title: Quadriceps low-frequency fatigue and muscle pain are contraction-type-dependent.
abstract: Eccentric contractions are thought to induce greater low-frequency fatigue (LFF) and delayed-onset muscle soreness (DOMS) than concentric contractions. In this study we induced a similar amount of eccentric quadriceps muscle fatigue during either a concentric or eccentric fatigue task to compare LFF and DOMS. Subjects (n = 22) performed concentric or eccentric fatigue tasks using 75% of the pre-fatigue maximal voluntary contraction (MVC) torque, and both tasks ended when the MVC eccentric torque decreased by 25% pre-fatigue. When subjects reached the failure criterion during the eccentric and concentric tasks, the concentric MVC was 78 +/- 9.8% and 64 +/- 8.4% of initial, respectively. LFF was greater after the concentric than the eccentric protocols (22 +/- 12.4% and 15 +/- 7.6% increase, respectively; P < 0.01). DOMS was over 100% greater for the eccentric protocol. These results indicate that DOMS is not dependent on the events that contribute to LFF.
authors.affiliation: Graduate Program in Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, 1-252 Medical Education Building, Iowa City, Iowa 52242-1190, USA.
authors.forename: Masaki
authors.initials: M
authors.lastname: Iguchi
authors.forename: Richard K
authors.initials: RK
authors.lastname: Shields
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004558:Electric Stimulation; D004576:Electromyography; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D052097:Quadriceps Muscle / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted