Soy and whey protein have different concentrations of leucine, an amino acid known to be a particularly potent simulator of muscle protein synthesis. The purpose of this study is to determine whether matching soy and whey protein supplements for leucine content instead of by total protein content would contribute to differences in strength increases and muscle growth in response to 12 wk of resistance training.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
DOUBLE
Enrollment
61
19 g whey protein isolate (contains 2 g leucine) was consumed daily by one intervention group.
26 g soy protein isolate (contains 2 g leucine) was consumed daily by the other intervention group.
Arizona State University
Phoenix, Arizona, United States
Lean Body Mass Change
assessed using dual energy x-ray absorptiometry (DEXA) scan for changes in lean body mass (kg)
Time frame: Post-12 week intervention
Muscle Tissue Thickness Change
assessed using changes in muscle thickness assessed by ultrasound (cm)
Time frame: Post-12 week intervention
Leg Girth Changes
assessed using circumference measurements (cm)
Time frame: Post-12 week intervention
Change in Peak Torque When Doing Leg Extensions
Assessed using an isokinetic dynamometer set at 60 degrees of motion per second (d/s)
Time frame: Post-12 week intervention
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