2007, Piran, Slovenia

Gravitational Physiology
maximum isometric contraction of the knee extensors of the dominant leg at 80
degrees of knee flexion were assessed, on each subject, using an isometric chair
dynamometer together with the corresponding EMG traces. Individual lower limbs
fat-free mass (FFM) was also assessed, before and after BR, by means a bioimpedance
method.
a) b)
Figure 1: Panel a): Schematic view of the EXER: CS: Carriage seat, FP: force
platform, WT: wire tachometer, HJ: hydraulic jack, Hi: Hinge; Cy: isokinetic cycle
ergometer. Panel b): Force (F, N) and velocity (v, m/s) are reported as a function of
time (t, s). Power (w, W) as a function of time as obtained how the product of force
and velocity (w(t)= F(t) x v(t)). Left vertical axis refers to F and w, right vertical axis
to v. The time interval during which maximal explosive power is developed is
indicated by the vertical arrows. The horizontal arrow indicates the force at which the
backwards movement of the carriage seat begins.
RESULTS
The data obtained in one subject on whom force and power increased with no change
in FFM were discarded.
The average force (Fm) and power (Pm), as well as the FFM of the lower limbs
decreased from 1076.2 ± 134.3 N, 1532.1 ± 230.0 W and 21.0 ± 3.1 kg before BR to
891.3 ± 110.5 N, 1133.2 ± 163.2 W and 18.8 ± 3.4 kg after BR. The corresponding
relative fall was calculated as :
[(Xb – Xa)/Xb] x 100
where X refers to the appropriate variable (Fm or Pm or FFM) and where Fm and Pm
are expressed per unit of FFM, before (b) and after (a) BR. The so obtained results are
reported in the following Table:
Fm Pm FFMm
Δ% Fall -16.7 ± 9.1 -24.6 ± 14.7 -10.5 ± 7.5
p (n = 9) 0.134 0.021 0.002
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