Doing leg extensions makes the front thigh muscle grow more evenly along its length than doing squats, which don’t stimulate that muscle as much.
Scientific Claim
Leg extension exercises lead to greater hypertrophy of the rectus femoris muscle at proximal, middle, and distal sites (increases of 11.4%, 12.3%, and 17.5%, respectively) compared to back squats (2.0%, 5.7%, and 7.9%) in untrained young women after 8 weeks of training, suggesting exercise-specific muscle activation patterns influence regional muscle growth.
Original Statement
“The LE experienced greater increases in the 3 RF sites (proximal: +11.4% vs. +2.0%; middle: +12.3% vs. +5.7%; distal: 17.5% vs. +7.9%; all p < 0.001).”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
probability
Can suggest probability/likelihood
Assessment Explanation
Although the study is an RCT and supports causal inference, the abstract lacks blinding confirmation, so definitive verbs are overly strong. 'Leads to' is acceptable but 'likely leads to' is more conservative and appropriate.
More Accurate Statement
“Leg extension exercises likely lead to greater hypertrophy of the rectus femoris muscle at proximal, middle, and distal sites (increases of 11.4%, 12.3%, and 17.5%, respectively) compared to back squats (2.0%, 5.7%, and 7.9%) in untrained young women after 8 weeks of training, suggesting exercise-specific muscle activation patterns influence regional muscle growth.”
Evidence from Studies
Supporting (1)
Comparison of Muscle Hypertrophy and Strength Adaptations Induced by Back Squat and Leg Extension Resistance Exercises.
Leg extensions made the front thigh muscle grow more than squats did, especially at the top, middle, and bottom parts — proving that different exercises target different parts of the same muscle.