When people ask how to set desk height for shoulder pain, they usually focus on chair height versus desk height. But shoulder fatigue at a desk rarely comes from height alone. It comes from how far the arm has to reach during real work—especially during fast typing‑to‑mousing cycles.
The farther the mouse or keyboard sits from the body, the more the shoulder lifts and the more effort each movement requires. To compensate, the torso leans forward slightly to land precise clicks or track the cursor. Those small leans repeat hundreds of times a day, creating cumulative shoulder and neck fatigue—even when posture looks “fine.”
| Common Belief | Why It Misses the Problem | What Actually Drives Fatigue |
|---|---|---|
| “My desk is too high.” | Height may be okay, but long reach still forces shoulder lift. | Reach distance increases effort and repeats strain across transitions. |
| “I have bad posture.” | Posture is often a downstream effect of distance‑driven fatigue. | Reach cycles exhaust stabilizers; posture collapses later. |
| “I need perfect chair height vs desk height.” | Numbers don’t correct device distance or desk‑edge interference. | Keeping devices inside the reach band reduces strain even if heights aren’t perfect. |
III. Geometry / Fit Variable
Geometry starts with distance: keep the pointing device inside the neutral band to prevent extra abduction and torque. Wide desks and thick front edges push the body back; the hand travels farther, and even with “good” numbers for ergonomic chair height vs desk height, effort climbs.
Scenario A — Data entry: frequent precision clicks require the device to live in‑band or fatigue arrives early. Scenario B — Dual displays: longer pointer paths lure the torso forward if distance is marginal; the fix is to restore distance and glide, not to chase millimeter‑perfect height figures.
Use the thresholds below as fast diagnostics for distance‑driven load. Think of them as a quick “How to set desk height for shoulder pain” sanity check—focused on reach first, heights second.
| Geometry Pair | Threshold / Delta | Predicted Risk |
|---|---|---|
| Torso → mouse reach | ≤ 300 mm (target band) | Torque contained; minimal FDM; “desk shoulder pain” unlikely in normal cycles |
| Torso → mouse reach | > 300 mm (over‑band) | Abduction ↑; torque ↑; repeated micro‑leans; “neck pain at computer” more likely |
| Desk front edge → forearm path | Bevel/thickness blocks glide | Micro‑lifts to clear edge → lean to land click; MMRT ↑; precision ↓ |
A wide desk pushes the mouse ~320 mm from the torso; the hand feels “just a bit far.” Shoulders abduct, torque rises, and tiny forward leans appear more often to hit small targets.
Outcome: Earlier fatigue and accuracy dips despite “ideal armrest height for desk” measurements on paper. Restore distance first; heights usually follow.
In real home offices, most desk shoulder pain begins with distance, not height. When the mouse or keyboard sits outside the neutral reach band, arm effort rises, shoulders lift, and small forward leans repeat—regardless of how “correct” chair height or desk height appear on paper. Restoring reach distance and forearm glide reduces load immediately; height adjustments then become minor refinements instead of ongoing fixes.
IV. Stability / Reserve Variable
Stability Reserve is how much steadiness remains when you start a move. If reach is over‑band, reserve is consumed early and the torso moves before the hand—an FDM event—so MMRT grows and the day feels heavier even with “correct” numbers. This is the main reason height‑only fixes fail.
Contributors include forearm support timing, uninterrupted glide at the desk front edge, and how consistently devices stay inside the band during fast transitions. Keep reserve high by protecting distance and glide first, then checking heights to maintain that protection.
| Condition | Effect on Reserve | Downstream Result |
|---|---|---|
| Forearm supported near device | Improves leverage | Torque contained; fewer FDM; smoother typing posture cycles |
| Device outside neutral reach band | Reserve consumed early | Lean events ↑; MMRT ↑; precision ↓ across the session |
| Front edge demands micro‑lift | Abduction ↑ at initiation | Torque ↑; more retargeting leans (FDM) on small UI elements |
Reaching for the mouse, the torso subtly moves first to “close the gap.” Even though heights look fine, each selection starts with a tiny lean, then control returns. Repeat that hundreds of times and you’ve built a fatigue day.
