Table 5.

Associations Between Quadriceps Strength, Ultrasound Measures, and Self-Reported Outcome Scores

Variable	International Knee Documentation Committee Score		Knee Injury and Osteoarthritis Outcome Subscale Scores
			Pain		Symptoms		Activities of Daily Living		Sport and Recreation		Quality of Life
	β Value	ΔR2	β Value	ΔR2	β Value	ΔR2	β Value	ΔR2	β Value	ΔR2	β Value	ΔR2
Peak torque, Nm/kg	−1.944	0.009	0.670	0.002	1.989	0.016	0.882	0.008	1.336	0.004	−0.459	<0.010
Rate of torque development, Nm/kg/s	0.381	0.033	0.192	0.012	0.071	0.002	0.145	0.02	0.084	0.001	−0.04	0.001
Vastus lateralis
Cross-sectional area, mm2	0.007	0.103a	0.004	0.046	0.005	0.09	0.009	0.024	0.009	0.125a	0.005	0.021
Echo intensity, arbitrary units	−0.298	0.081a	−0.174	0.037	−0.268	0.110a	0.002	<0.010	−0.224	0.037	−0.538	0.111a

Abbreviation: β, weight, unstandardized.

^aP < .05. Covariates = time since anterior cruciate ligament reconstruction, sex, and Tegner physical activity level. Subcutaneous fat thickness was added as a covariate for the echo intensity regression models.