Manual Material Handling | Energy Consumption | Body Moment | Hand Tool Design | Gaurav Singh Rajput

1. Manual Material Handling |
Energy Consumption | Body
Moment | Hand Tool Design
By: Gaurav Singh Rajput
@gauravkrsrajput

2. What is material handling?
Seizing, holding, grasping, turning, or otherwise
working with the hand or both hands. Fingers
are involved only to the extent that they are an
extension of the hand, such as to turn a switch
or to shift automobile gears
Manual material handling includes any
tasks which require a person to lift, lower,
push, pull, hold or carry any object or
material.

4. Health Effects of Manual Materials Handling
• Short and long term health effects like lacerations, bruises,
fractures, cardiovascular strain, such as increased heart rate and
blood pressure; muscular fatigue, chronic bronchitis,
musculoskeletal injuries to the spine and back.
• National Safety Council reports that injuries associated with MMH
account for about 25 percent of all industrial injuries and result in
about 12 million lost workdays per year and over $1 billion in
compensation costs
• Considering only the work related back strains and sprains, almost
50% of such injuries occur while lifting objects. An additional 9%
occur while pushing or pulling & about 6 % occur while holding,
wielding, throwing or carrying objects

5. •Muscles and ligaments of the back can
fail under excessive tension.
•Abdominal contents may be extruded
through the abdominal cavity due to
excessive IAP (intra-abdominal pressure)
•Inter-vertebral disc may
herniate as the nucleus is
extruded under excessive compression.

6. Improving the workplace
• Manual handling of containers may expose workers to
physical conditions (e.g., force, awkward postures, and
repetitive motions) that can lead to injuries, wasted energy,
and wasted time.
• To avoid these problems, your organization can directly
benefit from improving the fit between the demands of
work tasks and the capabilities of your workers.
• Remember that workers’ abilities to perform work tasks
may vary because of differences in age, physical condition,
strength, gender, stature, and other factors.

7. What to Look for
The main risk factors, or conditions, associated with the development
of injuries in manual material handling tasks include:
• Awkward postures (e.g., bending, twisting)
• Repetitive motions (e.g., frequent reaching, lifting, carrying)
• Forceful exertions (e.g., carrying or lifting heavy loads)
• Pressure points (e.g., grasping [or contact from] loads, leaning
against parts or surfaces that are hard or have sharp edges)
• Static postures (e.g., maintaining fixed positions for a long time)

8. Types of Ergonomic Improvements
1. Engineering improvements
2. Administrative improvements

9. 1. Engineering improvements
• These include rearranging, modifying, redesigning,
providing or replacing tools, equipment,
workstations, packaging, parts, processes, products,
or materials

10. 2. Administrative Improvements
Observe how different workers perform the same tasks to get ideas for
improving work practices or organizing the work. Then consider the
following improvements
• Alternate heavy tasks with light tasks.
• Provide variety in jobs to eliminate or reduce repetition (i.e., overuse of
the same muscle groups).
• Adjust work schedules, work pace, or work practices.
• Provide recovery time (e.g., short rest breaks).
• Modify work practices so that workers perform work within their power
zone (i.e., above the knees, below the shoulders, and close to the body).
• Rotate workers through jobs that use different muscles, body parts, or
postures.

11. Improvement strategies

12. Improvements
Case 1
• Easier Ways to Manually Lift, Lower, Fill, or Empty
Containers
Consider the following options that will:
• Reduce reaching and bending.
• Reduce the stress on your back and shoulders.
• Reduce the effort and force needed to perform work
tasks.

13. Keep the load close to your body and lift by pushing up with your legs
Lean the sack
onto your
kneeling leg.
Slide the sack up
onto your kneeling
leg.
Slide the sack onto the other leg
while keeping the sack close to your
body.

14. Use portable steps
Use stationary work surfaces.
scissors lift.

16. • Alternatives to Manual Handling of Individual Containers
Change the container.
Use a tool.
Use non-powered equipment.
Use powered equipment

17. Improvement Options for Lifting
Team Lift
Lifting Device
Turntable

18. Energy
• When we consume plant and animal products, the carbohydrates, fats, and
protein are broken down during digestion, releasing energy and nutrients.
• Some of the energy from these foods is used immediately for various body
functions, and some is stored as energy to be used at a later time.
• The chemical energy provided by food is ultimately transformed into mechanical
energy.
• Process of converting food energy into mechanical work goes on
continuously, maintaining the body’s life-sustaining processes and keeping
body temperature at 37C.
• When we exercise, we use the energy in food to make the muscles contract
• Not perfectly efficient in converting energy into work, also create heat.
• Energy is measured in units called calories.
• Most of the food we eat contains energy.
• Everything we do (even sleeping) requires energy.

