title: Effects of training on potassium, calcium and hydrogen ion regulation in skeletal muscle and blood during exercise.
abstract: Ionic regulation is critical to muscle excitation, contraction and metabolism, and thus for muscle function during exercise. This review focuses on the effects of training upon K+, Ca2+ and H+ ion regulation in muscle and K+ regulation in blood during exercise. Training enhances K+ regulation in muscle and blood and reduces muscular fatiguability. Endurance, sprint and strength training in humans induce an increased muscle Na+, K+ pump concentration, usually associated with a reduced rise in plasma [K+] during exercise. Although impaired muscle Ca2+ regulation plays a vital role in fatigue, little is known about possible training effects. In rat fast-twitch muscle, overload-induced hypertrophy and endurance training were associated with reduced sarcoplasmic reticulum Ca2+ uptake, consistent with fast-to-slow fibre transition. In human muscle, endurance and strength training had no effect on muscle Ca2+ ATPase concentration. Whilst muscle Ca2+ uptake, release and Ca2+ ATPase activity were depressed by fatigue, no differences were found between strength athletes and untrained individuals. Muscle H+ accumulation may contribute to fatigue during intense exercise and is also modified by sprint training. Sprint training may increase muscle Lac- and work output with exhaustive exercise, but the rise in muscle [H+] is unchanged or attenuated, indicating a reduced rise in muscle [H+] relative to work performed. Muscle buffering capacity can be dissociated from this improved H+ regulatory capacity after training. Thus, training enhances muscle and blood K+ and muscle H+ regulation during exercise, consistent with improved muscular performance and reduced fatiguability; however, little is known about training effects on muscle Ca2+ regulation during contraction.
authors.affiliation: Department of Physical Education and Recreation, Victoria University of Technology, Footscray, Australia.
authors.forename: M J
authors.initials: MJ
authors.lastname: McKenna
authors.forename: A R
authors.initials: AR
authors.lastname: Harmer
authors.forename: S F
authors.initials: SF
authors.lastname: Fraser
authors.forename: J L
authors.initials: JL
authors.lastname: Li
mesh_terms: D000818:Animals; D002118:Calcium / Q000097:blood / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology*; D010806:Physical Education and Training; D011188:Potassium / Q000097:blood / Q000378:metabolism*; D051381:Rats
chemical_list: D011188:Potassium; D002118:Calcium