Outcome: lean counts (FDM) rise, MMRT lengthens, and precision fades—textbook reach‑driven stability loss, not a pure height problem.
Stability reserve determines whether desk work feels light or exhausting. When reach is too long or forearm glide is interrupted, reserve is consumed early and the body compensates with repeated lean events and slower recovery. This is why height-only ergonomic fixes often fail. Keeping devices close and support consistent preserves reserve and prevents fatigue from accumulating across the day.
V. Transition Event
Desk sessions feel hardest during rapid switches—typing → mousing, mousing → writing, or scanning between displays. If the device sits over the reach band, each switch raises shoulder abduction and arm torque; the torso then leans to land small targets, producing a forward displacement moment (FDM). Repeat that pattern and desk shoulder pain grows even when heights look fine.
Transitions compress timing: a longer reach increases initiation cost, so small leans multiply across the hour. This is the main reason height‑only fixes often disappoint—the key mechanism is reach‑cycle timing, not raw seat/desk numbers. See the Home Office Transition Matrix and how VLPS protects the shoulders for why stability drops when leans repeat.
| Transition Event | Primary Variable Shift | Resulting Risk (Mechanism) |
|---|---|---|
| Typing → Mousing | Reach length ↑; abduction ↑ | Arm torque ↑; FDM spike; recovery (MMRT) lags → typing posture pain rises |
| Mousing → Writing | Front‑edge interruption → micro‑lift | Abduction + lean mix; precision dip; retargeting overhead ↑ |
| Primary → Secondary display scan | Longer pointer path at marginal distance | More retargeting leans (FDM) if device sits forward/outside shoulder line |
Every 20 seconds you switch from keys to mouse to click tiny UI elements. With reach over‑band, shoulders abduct first, then a small lean seals the click. By late morning, MMRT stretches and neck pain at computer appears even though your numbers are “ideal.”
The hardest moments at a desk occur during rapid task switches, not while sitting still. If reach distance is excessive, each typing-to-mousing transition raises shoulder effort and triggers small forward leans to land precise clicks. Repeated hundreds of times, these transitions drive desk shoulder pain and neck pain at the computer—even when chair and desk heights look correct.
VI. Asymmetry & Real‑World Distortions
Real desks aren’t perfect. A mouse slightly outside the shoulder line, a thick front edge, or cable drag nudging the device outward will bias the reach path. The more the path favors one side, the more abduction and arm torque concentrate there—classic “mouse too far shoulder pain.” Use the VBU Audit Card for Armrest Stability to confirm whether support timing is consistent across both sides.
| IF | THEN | RESULT |
|---|---|---|
| Mouse sits outside shoulder line | Abduction increases to reach | Torque ↑; lean events ↑; fatigue earlier on that side |
| Front edge interrupts forearm glide | Micro‑lift on approach | Retargeting lean (FDM) → MMRT ↑ → precision ↓ |
| Cable drag adds resistance on small moves | Extra reach or force used to compensate | Torque ↑; more frequent micro‑leans; desk shoulder pain trend line ↑ |
Small asymmetries quietly concentrate strain on one side of the body. A mouse outside the shoulder line, a thick desk edge, or cable drag shifts the reach path outward, increasing arm effort and fatigue on the dominant side. Maintaining a symmetric, in-band reach path matters more than visual neatness and is key to preventing recurring mouse-related shoulder pain.
