Human Power

The human body is a machine. A biological machine, capable of working at a certain rate. For example an 80 kg man may be able to run up a flight of 50 steps, each step 16 cm high, in 20 seconds. He does a useful amount of work equal to the increase in gravitational potential energy,

The rate at which the man does useful work isalthough of course, since the human body is a machine less than 100% efficient, the rate at which it consumes energy is a great deal more than this, since a lot of energy is wasted as heat.

In a single day and average man might consume about 12000 kJ of energy as food. In a day there are 60*60*24=86400 seconds so the human body consumes energy at the rate of about

The rate at which the muman body consumes energy depends on what it is doing. Obvious strenuous activities demand a lot more power to be produced than non strenuous activities. The energy produced by the human body during various activities is shown in the table below.

Activity

W1)

Reclining

83

Seated relaxed

104

Standing relaxed

126

Sedentary activity (office, dwelling, school,laboratory)

126

Car driving

144

Graphic profession - Book Binder

153

Standing, light activity (shopping, laboratory,light industry)

167

Teacher

171

Domestic work -shaving, washing and dressing

180

Walking on the level, 2 km/h

198

Standing, medium activity (shop assistant, domesticwork)

209

Building industry - Brick laying (Block of 15.3 kg)

225

Washing dishes standing

261

Domestic work - raking leaves on the lawn

306

Domestic work - washing by hand and ironing(120-220 W)

306

Iron and steel - ramming the mould with a pneumatichammer

315

Building industry -forming the mould

324

Walking on the level, 5 km/h

360

Forestry -cutting across the grain with a one-manpower saw

369

Volleyball

418

Calisthenics

470

Building industry - loading a wheelbarrow withstones and mortar

495

Bicycling Golf Softball

522

Gymnastics

574

Aerobic Dancing Basketball Swimming

624

Sports - Ice skating, 18 km/h

648

Agriculture - digging with a spade (24 lifts/min.)

674

Skiing on level, good snow, 9km/h Backpacking Skating ice or roller Tennis

729

Handball Hockey Racquetball Cross Country Skiing Soccer

835

Running 12 min/mile Forestry - working with an axe (weight 2 kg. 33 blows/min.)

900

Sports - Running in 15 km/h

990

Add comment

Security code
Refresh