myogait
Markerless video-based gait analysis toolkit.
Author: Frederic Fer, Institut de Myologie (f.fer@institut-myologie.org)
Quick Start
The validated end-to-end pipeline in one call — works on a video, a
pre-extracted .myogait.json, or a .c3d optical-capture file:
import myogait as mg
result = mg.run_pipeline("walk.mp4", model="sapiens2-quick")
result["stats"] # cadence, stance %, ROM, symmetry, ...
result["cycles"] # normalized gait cycles (0-100%)
result["quality"]["warnings"] # anything that should temper interpretation
run_pipeline applies the benchmarked defaults (Butterworth 4 Hz,
flexion-positive sign convention independent of walking direction, Zeni
events, physiological cycle window, direction-consistent cycle filter)
and reports quality diagnostics — tracking coverage, out-of-plane
distortion, insufficient cycle counts — instead of failing silently.
Every step remains available individually; see the
tutorial.
Validation
Sagittal joint angles over the gait cycle: myogait from a single lateral video (blue) vs marker-based optical capture (black), mean ± SD pooled over three healthy adults (~30 paired trials each side). Waveforms and peak timings superimpose across all three joints; the small hip offset is a stable zero-definition difference, calibratable per site.
myogait's sagittal kinematics have been validated against optical motion capture (Vicon, marker-based) on healthy adults across two independent laboratories, two camera types and two pose-model generations (fixed lateral action camera at 60 fps and a consumer smartphone), plus neuromuscular patients:
| Measure | Agreement with optical capture |
|---|---|
| Waveform correlation (hip / knee / ankle) | r = 0.99 / 0.98 / 0.90 |
| Curve RMSE after zero-offset removal | 2.4 – 4.0° |
| Stride time | bias 0.00 s, LoA ± 0.03 s |
| Cadence | bias 0.9 steps/min, LoA ± 3.3 |
| Stance phase | bias 0.5 %, LoA ± 2.4 |
| Knee ROM | bias −0.7°, LoA ± 5.3° |
| Peak-timing error (hip / knee) | ≤ 2 % of the gait cycle |
| Peak knee angular velocity | bias −3°/s on ~290°/s (≈ 1 %) |
Repeatability (within-subject, per-cycle SD) supports a minimal detectable change below 5° for hip and knee parameters when ~5–10 cycles are averaged (about three walkway passes). Absolute ankle peak angles are the least robust output on 2-D video — ankle ROM and waveform shape are reliable; treat absolute ankle values as screening-grade.
Figures above are means over 100+ paired video–optical trials (>500 gait cycles). The full accuracy reference (Bland-Altman per parameter, MDC vs number of cycles, per-phase error profiles) ships as a PDF report generated by the validation harness.
Features
Pose estimation
- 11 interchangeable backends — MediaPipe, YOLO, Sapiens (3 sizes), Sapiens 2 (4 sizes), ViTPose, RTMW, HRNet, RTMPose, OpenPose, AlphaPose, Detectron2 — behind one API;
available_models()reports what is installed without importing anything heavy - Monocular depth and 28/29-class body-part segmentation (Sapiens / Sapiens 2)
Gait analysis
- Sagittal joint angles with a walking-direction-independent, flexion-positive convention
- Gait events (Zeni, crossing, velocity, O'Connor + gaitkit detectors), cycle segmentation with duration and quality gates (landmark confidence / frame coherence)
- Spatio-temporal parameters (cadence, stride time, stance %), symmetry and variability indices, harmonic ratio, step length and walking speed with configurable anthropometric scaling (
femur_mm,foot_mm,femur_ratio) - Pathology screening (Trendelenburg, spastic, steppage, crouch) and biomechanical range validation
Quality & reference data
- Per-frame biomechanical coherence scoring; built-in quality diagnostics in
run_pipeline - Empirical adult normative curves (optical motion capture) with per-phase SD
- C3D reference support: marker-convention autodetection, isotropic loading, 3-D ankle reference, CMC / RMSE / Bland-Altman benchmark metrics
Output
- Publication-quality plots, multi-page PDF clinical report
- Export to CSV, Excel, OpenSim (
.mot/.trc), C3D - CLI (
extract,run,analyze,batch,download,info) and YAML/JSON pipeline configuration
