Even lifting light weights really slowly until you can't do another rep can make your muscles bigger, just like lifting heavy weights.
Scientific Claim
Low-load resistance training to failure at 40% one-repetition maximum, performed twice weekly for 8 weeks, is associated with a 9.8% to 10.6% increase in triceps cross-sectional area and a 5.7% to 8.3% increase in thigh cross-sectional area in trained individuals, suggesting muscle hypertrophy can occur without high mechanical tension.
Original Statement
“Both groups showed significant increases in triceps (S: 9.8±8.8%, L: 10.6±9.6%, p<0.05) and thigh (S: 5.7±4.7%, L: 8.3±6.4%, p<0.05) cross-sectional area.”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The study lacks confirmed randomization, so causal language like 'induces' or 'causes' is inappropriate. The observed increases are associated with the training protocol but cannot be definitively attributed to it without proper randomization.
More Accurate Statement
“Low-load resistance training to failure at 40% one-repetition maximum, performed twice weekly for 8 weeks, is associated with a 9.8% to 10.6% increase in triceps cross-sectional area and a 5.7% to 8.3% increase in thigh cross-sectional area in trained individuals.”
Evidence from Studies
Supporting (1)
Acute and Long-term Responses to Different Rest Intervals in Low-load Resistance Training
Even with light weights, lifting until you can't do another rep twice a week for 8 weeks made people’s triceps and thighs bigger — proving you don’t need heavy weights to build muscle.