Reliability
An interrater reliability test was carried out on a separate
occasion on uninjured athletes not participating in the study.
Two people (the primary investigator and an ATC) simultaneously
observed each athlete undertake the SLB test. The
athlete followed the previously outlined protocol for testing
except that two tests were done on both ankles. Each
examiner was blinded to the other’s results. The test was
scored positive or negative.
Statistical analysis
The analysis was done using SPSS v.11.5.We used the x2 test or
Fischer’s exact test when the expected frequency was less than
5 in one square of the 262 x2 test. TheMantel-Haenszelmethod
was used when controlling for confounding variables.
Power calculations for a b value of 0.2 and an a value of
0.05, with an estimated 18% sprain rate in a positive SLB test
and a 10% rate in a negative SLB test, produced a sample size
of 98 athletes needed in the positive and negative SLB test
groups. Interobserver variability in the interpretation of the
SLB test was computed using the k statistic including 95%
confidence intervals (CI).
RESULTS
During the course of the study, 28 ankle sprains were
reported in the 230 athletes. Demographic and study test
characteristics of the 230 athletes are listed in tables 1 and 2.
The association between a positive SLB test and ankle
sprains was significant (x2=5.833, df=1, p=0.016)