Our study had several limitations. A major concern was
the attrition rates in the active stretching group (18.2%)
and the passive stretching group (34.8%) that could
have affected group equivalency attributable to the
randomization process, thereby biasing the results. The
results of the intention-to-treat analysis, however, did not
differ from the results of the on-protocol analysis, and
this finding increases our confidence in the validity of
our findings. Eight subjects, accounting for approximately
75% of the attrition rate, were self-eliminated as
a result of conflicts with job training. The other 4
subjects were disenrolled due to unrelated medical
problems or because they moved to another area. In all
cases, the reasons for removal were unrelated to intervention.
Three-week measurements were available for 5
(2 in the active stretching group, 3 in the passive
stretching group) of the 12 subjects who dropped out of
the study.