title: Isometric strength training lowers the O2 cost of cycling during moderate-intensity exercise.
abstract: The effect of maximal voluntary isometric strength training of knee extensor muscles on pulmonary V'O(2) on-kinetics, the O(2) cost of cycling and peak oxygen uptake (V'O(2peak)) in humans was studied. Seven healthy males (mean ± SD, age 22.3 ± 2.0 years, body weight 75.0 ± 9.2 kg, V'O(2peak) 49.5 ± 3.8 ml kg(-1) min(-1)) performed maximal isometric strength training lasting 7 weeks (4 sessions per week). Force during maximal voluntary contraction (MVC) increased by 15 % (P < 0.001) after 1 week of training, and by 19 % (P < 0.001) after 7 weeks of training. This increase in MVC was accompanied by no significant changes in the time constant of the V'O(2) on-kinetics during 6 min of moderate and heavy cycling intensities. Strength training resulted in a significant decrease (by ~7 %; P < 0.02) in the amplitude of the fundamental component of the V'O(2) on-kinetics, and therefore in a lower O(2) cost of cycling during moderate cycling intensity. The amplitude of the slow component of V'O(2) on-kinetics during heavy cycling intensity did not change with training. Training had no effect on the V'O(2peak), whereas the maximal power output reached at V'O(2peak) was slightly but significantly increased (P < 0.05). Isometric strength training rapidly (i.e., after 1 week) decreases the O(2) cost of cycling during moderate-intensity exercise, whereas it does not affect the amplitude of the slow component of the V'O(2) on-kinetics during heavy-intensity exercise. Isometric strength training can have beneficial effects on performance during endurance events.
authors.affiliation: Department of Physiology and Biochemistry, Faculty of Rehabilitation, University School of Physical Education, AWF-Kraków, Al. Jana Pawla II 78, Kraków, Poland. jerzy.zoladz@awf.krakow.pl
authors.forename: Jerzy A
authors.initials: JA
authors.lastname: Zoladz
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Szkutnik
authors.forename: Joanna
authors.initials: J
authors.lastname: Majerczak
authors.forename: Marcin
authors.initials: M
authors.lastname: Grandys
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Duda
authors.forename: Bruno
authors.initials: B
authors.lastname: Grassi
mesh_terms: D000328:Adult; D001642:Bicycling; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D053580:Muscle Strength; D010101:Oxygen Consumption