LocoHub Quick Reference

Print-friendly cheat sheet for daily use

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📐 Coordinate System

Y↑ (Superior)    X→ (Anterior)    Z↓ (Right)

Right-hand rule for positive rotations

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📊 Data Formats

Phase-Indexed	Time-Indexed
*_phase.parquet	*_time.parquet
150 points/cycle	Variable samples
Phase: 0-100%	Time: seconds
For averaging	For raw analysis

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🔤 Variable Names (Copy-Ready)

Most Common - Ipsilateral

Kinematics

hip_flexion_angle_ipsi_rad
knee_flexion_angle_ipsi_rad
ankle_dorsiflexion_angle_ipsi_rad

Kinetics

hip_flexion_moment_ipsi_Nm
knee_flexion_moment_ipsi_Nm
ankle_dorsiflexion_moment_ipsi_Nm

Segment Angles

pelvis_sagittal_angle_rad
trunk_sagittal_angle_rad
thigh_sagittal_angle_ipsi_rad
shank_sagittal_angle_ipsi_rad
foot_sagittal_angle_ipsi_rad

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➕➖ Sign Conventions

Joint	Motion	Positive (+)	Zero (0)
Hip	Flexion	Thigh forward	Vertical
Knee	Flexion	Heel to buttocks	Full extension
Ankle	Dorsiflexion	Toes up	90° foot-shank
Pelvis	Sagittal	Anterior tilt	Neutral

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🔄 Unit Conversions

# Degrees ↔ Radians
rad = deg * π/180 = deg * 0.01745
deg = rad * 180/π = rad * 57.296

# Phase conversions
percent = index / 1.49
index = int(percent * 1.49)

# Contralateral offset
phase_contra = (phase_ipsi + 50) % 100
index_contra = (index_ipsi + 75) % 150

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📏 Typical Ranges (Walking)

Joint Angles (radians)

Joint	Min	Max	(degrees)
Hip Flexion	-0.35	0.52	-20° to 30°
Knee Flexion	-0.05	1.05	-3° to 60°
Ankle Dorsiflex	-0.44	0.35	-25° to 20°

Joint Moments (Nm/kg)

Joint	Typical Peak
Hip	0.8 - 1.1
Knee	0.4 - 0.6
Ankle	1.2 - 1.6

Ground Reaction Forces (× Body Weight)

Direction	Walking	Running
Vertical	1.0 - 1.2	2.0 - 2.9
Anterior-Post	±0.2	±0.5
Medial-Lateral	±0.05	±0.1

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📝 Required Columns

All Datasets

• subject - Subject ID
• task - Activity type
• task_id - Specific variant
• task_info - Metadata string
• step - Cycle number

Phase Data Only

• phase_ipsi - 0-100%

Time Data Only

• time_s - Seconds

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🏷️ Task Classification

Level 1: Task

level_walking, incline_walking, decline_walking, stair_ascent, stair_descent, run, sit_to_stand, jump, squats

Level 2: Task ID

level, incline_5deg, incline_10deg, decline_5deg, stair_ascent, stair_descent

Level 3: Task Info

"speed_m_s:1.2,treadmill:true,incline_deg:10"

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🐍 Python Quick Start

from user_libs.python.locomotion_data import LocomotionData

# Load data
data = LocomotionData('dataset_phase.parquet')

# Get cycles
cycles, features = data.get_cycles(
    subject='SUB01',
    task='level_walking'
)

# Mean patterns
means = data.get_mean_patterns('SUB01', 'level_walking')

# Plot
data.plot_phase_patterns(
    'SUB01', 'level_walking',
    ['knee_flexion_angle_ipsi_rad']
)

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⚠️ Common Issues

Problem	Solution
Negative knee angles	OpenSim: 0° = full extension
Wrong phase alignment	0% = heel strike, not toe-off
Unit errors	Use radians, not degrees
Missing contra	Generate from ipsi + 50% phase

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🔍 Validation Checks

✓ 150 points per cycle
✓ Phase: 0-100%
✓ Angles in radians
✓ Required columns present
✓ Within anatomical limits

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📚 Key References

• Coordinate System: X=Anterior, Y=Superior, Z=Right
• Phase Points: 0=heel strike, 50≈opposite heel, 100=next heel
• Ipsi/Contra: Ipsi=reference leg, Contra=opposite leg

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Locomotion Data Standard v2.0 | Quick Reference