Motion Study is a systematic analysis of the body motions employed by a worker while performing a task, with the goal of eliminating wasteful actions and establishing the most efficient method. Pioneered by Frank and Gilbreth, it involves breaking down work into fundamental movement elements called “Therbligs” (such as search, select, grasp, and hold). By scrutinizing these micro-motions, analysts can redesign the work method to reduce fatigue, minimize unnecessary movements, and optimize the sequence of operations. The objective is to find the “one best way” to perform a job, leading to increased productivity, reduced operator stress, and more effective use of human effort, often complementing Time Study in work measurement.
Calculations of Motion Study:
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Record Movements:
The complete operation is recorded using a camera or observation chart to capture all motions involved in performing the task.
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Classify Motions:
Each motion is broken down into small elements known as Therbligs (basic hand or body movements like reach, grasp, move, release, etc.).
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Measure and Time Motions:
Each motion is measured in terms of time and distance using micro-motion analysis or chronocyclegraphs.
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Analyze Efficiency:
Each motion is analyzed to identify unnecessary or non-productive movements that can be reduced or eliminated.
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Develop an Improved Method:
The most efficient sequence of motions is established and standardized to minimize fatigue and maximize productivity.
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Calculate Time Savings:
The difference between the time required in the old method and the improved method represents the time saved due to motion optimization.
Time Saved = Old Method Time − Improved Method Time
Example:
If the old method takes 10 minutes and the improved method takes 8 minutes,
Time Saved = 10 − 8 = 2 Minutes
Thus, motion study helps calculate efficiency improvements by quantifying time and motion savings achieved through systematic motion analysis and redesign.
Uses of Motion Study:
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Elimination of Wasteful Movements
Motion Study is used to identify and remove unnecessary, inefficient, or fatiguing motions from a work cycle. By analyzing fundamental “Therbligs” (basic motion elements), practitioners can spot non-value-added actions like unnecessary “search,” “select,” or “hold.” This purification of the work method streamlines the operation, allowing the task to be completed in less time with less physical and mental effort. The direct result is a significant reduction in time and energy wasted on unproductive motions, leading to a leaner and more efficient process.
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Design of Improved Work Methods
A core use is to design the most efficient sequence of motions—the “one best way” to perform a task. By studying and comparing different motion patterns, analysts can synthesize an optimal method that sequences movements for maximum smoothness and rhythm. This involves improving the layout of the workplace to ensure tools and materials are within easy reach and pre-positioned. The outcome is a standardized, superior work method that becomes the benchmark for all operators, ensuring consistency and peak efficiency.
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Reduction of Worker Fatigue
Motion Study aims to minimize physical and mental strain by designing ergonomic work methods. It identifies and eliminates motions that cause excessive fatigue, such as awkward postures, long reaches, or heavy lifting. The work is redesigned to promote natural body movements and rhythm. This not only improves the worker’s comfort and well-being but also sustains a higher level of performance throughout the workday. Reduced fatigue leads to fewer errors, lower absenteeism, and a healthier, more motivated workforce.
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Effective Tool and Workplace Design
The findings of Motion Study directly inform the design of tools, equipment, and the workstation layout. It provides data on the most efficient placement of materials, bins, and controls to minimize reaching and walking. This leads to the development of ergonomic tools that are easier and faster to use. A well-designed workplace, based on motion economy principles, ensures a logical flow of work and allows the operator to perform their tasks with maximum comfort and minimum effort, thereby boosting overall productivity.
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Setting Reliable Time Standards
Motion Study provides the methodological foundation for accurate Time Study. Before timing a task, it is essential to first standardize the method. By using Motion Study to establish the most efficient sequence of motions, the subsequent Time Study measures a method that is already optimized. This ensures that the resulting standard time is based on the “one best way,” making it a fair, consistent, and achievable benchmark for scheduling, costing, and measuring performance. It prevents the codification of inefficient methods into time standards.