International conference – Women’s health and workMarch 4-6 2015, Brussels

Physical Strength: Results and Differences in Age and Gender

Patrick Serafin, André Klußmann, Christoph Mühlemeyer, Inna Levchuk, Karl-Heinz Lang, Hansjürgen Gebhardt

Institute of occupational Health, Safety and Ergonomics e.V. – ASER, Wuppertal

Background

• Objective: support ergonomic product and workplace design – in manufacturing of work equipment, tools

(e.g. tools such as pliers, screwdrivers, etc); – in manufacturing of products from the private sector

(e.g. appliances such as can openers, etc)– in ergonomic job and task analysis

• Challenge: demographic change – larger proportion of older people in the total population; – larger proportion of older workers at the workplaces.

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Background

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Trend behavior of the maximum static muscle strength in male and female persons in the course of life (according to Hollmann and Hettinger, 2000)

0 10 20 30 40 50 60 70

20

40

60

80

100

0

ave

rag

e m

axim

um

fo

rce

(%

)

age in years

males males

females females

Sample: Population? Employees? Number of participants?

Which method for force estimation? How many Newtons are 100 %?

Which force cases were estimated?… standard deviation, confidence interval …

Aims and Methods

• Aims– Population sample on hand dimensions and different cases of

maximum force

• Methods – Standardized force measurements (in standing positions)

• pulling

• gripping

• turning (screwdriver)

– Determination of hand sizes• 3-D hand-scanner

• templates, etc.

– Standardized questionnaire - personal data• age, gender, body height / weight

• sports, leisure time activities

• occupational activities and physical exposures

• musculoskeletal symptoms and disorders

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Methods: Standardized force measurements

• Height-adjustable test stand to equalize individual variations of anthropometric dimensions

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Methods: Standardized force measurements

• Measurement of pulling strength

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Methods: Standardized force measurements

• Measurement of grip strength

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Methods: Standardized force measurements

• Measurement of torque strength

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left hand right hand

Body posture during force measurement

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pulling strength grip strength torque strength

Sample: n=1,207; including 428 females and 779 males

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Results: pulling strength

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Results: grip strength

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Results: torque strength

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Strength ratio of women and men

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0.66

0.62

0.55

Summary / Discussion

• Ratio of maximum force between men and women F / M varies from 0.55 to 0.66

• The level of maximum force only slightly differs among participants in the age from 15 to 69 years

• In the age groups between 20 and 59 years (nearly) no significant differences in the level of force can be seen

• These results are not in accordance with most data from literature, like e.g. from Hollmann & Hettinger (2000). In this publication (among others), the 20 to 25 years old males were described as strongest, with permanent significantly decreasing force with increasing age.

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Limiations

• Cross-sectional study

• Individual force progress during life can not be deduced

• Statements about (sub-)maximum forces with frequent execution can not be derived

• Statements about dexterity and endurance can not be derived– possibly here: major differences in the age groups

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Outlook

• Preliminary, descriptive analyzes show no significant differences between physically active and inactive people– Further analysis on this topic are required

• Correlations between hand dimensions and force could give more useful information for ergonomic design of products.– Further analysis on this topic are required

• Outlook: Multivariate analyzes including– Sports, leisure activities, MSDs– Relationships between the types of force.

• Target: Implementation of data in planning programs of product developers.

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• Thank you for your attention

• Patrick SerafinInstitute ASER e.V.Corneliusstr. 31, 42329 WuppertalGermanyEmail: serafin@institut-aser.de

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