improved by a mean of 52 seconds (SD 40) in the experimental group, whereas the control group
improved by a mean of 12 seconds (SD 26). This was a statistically significant difference (MD 39 seconds, 95% CI 20 to 59), as shown in Table 2. When calculated as a standardised effect size, the between-group difference of 39 seconds equated to a Cohen’s d of 1.19.