Interestingly, after HF but not LF training, the unusual high forces at the low frequency range of the force-frequency relationship decreased, possibly due to a reduced activation per impulse. After LF but not HF training, force oscillation amplitudes declined (by 33%) as relaxation tended to slow, which may have opposed possible effects of reduced activation as seen after HF training. Finally, fatigue resistance also increased rapidly after LF training (by 43%) but not after HF training. These results indicate that different types of training may selectively change different aspects of function in disused muscles.
Collaborative research carried out in Amsterdam and Nijmegen and in collaboration with Professor David Jones of Birmingham University studied the effect of using different frequencies of electrical stimulation when training leg muscles of spinal cord injured people.
Muscle & Nerve 2002 Apr;25(4):559-67.