Installation
pip install myogait
Install with a specific pose estimation backend:
pip install myogait[mediapipe] # MediaPipe (lightweight, CPU)
pip install myogait[yolo] # YOLO via Ultralytics
pip install myogait[sapiens] # Sapiens v1 (Meta AI) + Intel Arc GPU support
pip install myogait[sapiens2] # Sapiens 2 (Meta AI, ICLR 2026) — see "Sapiens 2" section below for one-shot setup
pip install myogait[vitpose] # ViTPose via HuggingFace Transformers
pip install myogait[rtmw] # RTMW 133-keypoint whole-body
pip install myogait[mmpose] # HRNet / RTMPose via MMPose
pip install myogait[alphapose] # AlphaPose FastPose
pip install myogait[detectron2] # Detectron2 Keypoint R-CNN
pip install myogait[all] # All backends
Supported Pose Estimation Backends
| Backend | Install | Notes |
|---|---|---|
| MediaPipe | pip install myogait[mediapipe] |
Fast, good for real-time. 33 landmarks |
| YOLOv8-Pose | pip install myogait[yolo] |
Fast, robust. 17 COCO keypoints |
| ViTPose | pip install myogait[vitpose] |
State-of-the-art accuracy |
| Sapiens | pip install myogait[sapiens] |
Meta model, depth estimation |
| Sapiens 2 | pip install myogait[sapiens2] |
Meta ICLR 2026, +4 mAP, 4K support |
| RTMPose/RTMLib | pip install myogait[rtmw] |
Real-time, ONNX optimized |
| MMPose | pip install myogait[mmpose] |
Academic reference, many models |
| OpenPose | Built-in (OpenCV DNN) | Historical baseline, bottom-up. 17 COCO keypoints |
| AlphaPose | pip install myogait[alphapose] |
Top-down baseline, biomechanics standard |
| Detectron2 | pip install myogait[detectron2] |
Meta academic baseline, Keypoint R-CNN |
GPU Support
All models support NVIDIA CUDA GPUs. Sapiens and ViTPose also support
Intel Arc / Xe GPUs (via intel-extension-for-pytorch).
| Model | CUDA | Intel Arc (XPU) | CPU |
|---|---|---|---|
| MediaPipe | — | — | yes |
| YOLO | yes | — | yes |
| Sapiens (pose, depth, seg) | yes | yes | yes |
| Sapiens 2 (pose, depth, seg) | yes | yes | yes |
| ViTPose | yes | yes | yes |
| RTMW | yes (onnxruntime) | — | yes |
| HRNet / RTMPose | yes | — | yes |
| OpenPose | yes (OpenCV DNN) | — | yes |
| AlphaPose | yes | yes | yes |
| Detectron2 | yes | — | yes |
Supported Pose Models
| Name | Keypoints | Format | Backend | Install |
|---|---|---|---|---|
mediapipe |
33 | MediaPipe | Google MediaPipe Tasks (heavy) | pip install myogait[mediapipe] |
yolo |
17 | COCO | Ultralytics YOLOv8-Pose | pip install myogait[yolo] |
sapiens-quick |
17 COCO + 308 Goliath | COCO | Meta Sapiens 0.3B (336M params) | pip install myogait[sapiens] |
sapiens-mid |
17 COCO + 308 Goliath | COCO | Meta Sapiens 0.6B (664M params) | pip install myogait[sapiens] |
sapiens-top |
17 COCO + 308 Goliath | COCO | Meta Sapiens 1B (1.1B params) | pip install myogait[sapiens] |
sapiens2-quick |
17 COCO + 308 Goliath | COCO | Meta Sapiens 2 0.4B (ICLR 2026) | pip install myogait[sapiens2] |
sapiens2-mid |
17 COCO + 308 Goliath | COCO | Meta Sapiens 2 0.8B | pip install myogait[sapiens2] |
sapiens2-top |
17 COCO + 308 Goliath | COCO | Meta Sapiens 2 1B | pip install myogait[sapiens2] |
sapiens2-ultra |
17 COCO + 308 Goliath | COCO | Meta Sapiens 2 5B | pip install myogait[sapiens2] |
vitpose |
17 | COCO | ViTPose-base (HuggingFace) | pip install myogait[vitpose] |
vitpose-large |
17 | COCO | ViTPose+-large (HuggingFace) | pip install myogait[vitpose] |
vitpose-huge |
17 | COCO | ViTPose+-huge (HuggingFace) | pip install myogait[vitpose] |
rtmw |
17 COCO + 133 whole-body | COCO | RTMW via rtmlib | pip install myogait[rtmw] |
hrnet |
17 | COCO | HRNet-W48 via MMPose | pip install myogait[mmpose] |
mmpose |
17 | COCO | RTMPose-m via MMPose | pip install myogait[mmpose] |
openpose |
17 | COCO | CMU OpenPose via OpenCV DNN | Built-in |
alphapose |
17 | COCO | AlphaPose FastPose (ResNet-50) | pip install myogait[alphapose] |
detectron2 |
17 | COCO | Keypoint R-CNN (R50-FPN, 3x) | pip install myogait[detectron2] |
Sapiens Auxiliary Models
In addition to pose, Sapiens provides depth estimation and body-part segmentation. These run alongside any Sapiens pose model to enrich per-landmark data.
