Brink, S. van den (Sebastiaan) (2017) Muscle coordination and local metabolism in cyclic upper body exercise: working mechanisms of physical adaptation and motor learning. thesis, Human Movement Sciences.
Full text available on request.Abstract
Introduction: Mechanical efficiency (ME) has been found to improve as a result of low-intensity interventions. However, underlying working mechanisms at the level of individual muscles, their local energy metabolism and coordination have been negated so far. The aim of this research was therefore on the changes in ME, force and acceleration output, muscle activation and local muscle metabolism as a result of a three-week handcycle-like practice intervention. Methods: The newly developed platform using a MR-compatible handcycle allowed for a multitude of measurement tools. Three male able-bodied participants were included in the study. The intervention consisted of two pre- and post-tests and eight training sessions which resulted in a total of 80 minutes of handcycling. During the first pre- and post-test measurements of gas exchange, force and acceleration output and muscle activation were performed. During the second pre- and post-test phosphocreatine depletion, phosphomonoester accumulation and pH were determined using 31P-Magnetic Resonance Spectroscopy. In addition, force and acceleration data were gathered during training sessions. Results: The results indicated improvements in ME as a result of a three-week practice intervention. In addition, a reduction in heart rate and RER was found. The mean absolute force, delivered power output and sideways acceleration were found to be reduced. The mean force, indicating pushing or pulling movements, changed but the favor for either pushing or pulling remained mostly unchanged. Furthermore, a reduction was found in the mean percentage of EMG activation. The Coefficient of Variation of force output and EMG activation varied. The results of 31P-MRS measurements showed both improvements and decline. Conclusions: The low-intensity intervention resulted in an overall increase in ME. The improvement in ME mostly correlated to a larger reduction in delivered negative work and reduced muscle activation. Both predominantly pushing and pulling propulsion techniques were observed. However, a combined use appeared to be of higher efficiency. A slight shift in propulsion technique was found but the favor for either pushing or pulling remained. Furthermore, variability of muscle activation and force output appeared to be of less influence on the improvements in ME. Contradicting results towards the hypothesis were found regarding local muscle metabolism. The participants who were expected to show the largest improvements either remained similar or declined in terms of ATP efficiency. An explanation would be the fact that these participants experienced a significantly higher workload during the metabolic measurements of the post-test. Keywords: Motor learning, Propulsion technique, 31P-MRS, Energy metabolism.
| Item Type: | Thesis (UNSPECIFIED) |
|---|---|
| Supervisor name: | Vegter, dr. R.J.K. and Jeneson, dr. J.A.L. and Woude, prof. dr. L.H.V. van der |
| Faculty: | Medical Sciences |
| Date Deposited: | 04 May 2022 09:46 |
| Last Modified: | 04 May 2022 09:46 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/3226 |
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