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>
Rituals of verification: the role of simulation in developing and evaluating empathic communication.
Physician-Patient Relations; Communication; Patient Satisfaction; Reproducibility of Results; Attitude of Health Personnel; Physician's Role; Educational Measurement; Students; Education; Empathy; Role Playing; Human; Patient Simulation; Medical; Bias (Research); Power; Rituals and Ceremonies; Clinical Competence – Standards; Educational Measurement – Standards
The use of simulation and standardized patients in medical education is firmly established. In this 'point-counterpoint' format we debate not their important function but the extent to which they are used to establish 'evidence' for trainees' empathic communication skills beyond their surface manifestations. We also question such issues as the power dynamics implicit in simulation when patients are not really worried or dependent but rather students who are under the evaluative surveillance gaze, often relying on formulaic and superficial behaviors associated with good communication. We offer educative experiences in narrative domains as opportunities to develop the habits of thinking and authentic feeling often absent in evaluative-based simulations.
Wear D; Varley JD
Patient Education & Counseling
2008
2008-05
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.pec.2008.01.005" target="_blank" rel="noreferrer noopener">10.1016/j.pec.2008.01.005</a>