VII. Downstream Propagation
Small reach errors propagate. Over‑band distance raises abduction and arm torque; the torso leans to finish control (FDM); recovery (MMRT) lengthens; and accuracy dips. Across hours, posture resets multiply and neck pain at computer appears—even with respectable ergonomic chair height vs desk height numbers. This is the common failure pattern we observe.
| Step | Trigger | Observable Effect |
|---|---|---|
| 1 | Device sits beyond reach band | Abduction ↑; arm torque ↑; subtle shoulder lift starts |
| 2 | Lean to complete precise targets | FDM spikes; MMRT lag; more retargeting corrections |
| 3 | Transitions repeat through the morning | Accuracy dips; earlier fatigue; posture resets grow in frequency |
Reach errors rarely hurt immediately—they propagate. Longer reach increases shoulder lift and arm effort, repeated lean events slow recovery, and precision gradually drops. Over hours, posture resets multiply and discomfort appears despite respectable ergonomic chair height versus desk height numbers. Stopping the chain early by correcting reach prevents the cascade entirely.
VIII. Metrics Feeding Transition Risk
A short metric set explains most reach‑cycle fatigue: Reach distance (mm), Shoulder abduction (°) as a proxy for arm torque, FDM (Nm) for forward lean cost, and MMRT (ms) for recovery time. Track these during a 2‑minute mixed task and you’ll see why height‑only tweaks often underperform.
| Metric | Operational Inputs | Diagnostic Interpretation |
|---|---|---|
| Reach distance (mm) | Torso → mouse at neutral; repeat mid‑task | > 300 mm predicts abduction ↑, torque ↑, and frequent lean (FDM) |
| Shoulder abduction (°) | Angle needed to maintain contact without lift | Higher angle = higher arm torque; fatigue arrives sooner |
| FDM (Nm) | Estimate from forward lean + body segment leverage | Rising FDM correlates with longer MMRT and accuracy loss |
| MMRT (ms) | Time to regain stability after a move | MMRT ↑ when reach‑driven leans repeat; day feels “busy” |
A small set of metrics explains most desk fatigue: reach distance, shoulder abduction, lean frequency, and recovery time. When these drift upward together, fatigue and accuracy loss follow predictably. Tracking these signals during a short mixed task reveals why height tweaks underperform—and why correcting reach distance delivers faster, more reliable relief.
IX. Risk Diagnostic
Use these binary checks to confirm reach‑driven fatigue. If most “Yes” answers cluster during transitions, distance—not height—is the driver of your desk shoulder pain.
- Are precise clicks slower by late morning? → Yes = reach over‑band; torque + FDM accumulating.
- Do shoulders lift subtly when pointing starts? → Yes = abduction ↑; arm torque ↑ even at “good” heights.
- Do you lean in before small selections? → Yes = FDM event; count frequency across ten minutes (MMRT likely ↑).
Effective diagnosis starts with mechanism, not posture labels. If shoulders lift at the start of pointing, precise clicks slow down, or you lean in to finish small targets, reach cycles—not chair height—are driving the strain. Identifying these signals early prevents the common loop of chasing perfect numbers without reducing workload.
X. Engineering Criteria
Structural checks to keep distance inside the neutral band and prevent lean events. These reflect the article’s core variables—Reach, Abduction/Torque, and FDM—not just “ergonomic chair height vs desk height.”
| Criterion | Rationale (Mechanism) | Check Method |
|---|---|---|
| Reach distance ≤ 300 mm | Limits leverage; lowers arm torque; reduces FDM events | Measure torso → mouse at neutral and mid‑task; adjust device inward if over‑band |
| Shoulder abduction minimized (task‑typical) | Lower abduction reduces arm torque demand | Observe arm path during repeated clicks/drag; reduce outward placement and edge interference |
| FDM near‑zero during a 2‑minute mixed task | Less forward lean → shorter MMRT → steadier precision | Video a short session; count leans; re‑position to cut events to ~0 in normal cycles |
Entity‑based navigation: See the VBU Audit Card for Armrest Stability · Learn how Vertical Load Path Stability (VLPS) protects the shoulders · Compare reach‑cycle timing in the Home Office Transition Matrix.