Depth Estimation
Monocular relative depth. Per-landmark depth values (closer = higher)
are stored in each frame as landmark_depths.
| Size | HuggingFace repo |
|---|---|
| 0.3b | facebook/sapiens-depth-0.3b-torchscript |
| 0.6b | facebook/sapiens-depth-0.6b-torchscript |
| 1b | facebook/sapiens-depth-1b-torchscript |
| 2b | facebook/sapiens-depth-2b-torchscript |
Body-Part Segmentation
28-class segmentation (face, torso, arms, legs, hands, feet, clothing...).
Per-landmark body-part labels are stored in each frame as landmark_body_parts.
| Size | mIoU | HuggingFace repo |
|---|---|---|
| 0.3b | 76.7 | facebook/sapiens-seg-0.3b-torchscript |
| 0.6b | 77.8 | facebook/sapiens-seg-0.6b-torchscript |
| 1b | 79.9 | facebook/sapiens-seg-1b-torchscript |
Sapiens 2 (ICLR 2026)
Sapiens 2 improves over v1 with +4 mAP (pose), +24.3 mIoU (seg), and 45.6%
lower angular error (normals). Same Goliath 308 keypoint layout as v1.
Requires torch>=2.7 and safetensors.
| Size | HuggingFace pose repo | HuggingFace depth repo | HuggingFace seg repo |
|---|---|---|---|
| 0.4b | facebook/sapiens2-pose-0.4b |
facebook/sapiens2-depth-0.4b |
facebook/sapiens2-seg-0.4b |
| 0.8b | facebook/sapiens2-pose-0.8b |
facebook/sapiens2-depth-0.8b |
facebook/sapiens2-seg-0.8b |
| 1b | facebook/sapiens2-pose-1b |
facebook/sapiens2-depth-1b |
facebook/sapiens2-seg-1b |
| 5b | facebook/sapiens2-pose-5b |
facebook/sapiens2-depth-5b |
facebook/sapiens2-seg-5b |
Sapiens 2 segmentation uses 29 classes (adds Eyeglass at index 2).
Plug-and-play setup
Meta ships Sapiens 2 weights as .safetensors and the Python package that
rebuilds the model architecture lives only on GitHub (not PyPI).
myogait ships a one-shot helper that handles the bridge:
# 1) myogait + Sapiens 2 runtime deps
pip install myogait[sapiens2]
# 2) one-shot setup: installs Meta `sapiens` from GitHub, downloads the
# weights, traces a TorchScript .pt2 cached in ~/.myogait/models/.
# From now on inference no longer needs the Meta package.
myogait setup-sapiens2 --size 0.4b --cleanup-safetensors
Once that command finishes, mg.extract(..., model="sapiens2-quick")
loads the cached .pt2 directly — no Meta package required, no internet
on subsequent runs. Repeat for --size 0.8b, 1b, 5b if you want
the larger variants. The .pt2 is device-specific (constants get
baked at trace time), so the helper traces on the device myogait will
use at inference (CUDA > XPU > CPU, in that order).
If you prefer to keep the Meta sapiens package around (e.g. for
research code that imports it directly), drop the --uninstall-sapiens
flag — it stays installed but is not on the inference path anymore.
Usage
# Sapiens v1 — pose + depth + segmentation
myogait extract video.mp4 -m sapiens-quick --with-depth --with-seg
# Sapiens 2 — same API, better accuracy
myogait extract video.mp4 -m sapiens2-top --with-depth --with-seg
# Python
from myogait import extract
data = extract("video.mp4", model="sapiens2-top", with_depth=True, with_seg=True)
End-to-end demo (extract + overlay + side-by-side + angle plots)
python examples/sapiens2_compare_pipeline.py path/to/video.mp4 --out-dir out
Produces in out/:
<stem>_<model>.json— pivot data per model (mediapipe, sapiens-quick, sapiens2-quick), reused on subsequent runs<stem>_<model>.mp4— skeleton overlay per modelcompare_3way_slow.mp4— three panels side-by-side at half-speed with legends and a darkened background so the skeleton stands outcompare_angles.png— per-cycle hip / knee / ankle curves on left and right side, every cycle thin + each model's mean thick
The skeleton-on-video alignment honours data["frames"][i]["frame_idx"],
so the auto-cropped intro of long recordings is rendered correctly across
all models.
Experimental Input Degradation (robustness studies)
myogait includes an experimental pre-extraction degradation layer for
controlled robustness studies (frame-rate, resolution, contrast, perspective).
