Human limb skeletal muscle wasting and architectural remodeling during five to ten days intubation and ventilation in critical care - an observational study using ultrasound

© 2016 The Author(s).Background: Critically ill patients frequently suffer muscle weakness whilst in critical care. Ultrasound can reliably track loss of muscle size, but also quantifies the arrangement of the muscle fascicles, known as the muscle architecture. We sought to measure both pennation angle and fascicle length, as well as tracking changes in muscle thickness in a population of critically ill patients. Methods: On days 1, 5 and 10 after admission to critical care, muscle thickness was measured in ventilated critically ill patients using bedside ultrasound. Elbow flexor compartment, medial head of gastrocnemius and vastus lateralis muscle were investigated. In the lower limb, we determined the pennation angle to derive the fascicle length. Results: We recruited and scanned 22 patients on day 1 after admission to critical care, 16 were re-scanned on day 5 and 9 on day 10. We found no changes to the size of the elbow flexor compartment over 10days of admission. In the gastrocnemius, there were no significant changes to muscle thickness or pennation angle over 5 or 10days. In the vastus lateralis, we found significant losses in both muscle thickness and pennation angle on day 5, but found that fascicle length is unchanged. Loss of muscle on day 5 was related to decreases in pennation angle. In both lower limb muscles, a positive relationship was observed between the pennation angle on day 1, and the percentage of angle lost by days 5 and 10. Discussion: Muscle loss in critically ill patients preferentially affects the lower limb, possibly due to the lower limb becoming prone to disuse atrophy. Muscle architecture of the thigh changes in the first 5days of admission, in particular, we have demonstrated a correlation between muscle thickness and pennation angle. It is hypothesised that weakness in the lower limb occurs through loss of force generation via a reduced pennation angle. Conclusion: Using ultrasound, we have been able to demonstrate that muscle thickness and architecture of vastus lateralisundergo rapid changes during the early phase of admission to a critical care environment

Multivariate analysis of 200-m front crawl swimming performance in young male swimmers

The aim of the present study was to evaluate the biomechanical (stroke rate, stroke length, and stroke index), anthropometrical (body height, body mass, body mass index, arm span, shoulders width, thigh, leg and upper arm lengths), and muscle architectural (muscle thickness, pennation angle, and fascicle length) parameters as predictors of 200-m front crawl swimming performance in young male swimmers. Twenty-two county level male swimmers (mean ±SD: age: 14.52 ± 0.77 years; body height: 173 ± 5 m; body mass: 60.5 ± 5.7 kg) performed a 200-m front crawl swimming test in a 25-m pool. Stepwise regression analysis revealed that biomechanical parameters (87%) characterized best 200-m front crawl swimming performance, followed by anthropometrical (82%) and muscle architectural (72%) parameters. Also, stroke length (R2 = 0.623), body height (R2 = 0.541), fascicle length of Triceps Brachii (R2 = 0.392) were the best single predictors that together explained 92% of the variability of the 200-m front crawl swimming performance in these swimmers. As a conclusion, with respect to higher performance prediction power of biomechanical parameters, technique should represent the core of the training program at these ages. In addition, these findings could be used for male young swimmers selection and talent identification

Implementing Ultrasound Imaging for the Assessment of Muscle and Tendon Properties in Elite Sports: Practical Aspects, Methodological Considerations and Future Directions.

Ultrasound (US) imaging has been widely used in both research and clinical settings to evaluate the morphological and mechanical properties of muscle and tendon. In elite sports scenarios, a regular assessment of such properties has great potential, namely for testing the response to training, detecting athletes at higher risks of injury, screening athletes for structural abnormalities related to current or future musculoskeletal complaints, and monitoring their return to sport after a musculoskeletal injury. However, several practical and methodological aspects of US techniques should be considered when applying this technology in the elite sports context. Therefore, this narrative review aims to (1) present the principal US measures and field of applications in the context of elite sports; (2) to discuss, from a methodological perspective, the strengths and shortcomings of US imaging for the assessment of muscle and tendon properties; and (3) to provide future directions for research and application