Engineering criteria work only when they control the true load drivers: reach distance, arm effort, and forward lean frequency during real tasks. Keeping devices inside the neutral reach band reduces shoulder and neck strain even when heights are not perfect. Chair and desk height matter—but only insofar as they preserve that reach relationship.
XI. VBU Matrix
Trade‑off Matrix: Map Reach, Shoulder Abduction (arm torque proxy), and FDM into three states: Aligned (reach in‑band; low torque; minimal FDM), Marginal (one variable out of bounds), and Unstable (two or more out). Diagnose which variable drives MMRT extension during transitions and correct that variable first.
The VBU Matrix prevents over-adjustment by revealing which variable actually degrades performance. In most desk setups, excessive reach—not height—pushes the system into a marginal or unstable state. Correcting the dominant driver first produces lasting improvement instead of temporary comfort.
XII. VBU Audit Card
Component Audited: Armrest Stability (forearm support module)
Intended Role: Maintain continuous forearm contact aligned to the desk plane so the hand stays inside the reach band without shoulder lift.
Life‑Span Risks: Foam collapse causing height drift; loose pivots generating wobble; hard‑edge pressure reducing dwell time; mis‑set width preventing symmetric support.
Failure Signature: Rising shoulder abduction during pointing, intermittent forearm contact, and frequent micro‑leans (FDM) by late morning—classic desk shoulder pain.
Field Test: Track reach (mm) and lean initiations over 10 minutes; if reach > 300 mm and lean count > 8, the armrest is not maintaining the band.
Entity‑based navigation: Learn how Vertical Load Path Stability (VLPS) protects the shoulders · Compare reach‑cycle timing in the Home Office Transition Matrix.
Component drift is a hidden cause of recurring desk pain. When armrests lose height, stability, or alignment, forearm support breaks down and reach moves outside the neutral band. Auditing armrest performance makes this failure visible and prevents shoulder and neck pain from returning after height adjustments.
XIII. Cross-System Intelligence
Reach-driven desk fatigue is not a unique problem—it follows the same mechanical patterns that appear across other furniture systems analyzed in the VBU Furniture Lab. When a system is repeatedly loaded outside its neutral operating range, small inefficiencies amplify into instability, fatigue, or loss of control. At the desk, this amplification takes the form of longer reach, higher arm torque, and repeated forward-lean events (FDM).
In Why Cheap Dining Chairs Wobble (Joint Torque) , undersized joints and micro-slack grow worse under repetition, turning ordinary sitting into visible wobble. The same logic applies to desk work: when the pointing device sits just beyond the neutral reach band, the arm operates with extra leverage. Shoulder abduction increases, torque rises, and each typing-to-mousing transition behaves like a loose joint—small errors magnify into repeated forward leans and declining precision.
A related pattern appears in The Ergonomic Pivot: Clearance & Kinetic Comfort , which shows that comfort depends on staying inside a neutral movement envelope with smooth recovery timing. At the desk, a mouse positioned outside that envelope lengthens recovery after each move (MMRT). The hand overshoots, the torso leans to finish control, and each retargeting adds another FDM event. What feels like “busyness” is actually a timing failure caused by distance.
The same energy-transfer logic underlies Why Your Bed Shakes: Motion Transfer & Structural Continuity . When continuity breaks, movement shows up where it shouldn’t. In desk work, over-reach creates a similar discontinuity: the torso moves first to close distance, then the hand regains control. That sequencing reversal is the defining signature of forward displacement moments (FDM) and explains why fatigue accumulates even when chair height and desk height look “correct.”
| Shared Mechanism | Desk Translation | Resulting Risk |
|---|---|---|
| Slack amplified by repetition | Over-band reach increases leverage and arm torque | Frequent FDM; earlier shoulder and neck fatigue |
| Neutral envelope violation | Device sits outside reach band; recovery slows (MMRT) | Precision loss; work feels effortful and “busy” |
| Continuity break in load path | Torso initiates movement before the hand | Overshoot, retargeting cost, cumulative strain |
Across systems, the lesson is consistent: small deviations become large problems when repeated. Whether it is joint slack in a chair, motion transfer in a bed frame, or reach distance at a desk, operating outside the neutral range amplifies load, disrupts timing, and degrades control. Desk shoulder pain is therefore not a posture problem or a height problem—it is a repetition-plus-leverage problem. Solve the distance and continuity first, and the rest of the system stabilizes.
