Magnetic Resonance-Compatible Arm-Crank Ergometry: A New Platform Linking Whole-Body Calorimetry to Upper-Extremity Biomechanics and Arm Muscle Metabolism

Riemer J K Vegter; Sebastiaan van den Brink; Leonora J Mouton; Anita Sibeijn-Kuiper; Lucas H V van der Woude; Jeroen A L Jeneson

doi:10.3389/fphys.2021.599514

Magnetic Resonance-Compatible Arm-Crank Ergometry: A New Platform Linking Whole-Body Calorimetry to Upper-Extremity Biomechanics and Arm Muscle Metabolism

Front Physiol. 2021 Feb 19:12:599514. doi: 10.3389/fphys.2021.599514. eCollection 2021.

Authors

Riemer J K Vegter¹, Sebastiaan van den Brink¹, Leonora J Mouton¹, Anita Sibeijn-Kuiper², Lucas H V van der Woude^{1

3}, Jeroen A L Jeneson^{2

4}

Affiliations

¹ Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, Netherlands.
² Department of Biomedical Sciences of Cells and Systems, Cognitive Neuroscience Center, University Medical Center Groningen, Groningen, Netherlands.
³ Center for Rehabilitation, University Medical Center Groningen, Groningen, Netherlands.
⁴ Center for Child Development and Exercise, Wilhelmina's Children's Hospital, University Medical Center Utrecht, Utrecht, Netherlands.

Abstract

Introduction: Evaluation of the effect of human upper-body training regimens may benefit from knowledge of local energy expenditure in arm muscles. To that end, we developed a novel arm-crank ergometry platform for use in a clinical magnetic resonance (MR) scanner with ³¹P spectroscopy capability to study arm muscle energetics. Complementary datasets on heart-rate, whole-body oxygen consumption, proximal arm-muscle electrical activity and power output, were obtained in a mock-up scanner. The utility of the platform was tested by a preliminary study over 4 weeks of skill practice on the efficiency of execution of a dynamic arm-cranking task in healthy subjects.

Results: The new platform successfully recorded the first ever in vivo ³¹P MR spectra from the human biceps brachii (BB) muscle during dynamic exercise in five healthy subjects. Changes in BB energy- and pH balance varied considerably between individuals. Surface electromyography and mechanical force recordings revealed that individuals employed different arm muscle recruitment strategies, using either predominantly elbow flexor muscles (pull strategy; two subjects), elbow extensor muscles (push strategy; one subject) or a combination of both (two subjects). The magnitude of observed changes in BB energy- and pH balance during ACT execution correlated closely with each strategy. Skill practice improved muscle coordination but did not alter individual strategies. Mechanical efficiency on group level seemed to increase as a result of practice, but the outcomes generated by the new platform showed the additional caution necessary for the interpretation that total energy cost was actually reduced at the same workload.

Conclusion: The presented platform integrates dynamic in vivo ³¹P MRS recordings from proximal arm muscles with whole-body calorimetry, surface electromyography and biomechanical measurements. This new methodology enables evaluation of cyclic motor performance and outcomes of upper-body training regimens in healthy novices. It may be equally useful for investigations of exercise physiology in lower-limb impaired athletes and wheelchair users as well as frail patients including patients with debilitating muscle disease and the elderly.

Keywords: 31P-magnetic resonance spectroscopy; arm-crank ergometer; biomechanics; calorimertry; physiology; upper-body exercise.