Aim:  Effects of submaximal stimulation frequencies on myofascial force transmission were investigated for rat anterior crural muscles with all motor units activated.

Methods:  Tibialis anterior and extensor hallucis longus (TAEHL) muscles were kept at constant muscle–tendon complex length, but extensor digitorum longus muscle (EDL) was lengthened distally. All muscles were activated simultaneously at 10, 20, 30 and 100 Hz within an intact anterior crural compartment.

Results:  At lower frequencies, significant proximo‐distal EDL force differences exist. Absolute EDL proximo‐distal active force differences were highest at 100 Hz (ΔF_dist‐prox = 0.4 N). However, the normalized difference was highest at 10 Hz (ΔF_dist‐prox = 30%F_dist). Firing‐frequency dependent shifts of the ascending limb of the EDL length–force curve to higher lengths were confirmed for a muscle within an intact compartment, although effects of firing frequency assessed at proximal and distal EDL tendons differed quantitatively. As EDL was lengthened distally, TAEHL distal isometric active force decreased progressively. The absolute decrease was highest for 100 Hz (ΔF_{from initial} = −0.25 N). However, the highest normalized decrease was found for 10 Hz stimulation (ΔF_{from initial} = −40%).

Conclusions:  At submaximal stimulation frequencies, myofascial force transmission is present and the fraction of force transmitted myofascially increases with progressively lower firing frequencies. Evidently, the stiffness of epimuscular myofascial paths of force transmission decreases less than the stiffness of serial sarcomeres and myotendinous pathways. It is concluded that low firing frequencies as encountered in vivo enhance the relative importance of epimuscular myofascial force transmission with respect to myotendinous force transmission.