GENERAL RESEARCH INTERESTS:

I aim to understand how animals function mechanically and physiologically in their environment. Specifically, I integrate biomechanics, muscle physiology and functional morphology to elucidate the mechanisms underlying locomotion and feeding in vertebrates. An emerging focus is how exercise-induced fatigue influences in vivo muscle function and locomotor stability in bipedal vertebrates. Using guinea fowl as a model system, I am exploring topics that are applicable to human health and funciton. Given that the physiological mechanisms underlying locomotion and feeding have been modified over major evolutionary transitions in vertebrate ecology, I study various aspects of evolutionary adaptation by coupling my mechanical approaches with evolutionary and ecological perspectives. The following are several past and current research initiatives.

1. Muscle dynamics and biomechanics of vertebrate locomotion (see pubs 1, 2, 3, 6, 14, 15, 16 &20)

2.  Effects of exercise-induced fatigue on skeletal muscle mechanics and activation patterns (see pub 18)

3.  The relationships between muscle fatigue and locomotor stability

4.  The neurobiology and biomechanics of tail autotomy in lizards (see pub 19)

5.  Physiology, biomechanics and evolution of predator-prey interactions in vertebrates (see pubs 6, 9, 10 & 11)

6. Hydrodynamics and biomechanics of suction feeding in fishes (see pubs 4, 5, 7, 8, 12 & 13)

EXPERIMENTAL TECHNIQUES:

1. Digital particle image velocimetry (DPIV): This is a modern computational technique that permits the visualization of fluid movement. I use this to determine flow patterns during suction feeding in fishes.

2. Electromyography (EMG): This technique allows one to measure the electrical activity in a muscle using indwelling electrodes. I use this to quantify the intensity and timing of activation patterns during dynamic locomotion.

3. Sonomicrometry: This technique utilizes ultrasonic pulses between piezoelectric crystals to measure distances in real time. For example, I implant these into muscles to measure the changes in length along a fascicle.

4. High-speed digital video: I use a pair of Photron APX-RS cameras (capable of filming 250,000 images/second) to quantify three-dimensional high-speed movements during locomotion and prey capture.

5. In vivo pressure recordings: By surgically implanting pressure transducers into the mouth (buccal) cavities of fishes, I quantify the pressure within the buccal cavity relative to the surrounding fluid during suction feeding in fishes.