Tension transients (lower traces) and changes in total fibre length (upper traces) and in sarcomere length (middle traces) in two experiment where T-jumps of about constant amplitude were applied to muscle fibres 35 (A) and 5 ms (B) after length steps of different sign and amplitude. Initial temperature was ∼5.5 °C. A, final temperature 21.0 (trace 9), 22.1 (trace 10), 21.7 (trace 11), 21.8 (trace 13) and 21.9 °C (trace 15). Fibre dimensions: 1.80 mm × 4220 μm2, sarcomere length 2.50 μm. B, final temperature 26.3 (trace 20), 25.6 (trace 21) and 26.4 °C (trace 22). Fibre dimensions: 2.10 mm × 3340 μm2, sarcomere length 2.50 μm.