Medicine and science in sports and exercise
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Med Sci Sports Exerc · Jan 2012
ReviewActiGraph and Actical physical activity monitors: a peek under the hood.
Since the 1980s, accelerometer-based activity monitors have been used by researchers to quantify physical activity. The technology of these monitors has continuously evolved. For example, changes have been made to monitor hardware (type of sensor (e.g., piezoelectric, piezoresistive, capacitive)) and output format (counts vs raw signal). ⋯ This article may help researchers gain a better understanding of the functioning of activity monitors. For example, a common misconception among physical activity researchers is that the ActiGraph GT1M and GT3X are piezoelectric sensor-based monitors. Thus, this information may also help researchers to describe these monitors more accurately in scientific publications.
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Med Sci Sports Exerc · Jan 2012
Randomized Controlled TrialEffects of resistance training on adiposity and metabolism after spinal cord injury.
This pilot work was conducted to evaluate the effects of neuromuscular electrical stimulation resistance training (RT) of the paralyzed knee extensor muscle groups on skeletal muscle and intramuscular fat (IMF) cross-sectional areas, trunk visceral adipose tissue (VAT), carbohydrate, and lipid profiles in men with spinal cord injury. ⋯ Twice-weekly evoked RT to the paralyzed lower extremities resulted in significant skeletal muscle hypertrophy that was associated with reduction in VAT, VAT/subcutaneous adipose tissue ratio, and percent IMF. Significant improvements in insulin profile and lipid metabolism were noted in the RT + diet when compared with diet alone.
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Med Sci Sports Exerc · Jan 2012
ReviewProtocols for evaluating equivalency of accelerometry-based activity monitors.
A wide array of accelerometer-based activity monitors has been developed to facilitate objective monitoring of physical activity behaviors, but it has proven difficult to equate outputs from different monitors. On the surface, commercially available monitors seem to be performing the same basic task-monitoring total body acceleration. ⋯ To advance physical activity assessment and improve our ability to compare results across studies using different monitors, it is important to conduct functional equivalency studies in a standardized and systematic way. This article summarizes issues associated with monitor equivalency and proposes methods for standardization and quality control in future research.