19. This food item contains
110 Calories in 1 cup or
34 g serving.

20. The human body converts the food consumed by the individual into energy. The
amount of energy provided by food is typically measured either
in calories or kilojoules.
Physical activity ratio
(PAR)

21. Oxygen Consumption (Uptake)
Oxygen is used to metabolize food stuffs and release energy. The amount of energy released
depends, in part, upon what food stuffs are being metabolized.
1 L of O2 5 kcal of energy.
Therefore, by measuring the oxygen consumption during work, we can directly estimate the
energy consumption.

22. Volume of oxygen consumed per unit time (or oxygen uptake)
• Volume of inspired air per unit time is measured.
• Air contains approximately 21 % oxygen, so the amount of oxygen inspired
per unit time can be easily determined.
• The volume of expired air per unit time is also measured and samples of
expired air are taken.
• The samples are analysed to determine the percentage of oxygen in them.
Maximum Aerobic Power (MAP)
Increasing the rate of work causes a linear increase in oxygen uptake, to a
point, after which oxygen uptake levels off. The level at which oxygen uptake
levels off is called the maximal oxygen uptake or maximum aerobic power
(MAP).
Maximum aerobic power is-defined as the highest oxygen uptake an
individual can attain during exercise while breathing air at sea level. At the
level of maximum aerobic power, energy metabolism is largely anaerobic and
lactic acid level in the muscle tissue and blood rises sharply.
The higher a person's MAP, the greater the efficiency of the cardiovascular
system.

24. The most straightforward method for determining a person's maximum aerobic power is
to have the individual exercise on a treadmill or bicycle ergometer (exercise involving large
muscle groups).
The workload (incline, resistance, or rate of work) is increased until oxygen uptake levels
off.
Measurement of Maximum Aerobic Power

25. Heart Rate
Oxygen consumption is directly related to energy expenditure but is cumbersome to assess in
a real-world work situation.
As it turns out, there is a linear relationship between oxygen consumption and heart rate,
and heart rate is very easy to measure.

26. Grades of Work

27. Factors Affecting Energy Consumption
Methods of Work
maintenance of good postural
balance, one that affects
the body's centre of gravity the
least.
Work Posture

28. Work Rate
Still another factor that affects
the workload is the work rate, or
pace.·
Tool Design

29. CONTROLLING ENERGY EXPENDITURE
• Recommended limits
Various upper limits of energy expenditure for daily work have been proposed.
Michael, Hutton, and Horvath (1961) and Blink (1962), for example, suggest that workloads
should not exceed about 35 % of a person's maximum aerobic power over an 8-h day.

30. • Work-Rest Cycles.
• Exercise Training
We know that exercise training makes us more physically fit and better able to
perform physical work without fatigue. Exercise training can increase maximum aerobic
power, reduce heart rate, reduce blood pressure, and increase muscle strength and
endurance. All of these changes reduce the level of strain experienced for a given level of
workload stress.

31. Factors influencing the power and capacity for
physical activity ( risk factors)

32. Energy Expenditure
• The human body spends energy for many different purposes, such as life-sustaining
metabolic functions, digestion, and physical activity. Energy expenditure will fall within one
of the following three categories:
– Basal or resting metabolic rate (BMR or RMR)
– Thermic effect of food (TEF): Apart from resting metabolism and activity energy
expenditure, the body also burns calories every time you eat. This is referred to as the
thermic effects of food
– Energy expenditure of activity (EEA)
• Overall Energy Expenditure = RMR + TEF + EEA
• BMR
– Amount of energy per minute the body uses to maintain a quiet resting state
– Approximately 1 Cal per minute (1440 minutes in a day x 1 Cal/min = 1440 Cal per day)
– 60% to 75% of the energy used every day is needed to maintain the essential body
functions that sustain life
• BMR measurements are typically taken in a darkened room upon waking after 8 hours of
sleep and 12 hours of fasting (to ensure that the digestive system is inactive), with the
subject resting in a reclining position.
• RMR measurements are typically taken under less restricted conditions than BMR
measurements, and do not require the subject to spend the night sleeping in the test
facility prior to measurement. As a result, RMR has become the more popular measure,
and BMR is not often measured anymore.

