Sebastian Mathes, Tobias Link, Niklas Lehnen, Joachim Mester, Patrick Wahl

Publication: Chapter in Book/Report/Conference proceedingConference contribution - Published abstract for conference with selection processResearchpeer-review


Introduction Electromyostimulation (E) might be a useful tool to intensify endurance training without performing high external workloads. Therefore, the purpose of the present study was to investigate for the first time the chronic effects of superimposed E during cycling on aerobic and anaerobic capacity as well as on markers of muscle damage. Methods 21 male subjects (age: 23.4±4.9, mass: 76.3±9.4 kg, rel. VO2peak: 57±4.5 ml min-1 kg-1) were randomly assigned to either a cycling (C) or cycling with superimposed E (C+E) intervention group. They performed 14 training sessions over a four-week period. Depending on the group, each training session consisted of 60 min cycling at 60% PPO with or without superimposed E. Before and after training phase, subjects completed 1) a step test to determine VO2peak, peak power output (PPOST), power at 2 mmol l-1 blood lactate (PL2), onset of blood lactate accumulation (OBLA), and maximal fat oxidation rate (Fatmax); 2) a 30 sec Wingate anaerobic test to determine PPOW, mean power output (MPOW), and maximal rate of blood lactate accumulation (dLa dtmax-1); 3) a 20-min time-trial to determine MPOTT; and 4) maximal isometric/dynamic strength tests in leg curl and leg extension. Creatine kinase (CK) and lactate dehydrogenase (LDH) were determined over the whole training period. Fur- thermore, the person’s perceived physical state (PEPS) and the perceived physical pain (visual analog scale (VAS)) were recorded. Results According to PEPS and VAS, both interventions were equally demanding from the subject’s point of view. Only C+E caused significant increases in PL2 (C+E: +12% vs. C: +7%) and OBLA (C+E: +8% vs. C: +6%)), however, no significant differences were found between groups. Nevertheless, Cohen’s d revealed small effects between C+E and C (d=0.38; d=0.32). Significant differences between both groups were found for dLa dtmax-1 (C+E: +12% vs. C: +2%). Furthermore, Cohen’s d revealed small effects between both interventions (d=0.49). Only C caused significant increases in VO2peak (C: +7% vs C+E: 2%; d=0.37). Fatmax was significantly different between groups with higher change after C (C+E: -6% vs C: +12%; d=0.6). PPOST, MPOTT, MPOW and PPOW were significantly increased for both groups, however, C+E and C did not differ between each other. Effects for maximal strength could not be observed. Furthermore, only C+E caused significant increases in levels of CK and LDH. Discussion In conclusion, the results suggest that long-term endurance training with superimposed E affects aerobic and anaerobic capacity less on systemic level, but rather on a local level. Due to increases in PL2 and OBLA, higher increases in dLa dtmax-1, and no increase in VO2peak we presume that C+E improves glycolytic flux and lactate turnover by increased anaerobic and oxidative enzyme activities more than cardiovascular factors. Therefore, it can be speculated that C+E might contribute to improve endurance training efficiency in performance and health particularly by increasing lactate thresholds.
Original languageEnglish
Title of host publicationBook of Abstracts of the 20th annual Congress of the EUROPEAN COLLEGE OF SPORT SCIENCE
EditorsA. Radmann, S. Hedenborg
Number of pages1
PublisherEuropean College of Sport Science
Publication date07.2015
ISBN (Print)978-91-7104-567-6
Publication statusPublished - 07.2015
EventAnnual Congress of the EUROPEAN COLLEGE OF SPORT SCIENCE - Malmö, Sweden
Duration: 24.07.201527.07.2015
Conference number: 20 (Conference's information)