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arxiv: 2604.19834 · v1 · submitted 2026-04-21 · 💻 cs.CV

Recognition: unknown

KD-Judge: A Knowledge-Driven Automated Judge Framework for Functional Fitness Movements on Edge Devices

Arun Iyengar, Fan Li, Lanyu Xu, Lucas Alves, Shaibal Saha, Yunge Li

Authors on Pith no claims yet

Pith reviewed 2026-05-10 03:31 UTC · model grok-4.3

classification 💻 cs.CV
keywords functional fitnessautomated judgingrule-based systemsedge devicespose estimationrepetition analysisknowledge-driven AILLM pipeline
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The pith

KD-Judge converts fitness rulebooks into executable code that a computer uses to judge exercise repetitions deterministically on edge devices.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper presents KD-Judge as a way to automate judging of functional fitness movements by turning unstructured rule standards into machine-readable instructions. It relies on large language models with retrieval and step-by-step reasoning to structure the rules, then applies them through pose analysis and kinematic checks to decide if each repetition is valid. This creates a transparent, rule-based alternative to opaque scoring models. Tests on the CFRep dataset show reliable rule structuring and accurate assessments that run faster than real time, with added caching that cuts computation sharply on hardware like the Jetson AGX Xavier.

Core claim

KD-Judge converts unstructured rulebook standards into executable representations using an LLM-based retrieval-augmented generation and chain-of-thought rule-structuring pipeline, incorporates the structured rules into a deterministic rule-based judging system with pose-guided kinematic reasoning to assess rep validity and temporal boundaries, and applies a dual caching strategy to achieve faster-than-real-time execution and substantial speedups on edge devices.

What carries the argument

The LLM-based retrieval-augmented generation and chain-of-thought pipeline that structures rules, combined with deterministic pose-guided kinematic reasoning and selective dual caching for edge efficiency.

If this is right

  • Reliable rule-structuring and accurate rep-level assessment on the CFRep dataset.
  • Faster-than-real-time execution with real-time factor below 1 on tested hardware.
  • Speedups of up to 3.36 times for pre-recorded videos and 15.91 times for live streams on resource-limited edge devices when caching is used.
  • Transparent and deterministic judgments that can complement human judging in training and competition settings.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same rule-structuring approach could apply to other rule-heavy domains such as gymnastics or weightlifting competitions where consistency matters.
  • Caching mechanisms for redundant pose computations might transfer to other real-time vision tasks on edge devices facing similar data streams.
  • Integration into fitness apps could provide immediate, rule-based feedback during workouts without needing constant cloud access.

Load-bearing premise

The LLM-based retrieval-augmented generation and chain-of-thought rule-structuring pipeline accurately converts unstructured rulebook standards into complete, error-free executable representations that match human intent.

What would settle it

A direct comparison on movements outside the CFRep dataset where the system's rep validity decisions are checked against a panel of human judges using the identical rulebooks, looking for systematic mismatches in boundary detection or validity calls.

Figures

Figures reproduced from arXiv: 2604.19834 by Arun Iyengar, Fan Li, Lanyu Xu, Lucas Alves, Shaibal Saha, Yunge Li.

Figure 1
Figure 1. Figure 1: Redundancy analysis motivating dual strategy cache [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 3
Figure 3. Figure 3: Overview of Stage 1 RAG pipeline for converting [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Overview of Stage 3 Judge System: The judge system [PITH_FULL_IMAGE:figures/full_fig_p005_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Overview of dual strategy cache mechanism. Frame [PITH_FULL_IMAGE:figures/full_fig_p006_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Cosine similarity threshold comparison for IF3 and [PITH_FULL_IMAGE:figures/full_fig_p008_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Rep-level latency and speedup (× relative to the w/o cache baseline) across different pose estimation models using cache-based techniques on edge devices. W/o Cache DC RTC Combined RTF=1 HRNet-W32 RTMPose-L RTMPose-X RTMO-L 0.0 1.0 1.2 RTF (a) RTX 3080 HRNet-W32 RTMPose-L RTMPose-X RTMO-L 0 1 2 RTF (b) AGX Xavier [PITH_FULL_IMAGE:figures/full_fig_p011_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: RTF analysis across pose models with caching strate [PITH_FULL_IMAGE:figures/full_fig_p011_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: Adaptability analysis of KD-Judge on double under. [PITH_FULL_IMAGE:figures/full_fig_p011_9.png] view at source ↗
read the original abstract

Functional fitness movements are widely used in training, competition, and health-oriented exercise programs, yet consistently enforcing repetition (rep) standards remains challenging due to subjective human judgment, time constraints, and evolving rules. Existing AI-based approaches mainly rely on learned scoring or reference-based comparisons and lack explicit rule-based, limiting transparency and deterministic rep-level validation. To address these limitations, we propose KD-Judge, a novel knowledge-driven automated judging framework for functional fitness movements. It converts unstructured rulebook standards into executable, machine-readable representations using an LLM-based retrieval-augmented generation and chain-of-thought rule-structuring pipeline. The structured rules are then incorporated by a deterministic rule-based judging system with pose-guided kinematic reasoning to assess rep validity and temporal boundaries. To improve efficiency on edge devices, including a high-performance desktop and the resource-constrained Jetson AGX Xavier, we introduce a dual strategy caching mechanism that can be selectively applied to reduce redundant and unnecessary computation. Experiments demonstrate reliable rule-structuring performance and accurate rep-level assessment, with judgment evaluation conducted on the CFRep dataset, achieving faster-than-real-time execution (real-time factor (RTF) < 1). When the proposed caching strategy is enabled, the system achieves up to 3.36x and 15.91x speedups on resource-constrained edge device compared to the non-caching baseline for pre-recorded and live-streaming scenarios, respectively. These results show that KD-Judge enables transparent, efficient, and scalable rule-grounded rep-level analysis that can complement human judging in practice.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 0 minor

