Fitbits for birds (IMAGE) McGill University Caption Because of what this research shows about the relationship between muscle structure and flight performance, scientists will be able to use this non-invasive technology to measure muscle structure and definition in future. Credit Kristen Lalla Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.