be separately measured.
The strength of a muscle is measured by the utmost force which it can
exert _once_; its endurance by the number of times it can repeat a given
exertion _well within its strength_.

After much consideration and consultation it was decided not to place
reliance on the ordinary ergographs as a means of measuring endurance.
Instead, seven simple gymnastic tests of physical endurance were
employed, and one of mental endurance. The seven physical tests were:

(1) Rising on the toes as many times as possible.

(2) Deep knee bending, or squatting as far as possible and rising to the
standing posture, repeating as often as possible.

(3) While lying on the back, raising the legs from the floor to a
vertical position and lowering them again, repeating to the point of
physical exhaustion.

(4) Raising a 5-lb. dumb-bell (with the triceps) in each hand from the
shoulder up to the highest point above the head, repeating to the point
of physical exhaustion.

(5) Holding the arms from the sides horizontally for as long a time as
possible.

(6) Raising a dumb-bell (with the biceps) in one hand from a position in
which the arm hangs down, up to the shoulder and lowering it again,
repeating the motion to the point of physical exhaustion. This test was
taken with four successive dumb-bells of decreasing weight, viz., 50,
25, 10 and 5 lbs. respectively.

(7) Running on the gymnasium track at a speed to suit the subject, to as
great a distance as possible.

The mental test consisted of adding specified columns of figures as
rapidly as possible, the object being to find out whether the rapidity
of performing such work tended to improve during the experiment.

PERCENTAGE OF IMPROVEMENT IN ENDURANCE (EXACT OR UNDERSTATED) OF EIGHT
MEN.

AVERAGE.
B Lq. Lw. M P R T W
Jan.-Mar. 33+ 36 50 -- 26 18+ 66+ 33
Jan.-June 84+ 84+ 181 29 56+ 89+ 80+ 107+

The figures of this table show an undoubted increase in endurance, both
for the first half and more especially for the whole period of the
experiment.

Three methods of estimating the increase of endurance between January
and June were used. These may be put together in the following table:

PERCENTAGE OF INCREASE OF ENDURANCE, JANUARY TO JUNE, BY THREE METHODS.

AVERAGE SIX TESTS.
B E Lq. Lw. M P R T W
85 13 194 95 212 56+ 73 66 109

OMITTING DOU