XIV. Common Mistakes & Engineered Fixes
Most desk shoulder pain and neck pain at a computer persist because people fix the wrong variable. Common ergonomic desk mistakes—adjusting chair height, raising the desk, or buying a new chair—often leave reach distance unchanged. When the mouse, keyboard, or forearm support sits outside the neutral reach band, arm torque rises and small forward leans repeat, even if “ergonomic” height numbers look correct. This section identifies the most frequent setup errors and explains why they fail—so desk fatigue can be solved at its true mechanical source.
Mistake → Failure → Principle
Pushing the chair back to clear a thick desk front edge →
the pointing device moves beyond the neutral reach band →
shoulder abduction increases, arm torque rises, and forward displacement moments (FDM) repeat.
Principle: protect reach distance and forearm glide before adjusting chair or desk height.
Fixing chair height only →
reach distance remains unchanged →
leverage-driven fatigue persists even with “correct” ergonomic numbers.
Principle: correct the variable that drives mechanical load first, not the most visible dimension.
Ignoring cable drag or surface friction →
extra force is required to move the mouse →
repeated retargeting leans appear during precision tasks.
Principle: smooth the movement path so the device stays controllable inside the reach band.
Across these mistakes, the pattern is consistent: desk pain is rarely caused by height alone, but by distance, leverage, and interrupted glide. When reach remains over-band, correcting chair height or desk height cannot prevent shoulder lift, forward displacement moments (FDM), or accumulating fatigue. Engineered fixes work only when they target the variable driving load first—reach distance—then support it with stable forearm contact and clear movement paths. Eliminate the leverage error, and many “ergonomic” problems resolve without further adjustment.
XV. The Engineered Standard
The engineered standard defines how a desk workstation must perform to prevent shoulder pain, neck pain at a computer, and reach-driven fatigue during real work. Instead of focusing on chair height vs desk height, this standard targets the primary failure mechanism identified throughout this article: excessive reach distance that increases arm torque and triggers repeated forward displacement moments (FDM). By keeping the pointing device inside a defined reach band during typing-to-mousing transitions, the standard preserves control, stability, and precision across the workday.
This approach establishes measurable operating boundaries that neutralize leverage before fatigue accumulates. When reach, shoulder abduction, and forward lean remain within limits, recovery stays fast, transitions stay smooth, and desk shoulder pain is far less likely—even if desk and chair heights are not perfectly tuned.
Failure → Required Spec → (Optional) VBU Solution
| Failure Mechanism | Required Engineering Spec |
|---|---|
| Reach-driven torque rise | Torso → mouse reach ≤ 300 mm at neutral posture |
| Frequent forward lean (FDM) | Zero-lean targeting during a 2-minute mixed task |
| Abduction growth during switches | Shoulder abduction minimized at common targets |
Solutions appear only when they meet or exceed the defined engineering specifications.
Applied together, these specifications convert desk ergonomics from trial-and-error adjustment into verifiable performance. When reach stays inside the neutral band, shoulder lift decreases, forward leans disappear, and micro-movement recovery remains fast. The result is a workstation that resists fatigue not by chasing perfect height numbers, but by eliminating the leverage errors that actually drive shoulder and neck strain during desk work.
XVI. People Also Ask (PAA)
- Why doesn’t changing desk or chair height stop my fatigue? Because reach distance usually drives effort. Over‑band distance increases abduction and arm torque; a small forward lean (FDM) repeats during typing→mousing. Fix distance first—heights often become “good enough” once the device is in‑band.
