unloading. Thus, the bicycle ergometer may have the potential
to attenuate “systemically” the negative effects of microgravity
on several physiological functions in the human species.
However, it is not yet known whether or not cycle-ergometer
exercise can prevent unloading-induced dysfunction and
atrophy in the human calf. The purpose of this study was,
therefore, to clarify whether intense interval cycle-ergometer
training can prevent unloading-induced dysfunction and
atrophy in the human calf.
To accomplish the aim of this study, we used the unilateral
lower limb suspension (ULLS) developed by Berg et al. (1991)
as the unloading model. Further, we measured not only
strength in the planter flexion but also central activation
(voluntary activation) by using the twitch interpolation
technique (Shield and Zhou, 2004), and determined muscle
size by utilizing magnetic resonance imaging (MRI). The
reason for this was that there have been conflicting results in
the past on whether a decline in muscular functions following
unweighting is due to neural or atrophic factors (Clark et al.,
2006).