Force Generation and Ca²⁺ Release in Isolated Muscle Fibers during Stimulation

<div><p>(A) No differences were seen in total force generation in isolated muscle fibers. Mechanically dissected fibers from the flexor brevis muscle were subjected to a fatiguing protocol. Neither initial nor final forces differed between HIF-1α KO and WT fibers.</p> <p>(B) Ca²⁺ release and reuptake in HIF-1α KO and WT fibers was not different during the stimulation protocol. Ca²⁺ levels were measured in individual fibers through use of fura-2 Ca²⁺ indicator. The altered substrate utilization did not affect the ability of the fibers to maintain proper Ca²⁺ flux.</p>