If you train your legs with the leg press machine for 9 weeks, you’ll get stronger and your thighs will get bigger—even if you do it just once a week or spread it out over three days.
Scientific Claim
In resistance-trained men, the unilateral leg press exercise can produce significant increases in maximal strength and quadriceps muscle size after 9 weeks of training, regardless of whether frequency is one or three times per week.
Original Statement
“All conditions effectively increased 1RM and CSA (p<0.001); however, no significant differences were observed in the values of 1RM (p = 0.454) and CSA (p = 0.310) between the RT frequencies...”
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 used pre-post measurements with statistical significance (p<0.001) and controlled conditions, supporting definitive language for the observed effect within the studied population.
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Randomized Controlled TrialLevel 1bCausal effect of unilateral leg press training on strength and hypertrophy in trained men over 9 weeks.
Causal effect of unilateral leg press training on strength and hypertrophy in trained men over 9 weeks.
What This Would Prove
Causal effect of unilateral leg press training on strength and hypertrophy in trained men over 9 weeks.
Ideal Study Design
Double-blind RCT with 60 trained men randomized to unilateral leg press (9 sets/week, 75% 1RM) vs. no training control, measuring 1RM and quadriceps CSA via MRI at baseline and 9 weeks, with diet and activity controlled.
Limitation: Ethical constraints prevent true 'no training' control in trained populations; placebo effect difficult to blind.
Prospective Cohort StudyLevel 2bLong-term effectiveness and sustainability of unilateral leg press training on strength and hypertrophy in trained men.
Long-term effectiveness and sustainability of unilateral leg press training on strength and hypertrophy in trained men.
What This Would Prove
Long-term effectiveness and sustainability of unilateral leg press training on strength and hypertrophy in trained men.
Ideal Study Design
Prospective cohort of 100 trained men performing unilateral leg press 1–3x/week for 12 months, with quarterly 1RM and MRI CSA measurements, tracking adherence and volume progression.
Limitation: Cannot isolate leg press as the sole variable if participants perform other exercises.
Evidence from Studies
Supporting (1)
Effect of different training frequencies on maximal strength performance and muscle hypertrophy in trained individuals—a within-subject design
The study found that doing leg presses once a week or three times a week gave the same strength and muscle gains in trained men, as long as the total amount of work was the same. So yes, frequency doesn’t matter — the claim is right.