The relationship between maximum jumping performance and hind limb morphology/physiology in domestic cats (Felis silvestris catus)
Michelle A. Harris1,* and
Karen Steudel2
1 Biology Core Curriculum, University of Wisconsin-Madison, 307 Noland Hall,
250 N. Mills Street, Madison, WI 53706, USA
2 Department of Zoology, University of Wisconsin-Madison, Birge Hall, 430
Lincoln Drive, Madison, WI 53706, USA
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Fig. 1. Summary of studies of the relationship between limb length and various
locomotor performance categories in terrestrial vertebrates. The year of each
study is shown in parentheses. Studies shown in bold represent reports of
significant relationships between limb length and designated locomotor
performance; those shown in regular font did not find significant
relationships. Studies designated with an asterisk used lizards as the model
species. The animals used in the remaining studies (salamanders, large
ungulates, frogs and cats) are indicated by silhouettes. Note that the
majority of the investigations of the limb-length—jump performance
relationship have used frogs as subjects, and that the current study is the
only one to use an endothermic system.
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Fig. 2. Diagram of jump enclosure. Cats took off from an adjustable platform and
jumped upwards to the stationary landing box.
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Fig. 3. Digital video frames showing typical stages of the takeoff period preceding
cat jumps: (A) deep crouch, (B) mid-takeoff and (C) full extension of torso
and hind limb at takeoff. Note the three calibration lines (joined, forming
two right angles) in the background and the reflective dots designating the 11
anatomical landmarks whose movement was used to calculate maximum takeoff
velocity (TOV).
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Fig. 4. Diagram of the left hind limb bones of a cat showing the three extensor
muscles measured in this study: semimembranosus (hip extensor), vastus
lateralis (knee extensor) and lateral gastrocnemius (ankle extensor).
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Fig. 5. Ratio of potential to kinetic energy generated during takeoff vs.
residual fat mass (calculated from a regression of fat mass on lean body mass)
(Pearson product-moment correlation coefficient: r=0.678,
P=0.002, y=0.479x+0.00011).
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Fig. 6. Scan of SDS-PAGE gel showing myosin heavy chain (MHC) isoforms isolated
from the cat lateral gastrocnemius muscle and from a rat skeletal muscle
standard. Note that rat skeletal muscle contains a fourth isoform, Type IIb,
which is not found in cat skeletal muscle. In the cat samples, the MHC Type I
isoform migrates the furthest, followed by the Type IIx and Type IIa isoforms,
respectively.
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Fig. 7. Maximum takeoff velocity (TOV) on day 2 vs. day 1, demonstrating
the repeatability of jump performance over the two days on which it was
measured for each cat (Pearson product-moment correlation coefficient:
r=0.841, P<0.0001, y=0.889x+41.88).
There was no difference in mean TOV on day 1 vs. day 2 (paired
t-test: t=-1.072, P=0.299). The reference line
shown has a slope of 1.0.
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Fig. 8. (A) Significant negative relationship between the ratio of extensor muscle
mass/body mass and body fat mass (r=-0.720, P=0.001,
y=-2.3x10-6x+0.019). (B) Significant
positive relationship between maximum takeoff velocity (TOV) and the ratio of
extensor muscle mass/body mass (r=0.647, P=0.004,
y=7571x+220.9).
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© The Company of Biologists Ltd 2002
