Size Matters Flashcards
Alexander, Jayes, Maloiy and Wathuta - April 1979
HYPOTHESIS
- If mammals of different sizes are geometrically similar, the lengths/diameters of corresponding limbs are proportional to body mass^0.33
- Mcmahons theory predicts length ∝ BM^0.25 and diameter ∝ BM^0.38
Alexander, Jayes, Maloiy and Wathuta - April 1979
RESULTS
- Length ∝ BM^0.35
- Diameter ∝ BM^0.36
Alexander, Jayes, Maloiy and Wathuta - April 1979
METHOD
- 435 different measurements obtained
- Measurements from bones on 1 side of the body
- Steel rule and vernier caliper used
Least squares regression used to obtain allometric Eq
A.A.Biewener - January 1982
HYPOTHESIS
Bone strength varies with animal size
A.A.Biewener - January 1982
Results
- No significant strength difference found in bones of various size therefore large animals have less SF
- Small animal bones far stronger than necessary or other aspects of locomotion act to decrease peak locomotory stresses
A.A.Biewener - January 1982
METHOD
Fracture strength of principle ones tested in 3-point bending and compared with published data
A.A.Biewener - July 1989
HYPOTHESIS
- Theorised that peak bone stress in mammals from 0.1kg-300kg is independent of bone size and a SF of 2-4 is maintained
- These stress changes achieved by a size dependent change in limb posture (crouched for mammals, upright for larger species)
A.A.Biewener - July 1989
RESULTS
- Mechanical advantage increased with body mass (forelimb and hindlimb)
- Overall scaling ∝ BM^0.258
- Newtons/kg decreases with size through EMA
A.A.Biewener - July 1989
METHOD
- Different sized mammals made to run over force platform
- Filmed with lateral view to determine EMA
S.R.Bullimore and J.F.Burn - December 2003
HYPOTHESIS
- For animals to move in a dynamically similar way, they must exhibit distortions of limb structure to compensate for size independence of tendon elastic-modulus
- Tendon EM has significant effect on dynamics of locomotion due to effect on limb stiffness
S.R.Bullimore and J.F.Burn - December 2003
RESULTS
Mammals show some dynamic similarity at equal Froude No, but other parameters will systematically deviate from dynamic similarity
Garland - June 1982
HYPOTHESIS
Determine empirical relationship between max running speed and body mass
Garland - June 1982
RESULTS
- MRS scales as BM^0.17
- Agrees with predictions of dynamically similar animals
- Optimal speed with regards to running approx 119kg
Garland - June 1982
METHOD
Comparison of available data on speed of mammals
C.M.Pollock and R.E.Shadwick - August 1993
HYPOTHESIS
Investigated allometric relationships between mechanical properties of various limb tendons and body mass
C.M.Pollock and R.E.Shadwick - August 1993
RESULTS
Elastic modulus and hysteresis of digital flexor, ankle extensor and digital extensor tendons do not vary significantly between animals of different body mass
C.M.Pollock and R.E.Shadwick - August 1993
METHOD
The elastic modulus and hysteresis of digital flexor, ankle extensor and digital extensor tendons from 18 species of quadrupedal mammals from 0.5kg to 545kg were determined from cyclic tensile testing in vitro.
