title: Strength training prior to endurance exercise: impact on the neuromuscular system, endurance performance and cardiorespiratory responses.
abstract: This study aimed to investigate the acute effects of two strength-training protocols on the neuromuscular and cardiorespiratory responses during endurance exercise. Thirteen young males (23.2 ± 1.6 years old) participated in this study. The hypertrophic strength-training protocol was composed of 6 sets of 8 squats at 75% of maximal dynamic strength. The plyometric strength-training protocol was composed of 6 sets of 8 jumps performed with the body weight as the workload. Endurance exercise was performed on a cycle ergometer at a power corresponding to the second ventilatory threshold until exhaustion. Before and after each protocol, a maximal voluntary contraction was performed, and the rate of force development and electromyographic parameters were assessed. After the hypertrophic strength-training and plyometric strength-training protocol, significant decreases were observed in the maximal voluntary contraction and rate of force development, whereas no changes were observed in the electromyographic parameters. Oxygen uptake and a heart rate during endurance exercise were not significantly different among the protocols. However, the time-to-exhaustion was significantly higher during endurance exercise alone than when performed after hypertrophic strength-training or plyometric strength-training (p <0.05). These results suggest that endurance performance may be impaired when preceded by strength-training, with no oxygen uptake or heart rate changes during the exercise.
authors.affiliation: Exercise Research Laboratory, Physical Education School, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Matheus
authors.initials: M
authors.lastname: Conceição
authors.affiliation: Exercise Research Laboratory, Physical Education School, Federal University of Rio Grande do Sul, Porto Alegre, Brazil. ; Department of Health Sciences, Public University of Navarre, Spain. ; Faculty of Physical Education, University of Brasília.
authors.forename: Eduardo Lusa
authors.initials: EL
authors.lastname: Cadore
authors.affiliation: Department of Health Sciences, Public University of Navarre, Spain.
authors.forename: Miriam
authors.initials: M
authors.lastname: González-Izal
authors.affiliation: Department of Health Sciences, Public University of Navarre, Spain.
authors.forename: Mikel
authors.initials: M
authors.lastname: Izquierdo
authors.affiliation: Exercise Research Laboratory, Physical Education School, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Giane Veiga
authors.initials: GV
authors.lastname: Liedtke
authors.affiliation: Exercise Research Laboratory, Physical Education School, Federal University of Rio Grande do Sul, Porto Alegre, Brazil. ; Sports Sciences, Brunel University of West London.
authors.forename: Eurico Nestor
authors.initials: EN
authors.lastname: Wilhelm
authors.affiliation: Faculty of Physical Education, University of Brasília.
authors.forename: Ronei Silveira
authors.initials: RS
authors.lastname: Pinto
authors.affiliation: Department of Nutrition, Federal University of Health Sciences of Porto Alegre, Brazil.
authors.forename: Fernanda Reistenbach
authors.initials: FR
authors.lastname: Goltz
authors.affiliation: Department of Nutrition, Federal University of Health Sciences of Porto Alegre, Brazil.
authors.forename: Cláudia Dornelles
authors.initials: CD
authors.lastname: Schneider
authors.affiliation: Department of Nutrition, Federal University of Health Sciences of Porto Alegre, Brazil. ; Exercise Pathophysiology Research Laboratory, Clinical Hospital of Porto Alegre, RS, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Ferrari
authors.affiliation: Faculty of Physical Education, University of Brasília.
authors.forename: Martim
authors.initials: M
authors.lastname: Bottaro
authors.affiliation: Exercise Research Laboratory, Physical Education School, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Luiz Fernando Martins
authors.initials: LF
authors.lastname: Kruel
keywords: aerobic exercise; concurrent training; fatigue; maximal strength; surface EMG