Product Fit and Sizing

Kathleen M. Robinette, Ph.D., is a research consultant specializing in anthropometry, biostatistics, and fit and sizing for product development and assessment. She has more than 45 years’ experience, spearheading the development, management, and transitioning of new technologies in the field of engineering anthropometry, and led the field in the development of 3-D automated human scanning and modeling for product design and evaluation. She planned, organized, negotiated, and directed the first successful 3-D whole body human measurement survey (CAESAR), which produced more than 4,000 whole body models which continue to be used around the world today. She is a Fellow of the Air Force Research Laboratory from which she retired after 30 years of service and is an Honorary Fellow of the Human Factors and Ergonomics Society. She was Professor and Head of the Department of Design, Housing, and Merchandising at Oklahoma State University 2012-2015 and she established and directed the Human Factors department for Magic Leap Inc. 2015-2017 implementing fit mapping into the product development process. Kathleen has a Ph.D. in Biostatistics and Epidemiology from the University of Cincinnati, an M.S. in Mathematics/Statistics from Wright State University, and a B.A. in Anthropology from Wright State University. Daisy Veitch, Ph.D., is currently the Director of Anthropometry for Anthrotech Inc. and has served as an anthropometry and fit consultant for commercial apparel industry for more than 25 years. She worked with Flinders Medical Center to develop and refine 3D body scanning for medical applications. She is the owner of a US design patent and has registered designs in Australia, Europe, United States, and the European Community. She also directed the Australian National Size and Shape Survey in 2002. She worked in industry for ten years doing technical garment construction and serving as product engineer for an apparel company. As a recognized expert, she was appointed as an International Judge for APDeC 2013 (Asia Pacific Design Challenge) http://apdec.net. Daisy developed her fashion and design skills in Adelaide, Australia, beginning with the Australian Wool Corporation Young Designer Award and Queen Elizabeth II Silver Jubilee Award for Young Australians, which took her to Paris, France where she studied at the La Chambre Syndicale de la Couture Parisienne. She received her Ph.D. from TU Delft (Industrial Design Engineering with a specialization in Medisign). She is a founding member of World Engineering Anthropometry Resources (WEAR) and served as Treasurer and Secretary General. Sandra Alemany, Ph.D., is a research scientist at the Instituto de Biomecánica de Valencia (IBV) and founded the Anthropometry Research Group in 2015. She led large-scale anthropometry surveys in Europe using 3D scanning technology and has experience in applying anthropometry to improve wearable fit including: footwear, electronic devices, orthotics, insoles and clothing. Recent developments include a 4D body scanner in movement and the development of two mobile apps to generate 3D body shapes from photographs. She is an expert advisor on European Standardization Committees of Anthropometry and Size System of Clothing and an expert reviewer of R&D projects for the European Commission. She is currently serving as Co-chair for the Anthropometry Technical Committee for the International Ergonomics Association. She received her PhD. from the University Polytechnic of Valencia in 2023 with research about fit and clothing size prediction from anthropometry. Karen Bredenkamp currently heads up the Human Factors team at Magic Leap Inc. Karen has more than 20 years’ industry experience in anthropometry survey design, data collection, analysis, and implementation in wearable product and workstation design, as well as wearable product fit research as part of the product selection or development processes. Between 2000 – 2016 Karen was employed at Ergonomics Technology, a division of the Armaments Corporation of South Africa (ARMSCOR), where she had a core role in the establishment of the 3D whole-body and foot Anthropometry databases for the ethnically diverse and unique South African National Defence Force (SANDF) population. Her activities furthermore involved providing anthropometry and fit inputs and evaluation support for product design as well as purchasing of SANDF clothing, footwear, protective wearable products, workstations, and occupant environments. She also has worked in the transportation, mining and commercial industries. Karen is currently serving as Co-chair for the Anthropometry Technical Committee for the International Ergonomics Association. She has an MSc in Biomedical Engineering from the University of Cape Town and an BEng in Mechanical Engineering from Stellenbosch University, South Africa.

