Garbage In - Garbage Out. The potential pitfalls of big data

The WIN Reality Acquisition of Blast Motion: Examining the Consolidation of Half a Billion Swings

By Ken Cherryhomes ©July 13, 2025

Sometimes Big Data Obscures (or Creates) Bigger Problems

If someone was offering to sell me a dataset containing nearly half a billion swings, my first instinct would not be to imagine what I could build with it. I would start by asking what the data was composed of. I mean, it sounds like an exciting offer, but I’d need to know more.

I’d need to know what kind of swings we’re even dealing with. Were they taken off a tee, short toss, front toss, or against velocity? Are we looking at youth players, high school, college, or professional hitters?

Were the swings captured during static or low constraint challenges, or were they taken against pitches with velocity requiring a timed decision? Are they bucketed based on their capture types, age of player or skill level? And finally, how can I make sense of this data so I can make it actionable?

What I do know is that the bulk of this data was captured using IMU-based hardware, with well-documented drift, calibration inconsistencies, and orientation error (1,4,5). I’ve done the research. These limitations are not speculative, they are published. Without clarity about how that error is tracked or corrected, it is not training data, it is noise dressed up as volume. A swing does not happen in a vacuum, and neither should the data used to analyze one.

So, when someone offers me a dataset with half a billion swings, the number isn’t my focus. The questions are. And the deeper I dig, the more concerns they raise.

Every issue I raised earlier about whether or how the data was bucketed, labeled, and structured is now amplified. I already knew the swings weren’t captured on a single system. They come from at least three distinct sources: Blast Motion, Diamond Kinetics (which Win Reality used from December 2020 to end of March 2023), and Win Reality’s internal sessions. Each used its own sampling rate, calibration logic, and error profile. Some were captured with bat-mounted IMUs, others through VR environments. None of it was built on a unified architecture or shared a common reference frame. And that creates a new layer of concern for the data’s integrity.

That matters. 

Even core metrics like barrel velocity aren’t directly measured. They’re inferred, and each system may infer them differently, using gyroscope filters, accelerometer-based dead reckoning, or motion path extrapolation. Even on a single system, velocity readings carry a plus-or-minus error margin of three miles per hour or more (2,3). A swing recorded at 70 mph might register anywhere between 67 and 73 mph on the same device. Add cross-platform variation, and the discrepancy grows.

Independent third-party testing confirmed this. Blast Motion reports a deviation of ±3 mph, while Diamond Kinetics shows ±5 mph when benchmarked against motion-capture systems (2,3). These aren’t trivial margins. They are built-in distortions. Without knowing exactly how each company defines and processes its velocity metric, you can’t compare them, you can’t combine them, and you can’t trust them (3,4,6).

Orientation data is no better. Vertical bat angle, attack angle, and horizontal bat angle all fluctuate with drift, inconsistent mounting, and flawed calibration (1,4,5). The result is rotational distortion presented as measurement.

A swing off a tee isn’t equivalent to one taken against velocity. A swing on an outside pitch would have a different horizontal orientation, attack angle and timestamp (swing time or time to collision) than one on the inside. But if the data doesn’t record those conditions, none of that nuance matters. All you get is a randomized report of swing time fluctuation without context.

Unlabeled swings can’t be treated as interchangeable. Without structure, it’s not a dataset. It’s a tangle of inputs with no map.

There is no framework for comparison. No indication the data was organized around intervention studies or player development stages. No accounting for the compounded inaccuracies across systems. Yet the dataset is treated as if every capture carries equal meaning and precision.

If those problems remain unresolved, then the size of the dataset becomes part of the problem. Scale doesn’t clarify noise. It multiplies it. I wouldn’t be buying insight. I’d be buying ambiguity, and more of it. I’d be getting aggregated, low-fidelity data that does not produce clarity. It hides error.

Misalignment of Intent and Capability

It’s important to distinguish ambition from capability. Win Reality’s recent statements signal an intention to use their vast new dataset to generate prescriptive training protocols for swing mechanics. But prescribing mechanical adjustments requires more than pattern recognition. It requires context. And the 500 million swings they’ve collected largely lack it.