33. Factors Affecting BMR/RMR
BMR/RMR, primarily related to lean tissue/fat-free mass, is influenced by a number of factors working
in combination, including the following:
Age: Metabolism slows with age (2% to 3% per decade after 30 years of age), primarily due to a loss
in muscle tissue due to inactivity, but also due to hormonal and neurological changes.
Gender: Generally, men have a faster metabolism than women because they tend to be larger and
have more muscle tissue.
Body size: Larger adult bodies have more metabolically active tissue, which leads to a higher
BMR/RMR.
Body composition: Muscle tissue uses more calories than fat, even at rest.
Genetic predisposition: Metabolic rate may be partly determined by genes.
Growth: Infants and children have a higher BMR/RMR related to the energy needs of growth and
maintenance of body temperature.
Hormonal and nervous controls: Hormonal imbalances can influence how quickly or how slowly the
body burns calories.
Environmental temperature: If temperature is very low or very high, the body has to work harder
to maintain a normal temperature; this increases the BMR/RMR.
Infection or illness: BMR/RMR increases if the body has to build new tissue or create an immune
response to fight infection.
Crash dieting, starving, or fasting: Eating too few calories encourages the body to conserve
through a potentially significant decrease in BMR/RMR. There can also be a loss of lean muscle
tissue, which further contributes to reducing BMR/RMR.
Physical activity: Hard-working muscles require extra energy during activity. Regular exercise
increases muscle mass, which increases energy consumption, even at rest.
Stimulants: Use of stimulants (e.g., caffeine) increases energy expenditure at rest. However, this is
not a healthy way to lose weight.

34. •The body cannot instantaneously increase the amount of oxygen to
working muscles when they begin working. There is a lag, or more
properly, a sluggish response during the first couple of minutes of work.
It is during this time that anaerobic glycolysis and the depletion of ATP
provide energy to the muscles. During these first few minutes, the body
experiences oxygen debt.
•Oxygen debt is the amount of oxygen required by the muscles after the
beginning of work, over and above that which is supplied to them
during the work activity.

35. Motor Skills
• A motor skill is a learned ability to cause a predetermined movement outcome with
maximum certainty.
• The goal of motor skills is to optimize the ability to perform the skill at the rate of success,
precision, and to reduce the energy consumption required for performance.
• Continuous practice of a specific motor skill will result in a greatly improved performance,
but not all movements are motor skills.

40. Types of body movements

42. In each
case, the mean and
the 5th to 95th
percentile range of
movement is given.

47. CTDs
• Cumulative trauma disorders (CTDs)
are
------injuries of the musculoskeletal
and nervous systems.
.

48. Collective term for syndromes
• discomfort
• impairment
• disability
• persistent pain in joints, muscles, tendons and
other soft tissues
with or without physical manifestations.

49. CAUSED BY
• Repetitive motions
• Assembly Line
• Lifting
• Climbing
• Painting
• Typing
• Tool Operations

50. • Forceful exertions –
pulling
pushing
lifting
gripping
moving heavy objects

51. • Awkward postures - body positions that are
not the natural resting position

52. • static postures - body positions held without
moving

53. • Mechanical compression of soft tissues in the
hand against edges or ridges (using tools or
objects which press against the palm)
• Fast movement of body parts
• Vibration, especially in the presence of cold
conditions
• Mental stress

54. • lack of sufficient recovery time (rest breaks,
days off)
• Exposure to cold temperatures, genetic
predisposition, stress and smoking may cause
the discomfort to occur sooner.

55. • CTD are found among cashiers in
supermarkets and among keyboard operators.
• Also, these injuries are quite often associated
with leisure and sports activities
• Tennis elbow is one of the better known
examples.
An irritation of the tissue
connecting the forearm muscle to
the elbow.

63. Tools with straight handles are for tasks where the force is exerted perpendicular to the
straightened forearm and wrist, for instance, when the force must be applied vertically.
Handle shape
Tools with "bent" or angled handles or tools with pistol-grips are
beneficial where the force is exerted in a straight line in the same
direction as the straightened forearm and wrist, especially when the
force must be applied horizontally