Abstract
Growing evidence points to the effectiveness of flywheel (FW) based iso-inertial resistance training in improving physical performance capacities. However, molecular adaptations induced by FW exercises are largely unknown. Eight resistance-trained men performed 5 sets of 10 maximal squats on a FW device. Muscle biopsies (fine needle aspiration technique) and blood samples were collected before (t0), and 2 h (t1) after FW exercise. Blood samples were additionally drawn after 24 h (t2) and 48 h (t3). Paired samples t-tests revealed significant increases, at t1, of mRNA expression of the genes involved in inflammation, in both muscle (MCP-1, TNF-α, IL-6) and peripheral blood mononuclear cells (IkB-α, MCP-1). Circulating extracellular vesicles (EVs) and EV-encapsulated miRNA levels (miR-206, miR-146a) significantly increased at t1 as well. Conversely, muscle mRNA level of genes associated with muscle growth/remodeling (IGF-1Ea, cyclin D1, myogenin) decreased at t1. One-way repeated measure ANOVAs, with Bonferroni corrected post-hoc pairwise comparisons, revealed significant increases in plasma concentrations of IL-6 (t1; t2; t3) and muscle creatine kinase (t1; t2), while IGF-1 significantly increased at t2 only. Our findings show that, even in experienced resistance trained individuals, a single FW training session modifies local and systemic markers involved in late structural remodeling and functional adaptation of skeletal muscle.
Highlights
Since the first appearance of an effective training apparatus able to combat the neuromuscular dysfunctions that occur during space flights (Berg and Tesch, 1994), gravity independent resistance exercise devices have found wide terrestrial applications in the fields of sports (de Hoyo et al, 2015), injury prevention (Askling et al, 2003), and clinical rehabilitation (Greenwood et al, 2007).Gravity independent devices employ a flywheel (FW), which is held by a fixed shaft anchored to a strap, to provide the resistance to muscular work
PBMC Gene Expression Levels Expression of IkB-α (FC = 1.50, 95% confidence interval (CI) = 1.16 to 1.88, p = 0.017, effect size (ES) = 1.11) and monocyte chemoattractant protein-1 (MCP-1) (FC = 1.50, 95% CI = 1.07 to 1.94, p = 0.013, ES = 1.18) genes increased significantly at t1, while mRNA levels of tumor necrosis factor-α (TNF-α) (FC = 0.95, 95% CI = 0.77 to 1.14, p = 0.432, ES = −0.29), IL-6 (FC = 1.29, 95% CI = 0.84 to 1.74, p = 0.216, ES = 0.48), and IL-6R (FC = 1.03, 95% CI = 0.86 to 1.21, p = 0.885, ES = 0.05) did not change significantly (Figure 4)
Using muscle fine needle aspiration (FNA) we demonstrated that MCP-1, TNF-α, and IL-6 gene expression increased 2 h after the FW training session
Summary
Since the first appearance of an effective training apparatus able to combat the neuromuscular dysfunctions that occur during space flights (Berg and Tesch, 1994), gravity independent resistance exercise devices have found wide terrestrial applications in the fields of sports (de Hoyo et al, 2015), injury prevention (Askling et al, 2003), and clinical rehabilitation (Greenwood et al, 2007).Gravity independent devices employ a flywheel (FW), which is held by a fixed shaft anchored to a strap, to provide the resistance to muscular work. By using FW devices a higher load than that of the concentric phase can be achieved with the eccentric action, namely “eccentric overload,” when the time of application of the breaking force needed to slow down the FW is intentionally reduced (for details, see: Berg and Tesch, 1994; Tesch et al, 2017). This makes it possible to perform eccentric exercise avoiding the difficulties associated with the complex technical optimization of a strictly eccentric regimen (i.e., third-party assistance, computer-guided electrically-powered devices, etc.)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
