Table 5.

Binary logistic regression models on ultrasound abnormality by demographic characteristics.

Outcome	Predictor		Odds ratio (95% CI)	p
Ultrasound abnormality at Achilles tendon (left or right)*	Gender (reference: female)	Male	2.61 (0.85, 8.01)	0.094
	Age (reference: 18–30 years old)	31–40 years	0.80 (0.17, 3.77)	0.774
		41–50 years	3.30 (0.69, 15.87)	0.136
		51+ years	3.72 (0.89, 15.64)	0.073
	Years of running (reference: started this year)	1–5 years	1.18 (0.19, 7.46)	0.861
		6–10 years	0.49 (0.06, 3.66)	0.483
		11+ years	0.60 (0.08, 4.54)	0.621
	Average miles per week of running over a year (reference: > 30 miles)	0–10 miles	2.21 (0.32, 15.20)	0.421
		11–20 miles	1.08 (0.16, 7.25)	0.937
		21–30 miles	5.66 (0.81, 39.45)	0.080
	Pre-race pain (reference: no)	Yes	1.69 (0.42, 6.82)	0.462
Ultrasound abnormality at patellar tendon (left or right)**	Gender (reference: female)	Male	3.70 (1.17, 11.74)	0.026
	Age (reference: 18–30 years old)	31–40 years	0.73 (0.18, 2.90)	0.655
		41–50 years	0.65 (0.14, 3.05)	0.583
		51+ years	0.59 (0.12, 2.88)	0.510
	Years of running (reference: started this year)	1–5 years	4.75 (0.41, 54.97)	0.212
		6–10 years	1.69 (0.13, 21.19)	0.688
		11+ years	2.21 (0.18, 27.53)	0.537
	Average miles per week of running over a year (reference: > 30 miles)	0–10 miles	0.36 (0.04, 3.38)	0.372
		11–20 miles	2.00 (0.35, 11.30)	0.434
		21–30 miles	3.05 (0.49, 19.01)	0.232
	Pre-race pain (reference: no)	Yes	1.03 (0.29, 3.65)	0.966

CI = confidence interval.

^*Model χ² = 18.06, p = 0.080

^**Model χ² = 15.95, p = 0.143.