Elastic Energy Storage In The Achilles Tendon During Running Gaits
Anthropology; Evolutionary Biology
Foster A D; Butcher M T; Smith G A; Young J W
American Journal of Physical Anthropology
2015
2015-03
Journal Article or Conference Abstract Publication
n/a
Gait ontogeny and the avoidance of impact forces
Anthropology; Evolutionary Biology
Webber J T; Foster A D; Raichlen D A
American Journal of Physical Anthropology
2016
2016-03
Journal Article
n/a
Ontogenetic allometry and architectural properties of the paravertebral and hindlimb musculature in Eastern cottontail rabbits (Sylvilagus floridanus): functional implications for developmental changes in locomotor performance
acceleration; force; muscle mass; ontogeny; physiological cross-sectional area; power; scaling
Due to small body size, an immature musculoskeletal system, and other growth-related limits on performance, juvenile mammals frequently experience a greater risk of predation than their adult counterparts. As a result, behaviorally precocious juveniles are hypothesized to exhibit musculoskeletal advantages that permit them to accelerate rapidly and evade predation. This hypothesis was tested through detailed quantitative evaluation of muscle growth in wild Eastern cottontail rabbits (Sylvilagus floridanus). Cottontail rabbits experience high rates of mortality during the first year of life, suggesting that selection might act to improve performance in growing juveniles. Therefore, it was predicted that muscle properties associated with force and power capacity should be enhanced in juvenile rabbits to facilitate enhanced locomotor performance. We quantified muscle architecture from 24 paravertebral and hindlimb muscles across ontogeny in a sample of n = 29 rabbits and evaluated the body mass scaling of muscle mass (MM), physiological cross-sectional area (PCSA), isometric force (Fmax ), and instantaneous power (Pinst ), along with several dimensionless architectural indices. In contrast to our hypothesis, MM and PCSA for most muscles change with positive allometry during growth by scaling at M b 1.3 and M b 1.1 , respectively, whereas Fmax and Pinst generally scale indistinguishably from isometry, as do the architectural indices tested. However, scaling patterns indicate that the digital flexors and ankle extensors of juvenile S. floridanus have greater capacities for force and power, respectively, than those in adults, suggesting these muscle properties may be a part of several compensatory features that promote enhanced acceleration performance in young rabbits. Overall, our study implies that body size constraints place larger, more mature rabbits at a disadvantage during acceleration, and that adults must develop hypertrophied muscles in order to maintain mechanical similarity in force and power capacities across development. These findings challenge the accepted understanding that juvenile animals are at a performance detriment relative to adults. Instead, for prey-predator interactions necessitating short intervals of high force and power generation relative to body mass, as demonstrated by rapid acceleration of cottontail rabbits fleeing predators, it may be the adults that struggle to keep pace with juveniles.
Butcher M T; Rose J A; Glenn Z D; Tatomirovich N M; Russo G A; Foster A D; Smith G A; Young J W
Journal of Anatomy
2019
2019-07
<a href="http://doi.org/10.1111/joa.12991" target="_blank" rel="noreferrer noopener">10.1111/joa.12991</a>
Spring Function Of The Achilles Tendon In Walking And Running Gaits
Anthropology; Evolutionary Biology
Foster A D; Young J W; Capobianco F F; Peabody J T; Puleo N A
American Journal of Physical Anthropology
2019
2019-03
Journal Article or Conference Abstract Publication
n/a
The Relationship Between Hindlimb Loading And Cross-sectional Morphology In Bipedal Rats
Anthropology; Evolutionary Biology
Foster A D
American Journal of Physical Anthropology
2016
2016-03
Journal Article or Conference Abstract Publication
n/a
The Spring In Their Step: Ontogeny Of Ankle Joint Mechanics In Eastern Cottontail Rabbits (sylvilagus Floridanus)
Zoology
Foster A D; Butcher M T; Smith G A; Young J W
Integrative and Comparative Biology
2015
2015-04
Journal Article or Conference Abstract Publication
n/a