Walking We applied the WISCI [33] to assess which kind
of assistive devices or personal assistance the participants
needed to cover 10 m.
To test the participants’ ability to adapt their gait to
several circumstances, we applied the Figure Eight Test
(FET), which was previously described in more detail
and shown to be valid [34]. The test required participants
to traverse a 10 m long figure of eight-shaped track 6
times, each time under a different condition, including:
– FET preferred: at preferred walking speed.
– FET maximal: at maximal safe walking speed.
– FET vision: subjects wore vision-blurring glasses.
– FET obstacle: Two obstacles, one in each curve, had
to be overstepped.
– FET foam: Subjects wore foamed soles under their
shoes.
– FET dual task: During walking, a list of questions
had to be answered as quickly as possible.
The time needed for each condition was recorded and
converted to walking speed (m/s). Except for FET maximal,
participants were directed to walk at self-selected
speed corresponding to their preferred comfortable
walking speed in everyday life.
We estimated energy expenditure with the Physiological
Cost Index (PCI) [35]. The PCI was assessed on a treadmill.
First, participants stood still for 2 min and the mean
heart rate of the last 10 s was used as heart rate at rest.
Then they walked for 3 min at the same speed as previously
determined in their first 10MWTat preferred speed.
The PCI was calculated as follows: PCI = (steady-state
heart rate – heart rate at rest)/ambulatory velocity.
We assessed symmetry of gait, which has been shown
to improve after locomotor-specific training in patients
with iSCI [20]. It is an important marker for the quality
of gait and an accurate indicator of changes in the walking
pattern, even on a sub-clinical level [36]. There is
evidence that gait symmetry also improves after lower
extremity strength training in patients with stroke [37].
Gait symmetry was measured by comparing lengths of
stance and swing phases of each single leg (by dividing
stance time [in % of whole step] right by stance time
left) with portable insoles. If the value was >1, it was
inverted to ensure comparability. Gait symmetry was measured
in 8 participants only, due to infrastructural issues.