title: Non-linear dynamics in muscle fatigue and strength model during maximal self-perceived elbow extensors training.
abstract: Our aim was to determine the dynamics in muscle strength increase and fatigue development during repetitive maximal contraction in specific maximal self-perceived elbow extensors training program. We will derive our functional model for m. triceps brachii in spirit of traditional Hill's two-component muscular model and after fitting our data, develop a prediction tool for this specific training system. Thirty-six healthy young men (21 +/- 1.0 y, BMI 25.4 +/- 7.2 kg/m(2)), who did not take part in any formal resistance exercise regime, volunteered for this study. The training protocol was performed on the isoacceleration dynamometer, lasted for 12 weeks, with a frequency of five sessions per week. Each training session included five sets of 10 maximal contractions (elbow extensions) with a 1 min resting period between each set. The non-linear dynamic system model was used for fitting our data in conjunction with the Levenberg-Marquardt regression algorithm. As a proper dynamical system, our functional model of m. triceps brachii can be used for prediction and control. The model can be used for the predictions of muscular fatigue in a single series, the cumulative daily muscular fatigue and the muscular growth throughout the training process. In conclusion, the application of non-linear dynamics in this particular training model allows us to mathematically explain some functional changes in the skeletal muscle as a result of its adaptation to programmed physical activity-training.
authors.affiliation: Laboratory for Functional Diagnostics, Department of Physiology, Medical School, University of Novi Sad, 3, Hajduk Veljko St. 21000 Novi Sad, Serbia. jpopadic@uns.ac.rs
authors.forename: Jelena Popadic
authors.initials: JP
authors.lastname: Gacesa
authors.forename: Tijana
authors.initials: T
authors.lastname: Ivancevic
authors.forename: Nik
authors.initials: N
authors.lastname: Ivancevic
authors.forename: Feodora Popic
authors.initials: FP
authors.lastname: Paljic
authors.forename: Nikola
authors.initials: N
authors.lastname: Grujic
mesh_terms: D000465:Algorithms; D001696:Biomechanical Phenomena; D004551:Elbow Joint / Q000502:physiology*; D006801:Humans; D008297:Male; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D017711:Nonlinear Dynamics; D010806:Physical Education and Training; D055815:Young Adult