First published online August 18, 2005
Journal of Experimental Biology 208, 3293-3302 (2005)
Published by The Company of Biologists 2005
doi: 10.1242/jeb.01764
Performance of guinea fowl Numida meleagris during jumping requires storage and release of elastic energy
Havalee T. Henry,
David J. Ellerby and
Richard L. Marsh*
Department of Biology, Northeastern University, 360 Huntington
Avenue, Boston, MA, 02115, USA
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Fig. 1. Diagrammatic view of a guinea fowl standing on the jumping platform. The
numbers show the positions marked on each bird. (1) anterior end of sternum;
(2) midpoint between synsacrum and base of neck; (3) mid-synsacrum directly
above the hip joint; (4) hip joint center; (5) knee joint center; (6) ankle
joint center; (7) toe joint center; (8) distal tip of digit III. (Inset)
Diagram indicating limb angles. (a) The hip angle was measured between a line
parallel to the markers on the back and a line from the hip joint center and
the knee joint center; (b) the knee angle was calculated with the law of
cosines using constant femur and tibiotarsus segment lengths and the measured
distance between the hip and ankle (between a and c); (c) the ankle angle was
measured between the tibiotarsus and metatarsus; (d) the toe angle was
measured between the tarsometatarsus and digit 3.
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Fig. 2. Bird outlines drawn from video of a typical jump sequence. Time (ms) is
relative to the beginning of the jump, defined as when the vertical
acceleration became positive. (1) Bird standing upright. (2) Bird lowering
itself into a deep pre-jump crouch. (3) Jump start – point of deepest
crouch and start of first upward movement when acceleration becomes positive.
(4) Beginning of wing upstroke. (5) Middle of wing upstroke. 6) Start of
downstroke. (7) Lift-off.
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Fig. 3. Limb angles during a representative jump. Red line, hip angle; blue line,
knee angle; black line, ankle angle; green line, toe angle.
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Fig. 4. Horizontal and vertical displacement of the center of mass during a
representative jump, based on kinematic data. Zero time is the start of the
jump, defined as when the vertical acceleration became positive.
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Fig. 5. Velocities during a representative jump, as measured from kinematic and
force-plate data. Red line, horizontal velocity measured from kinematics; blue
line, vertical velocity measured from kinematics; black line, vertical
velocity measured from force plate; brown line, horizontal velocity measured
from force-plate data.
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Fig. 6. Force records during a representative jump, as measured from kinematics and
measured using the force-plate. Values for force are expressed as multiples of
body weight. Red line, horizontal velocity measured from kinematics; blue
line, vertical velocity measured from kinematics; black line, vertical
velocity measured using the force plate; brown line, horizontal velocity
measured using the force plate.
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Fig. 7. Muscle-mass-specific horizontal and vertical power outputs during a
representative jump, as measured from kinematic and force-plate data. Red
line, horizontal velocity measured from kinematics; blue line, vertical
velocity measured from kinematics; black line, vertical velocity measured from
force plate; brown line, horizontal velocity measured from force plate.
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Fig. 8. Muscle-mass-specific total power output during a representative jump, as
measured from kinematic and force-plate data.
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© The Company of Biologists Ltd 2005
