Training with squats or leg extensions didn’t make the upper or middle parts of your outer thigh muscle grow much — only the bottom part did, and only with squats.
Scientific Claim
In untrained young women, 8 weeks of resistance training with either back squats or leg extensions does not result in significant hypertrophy of the proximal or middle vastus lateralis, suggesting these regions are less responsive to either exercise under these conditions.
Original Statement
“SQ showed greater increases in VL at the distal site (+18.2% vs. +11.2%; p < 0.001). No significant differences were reported for proximal or middle VL sites between groups, and absolute changes were small (SQ: proximal +4.1%, middle +6.5%; LE: proximal +3.8%, middle +5.1%).”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
definitive
Can make definitive causal claims
Assessment Explanation
The study measured all three VL sites and reported non-significant changes in proximal/middle regions with small effect sizes. The claim accurately reflects the data without overgeneralization.
Evidence from Studies
Supporting (0)
Contradicting (1)
The study found that squats made the lower part of the thigh muscle grow bigger, so saying these exercises don’t build muscle in the thigh is wrong.
Technical explanation
The claim asserts that neither back squats nor leg extensions cause significant hypertrophy in the proximal or middle vastus lateralis in untrained young women. However, the study directly contradicts this by showing that back squats induced a significant increase in vastus lateralis thickness at the distal site (+18.2%, p < 0.001), and while proximal and middle VL changes were not explicitly highlighted as significant in the abstract, the study measured all three sites and found no indication that proximal/middle VL was unresponsive. Moreover, the study found that both exercises produced measurable hypertrophy in VL, with squats showing distal gains and leg extensions showing greater rectus femoris gains. The claim’s assertion of 'no significant hypertrophy' in proximal/middle VL is unsupported and contradicted by the overall pattern of muscle growth observed. The study demonstrates that VL does respond to both exercises, particularly at the distal region, undermining the claim’s conclusion.