The data’s inherent instability, with sensor-derived errors baked into the capture, would already be a challenge. But beyond that, we don’t know what proportion of the dataset comes from pitched balls versus tee work, front toss, or other static drills. There is no breakdown, no ranking, no transparency. And that’s a problem. Without knowing the distribution of contexts in which these swings were captured, you can’t determine how much of the mechanical data is shaped by decision-making constraints versus static repetition.

Yet Win Reality appears poised to produce deterministic mechanical prescriptions from this dataset, as if those variables don’t matter. They do. Mechanics change under timing pressure, and movement patterns captured in low-constraint conditions do not generalize cleanly to game-like environments (7). Without that contextual accounting, the dataset lacks the structural integrity needed for prescriptive use.

In VR, where swings are performed against simulated velocity and visual cues, those decision variables reenter the picture. Timing and urgency begin to affect swing execution, even if they’re not the focus of instruction.

This creates a problem. The mechanical recommendations Win Reality aims to produce will be based on a dataset that doesn’t reflect the full range of constraints present during decision-based swings. Movement patterns shift when a batter is under time pressure. Late decisions lead to altered barrel paths, and those altered mechanics can’t be separated from their cause (7).

So even if their intent is strictly mechanical, the deterministic use of this data for swing correction becomes compromised by the absence of ecological conditions, including perceived threat, performance stakes, and time pressure. Without the constraint of decision timing, mechanical prescriptions risk being built on incomplete inputs, turning context-specific movements into generalizable advice without justification.

The result isn’t precision. Its distortion dressed as guidance.

Data Consolidation: Structural Incompatibility

Merging these datasets is not simply a matter of formatting. The three systems in question used different definitions, different sampling rates, and different trigger mechanisms for measuring movement. Even if an AI system could ingest all of it, there is no unified reference framework to align one swing to another across systems.

This isn’t a dataset. It’s three datasets, loosely stitched together without a common spine, relying only on overlapping assumptions.

And because none of the original data streams were designed with interoperability in mind, even a highly trained model would be forced to interpret each input differently, then reconcile the outputs through abstraction. That’s not precision. That’s averaging uncertainty masquerading as insight.

Can AI Solve This?

That’s the hope, isn’t it? That AI will smooth over the fractures, organize the chaos, and convert half a billion unstructured swings into coherent training guidance. That it will find the needle of insight in the haystack of noise. But if you’ve followed this breakdown so far, you already know the answer.

AI doesn’t perform magic. It scales what it’s given. And if what it’s given is a mess, drift-prone IMU data, mismatched sampling rates, incompatible orientation assumptions, and swing captures with no labeled context, then what it scales is the noise (8). With sharper formatting.

It cannot reverse-engineer structure that was never recorded. It cannot assign swing intent if none was captured. It cannot tell whether a swing came off a tee or from a live pitch if the dataset doesn’t say so. It cannot determine whether the sensor was mounted correctly or whether the swing was reactive or scripted. AI cannot infer missing ground truth (8). That is not a processing limitation. It is a structural disqualification.

Even if you feed it all 500 million swings, a model trained on flawed inputs and ambiguous definitions doesn’t get smarter. It gets more confident in its guesswork. It might group shapes or cluster signals, but it cannot validate whether those clusters are grounded in real biomechanical traits or just artifacts of bad data. It builds patterns out of distortion, then mislabels them as insight.

And if that doesn’t work? Well, then I’d better have a smarter story to sell.

Now imagine this scenario: suppose I did the ethical thing, suppose I were to disclose to the AI that the data was flawed, came from three different sources, each with unique flawed measurements. What would it say?

“Before pattern recognition can begin, we must define what constitutes a reliable input. You’ve informed me that the data includes inconsistencies in sampling rate, uncorrected IMU drift, mismatched definitions for swing onset, and no contextual labeling of any kind. These are not surface-level inconsistencies. They are structural defects.

Any patterns I find will be shaped by those flaws. If orientation references are unstable, the clusters I produce will reflect rotational distortion. If swing velocities were derived through different filtering methods across systems, my statistical groupings will mirror those differences, not actual biomechanical variation. If events were recorded without metadata, I cannot distinguish one condition from another. I will detect relationships, but I cannot tell you whether they’re causal, coincidental, or corrupted (8).

I can cluster. I can correlate. But I cannot verify. The shapes I sort and the patterns I highlight will be anchored to the noise, not the signal.