By default, it is disabled and applies no modification.
Python API:
from myogait import extract
data = extract(
"video.mp4",
model="mediapipe",
experimental={
"enabled": True,
"target_fps": 15.0, # frame-rate degradation
"downscale": 0.6, # spatial degradation
"contrast": 0.7, # contrast degradation
"aspect_ratio": 1.2, # non-square stretch
"perspective_x": 0.2, # side-like perspective skew
"perspective_y": 0.1, # forward/backward tilt skew
},
)
CLI:
myogait extract video.mp4 \
--exp-enable \
--exp-target-fps 15 \
--exp-downscale 0.6 \
--exp-contrast 0.7 \
--exp-aspect-ratio 1.2 \
--exp-perspective-x 0.2 \
--exp-perspective-y 0.1
Experimental VICON Alignment (Single Video)
For validation workflows, you can align one myogait result with one VICON trial and attach ground-truth comparison metrics to the JSON. This is experimental and disabled by default in the standard pipeline.
from myogait import run_single_trial_vicon_benchmark
data = run_single_trial_vicon_benchmark(
data, # myogait result dict
trial_dir="/path/to/trial_01_1", # contains *.mat files
vicon_fps=200.0,
max_lag_seconds=10.0,
)
# Results in data["experimental"]["vicon_benchmark"]
Experimental Single-Pair Benchmark Runner
You can run a full benchmark grid on one (video, vicon_trial) pair and
generate:
- one JSON per run (
<output_dir>/runs/*.json) - one CSV summary (
<output_dir>/benchmark_summary.csv) - one manifest (
<output_dir>/benchmark_manifest.json)
from myogait import run_single_pair_benchmark
manifest = run_single_pair_benchmark(
video_path="video.mp4",
vicon_trial_dir="/path/to/trial_01_1",
output_dir="./benchmark_out",
benchmark_config={
"models": ["mediapipe", "yolo"], # or "all"
"event_methods": "all", # or ["zeni", "gk_zeni", ...]
"normalization_variants": [
{"name": "none", "enabled": False, "kwargs": {}},
{"name": "butterworth", "enabled": True, "kwargs": {"filters": ["butterworth"]}},
],
"degradation_variants": [
{"name": "none", "experimental": {"enabled": False}},
{"name": "lowres", "experimental": {"enabled": True, "downscale": 0.7, "target_fps": 15.0}},
],
"continue_on_error": True,
},
)
print(manifest["summary_csv"])
This runner is experimental and intended for validation studies against an optical reference.
References
- Sapiens v1: Rawal et al., Sapiens: Foundation for Human Vision Models, ECCV 2024 — arXiv:2408.12569 — Code — Models
- Sapiens 2: Rawal et al., Sapiens 2: A Human Foundation Model, ICLR 2026 — arXiv:2604.21681 — Code — Models
ViTPose
Vision Transformer for pose estimation (NeurIPS 2022). Top-down architecture with RT-DETR person detector. Fully pip-installable via HuggingFace Transformers.
| Variant | Size | HuggingFace repo |
|---|---|---|
vitpose (base) |
90M | usyd-community/vitpose-base-simple |
vitpose-large |
400M | usyd-community/vitpose-plus-large |
vitpose-huge |
900M | usyd-community/vitpose-plus-huge |
- Paper: Xu et al., ViTPose: Simple Vision Transformer Baselines for Human Pose Estimation, NeurIPS 2022 — arXiv:2204.12484
- Paper: Xu et al., ViTPose++: Vision Transformer for Generic Body Pose Estimation, TPAMI 2024 — arXiv:2212.04246
RTMW (Whole-Body 133 Keypoints)
Real-Time Multi-person Whole-body estimation: body (17) + feet (6) + face (68) + hands (42) = 133 keypoints. Uses rtmlib (lightweight ONNX inference, no MMPose required).
| Mode | Pose Model | Speed |
|---|---|---|
performance |
RTMW-x-l 384x288 | Slower, most accurate |
balanced |
RTMW-x-l 256x192 | Default |
lightweight |
RTMW-l-m 256x192 | Fastest |
- Paper: Jiang et al., RTMPose: Real-Time Multi-Person Pose Estimation based on MMPose, 2023
- RTMW configs: MMPose cocktail14
- rtmlib: github.com/Tau-J/rtmlib
Other Pose Models
MediaPipe
Google's MediaPipe PoseLandmarker — 33 landmarks with full-body coverage. Uses the heavy model variant (most accurate). Auto-downloaded on first use.
YOLO Pose
Ultralytics YOLOv8-Pose — 17 COCO keypoints, fast single-shot detection.
