Eight males completed three experimental trials [ 0.2 g kg ( -1 ) ammonia chloride ( ACD ) ; 0.3 g kg ( -1 ) calcium carbonate ( PLA ) ; or 0.3 g kg ( -1 ) sodium bicarbonate ( ALK ) ] , each consisting of submaximal calf contractions at 55 % of maximal voluntary contraction ( MVC ) to task failure .