Stan L. Lindstedt, PhD
Office: Peterson Hall, Bldg. 22, Rm. 222
- comparative physiology
- muscle plasticity
- body-size constraints on function
The primary research interest in our laboratory is the
adaptive plasticity of vertebrate skeletal muscle. How is it that muscle adapts
to the nature and intensity of the demands placed upon it?
These changes involve shifts in metabolic properties such as
the densities of capillaries and mitochondria as well as contractile properties
such as the force, velocity and efficiency of contraction.
Skeletal muscle is remarkable in part because shifts in very
few structural components result in outcomes as diverse as muscles designed for
burst power, high frequency or posture, heat or sound production, to name just
a few. To investigate these properties of muscle, our research involves a
variety of techniques as well as animal and human models.
Techniques involve physiological investigation of work
output and oxygen consumption; quantitative ultrastructure with the electron
microscope and biochemical investigation of myosin isozymes and ATPase
activity; and finally, we use NMR spectroscopy to investigate high energy
phosphate regulation of aerobic muscle energetics. In addition to varing oxygen
demand, we examine the impact of varying oxygen availability (i.e.,
Our model systems include the rattlesnake tail-shaker
muscle; chronic cold exposure in mammalian muscle (muscle as a heater organ)
and investigation of respiratory and locomotor muscle adaptation in humans.
A shock absorber functions as a damper when a
noncompressible fluid is driven past a piston, converting kinetic energy to
heat. If the shock absorber is in series with a spring, then stretching the
spring-shock results in tension on the spring or extension of the shock,
depending on both the magnitude and time course of the force produced.
When an active muscle is lengthened during an eccentric
contraction, it behaves like a shock absorber-spring complex. In hiking
downhill, nearly all of the energy that stretches the active muscle is lost as
heat (extension of the shock).
In contrast, running mammals store most of the energy
required to stretch the muscle as elastic recoil potential energy (extension of
the spring), which can be recovered on the subsequent stride.
The time course of stretch and recovery of elastic recoil
energy are dependent on both the magnitude of the forces involved as well as
the compliance (spring property) of the muscle. As both of these properties are
body size dependent, small animals move with predictably higher stride
frequencies than do large animals.
S. L. Lindstedt, P. C. LaStayo and T. E. Reich
News in Physiological Sciences 16: 256-261, 2001.
Moon, B.R., K.E. Conley, S.L. Lindstedt and M.R.
Urquhart (2003) Minimal shortening in a high-frequency muscle. J. Expl. Biol.
LaStayo, P.C., G. Ewy, D. Pierotti, R. Johns,
S.L. Lindstedt (2003) The Positive Effects of negative work: Increased muscle
strength and decreased fall-risk in a frail-elderly population. J. Gerontology
LaStayo, P.C., J. Woolf, M.D. Lewek, L. Snyder-Mackler,
T. Reich, S.L. Lindstedt. (2003) Eccentric muscle contractions: Their
contribution to injury prevention rehabilitation and sport. J Ortho Sport Phys
Ther, 33: 557-571.
Schaeffer, P.C., J.J. Villarin and S.L.
Lindstedt (2003) Chronic cold exposure increases skeletal muscle oxidative
structure and function in Monodelphis domestica, a marsupial lacking brown
adipose tissue. Physiological and Biochemical Zoology 76: 877-887.
Villarin, J.J., P.J. Schaeffer, R.A. Markle,
S.L. Lindstedt (2003) Potential contribution of liver tissue to aerobic energy
balance following chronic cold exposure in the marsupial, Monodelphis
domestica. Comp. Biochem. Physiol. A 136: 621-630.