- Docs: docs.ultralytics.com
HRNet / RTMPose (MMPose)
HRNet-W48 and RTMPose-m via the OpenMMLab MMPose framework — 17 COCO keypoints.
- MMPose: github.com/open-mmlab/mmpose
- HRNet: Sun et al., Deep High-Resolution Representation Learning for Visual Recognition, TPAMI 2019
- RTMPose: Jiang et al., RTMPose: Real-Time Multi-Person Pose Estimation based on MMPose, 2023
OpenPose
CMU OpenPose — historical bottom-up baseline, 17 COCO keypoints via OpenCV DNN. No extra dependency needed (uses OpenCV DNN, included in core install). Model auto-downloaded on first use (~200 MB).
- Paper: Cao et al., Realtime Multi-Person 2D Pose Estimation using Part Affinity Fields, CVPR 2017
- Code: github.com/CMU-Perceptual-Computing-Lab/openpose
AlphaPose
AlphaPose FastPose (ResNet-50) — top-down baseline widely used in biomechanics. Uses YOLO person detection + heatmap-based pose estimation. Supports both the official AlphaPose library and a fallback PyTorch reimplementation.
- Paper: Fang et al., AlphaPose: Whole-Body Regional Multi-Person Pose Estimation and Tracking in Real-Time, TPAMI 2022
- Code: github.com/MVIG-SJTU/AlphaPose
Detectron2 / Keypoint R-CNN
Meta's Detectron2 with Keypoint R-CNN (ResNet-50-FPN, 3x schedule) — academic baseline. Built-in person detection and 17 COCO keypoint estimation in a single pass.
- Paper: Wu et al., Detectron2, 2019 ; He et al., Mask R-CNN, ICCV 2017
- Code: github.com/facebookresearch/detectron2
Tutorials & Examples
Basic Pipeline
The core workflow extracts pose landmarks from video, preprocesses the signal, computes joint kinematics, detects gait events, and derives spatio-temporal parameters.
from myogait import extract, normalize, compute_angles, detect_events
from myogait import segment_cycles, analyze_gait
# 1. Extract landmarks from video
data = extract("walking_video.mp4", model="mediapipe")
# 2. Preprocess: filter noise, handle gaps
data = normalize(data, filters=["butterworth"])
# 3. Compute joint angles (sagittal + frontal if depth available)
data = compute_angles(data)
# 4. Detect gait events (heel strikes, toe offs)
data = detect_events(data, method="gk_bike") # uses gaitkit Bayesian detector
# 5. Segment into gait cycles
cycles = segment_cycles(data)
# 6. Compute spatio-temporal parameters
stats = analyze_gait(data, cycles)
print(f"Cadence: {stats['spatiotemporal']['cadence_steps_per_min']:.1f} steps/min")
print(f"Walking speed: {stats['walking_speed']['speed_mean']:.2f} m/s")
Clinical Scores
Compute standardized gait quality indices used in clinical gait analysis laboratories worldwide.
from myogait import gait_profile_score_2d, sagittal_deviation_index
from myogait import gait_variable_scores, movement_analysis_profile
# GPS-2D: overall gait quality score (RMS deviation from normative)
gps = gait_profile_score_2d(cycles)
print(f"GPS-2D: {gps['gps_2d_overall']:.1f}")
# SDI: Sagittal Deviation Index (0-120, 100 = normal)
# Note: This is a z-score based index, NOT the GDI (Schwartz & Rozumalski 2008).
sdi = sagittal_deviation_index(cycles)
print(f"SDI: {sdi['gdi_2d_overall']:.1f}")
# Per-joint deviation scores
gvs = gait_variable_scores(cycles)
for side in ("left", "right"):
for joint, score in gvs[side].items():
print(f" {side} {joint}: {score:.1f}")
Data Quality Assessment
Evaluate landmark detection confidence and flag outliers before running the analysis pipeline.
from myogait import confidence_filter, detect_outliers, data_quality_score
from myogait import frame_coherence_score
# Filter low-confidence landmarks
data = confidence_filter(data, threshold=0.3)
# Detect and interpolate outliers
data = detect_outliers(data, z_thresh=3.0)
# Quality report
quality = data_quality_score(data)
print(f"Quality score: {quality['score']}/100")
# Per-frame coherence scoring (z-score based, adapts to any FPS)
data = frame_coherence_score(data)
print(f"Mean coherence: {data['coherence_summary']['mean']:.3f}")
print(f"Low frames: {data['coherence_summary']['low_coherence_frames']}")
Sagittal drift correction (opt-in)
Long recordings with a fixed camera show a slow angular drift (projection
artifact as the subject's distance to the camera changes): hip angles can
slide by 10–30° from the first to the last cycle. apply_linear_detrend()
(myogait.corrections) fits and removes that linear drift per joint while
preserving the anatomical mean and per-cycle ROM.
from myogait.corrections import apply_linear_detrend
data = apply_linear_detrend(data) # after compute_angles()
or via the CLI: myogait analyze video.json --detrend.
