If you're a woman new to lifting and do squats twice a week for two months, you'll get much stronger at squats and your outer thigh muscle near the knee will grow more than if you did leg extensions.
Scientific Claim
In untrained young women, 8 weeks of twice-weekly Smith machine back squat training causes a 46.7% increase in back squat 3RM strength and greater hypertrophy of the distal vastus lateralis (18.2%) compared to leg extensions, which do not produce similar gains in squat strength or distal vastus lateralis size.
Original Statement
“Smith machine back squat induced greater increases in 3RM-SQ (+46.7 vs. 21.3%; p < 0.001). Conversely, the SQ showed greater increases in VL at the distal site (+18.2% vs. +11.2%; p < 0.001).”
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 is a randomized controlled trial with objective strength and muscle thickness measurements. The causal verbs 'causes' and 'increase' are appropriate given the design, randomization, and significant p-values.
Evidence from Studies
Supporting (1)
The study found that squats made women much stronger at squats and bigger in one thigh muscle, while leg extensions didn’t help squat strength or that muscle as much—so the claim is right.
Technical explanation
The study directly supports the claim by demonstrating that 8 weeks of twice-weekly Smith machine back squat training in untrained young women led to a 46.7% increase in back squat 3RM strength, matching the claim exactly. Additionally, the study found that the squat group experienced a 18.2% increase in distal vastus lateralis hypertrophy, which is also identical to the claim. In contrast, leg extensions did not produce similar gains in squat strength (only 21.3% increase) or distal vastus lateralis size (11.2% increase), confirming the comparative claim. The study used identical training volume and duration, random assignment, and precise measurements, making the comparison valid. The only minor discrepancy is that the claim states leg extensions 'do not produce similar gains,' while the study shows they produced some gains—but significantly less, which still supports the claim’s intent.