Isometric tetanic force measurement method of the tibialis anterior in the rat.

Tetanic force measurements of rat tibialis anterior (TA) muscles have been described, but with a variety of stimulation parameters. This study presents a novel functional method of force measurement of the rat TA muscle and describes the optimization of stimulation parameters. Bilateral TA muscles in 10 male Lewis rats were attached to a force transducer after the corresponding hindlimb was fixed. Preload, stimulus intensity, duration, and frequency were optimized for each individual muscle and the isometric maximal tetanic muscle force was measured. The mean left side tetanic force as a percentage of the right was 100.0 +/- 4.4% and was statistically equivalent. Large standard deviations between sides (35-50%) were observed in the optimized parameters (preload, stimulus intensity, duration, and frequency). Optimization of the variables affecting isometric tetanic force resulted in reproducible and reliable side-to-side measurements of the TA muscle in the rat model.