Hugh E. McLoone

Alternative Computer Mouse Design and Testing to Reduce Finger Extensor Muscle Activity During Mouse Use

Objective: The purpose of this study was to design and test alternative computer mouse designs that attempted to reduce extensor muscle loading of the index and middle fingers by altering the orientation of the button switch direction and the force of the switch. Background: Computer users of two-button mouse designs exhibit sustained lifted finger behaviors above the buttons, which may contribute to hand and forearm musculoskeletal pain associated with intensive mouse use. Methods: In a repeated-measures laboratory experiment, 20 participants completed point-and-click, steering, and drag tasks with four alternative mouse designs and a reference mouse. Intramuscular and surface electromyography (EMG) measured muscle loading, and movement times recorded by software provided a measure of performance. Results: Changing the direction of the switch from a conventional downward to a forward design reduced (up to 2.5% maximum voluntary contraction [MVC]) sustained muscle activity (10th percentile EMG amplitude distribution) in the finger extensors but increased (up to 0.6% MVC) flexor EMG and increased movement times (up to 31%) compared with the reference mouse (p < .001). Implementing a high switch force design also increased flexor EMG but did not differ in movement times compared with the reference mouse (p < .001). Conclusion: The alternative mouse designs with altered switch direction reduced sustained extensor muscle loading; however, trade-offs with higher flexor muscle loading and lower performance existed. Application: Potential applications of this study include ergonomic and human computer interface design strategies in reducing the exposure to risk factors that may lead to upper extremity musculoskeletal disorders.

Award-Winning Qualities of the Microsoft Office Keyboard

The product design process begins with a statement of vision, values, and “mottos” and then achieves success after iterative prototyping and testing.

Evaluation of Microsoft's Comfort Curve Keyboard

The purpose of this study was to determine whether there were any postural, performance or perceived comfort differences between a conventional straight keyboard and a new ergonomic concept keyboard developed by Microsoft called the Comfort Curve. The concept keyboard was designed to promote more neutral postures in the wrist using a built-in, padded wrist rest to reduce wrist extension and curved keys in alphanumeric section of the keyboard to reduce ulnar deviation. Using a repeated measures design, 26 typists from various occupations randomly used each keyboard for a period of 15 minutes. Wrist postures were measured using electrogoniometers, typing speed and accuracy was measured using typing performance software and discomfort was subjectively measured in the hands, forearms and shoulders and neck. Compared to the conventional straight keyboard, the Comfort Curve keyboard reduced ulnar deviation by 2.2 ° (p < 0.01) and wrist extension by 6.5 ° (p <0.01). There was a small differences in typing speed (50.6 vs 51.8 WPM; p = 0.03) but no differences in accuracy (93.1% vs. 93.5%, p = 0.29) between the Comfort Curve and standard keyboards respectively. Subjective discomfort ratings in all measured body locations were lower with the Comfort Curve keyboard. The results indicate that the concept keyboard achieved its design goal of reducing wrist extension, ulnar deviation and discomfort while not compromising typing speed and accuracy.

Developing Miniature Force-Sensing Technologies for Measuring the Forces Applied to a Computer Mouse

Force-sensing technologies, 1.4 − 2.5 mm thick, were developed to measure the forces applied to the button and sides of a computer mouse. A force-sensing computer mouse was developed, built and tested for force measurement accuracy. The force-sensing technology could accurately measure the forces applied to the sides of a mouse and identify the location of force application. The force-sensing technology also accurately measured the forces applied to the mouse button with slight measurement errors at low forces. The force-sensing technologies developed in this study were made from commercially available materials, were relatively low cost and will be readily exportable to different mouse designs. These force-sensing technologies should assist manufacturers, designers and researchers in better understanding how various hand held devices and tools are gripped and operated.

Professional Issues: Leadership in the Product Development Process: Attitude Counts!

Editors Note: Our attitudes make a difference as we participate in the product development process and meet challenges that arise for us individually or for the team. The author offers 10 lessons learned about attitudes and how they have helped or hindered efforts to create superior user experiences and industry-leading products. Previous articles by Hugh McLoone in this Ergonomics in Design column have covered other aspects of leadership, including schedule constraints, decision making, communication, and teamwork. Questioning the design of an existing product – or even the research on which it is based – can help design teams find new ways to succeed.

Leadership During the Product Design Process: Teamwork, Roles, and Responsibilities:

D E S I G N • W I N T E R 2 0 0 9 C op yr ig ht 2 00 9 by H um an F ac to rs a nd E rg on om ic s So ci et y, In c. A ll ri gh ts r es er ve d. D O I 1 0. 15 18 /1 06 48 04 09 X 41 51 98 or an ergonomist or human factors professional, one of the joys of working in product development is being part of a multidisciplinary team. It’s a challenge and a pleasure to work with other professionals from industrial design, interaction design, user assistance, product planning, sales and marketing, research, software, and mechanical, electrical, and operations engineering. Each team member brings special talents. Everyone works together for the common goal of creating products that people enjoy using and that help them live better lives. The team’s collective contributions are necessary at each step of the product development lifecycle, from product definition to product sales, and back again for the next version.

Leadership During the Product Development Process: Communication

E R G O N O M I C S I N D E S I G N • W I N T E R 2 0 0 8 s HF/E professionals, we represent science. As designers, we represent art. Among business and technology leaders, we are often not understood and yet we must justify our value to the organization. While striving together to reach a common goal – to ship a successful product – we struggle to effectively communicate given our different backgrounds, priorities, and vocabularies. However, HF/E professionals have several ways to effectively communicate with product teams and business leaders.

Leadership During the Product Development Process: Decision Making

E R G O N O M I C S I N D E S I G N 2 9 ithin the first days – if not hours – of starting work on a product design team, a human factors/ergonomics (HF/E) practitioner will start fielding questions from colleagues: “What are the engineering constraints for a design specification?” “Should a new feature be added to a product?” “How should a new feature be designed?” In this article, I offer some suggestions for HF/E decision making.

Leadership During the Product Development Process: Making the Best of a Limited Schedule

Leadership During the Product Development Process: Making the Best of a Limited Schedule

Leadership in the Product Development Process Research Methods During Design

Creativity can be viewed as a chaotic or unplanned activity. The product design process often may seem like chaos as well, but this is not inevitable. Designers and human factors/ergonomics (HF/E) professionals follow a clear design process with phases, levels, and methods for creation of successful new products. Research methods are offered at the right time during this process to generate new concepts and to evaluate designs. We work together to create innovative, valued, and successful products via a generative, iterative, evaluative process.