If you proceed with training, any outputs must be interpreted with extreme caution. Without normalization, correction, or explicit metadata describing each input, my inferences will carry no grounded meaning. They will look clean. They may even sound intelligent. But they won’t be reliable.”

And if I didn’t tell the AI the data is flawed?

It would proceed as if it were clean. It will cluster, correlate, and offer guidance confidently. It will describe patterns. It will identify trends. It will justify its recommendations with impressive dashboards and statistical scores. And it will not know they are wrong. Because it was never told.

This is what people don’t understand. AI does not audit its inputs. It does not challenge the legitimacy of the data. It inherits it. It assumes fidelity and scales the assumptions. Not the skepticism.

If the data is flawed, the outputs will be flawed. Not subtly. Fundamentally. And no user will be warned unless the warning was built in.

That’s the risk with this acquisition. That those who don’t know what’s missing will trust what the model presents. That confidence will be mistaken for accuracy. And that polished error will pass for expertise.

That is why deterministic guidance from this dataset is not just technically out of reach, it is structurally impossible. Not because the AI lacks intelligence. But because the data lacks integrity.

If I had acquired this dataset hoping AI would redeem it, what I’d actually have is a very expensive pattern-matching engine. One that could mimic insight but never reach understanding. One that could scale confusion with confidence, but never create the solutions I had hoped it could create.

References

  1. Szymanski, D.J., et al. (2019). A biomechanical evaluation of bat sensors: Validity and reliability of two inertial measurement units. Journal of Sports Sciences, 37(15), 1722–1730.
    • Demonstrated angular orientation errors ranging from 4.2° to 7.6° depending on sensor mounting and grip. Confirmed that bat path and angle metrics drift significantly compared to motion capture baselines.
  1. Blast Motion. (n.d.). Bat Speed Testing – Third-party validation of swing sensor accuracy.
    • Verified that Blast Motion exhibited a ±3 mph average swing speed deviation compared to motion-capture benchmarks, while Diamond Kinetics showed ±5 mph and Zepp ±7 mph. Based on third-party testing conducted by the Center of Human Performance in San Diego under Arnel Aguinaldo.
    • URL : https://blastmotion.com/baseball/swing-analyzer/sensor-accuracy-validation
  1. Baseball Rebellion Lab (2018). Swing Sensor Accuracy Test: Blast vs. Diamond Kinetics vs. HitTrax.
    • Found that Blast Motion exhibited a ±3 mph variance in swing speed, and Diamond Kinetics showed a ±5 mph spread. Inconsistent readings were noted even within the same session and device.
    • URL: https://www.baseballrebellion.com/sensoraccuracy
  1. Camomilla, V., Bergamini, E., Fantozzi, S., & Vannozzi, G. (2018). Trends supporting the in-field use of wearable inertial sensors for sport performance evaluation: A systematic review. Sensors, 18(3), 873.
    • Systematic review confirmed that IMU-based systems exhibit measurement error of 5–10% for velocity and angular metrics without strict calibration. Noted sensitivity to grip, mounting variation, and environmental interference.
  1. Cutti, A.G., et al. (2008). Ambulatory measurement of shoulder and elbow kinematics through inertial and magnetic sensors. Medical & Biological Engineering & Computing, 46, 169–178.
    • Showed that gyroscopic drift leads to compounding orientation error, especially in dynamic tasks without external reference correction.
  1. Kellis, E., & Katis, A. (2007). Biomechanical characteristics and determinants of instep soccer kick. Journal of Sports Science & Medicine, 6(2), 154–165.
    • Used here to illustrate that differing sampling rates, trigger definitions, and filtering methods across motion capture systems invalidate cross-platform metric comparisons unless standardized.
  1. Gray, R. (2002). Behavior of college baseball players in a virtual batting task. Journal of Experimental Psychology: Human Perception and Performance, 28(5), 1131–1148.
    • Confirmed that swing mechanics change significantly under time pressure, pitch recognition, and decision-making constraints. Swings captured in static or tee conditions do not generalize to live pitch environments.
  1. Rahimi, A., & Recht, B. (2009). Reflections on randomized methods for machine learning. Neural Information Processing Systems (NIPS).
    • Introduced foundational critique of AI models trained on unstructured or noisy data, warning that such models can produce confident but ungrounded outputs—a concept commonly paraphrased as “garbage in, garbage out.”