The post-serve telemetry panel
After each serve the arena reports eight measurements. Understanding exactly how each one is computed stops you drawing the wrong conclusion from it.
| Metric | Definition | Healthy range |
|---|---|---|
| Serve power | Meter value at release, 0–100% | 55–80% |
| Contact speed | v₀ = 9 + 21 × power (m/s) | 20–26 m/s |
| Launch angle | Elevation above horizontal at contact | 5–14° |
| Net clearance | Ball-centre height at the net plane minus 2.43 m | +0.20 to +0.60 m |
| Flight distance | Horizontal distance from contact to landing | 13–19 m |
| Target deviation | Distance from landing to target-zone centre | < 1.5 m |
| Flight time | Simulated seconds from contact to floor | 0.9–1.4 s |
| Apex height | Highest point of the ball's centre | 3.0–4.5 m |
The result label is determined by the engine's boundary logic. Net means the ball's underside failed to clear the tape or the ball fell short of the net. Out means it landed beyond the lines or crossed outside the antennae. In means a legal landing, lines included. Ace means a legal landing inside your selected target zone.
Challenge-level metrics
Across a 10-serve set, the scoreboard aggregates four core statistics:
Accuracy % = (In + Ace) / serves × 100
Target-hit % = Ace / serves × 100
Average power = Σ power / serves
Score = Σ points (Ace = zone value + 1 if v₀ ≥ 20 m/s; In = 1; Out/Net = 0)
The theoretical maximum is 60 points: ten aces into five-point corners, each above 20 m/s. Accuracy tells you about reliability; target-hit rate tells you about precision. A player with 90% accuracy and 10% target hits is safe but predictable. A player with 60% accuracy and 40% target hits is dangerous but costly.
Benchmark tiers
| Tier | Score | Accuracy | Target hit | Avg deviation |
|---|---|---|---|---|
| Rookie | 0–11 | < 50% | < 10% | > 3.0 m |
| Developing | 12–23 | 50–70% | 10–30% | 2.0–3.0 m |
| Competitive | 24–35 | 70–85% | 30–50% | 1.3–2.0 m |
| Elite Server | 36+ | > 85% | > 50% | < 1.3 m |
These tiers are the same thresholds the arena uses when it grades your completed challenge.
Reading error patterns
Misses cluster in recognisable patterns, and each pattern points to a specific correction:
- Negative or near-zero clearance: launch angle is too low for your power. Raise the angle 2–3° before adding speed.
- Long outs with high clearance (> 0.8 m): too much angle or power. Reduce one, or enable topspin to pull the ball down.
- Wide outs: direction error. Deep corners leave little lateral margin, so aim 0.5–1 m inside the sideline.
- Consistent In but low target hits: the zone is being missed in a consistent direction. Check whether deviations are mostly short, long or sideways and adjust only that variable.
Dispersion and consistency
Average deviation hides an important detail: whether your misses are scattered or biased. Track the mean and standard deviation of landing distance separately:
mean offset = (1/n) · Σ (landing − target)
spread σ = √[ (1/(n−1)) · Σ (landing − mean)² ]
A large mean offset with small spread is good news: your technique is consistent and only the aim needs adjusting. A small mean with large spread means your aim is right but your execution varies — the fix is repetition at a single power level, as described in Power Control Mechanics.
Why ten serves is not enough on its own
Ten serves are ideal for a focused challenge but small for statistical certainty. For an accuracy rate of 70%, the standard error over ten serves is √(0.7 × 0.3 / 10) ≈ 0.145, so a 95% confidence interval runs from roughly 42% to 98%. Over 50 serves the interval narrows to about ±13 points. Treat single challenges as snapshots and judge progress over at least five sets.
A data-driven training loop
- Baseline: play three challenges with your natural style and record score, accuracy, target-hit rate and average power.
- Diagnose: identify the dominant error type using the patterns above.
- Isolate: change a single variable — angle, power or spin — for the next three sets.
- Compare: accept the change only if the average score or target-hit rate improves across all three sets.
- Escalate: once Competitive, switch targets toward higher-value zones using the expected-value method in Target Zone Strategy.
Try it: the arena's serve log records power, angle, clearance and deviation for every serve. Complete a set in the arena, then read your log against the healthy ranges above to find your first correction.