- What reach distance should I target for the mouse? Aim for ≤ 300 mm from torso to device at neutral posture. Inside this band, torque stays manageable and forward leans (FDM) are rare during quick switches; outside it, neck pain at computer appears sooner.
- How does shoulder abduction relate to desk shoulder pain? Abduction increases the arm’s moment arm, raising torque even before you feel it. Repetition turns small torque spikes into real fatigue—especially in high‑frequency switching.
- What is a forward displacement moment (FDM)? It’s the moment created when the torso leans forward to close distance for control. Each lean consumes stability and lengthens recovery; repeated FDM events make simple tasks feel harder later in the day.
- Should I fix heights or reach first? Fix reach first. When the device returns inside the band, abduction drops and FDM fades; many “height problems” resolve on their own. Heights still matter—but second to distance for fatigue control.
- Where do armrests fit into this? Armrests should support the forearm at desk plane so the hand stays in‑band without shoulder lift. If support drifts, distance and abduction grow, and mouse too far shoulder pain follows. See the VBU Audit Card for Armrest Stability.
XVII. FAQ
- How do I measure reach distance quickly? Sit neutral and measure from your torso to the device centerline. If it exceeds 300 mm, expect higher torque and more lean events (FDM) during switches; reduce distance before tweaking heights.
- What should I change first if I’m fatigued by 11 a.m.? Bring the device inside the reach band and ensure smooth front‑edge clearance. Re‑test transitions; if lead counts fall, you corrected the primary driver.
- My numbers say my ergonomics are ideal—why do I still lean? Because distance—not height—is pulling you forward. Over‑band reach forces abduction and lean to land targets. Restore distance and the urge to lean fades.
- Do cable and mouse‑pad friction really matter? Yes. Any resistance on small moves encourages extra reach or lean to compensate. Smooth the path so the device remains controllable inside the band.
- What if my desk is simply too deep? Reposition the device nearer; if needed, add a shallow accessory surface. Protect forearm glide at the front edge so abduction and lean don’t grow with use.
- How do I know the change worked? In a 2‑minute mixed task, count lean initiations. If near zero—and precision holds—reach is inside band, torque is down, and FDM is controlled.
XVIII. Conclusion
The long-running debate over desk height vs chair height misses the primary reason desk work feels tiring: reach distance. When the mouse or keyboard sits outside the neutral reach band, shoulder effort increases, arm torque rises, and small forward leans repeat during typing-to-mousing transitions. Over hours, those repeated reach cycles—not incorrect height—drive desk shoulder pain, neck pain at a computer, and declining precision.
Effective desk ergonomics starts by restoring distance before chasing height. Keep devices close, preserve forearm glide, and reduce repeated reaching so stability lasts deeper into the day. Fix the reach, and the heights usually fall into place — because comfort isn’t about sitting higher, it’s about working closer.
Glossary
Reach distance (mm): Torso→device length at neutral posture; primary driver of leverage and effort.
Shoulder abduction (°): Sideward arm angle that grows with distance; proxy for arm torque; keep low to reduce desk shoulder pain.
FDM (Nm): Forward Displacement Moment created by torso lean events during targeting; correlates with longer MMRT.
MMRT (ms): Micro‑Movement Recovery Time; how long it takes to regain stability after a move; increases with repeated leans.
VLPS: Vertical Load Path Stability; remaining steadiness under small perturbations; higher VLPS protects the shoulders.
Reach Cycle Fatigue: Accumulated shoulder/neck load created by repeated forward‑reach movements when chair–desk geometry fails to support neutral arm positioning.
Next article in the series: Why your ergonomic office chair hurts after 2 hours propagates how prolonged micro-compensations and postural drift at the chair–desk interface contribute to fatigue and discomfort over time.