Caveat: the correction family in this module was calibrated on healthy
adults; on pathological gait a real kinematic drift can be part of the
clinical picture. Keep the flag off by default and compare with/without
before drawing clinical conclusions (see the warnings at the top of
myogait/corrections.py).
Normative Comparison
Compare patient kinematics against published normative reference bands (Perry & Burnfield).
from myogait import plot_normative_comparison, get_normative_band
# Plot patient vs normative bands (Perry & Burnfield)
fig = plot_normative_comparison(data, cycles, plane="both")
fig.savefig("normative_comparison.png", dpi=150)
# Access raw normative data
band = get_normative_band("hip", stratum="adult")
mean, lower, upper = band["mean"], band["lower"], band["upper"]
Event Detection with gaitkit
myogait integrates multiple gait event detection algorithms, including Bayesian and ensemble methods from the gaitkit library.
from myogait import detect_events, event_consensus, list_event_methods
# List all available methods
print(list_event_methods())
# ['zeni', 'velocity', 'crossing', 'oconnor',
# 'gk_bike', 'gk_zeni', 'gk_ensemble', ...]
# Single method (gaitkit Bayesian BIS -- best F1 score)
data = detect_events(data, method="gk_bike")
# Consensus: vote across multiple detectors
data = event_consensus(data, methods=["gk_bike", "gk_zeni", "gk_oconnor"])
The neural detectors gk_intellevent and gk_deepevent additionally
require onnxruntime (or onnxruntime-directml on Windows without
CUDA). Install with pip install onnxruntime — the other detectors
work without it and out of the box.
Metric calibration — measured anthropometrics preferred over height
analyze_gait(), step_length() and walking_speed() accept
femur_mm (femur length) and foot_mm (foot length, heel → longest
toe) in addition to height_m. The scale hierarchy is:
- Femur + foot together: the two independent scale estimates are averaged for the tightest calibration (recommended for research).
- Femur alone (
femur_mm): use the measured femur directly. - Foot alone (
foot_mm): use the measured foot directly. - Height (
height_m): fallback, derives femur as 24.5 % of height. - Nothing → output in image-normalised units.
# Best: both measurements
stats = mg.analyze_gait(data, cycles, femur_mm=442, foot_mm=265)
# Quick-fix: femur only
stats = mg.analyze_gait(data, cycles, femur_mm=442)
# Fallback: height
stats = mg.analyze_gait(data, cycles, height_m=1.68)
Per-cycle biomarker export (Excel)
export_excel() emits a Biomarkers_per_cycle sheet with one row per
detected cycle: ROM, min / max / mean per joint, peak angular velocity
(deg/s), peak angular acceleration (deg/s²), phase-restricted peaks
(stance vs swing separately), plus the SCI-relevant clinical markers
(foot drop = ankle at HS, stiff-knee = peak knee flex in swing,
toe-clearance = min ankle in swing) and the swing-peak knee timing.
Makes per-cycle variability directly visible without post-processing.
mg.export_excel(data, "report.xlsx", cycles=cycles, stats=stats)
C3D loading with automatic marker-convention detection
load_c3d() reads any C3D file and returns a myogait-compatible pivot
dict. When marker_mapping is omitted the function autodetects the
convention among the registered families (Plug-in Gait, ISB, Helen
Hayes, ...) by scoring how many lower-limb markers each convention can
resolve, and falls back to a regex-based fuzzy match on the raw labels
if no registered convention scores high enough.
data = mg.load_c3d("trial.c3d") # autodetect
data["extraction"]["c3d_convention"] # → 'plug_in_gait' | 'iso_biomechanics' | ...
data["extraction"]["c3d_convention_scores"] # per-convention resolution count
# List / inspect / extend
list(mg.C3D_MARKER_CONVENTIONS.keys())
mg.C3D_MARKER_CONVENTIONS["plug_in_gait"]["LEFT_HIP"] # ['LASI', 'LPSI', 'LHJC']
# Autodetect just the convention (without loading the trajectories)
name, mapping, scores = mg.detect_c3d_convention(labels)
New conventions can be registered by editing
myogait.experimental_vicon.C3D_MARKER_CONVENTIONS (flat dict, keyed
by myogait landmark name).
