Table 1.

Collected data from fatigue protocols performed under various conditions

	n	T1/2(%)	Fmax,FAT/Fmax,CON(%)	[Ca]FAT/[Ca]CON(%)	ΔCa50(nm)
Control (22°C)	7	100	89 ± 3	62 ± 3	85 ± 22
37°C		55 ± 5*	91 ± 3	88 ± 5*	442 ± 146*†
Control (22°C)	6	100	89 ± 2	57 ± 7	71 ± 21
37°C + Tiron		102 ± 3	94 ± 2	60 ± 6	40 ± 6

All data from single fibres injected with indo-1. Each fibre was subjected to two fatigue protocols: a control at 22°C and a second protocol at 37°C either in the absence (upper two rows) or the presence (bottom row) of 5 mm Tiron. T_¹/2 is the time for force to decline to 50% in the standard fatigue protocol. F_max is the force in a 100 Hz tetanus in the presence of 10 mm caffeine; F_max,CON was determined in control (unfatigued) conditions and F_max,FAT was determined at the end of the fatigue protocol. [Ca] is the mean tetanic [Ca²⁺]_i; [Ca]_CON measured in the first tetanus of the protocol and [Ca]_FAT when the force had fallen to 50%. Ca₅₀ is the tetanic [Ca²⁺]_i which gives 50% of maximal force; ΔCa₅₀ is the difference between the value in control conditions and that obtained in the fatigued muscle. Parameters were compared by paired t tests for the first and second fatigue protocol.

^*P < 0.05 when comparing the first and second protocol

^†Mann-Witney Rank Sum test, P < 0.02.