Table 2.

Data on all primary outcomes for both groups

	Intervention group	Control group	Mean difference (95%CI)	P value
Comfort	8.06 ± 1.41	6.96 ± 2.03	1.10 (0.81 to 1.40)	< 0.0001
Injury rate	0.70 ± 1.01	1.21 ± 1.53	-0.51 (-1.28 to 0.25)	0.18
Running speed (miles per hour)	6.27 ± 1.03	6.00 ± 1.54	0.28 (0.06 to 0.50)	0.013

Values for the intervention group and control group are expressed as mean ± standard deviation. Statistical analysis used P values from unpaired two-tailed t-tests with Welch's correction. Significant difference was considered if P < 0.05. CI: Confidence interval. Injury rate: Number of injuries reported per participant over the 8-wk study period.