Fig 1.
Stimulation pattern and schematic view of the experimental protocol.
Upper panel presents the two stimulation patterns. Lower panel presents the experimental protocol. Warm-up consisted of 10 progressive voluntary contractions until the maximal voluntary contraction (MVC). The experimental session then began with different measurements (PRE measurements) including the determination of the optimal stimulation intensity for doublets, tetanic contractions and the session's pattern and tests with two MVCs and two 500 ms tetanic contractions at 20 and 80 Hz. Then, subjects underwent 30 minutes with one stimulation pattern. After the session, POST measurements were performed including two MVCs, doublets, two 500 ms tetanic contractions at 20 and 80 Hz.
Fig 2.
Voluntary and evoked torque in pre- and post-fatigue conditions.
(A) Maximal voluntary torque (Nm) values obtained before (black symbols) and immediately after (white symbols) the constant-frequency trains program (CFT) and doublet frequency train (DFT). (B) Average torque evoked during the first 5 (black symbols) and the last 5 contractions (white symbols) of each stimulation program. Values in the inner part of CFT and DFT represented mean values ± SD Values in the outer part of CFT and DFT represented individual values. *: statistical differences between PRE and POST values (P<0.05).
Table 1.
Neuromuscular parameters registered in the subgroup before (PRE) and after (POST) stimulation procedures.