title: Core Muscle Activity, Exercise Preference, and Perceived Exertion during Core Exercise with Elastic Resistance versus Machine.
abstract: Objectives. To investigate core muscle activity, exercise preferences, and perceived exertion during two selected core exercises performed with elastic resistance versus a conventional training machine. Methods. 17 untrained men aged 26-67 years participated in surface electromyography (EMG) measurements of five core muscles during torso-twists performed from left to right with elastic resistance and in the machine, respectively. The order of the exercises was randomized and each exercise consisted of 3 repetitions performed at a 10 RM load. EMG amplitude was normalized (nEMG) to maximum voluntary isometric contraction (MVC). Results. A higher right erector spinae activity in the elastic exercise compared with the machine exercise (50% [95% CI 36-64] versus 32% [95% CI 18-46] nEMG) was found. By contrast, the machine exercise, compared with the elastic exercise, showed higher left external oblique activity (77% [95% CI 64-90] versus 54% [95% CI 40-67] nEMG). For the rectus abdominis, right external oblique, and left erector spinae muscles there were no significant differences. Furthermore, 76% preferred the torso-twist with elastic resistance over the machine exercise. Perceived exertion (Borg CR10) was not significantly different between machine (5.8 [95% CI 4.88-6.72]) and elastic exercise (5.7 [95% CI 4.81-6.59]). Conclusion. Torso-twists using elastic resistance showed higher activity of the erector spinae, whereas torso-twist in the machine resulted in higher activity of the external oblique. For the remaining core muscles the two training modalities induced similar muscular activation. In spite of similar perceived exertion the majority of the participants preferred the exercise using elastic resistance.
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark.
authors.forename: Jonas
authors.initials: J
authors.lastname: Vinstrup
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark.
authors.forename: Emil
authors.initials: E
authors.lastname: Sundstrup
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark ; Physical Activity and Human Performance Group, SMI, Department of Health Science and Technology, Aalborg University, 9220 Aalborg, Denmark.
authors.forename: Mikkel
authors.initials: M
authors.lastname: Brandt
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark.
authors.forename: Markus D
authors.initials: MD
authors.lastname: Jakobsen
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark ; Prevention Health Exercise and Sport Research Group, Department of Physical Education and Sports, University of Valencia, 46010 Valencia, Spain.
authors.forename: Joaquin
authors.initials: J
authors.lastname: Calatayud
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark ; Physical Activity and Human Performance Group, SMI, Department of Health Science and Technology, Aalborg University, 9220 Aalborg, Denmark.
authors.forename: Lars L
authors.initials: LL
authors.lastname: Andersen