Figure 2. Typical experimental records of stress production and heat output of a representative trabecula at various muscle lengths (b–f) below its optimal length (a), at 5 Hz stimulation.

The muscle was returned to optimal length (a) before performing the next two interventions: DMSO and DMSO + blebbistatin (BBS), in that order. Trabecula dimensions: length, 2.82 mm; cross‐sectional area, 0.0347 mm². Its rate of heat production at L _o under control conditions was 4.91 μW. Note that the latter value exceeds the thermal resolution of the microcalorimeter by some 500‐fold.