Export to OpenSim / Pose2Sim
Export landmarks and kinematics in formats compatible with OpenSim musculoskeletal modeling and Pose2Sim multi-camera triangulation.
from myogait import export_trc, export_mot, export_openpose_json
from myogait import export_opensim_scale_setup, export_ik_setup
# OpenSim .trc markers file (with height-based unit conversion)
export_trc(data, "markers.trc", opensim_model="gait2392")
# OpenSim .mot kinematics
export_mot(data, "kinematics.mot")
# OpenSim Scale Tool setup XML
export_opensim_scale_setup(data, "scale_setup.xml", model_file="gait2392.osim")
# OpenSim IK setup XML
export_ik_setup("markers.trc", "ik_setup.xml", model_file="scaled_model.osim")
# Pose2Sim: export OpenPose-format JSON for triangulation
export_openpose_json(data, "./openpose_output/", model="BODY_25")
Video Overlay & Visualization
Generate annotated videos, anonymized stick-figure animations, and publication-ready dashboards.
from myogait import render_skeleton_video, render_stickfigure_animation
from myogait import plot_summary, plot_gvs_profile
# Skeleton overlay on original video
render_skeleton_video("video.mp4", data, "overlay.mp4", show_angles=True)
# Anonymized stick figure GIF
render_stickfigure_animation(data, "stickfigure.gif")
# Summary dashboard
fig = plot_summary(data, cycles, stats)
fig.savefig("dashboard.png", dpi=150)
# MAP barplot (Movement Analysis Profile)
fig = plot_gvs_profile(gvs)
fig.savefig("gvs_profile.png", dpi=150)
PDF Report
Generate a multi-page clinical report with kinematic plots, spatio-temporal tables, and normative comparisons.
from myogait import generate_report
# Generate clinical PDF report (French or English)
generate_report(data, cycles, stats, "rapport_marche.pdf", language="fr")
Multiple Export Formats
Export analysis results to a variety of tabular and structured formats for downstream processing and archival.
from myogait import export_csv, export_excel, to_dataframe, export_summary_json
# CSV files (one per data type)
export_csv(data, "./csv_output/", cycles, stats)
# Excel workbook
export_excel(data, "gait_analysis.xlsx", cycles, stats)
# Pandas DataFrame for custom analysis
df = to_dataframe(data, what="angles")
print(df.head())
# Compact summary JSON
export_summary_json(data, cycles, stats, "summary.json")
CLI Usage
Run the full pipeline on a video:
myogait run video.mp4 # MediaPipe (default)
myogait run video.mp4 -m sapiens-quick # Sapiens 0.3B
myogait run video.mp4 -m sapiens-top --with-depth # Sapiens 1B + depth
myogait run video.mp4 -m sapiens2-top --with-depth # Sapiens 2 1B + depth
myogait run video.mp4 -m sapiens2-ultra # Sapiens 2 5B
myogait run video.mp4 -m vitpose # ViTPose
myogait run video.mp4 -m rtmw # RTMW 133 keypoints
Extract landmarks only:
myogait extract video.mp4 -m sapiens-top --with-depth --with-seg
Analyze previously extracted results:
myogait analyze result.json --csv --pdf
Optional lateral-label correction:
from myogait import correct_lateral_labels
# Default: conservative global inversion correction
data = correct_lateral_labels(data)
# Opt-in: recover isolated ankle/knee/heel swaps during crossings
data = correct_lateral_labels(data, mode="partial")
Batch process multiple videos:
myogait batch *.mp4 -o results/
Download models:
myogait download --list # list all available models
myogait download sapiens-0.3b # Sapiens v1 pose 0.3B
myogait download sapiens-depth-1b # Sapiens v1 depth 1B
myogait download sapiens2-1b # Sapiens 2 pose 1B
myogait download sapiens2-ultra # Sapiens 2 pose 5B
Inspect a result file:
myogait info result.json
API Reference
All functions operate on a single data dict that flows through the pipeline.
