The aim was to determine the efects of changing pulse duration and electrode size on muscle
contractile properties. Thirty-six healthy young male participated in the study (age 24.8±5.8 years;
height 178.2±0.6cm; body mass 71.8±7.3kg; self-reported weekly moderate intensity activity
3.5±1.2h·week−1). Tensiomyography was used to assess rectus femoris (RF) and vastus medialis
(VM) muscles neuromuscular properties of the dominant leg according to the electrode size (3.2–5cm)
and the stimulus length (0.2, 0.5, and 1ms). Maximal radial displacement (Dm); Contraction time
(Tc); Delay time (Td); Sustained time (Ts) and Half relaxation time (Tr) were measured. Relative and
absolute reliability was quantifed. To analyze the efects of the electrode and the stimulus length, a
repeated-measures analysis of variance was used. Dm and Tc parameters showed for both muscles
an excellent relative (0.95–0.99) and absolute reliability (1.6–4.2%). However, Ts and Tr showed low
values of absolute reliability (4.4–40.9%). The duration of the stimulus length applied to the RF and VM
and electrode size signifcantly infuences muscle’s contractile properties (p<0.05; η2
p=0.09–0.60).
The Dm increases substantially as the duration of the stimulus increases and with the use of the larger
electrode in both muscles. However, Tc and Td are less afected by both conditions and not entirely
clear. Practically, our study suggests that a stimulus pulse duration of 1ms together with a 5 × 5cm
electrode is necessary to reach a reliable and reproducible assessment of both RF and VM muscles
contractile properties.Ciencias de la Actividad Física y del Deport
