Exploring the Relationship between Ultrasonographic Measures of the Quadriceps and Knee Extensor Muscle Fitness in Endurance-Trained Individuals

Table 1

Correlation of quadriceps muscles ultrasonography measures with maximal strength and local muscle endurance.

Measure	1 repetition maximum		Total repetitions
	Pearson correlation	value	Pearson correlation	value
Rectus femoris
Muscle thickness	0.299	0.155	0.120	0.576
Echo intensity	0.049	0.820	−0.130	0.545
Corrected EI	−0.400	0.053	−0.130	0.546
Vastus intermedius
Muscle thickness	0.526	0.008	−0.105	0.624
Echo intensity	−0.446	0.029	0.156	0.466
Corrected EI	−0.643	<0.001	0.049	0.822
Vastus lateralis
Muscle thickness	0.449	0.028	0.076	0.723
Echo intensity	−0.368	0.077	0.120	0.577
Corrected EI	−0.594	0.002	0.040	0.851

Denotes significant correlation at the level.