Quadriceps muscle use in the flywheel and barbell squat
2011 (English)In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, Vol. 82, no 1, 13-19 p.Article in journal (Refereed) Published
Background: Resistance exercise has been proposed as an aid to counteract quadriceps muscle atrophy in astronauts during extended missions in Orbit. While space authorities have advocated the squat exercise should be prescribed, no exercise system suitable for in-flight use has been validated with regard to quadriceps muscle use. We compared muscle involvement in the terrestrial “gold standard” squat using free weights and a non-gravity dependent flywheel resistance exercise device aimed at use in space. Methods: Ten strength-trained men performed five sets of 10 repetitions using the Barbell Squat (BS; 10 repetition maximum) or Flywheel Squat (FS; each repetition maximal), respectively. Functional magnetic resonance imaging (MRI) and surface electromyography (EMG) techniques assessed quadriceps muscle use. Exercise-induced contrast shift of MR images was measured by means of transverse relaxation time (T2). EMG root mean square (RMS) was measured during concentric (CON) and eccentric (ECC) actions and normalized to EMG RMS determined during maximal voluntary contraction. Results: The quadriceps muscle group showed greater exercise-induced T2 increase following FS compared with BS. Among individual muscles, the rectus femoris displayed greater T2 increase with FS (+24±14%) than BS (+8±4%). Normalized quadriceps EMG showed no difference across exercise modes. Discussion: Collectively, the results of this study suggest that quadriceps muscle use in the squat is comparable, if not greater, with flywheel compared with free weight resistance exercise. Data appears to provide support for use of flywheel squat resistance exercise as a countermeasures adjunct during spaceflight.
Place, publisher, year, edition, pages
Alexandria, VA: Aerospace Medical Association , 2011. Vol. 82, no 1, 13-19 p.
functional MRI, inertial resistance, knee extension, spaceflight, surface EMG
Physiology Sport and Fitness Sciences
IdentifiersURN: urn:nbn:se:kth:diva-42166DOI: 10.3357/ASEM.2867.2011ISI: 000285903500004PubMedID: 21235100OAI: oai:DiVA.org:kth-42166DiVA: diva2:446092
QC 201111162011-10-062011-10-062011-12-07Bibliographically approved