Chapter 1 Introduction 1

Abstract 1

Sustainable Product Evaluation, Engineering and Design Process (SPEED) 3

Inputs 6

Design loop 7

Sizing loop 8

How to use this book 13

Chapter 2 Inputs and Getting Started 16

Abstract 16

Products 17

Requirements and Constraints 17

Design Concept 21

Resources 24

Tools 24

Analysis & data management tools 25

Questionnaires 29

Anthropometry 35

Manual tool assessment 42

Imaging tool assessment 45

Physical fit measuring tools 57

Personnel and facilities 61

Personnel 61

Facilities 67

Use of human subjects 67

Test site considerations 68

Target population (TP) sampling and planning 70

Starting TP Sample 71

Planning full TP sample 77

Weighting samples 84

What can go wrong 86

Chapter 3 Cases and Fit Models 91

Abstract 91

Selecting cases 93

Selecting cases with raw data 98

Base size and base size case 105

Multiple cases 119

PCA alternative for selecting key variables 126

Selecting cases with aggregate data 135

Using cases to create mock-ups and prototypes 143

Physical manikins 148

Digital manikins 154

Original point cloud 157

Surfaced manikin 157

Watertight surfaced manikin 157

Standardized homologous watertight manikin 158

Parameterized database manikin 158

Chapter 4 Testing and Analysis Procedures 166

Abstract 166

Experimental design 169

Analysis methods 174

Student’s t-test 176

Paired t-test (repeated measures with 2 treatments) 180

Wilcoxon signed-rank test 181

Wilcoxon rank-sum test (Mann Whitney test) 182

Proportion test 182

Chi-squared test for independence 184

Bivariate correlation 185

General Linear Models 185

Analysis of variance (ANOVA) 188

Linear regression/stepwise linear regression 189

Discriminant analysis 191

Logistic regression 193

Design loop tests and analysis 196

Pilot tests 197

Stand-alone trade studies 198

Comparison of two treatments using paired test design 200

Comparison of two treatments using independent samples 202

Comparison of three or more treatments using repeated measures design 202

Comparison of three or more treatments using independent measures design 205

Prototype fit tests 205

Scenario 1: First prototype iteration with just one size 209

Scenario 2: Existing product with fit and sizing issues in multiple sizes 211

Sizing loop tests and analysis 219

Evaluating the cost versus benefit of sets of sizes 221

Determining the tariff 223

Size prediction 228

Chapter 5 Mass Produced Apparel 231

Abstract 231

Background 231

Fit audit and the Sustainable Fit Standard 233

Grading and the Sweetspot 236

Benefits of the SPEED process 239

Case studies 239

Case study 1: Manufacturer / retailer design, sizing, tariff, & fit standard development 240

Case study 2: Assessment for purchasing an existing product aided by 3D scanning 252

Case study 3: Assessment for purchasing tariff 256

Case study 4: Prototype test to determine the correct alteration 262

Chapter 6 Head and Face Wearables 268

Abstract 268

Background 268

Center of mass vs neck strain 270

Sensitivity to temperature 271

Head orientation and alignment 272

Head anthropometry 281

Case studies 286

Case study 1: Design loop testing of a head wearable to demonstrate use of product based head orientation 286

Case study 2: Design loop testing with a non-functioning mockup including early COF 290

Case study 3: Design loop updates in COF 304

Case study 4: A trade study to investigate temple band closing force 309

Case study 5: Design loop evaluation tools highlighting inputs to design changes 320

Case study 6: Importance of fit testing to predict sizing numbers for purchasing 331

Chapter 7 Footwear 339

Abstract 339

Background 339

Issues with different footwear types 343

Dress shoes and casual footwear 344

Safety, protective, and occupational footwear 349

Sports footwear 351

Key Performance Indicators (KPIs) 352

Concept-of-Fit (COF) 355

Subject assessment 355

The Sustainable Fit Standard 358

Target user profile 359

Foot anthropometry and anatomy 360

Foot as a static structure 361

The dynamics of the foot 363

Foot anthropometry methods 367

Variability of the of the foot anthropometry: sex, age, demographics 371

Resources, planning, and preparation 376

Case studies 379

Case study 1: The design loop of casual and fashion footwear 379

Case study 2: Application to footwear innovation 389

Glossary 391

Index 403