February 07, 2014

The Effect of High Intensity Interval Training (HIT) on Skeletal Muscle

Michael Murphy '14

Abstract:

Skeletal muscle holds several vital functions in our body including heat production and force production for breathing, support, and locomotion. To optimize our aerobic and anaerobic capacities, we must maintain a level of exercise in our daily lives. Yet instead of wasting so much time trying to get fit, maybe we can look more towards optimizing the deeper mechanism in the skeletal muscle behind building this tolerance: mitochondrial associated proteins. Currently, research shows that a similar increase can be found in exercise tolerance (aerobic and anaerobic) and mitochondrial protein following both low-volume High Intensity Interval Training (HIT) and short-term endurance training. This finding has provided a potential alternative to endurance training that will require significantly less training time for the same results. The purpose of this study was two-fold: 1) to confirm previous low-volume HIT results of increased aerobic and anaerobic capacities, and 2) to evaluate changes induced by 4 weeks of low-volume HIT in the mitochondrial-related protein content of skeletal muscle. 8 recreationally active males from Queen’s University completed the 4-week HIT program consisting of 4 weekly sessions. Each session took place on a Monark Ergomedic 874E ergometer, which was set at a resistance weight of 170% of the participant’s peak aerobic power. The “Tabata Protocol” based study had the participants complete 4 minute sessions of 8 20 second intervals, with 10 seconds of rest between each interval. Muscle biopsies were taken prior to and after the completion of the study (pre- and post-training). In addition, participants completed a VO₂peak test and a Wingate test pre-, mid-, and post-training for comparison. Significant increases were found in VO₂peak, aerobic power (mean and peak), mitochondrial proteins COX I and COX IV, and whole-muscle and nuclear extractions of PGC-1α. These results appear to compare favorably with other previous HIT and short term-endurance studies requiring longer training sessions, but a direct study for comparison is yet to be completed. The demonstration from this study that several mitochondrial protein, PGC-1α protein content, and exercise capacity (aerobic and anaerobic) can be improved in only 4 min of total training time per day, 4 days per week using low volume HIT cycle training, warrants a path for future studies in the underlying mechanisms behind the increases seen in this training protocol.

Identification of Human Remains: an Intersection Between DNA Analysis and Forensic Entomology

Jon Pinke '14

Abstract:

DNA analysis in forensic science has progressed to the point of absurd statistical values and near irrefutable certainties. DNA evidence from crime scenes is collected, processed, and conclusions are made linking a suspect to a crime scene. However, DNA analysis in respect to identification of human remains that are otherwise unidentifiable and/or not suitable for DNA analysis via commission of a crime is not as prevalent in the field. Forensic Entomology offers an established method of determining postmortem interval of a corpse, and the collection of insects feeding on an unidentified/unidentifiable body for DNA analysis allows a timeline of events to be better constructed by investigators. Here, the identification of human remains through the analysis of short tandem repeats (STR) of DNA harvested from the gastrointestinal contents of fly larvae is explored and applied in case examples.