Whether you lift your arm weights slowly or with a little swing, your biceps and triceps both get noticeably bigger after eight weeks of training—your triceps grow even more than your biceps.
Scientific Claim
For untrained individuals, both strict form and external momentum during biceps curls and triceps pushdowns lead to small to medium increases in elbow flexor muscle thickness and medium to large increases in elbow extensor muscle thickness over eight weeks.
Original Statement
“Within-condition analyses using standardized mean difference estimates indicated that interventions were likely to produce small to medium increases in muscle thickness for the elbow flexors and medium to large increases for the elbow extensors.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
probability
Can suggest probability/likelihood
Assessment Explanation
The study used within-group standardized mean differences to describe changes, and probabilistic language ('likely to produce') correctly reflects the Bayesian framework and lack of frequentist p-values.
More Accurate Statement
“For untrained individuals, both strict form and external momentum during biceps curls and triceps pushdowns are likely to lead to small to medium increases in elbow flexor muscle thickness and medium to large increases in elbow extensor muscle thickness over eight weeks.”
Evidence from Studies
Supporting (0)
Contradicting (1)
Do Cheaters Prosper? Effect of Externally Supplied Momentum During Resistance Training on Measures of Upper Body Muscle Hypertrophy
The study found that cheating with momentum and doing exercises strictly both led to about the same muscle growth — neither was better or worse, so the claim that they produce different levels of growth is wrong.