Fig. 3.

Sex-difference in mechano-energetics as functions of stimulus frequency. (A) Record of the measured rate of heat production and twitch stress from a trabecula contracting isometrically under the frequency protocol. In this example, the order was as shown: 3 Hz, 5 Hz, 6 Hz, and 4 Hz. Stimulation was halted between frequency steps. (B) Average values of active stress and diastolic stress as functions of stimulus frequency. (C) Average values of twitch duration at 5% (t₉₅) and 50% (t₅₀) of peak stress as functions of stimulus frequency. (D) Average values of heat as functions of frequency. No statistical difference between sex groups can be detected.