High-power resistance exercise induces MAPK phosphorylation in weightlifting trained men

• Published in: Applied physiology, nutrition, and metabolism Vol. 37; no. 1; pp. 80 - 87
• Main Authors: Galpin, Andrew J., Fry, Andrew C., Chiu, Loren Z.F., Thomason, Donald B., Schilling, Brian K.
• Format: Journal Article
• Language: English
• Published: Canada NRC Research Press 01.02.2012; Canadian Science Publishing NRC Research Press
• Subjects: Adult; Analysis of Variance; Biopsy; Cellular control mechanisms; Enzyme Activation; exercice physique; exercise; Health aspects; humain; human; Humans; Isometric exercise; JNK Mitogen-Activated Protein Kinases - metabolism; Male; men; metabolism; mitogen-activated protein kinase; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase 3 - metabolism; Mitogen-Activated Protein Kinases - metabolism; muscle; Muscle Contraction; muscle squelettique; Muscle Strength; Muscles; Musculoskeletal system; nutrition; p38 Mitogen-Activated Protein Kinases - metabolism; Phosphorylation; Physiological aspects; power; puissance; Quadriceps Muscle - enzymology; Resistance Training; Signal transduction; signaling; signalisation; skeletal; skeletal muscle; Sports training; strength training; Time Factors; Weight Lifting; Weightlifting; Young Adult
• ISSN: 1715-5312; 1715-5320; 1715-5320
• DOI: 10.1139/h11-131

Power is critical to muscle performance, specifically in athletic populations. Mitogen-activated protein kinase (MAPK) pathways (extracellular signal-regulated protein kinase (ERK 1/2), p38, and c-Jun NH 2 -terminal kinase (JNK)) are intracellular signal transduction mechanisms that partially regulate exercise-induced skeletal muscle alterations. These pathways are highly responsive to exercise, but their reaction to high power, multi-joint resistance exercise is yet to be examined. Nine weightlifting-trained men performed 15 sets of three repetitions of a dynamic clean pull exercise at 85% of their one repetition maximum. Vastus lateralis biopsies were obtained prior to (pre) and after the 8th (mid) and 15th set (post) of exercise. Three subjects returned to serve as non-exercising controls for a similar sequence of biopsies (CON). The ratio of phosphorylated MAPK to total MAPK increased significantly for p38 (3.0 fold, p < 0.05) and JNK (2.4 fold, p < 0.05) by the mid biopsy. ERK 1/2 phosphorylation followed a similar trend (2.3 fold) (p = 0.052). The ratio of phosphorylation to total MAPK did not differ from mid to post biopsy. None of the pathways were phosphorylated above resting in the CON condition (p > 0.05), and thus the biopsy procedure itself did not account for the entire increase in MAPK phosphorylation during EX. These data indicate MAPK pathways are activated early and remain elevated throughout the duration of high power resistance exercise. These findings help describe the mechanisms partially responsible for chronic adaptations in response to high intensity, high power resistance training in humans.