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5



gression rate (Fig. 1), .Thus, the slope for any
rate of progression may be taken from Figure 1.
A family of tines can then be .drawn which
allows rapid estimation of energy expenditure
for any grade between 0 and 97 and any rate of
progression between 1.5 and 4.0 miles per hour
for subjects with loads up to 30 Kg (Fig. 2).

The pooled data from this study and open
literature (1,3) were treated statistically and
the following curve fitting formula evolved
relating progression rate, load and grade over
the ranges, 1.5 to 4.5 mph (S), 0 to 30 Kg load
(L), 0- 9% grade (G).

Energy cost (70 Kg subject), Keal/min = 4.3

+ [-LIS — 0.22S"] + [-6.3G + 8.2GS — 0.05GS"
+3.6G°S'] + [4.06LG — 1.77LGS + 0.003LS*
+ 0.24LGS* — 0.06LG’S’}
Calculations of predicted values for energy cost
from this formula are in close agreement with
observed values and with predicted values
using the formula presented by Bobbert (3).
However, Figure 2, with appropriate interpo-
lation, should be more useful than application
of either formula. The fact that the present
results agree with earlier work (1) indicates
that reasonable estimates can be made for en-
ergy expenditure under a wide variety of
conditions.

Variations in such parameters as stature,
stride, physical condition, and skill in adjust-
ment of a load all influence the energy cost of
prsgcession. For this reason estimates of en-
ergy cost must be regarded as first approxima-
tions subject to correction for naturd of the
terrain, physical condition, stature of the sub-
ject, and other variables. Héwever, it seems
probable that for-a given rate of progression
and grade the enérgy cost per unit weight is
essentially the same, regardless of the distribu-
tion of total weight between body’ weight and
load within the range 0 to 30 Kg load for a
reasonably fit individual.

REFERENCES

1, Passmore, R. and J. V. G. A. Dumin, Physiol.
Rev, 35:801, 1955.

. Weir, J.B. DeV. J. Physiol. 109:1, 1949,
3. Bobbert, A. C. J. Appl. Physiol. 15:1015, 1960.

re

Some Characteristics Of Test Subjects

Subject

me Noe

Oo D

Mean

Age
yrs
28
19
19
21
21
21
19
33
21
21
22

Table I
Height Weight
cm Kg
172 69.5
175 80.8
175 59.5
183 70.8
175 84.0
178 77.6
180 745
178 84.9
178 83.1
183 713
178 75.6

- JoFat

9.5
16.3
9.0
9.1
10.1
11,3
10.0
12.8
12.2
8.7
10.9


FAA AC 6

ENERGY COST
GRACE

SLOPE,

ENERGY COST
keal/min/KG tat
8

8

2-271

ase
7 °
Ole
‘
010 F
008 F °
006 F
004 F __
.
802 F
° 1 1 1
2 3 4
PROGRESSION RATE, mph
Ficcne I~ Slope of the curve for energy cost versus grade
plotied against progress:
6

14

12

3

2

© BOBBERT (3
@ THIS STUDY

y

Numbers on curves rater to Treadmill speed In miles per hour

=

UNE,

GRADE, %

2—Graph for estinating
provression betwe
and: grades up to

~4-

energy cost for rates uf
Sand 4.0 miles per hour,
with loads up te 30 Ky.


AD ~> $0667

PREDICTION OF
ENERGY COST OF
TREADMILL WORK

@ /./ 0

625

FEDERAL AVIATION AGENCY
Civil Aeromedical Research Institute

AERONAUTICAL CENTER
OKLAHOMA CITY, OKLAHOMA

~

APRIL 1962



PREDICTION OF
ENERGY COST OF TREADMILL WORK

P. F. lampietro, Ph.D.

Environmental Physiology Branch
Civil Aeromedical Research Institute

and
Ralph F. Goldman, Ph.D.

Military Ergonomics Branch
U.S. Army Research Institute of Environmental Medicine
Natick, Massachusetts

a

FEDERAL AVIATION AGENCY
AERONAUTICAL CENTER
CIVIL AEROMEDICAL RESEARCH INSTITUTE
OKLAMOMA CITY,
April 1962



ee

Ym

PREDICTION OF ENERGY COST OF TREADMILL WORK

P. F. lampietro, Ph.D., and Ralph F. Goldman, Ph.D.

oat saa ,
he relative contributions of rate of progression (1.5 to 4.0 mph),

grade (4 to 9%), and lo:
mill work were determ

ically with some of the available energy cost
rovided for estimating energy expenditure. It was tenta-
that for grade walking over th
ssentially the same w:
lata are useful in that a correlation hetween the
mill studies using different speeds and

useful graph is
tively conclude:
cost per unit weight is e:
body or the load. The d
diverse literature reports on tread:

Joads is made feasible. i?

INTRODUCTION

In a current attempt to formulate an expres-
sion relating the energy cost of progression with
such parameters as load, speed and grade, in-
formation on the interaction of load and speed
with grade was not available. Experimental
work was carried out to supply this data and
the results have been irleorporated with other
data (1, 3) for the energy cost of walking at
various speeds and grades with no lgad and

t

carrying loads on the level. {

‘
METHODS?

Ten men in good physical condition were
selected from a group of volunteer subjects;
their physical characteristits are preser ted in
Table I. The subjects walked on two large
(4 man) treadmills which were set at a given

ade (3%, 6%, or 9%) and speed (1.5, 2.5, 3.5 or
4 mph). Three standard loads were selected
‘and made up on packboards so that the total
weight of loa# and packing was 10, 20 or
30 Kilograms. All measurements were com:
pleted by 1045 hours.

Duplicate Tissot collections of expired air
were taken on each subject during the Jast fif-

ad (10 to 30 Kg), to the total energy cost of tread-
ined. The data obtained were

integrated graph-
data in the literature. A

e ranges studied, the energy
hether the weight is of the

teen minutes of a 45-minute walk and oxygen
concentration was measured with a Beckman
paramagnetic 0, enalyzer. Energy cost was
calculated according to the method suggested
by Weir (2).
Load, speed and grade were statistically ran-
domized to minimize training effects. The de-
sign for the study called for 22 conditions (i.e.
3¢ slope, 10 Kg foad, 2.5 mph; 3% slope, 20 Kg
load, 2.5 mph; ete., Table II) with five subjects
studied in each condition. Subjects were ranked
with respect to percent body fat so that the five
subjects studie for a given condition repre-
sented a cross-section within the relatively nar-
row range of body fat presented by the group,
thus reducing the effect of individual variation.

, RESULTS AND DISCUSSION

The results (Table If) show that energy cost
per unit weight (subject weight plus loads of
from 10 to 30° Kg) is a constant for a given
grade and speed, Using data from Bobbert
(3), to suppply values for the energy cost of
walking on the level, it possible to calculate
the slopes of the curves for energy cost versus
grade at each of the progression rates studied.
These stopes were then plotted against pro-

as

-1l-