title: Changes in resting mitogen-activated protein kinases following resistance exercise overreaching and overtraining.
abstract: OBJECTIVE
  Many physiological maladaptations persist after overreaching and overtraining resistance exercise (RE). However, no studies have investigated changes in mitogen-activated protein kinases (MAPK) after overtraining in humans, despite their critical role regulating exercise-induced muscular adaptations. The purpose of this study was to describe the changes in total and resting phosphorylation status of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH2-terminal kinase (JNK) and p38-MAPK following a period of RE overreaching or overtraining.
  
  
  METHODS
  Following 2-4 weeks of normal training (low volume/low intensity), two groups of males performed either a high-power overreaching protocol (HPOR n = 6, mean ± SD, age 23 ± 3.4 years, mass 86.5 ± 17.7 kg, height 1.77 ± 0.06 m) or high-intensity overtraining protocol (HIOT n = 8, age 19.8 ± 1.8 years, mass 76.8 ± 6.7 kg, height 1.8 ± 0.06 m). Resting muscle biopsies were obtained at baseline (BL; end of normal training period) and 24 h after the final session of stressful training (i.e., HPOR or HIOT programs). Total MAPK and ratio of phosphorylated/total (p-MAPK)- ERK1/2, JNK, and p38-MAPK were analyzed via western blotting. 2 × 2 (group × time) ANOVA determined differences in MAPK between BL and post-training protocols.
  
  
  RESULTS
  Compared to BL, total-ERK increased after HPOR, but decreased after HIOT (p ≤ 0.05). p-ERK1/2/total-ERK increased after HIOT (p ≤ 0.05). The ratio of p-JNK/total-JNK and p-ERK1/2/total-ERK decreased after HPOR (p ≤ 0.05); however, this result was primarily due to increased total MAPK content. p-p38-MAPK decreased after HPOR (p ≤ 0.05).
  
  
  CONCLUSIONS
  Total and p-MAPK are differentially expressed after HPOR and HIOT RE. These changes are likely involved in the maladaptation reported in overreaching and overtraining exercise. This is the first study describing altered MAPK in RE overtrained and overreached humans.
authors: Department of Health, Sport, and Exercise Sciences, University of Kansas, 1301 Sunnyside Ave, Lawrence, KS, 66045, USA.
authors: Justin X
authors: JX
authors: Nicoll
authors: Department of Health, Sport, and Exercise Sciences, University of Kansas, 1301 Sunnyside Ave, Lawrence, KS, 66045, USA. acfry@ku.edu.
authors: Andrew C
authors: AC
authors: Fry
authors: Department of Kinesiology, Center for Sport Performance, California State University, Fullerton, Fullerton, CA, 92831, USA.
authors: Andrew J
authors: AJ
authors: Galpin
authors: Department of Health, Sport, and Exercise Sciences, University of Kansas, 1301 Sunnyside Ave, Lawrence, KS, 66045, USA.
authors: Adam J
authors: AJ
authors: Sterczala
authors: Department of Physiology and Biophysics, University of Tennessee-Memphis, Memphis, TN, 38163, USA.
authors: Donald B
authors: DB
authors: Thomason
authors: Human Performance Laboratories, Department of Exercise and Sport Sciences, University of Memphis, Memphis, TN, 38152, USA.
authors: Christopher A
authors: CA
authors: Moore
authors: Human Performance Laboratories, Department of Exercise and Sport Sciences, University of Memphis, Memphis, TN, 38152, USA.
authors: Lawrence W
authors: LW
authors: Weiss
authors: Neuromusculoskeletal Mechanics Research Program, Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB, Canada.
authors: Loren Z F
authors: LZ
authors: Chiu
mesh_terms: D012090:Cumulative Trauma Disorders / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D020935:MAP Kinase Signaling System; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000293:injuries* / Q000503:physiopathology*; D055070:Resistance Training / Q000009:adverse effects*; D012146:Rest; D055815:Young Adult
chemical_list: D020928:Mitogen-Activated Protein Kinases
keywords: High-intensity exercise; High-power exercise; Muscle; Signal transduction; Signaling; Stressful exercise