| Function | Description |
|---|---|
| Core pipeline | |
extract(video, model, experimental=None) |
Extract pose landmarks from video |
normalize(data, filters) |
Filter and normalize landmark trajectories |
compute_angles(data) |
Compute sagittal joint angles |
compute_frontal_angles(data) |
Compute frontal plane angles (requires depth) |
detect_events(data, method) |
Detect gait events (15 methods incl. gaitkit) |
event_consensus(data, methods) |
Multi-method voting for robust event detection |
segment_cycles(data) |
Segment into individual gait cycles |
analyze_gait(data, cycles) |
Compute spatio-temporal parameters |
run_single_trial_vicon_benchmark(data, trial_dir) |
Experimental VICON alignment + metrics (single trial) |
run_single_pair_benchmark(video, trial_dir, output_dir, benchmark_config=None) |
Experimental benchmark grid runner (single video + single VICON trial) |
| Clinical scores | |
gait_profile_score_2d(cycles) |
GPS-2D: overall gait deviation (sagittal + frontal) |
sagittal_deviation_index(cycles) |
SDI (Sagittal Deviation Index): z-score based 0-120 index (100 = normal). Not the GDI. |
gait_variable_scores(cycles) |
Per-joint deviation vs normative |
movement_analysis_profile(cycles) |
MAP barplot data |
| Quality | |
confidence_filter(data) |
Remove low-confidence landmarks |
detect_outliers(data) |
Detect and interpolate spikes |
data_quality_score(data) |
Composite quality score 0-100 |
frame_coherence_score(data) |
Per-frame biomechanical coherence [0,1] (z-score based) |
fill_gaps(data) |
Interpolate missing landmark gaps |
| Analysis | |
walking_speed(data, cycles) |
Estimated walking speed |
step_length(data, cycles) |
Step/stride length estimation |
stride_variability(data, cycles) |
CV of spatio-temporal parameters |
arm_swing_analysis(data, cycles) |
Arm swing amplitude and asymmetry |
segment_lengths(data) |
Anthropometric segment lengths |
detect_pathologies(data, cycles) |
Pattern detection (equinus, antalgic, etc.) |
| Visualization | |
plot_summary(data, cycles, stats) |
Summary dashboard |
plot_normative_comparison(data, cycles) |
Patient vs normative bands |
plot_gvs_profile(gvs) |
Movement Analysis Profile barplot |
render_skeleton_video(video, data, out) |
Skeleton overlay on video |
render_stickfigure_animation(data, out) |
Anonymized stick figure GIF |
| Export | |
export_csv(data, dir, cycles, stats) |
CSV files |
export_mot(data, path) |
OpenSim .mot kinematics |
export_trc(data, path) |
OpenSim .trc markers |
load_c3d(path) |
Load VICON C3D file into myogait data dict |
export_openpose_json(data, dir) |
OpenPose JSON for Pose2Sim |
export_opensim_scale_setup(data, path) |
OpenSim Scale Tool XML |
export_ik_setup(trc, path) |
OpenSim IK setup XML |
to_dataframe(data, what) |
Pandas DataFrame |
generate_report(data, cycles, stats, path) |
Multi-page clinical PDF report |
validate_biomechanical(data, cycles) |
Validate against physiological ranges |
Configuration
myogait supports YAML and JSON pipeline configuration files:
from myogait import load_config, save_config
config = load_config("pipeline.yaml")
config["filter"]["method"] = "butterworth"
config["filter"]["cutoff"] = 6.0
save_config(config, "pipeline_updated.yaml")
Experimental degradation can also be set in config (disabled by default):
extract:
model: mediapipe
experimental:
enabled: false
target_fps: null
downscale: 1.0
contrast: 1.0
aspect_ratio: 1.0
perspective_x: 0.0
perspective_y: 0.0
JSON Output Format
When using Sapiens (v1 or v2) with depth and segmentation:
{
"extraction": {
"model": "sapiens2-top",
"depth_model": "sapiens2-depth-1b",
"seg_model": "sapiens2-seg-1b",
"auxiliary_format": "goliath308",
"seg_classes": ["Background", "Apparel", "Eyeglass", "Face_Neck", "..."]
},
"frames": [
{
"frame_idx": 0,
"landmarks": { "NOSE": {"x": 0.52, "y": 0.31, "visibility": 0.95} },
"goliath308": [[0.52, 0.31, 0.95], "..."],
"landmark_depths": { "NOSE": 0.73, "LEFT_HIP": 0.45, "..." : 0.0 },
"landmark_body_parts": { "NOSE": "Face_Neck", "LEFT_HIP": "Left_Upper_Leg" }
}
]
}
Acknowledgments
myogait is developed at the Institut de Myologie (Paris, France) by the PhysioEvalLab / IDMDataHub team.
This work is supported by:
- AFM-Téléthon — French Muscular Dystrophy Association
- Fondation Myologie — Research foundation for muscle diseases
- Téléthon — Annual fundraising event for rare disease research
Citation
If you use myogait in your research, please cite:
@software{myogait,
author = {Fer, Frederic},
title = {myogait: Markerless video-based gait analysis toolkit},
year = {2025},
institution = {Institut de Myologie, Paris, France},
publisher = {GitHub},
url = {https://github.com/IDMDataHub/myogait}
}
A peer-reviewed publication is in preparation.
License
This project is licensed under the MIT License. See LICENSE for details.
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