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walking function at the final evaluation (5). Thus, poor
baseline function does not preclude benefit, but training
is perhaps most useful for those who can already walk
a little (4, 5, 7, 8).
Was the onset of training too late?
In 3 trials with early enrolment (≥ 7 months, 9–11
months or 1+ years post-injury) walking ability im-
proved significantly (7, 8, 24). Yang et al., studying 22
participants with post-injury time ≥ 7 months, found
significant 27-m improvement in distance walked in the
BWSLT group (focus on endurance training), similar to
our findings, compared with 10 m in controls (precision
training) (8). Harkema et al. report the greatest impro-
vements among those recruited ≤ 1–3 years post-injury,
compared with later onset of training, whereas training
initiated > 3 years post-injury, resulted in less functional
improvement (5). Findings among the group with long-
est post-injury time were similar to our results. Several
of our subjects were included even later than this. In-
terestingly, some have also reported good results with
training starting several years after SCI (21). BWSLT
should possibly start earlier, but then spontaneous re-
covery of function is frequent, and a much larger study
is required to account for large variations (27).
Improvements in secondary outcomes
Balance control scores were below 45 at baseline, indi-
cating poor balance (18), and did not improve. Some (3,
5, 21), but not all BWSLT studies (7), show improved
balance. Falls and fall-related injuries are well-known
complications after SCI (28), and improvement gained
in truncus stability and balance after BWLT could
contribute to the prevention of such events.
In spite of the training, there was no improvement in
maximal oxygen uptake. Alexeeva et al. (7) reported
similar findings. The negative findings are, however,
not surprising because testing was done with arm crank
cycling, while training was directed at legs and trunk.
Could our training programme be non-optimal?
The present training protocol was conventional. We
doubt whether patients would tolerate more intense or
longer training, and this was also limited by available
resources. Furthermore, recently no correlation was
found between training dose and outcome in various gait
training protocols (29). However, increasing the amount
of over-ground training could be considered (4, 15, 24).
Study strengths, weaknesses and limitations
This study has several strengths. The single-centre
study design reduces method variation, and the single-
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blind design reduces evaluation bias. Post-injury time
>2 years reduces spontaneous improvement, allowing
a lower number of study subjects. The main weakness
is the slow rate of patient recruitment, which forced us
to close the study when only two-thirds of the target
patient number was reached. Post-hoc analysis revea-
led that, assuming better balanced groups, we would
need a study size between 76 and 208 participants to
detect significant improvements. Thus, the study was
statistically underpowered, resulting in unbalanced
groups at baseline (Table I), and a low probability
of detecting modest improvements. The number of
eligible and willing subjects was overestimated. Due
to our 2-year post-injury requirement, some subjects
had adapted well, and were reluctant to invest time,
travelling and efforts on a project with an uncertain
outcome. Another limitation is that we relied on usual
care for the control group. At least 2 control subjects
increased their training during the trial, attenuating the
effect size of the intervention. Also, the majority of the
control group had over-ground gait training as part of
their regular physical therapy. Despite the limitations
of the present study, our experience illustrates the
complexity of conducting such clinical research.
Conclusion
BWSLT with manual assistance was well tolerated,
and led to statistically non-significant improvements
in walking and lower extremity muscle strength. The
present results neither prove nor disprove the efficacy
of this training, but suggest that the benefit is, at the
best, modest in patients with poor function long after
injury. Future research should include a higher number
of participants and use block randomization based on
function.
ACKNOWLEDGEMENTS
Several factors made this study possible: healthcare, including
rehabilitation, is free of charge in Norway, allowing subjects to
receive inpatient rehabilitation; the 3 primary rehabilitation cen-
tres for SCI in Norway all contributed to patient recruitment; and
the project was supported financially both by the government
and non-governmental institutions (the Norwegian Health Aut-
horities and Norwegian Health and Rehabilitation funds). This
study was initiated by 2 patient organizations (LARS – National
association of the spinal cord injured and LTN – National asso-
ciation of the traffic injured) and could not have been completed
without their continuous help and involvement throughout the
study. The efforts of staff, who guided the locomotor training
in Tromsø, are highly appreciated, as well as the testing team
at Sunnaas Rehabilitation Hospital.
Study funding. The study was funded by the Norwegian Health
Authorities and Norwegian Health and Rehabilitation Funds.
The authors have no conflicts of interest to declare.