Summary. The paper introduces KD-Judge, a knowledge-driven framework for automated judging of functional fitness movements. It uses an LLM-based retrieval-augmented generation and chain-of-thought pipeline to convert unstructured rulebook standards into executable machine-readable representations. These structured rules feed a deterministic rule-based judging system that performs pose-guided kinematic reasoning to determine repetition validity and temporal boundaries. A dual caching strategy is proposed to reduce redundant computation on edge devices. Evaluation on the CFRep dataset reports faster-than-real-time execution (RTF < 1) and speedups of up to 3.36x (pre-recorded) and 15.91x (live-streaming) on a Jetson AGX Xavier compared to a non-caching baseline.

Significance. If the rule-structuring step is shown to faithfully capture human intent, the framework would provide a transparent, deterministic alternative to learned or reference-based scoring methods for fitness assessment. The caching mechanism directly addresses deployment constraints on resource-limited hardware, potentially enabling practical use in training, competition, or health programs where real-time rule enforcement is needed.

major comments (2)
  1. [Abstract] Abstract: The claims of 'reliable rule-structuring performance' and 'accurate rep-level assessment' are presented without any quantitative metrics (condition-level precision, human-expert agreement, failure-case analysis, or baseline comparisons). This is load-bearing for the central claim because the deterministic kinematic judgments rest entirely on the fidelity of the LLM+RAG+CoT translation step; a systematic mis-mapping of temporal or kinematic constraints would invalidate all downstream results.
  2. [Experiments] Experiments section: No dataset details (number of movements, rules, ground-truth annotations, or split statistics) or error analysis for the CFRep evaluation are supplied, preventing assessment of whether the reported speedups and RTF < 1 actually support the accuracy claims under realistic rule variations.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive and detailed comments on our manuscript. These observations highlight important aspects of clarity and substantiation that will strengthen the paper. We provide point-by-point responses below and will revise the manuscript to address the concerns.

read point-by-point responses
  1. Referee: [Abstract] Abstract: The claims of 'reliable rule-structuring performance' and 'accurate rep-level assessment' are presented without any quantitative metrics (condition-level precision, human-expert agreement, failure-case analysis, or baseline comparisons). This is load-bearing for the central claim because the deterministic kinematic judgments rest entirely on the fidelity of the LLM+RAG+CoT translation step; a systematic mis-mapping of temporal or kinematic constraints would invalidate all downstream results.

    Authors: We acknowledge that the abstract asserts reliable rule-structuring and accurate assessment without accompanying quantitative metrics, and that this is a critical point given the reliance on the LLM+RAG+CoT pipeline for downstream determinism. While the CFRep dataset evaluation provides end-to-end evidence of rep-level performance, we agree that direct metrics for the structuring step are necessary to fully support the claims. In the revised manuscript, we will add quantitative results including condition-level precision/recall for rule extraction, human-expert agreement scores on structured rules, failure-case analysis of mis-mapped constraints, and comparisons to baseline rule-structuring approaches. These will be incorporated into the Experiments section, with the abstract updated to reference the new metrics. revision: yes

  2. Referee: [Experiments] Experiments section: No dataset details (number of movements, rules, ground-truth annotations, or split statistics) or error analysis for the CFRep evaluation are supplied, preventing assessment of whether the reported speedups and RTF < 1 actually support the accuracy claims under realistic rule variations.

    Authors: We agree that the Experiments section lacks sufficient dataset specifics and error analysis, which limits evaluation of how the accuracy claims hold under rule variations alongside the efficiency results. The current text references the CFRep dataset for judgment evaluation but omits details on the number of movements and rules, ground-truth annotation process, split statistics, and any error breakdown. In the revision, we will expand the section to include these elements: dataset composition (movements, rules, and variations), annotation methodology and inter-annotator reliability, data splits, and error analysis (e.g., accuracy stratified by movement type or rule complexity). This will enable readers to assess whether the RTF < 1 and speedups (3.36x pre-recorded, 15.91x live) are supported by robust accuracy under realistic conditions. revision: yes

Circularity Check

0 steps flagged

No circularity in derivation chain

full rationale

The paper describes an LLM RAG+CoT pipeline that converts external rulebooks into executable rules, followed by a deterministic pose-based kinematic judge and a caching optimization, all evaluated on the independent CFRep dataset with measured RTF and speedup numbers on Jetson hardware. No equations, parameters, or claims reduce by construction to their own inputs; there are no self-citations that bear the central load, no fitted quantities renamed as predictions, and no ansatz or uniqueness results imported from prior author work. The performance assertions are grounded in external data and timing measurements rather than tautological re-derivations.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The framework depends on standard assumptions about pose estimation reliability and LLM rule extraction fidelity but introduces no explicit free parameters, new physical entities, or ad-hoc axioms beyond domain-standard computer vision and language model capabilities.

axioms (2)
  • domain assumption Pose estimation from video provides sufficiently accurate kinematic data for validating fitness movement rules.
    The judging system relies on pose-guided kinematic reasoning to determine rep validity and temporal boundaries.
  • domain assumption LLM retrieval-augmented generation with chain-of-thought produces faithful machine-readable rule representations from unstructured text.
    Central pipeline step for converting rulebooks into executable form.

pith-pipeline@v0.9.0 · 5597 in / 1437 out tokens · 67578 ms · 2026-05-10T03:31:38.741798+00:00 · methodology

discussion (0)

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