Whether you use a cable machine or a barbell to do preacher curls for 10 weeks, your biceps will grow about the same amount — the exact way you apply resistance doesn’t matter much for muscle size.
Scientific Claim
Ten weeks of preacher curl training with either a cable-pulley system or barbell increases biceps brachii thickness by approximately 7–8% in young, untrained adults, with no statistically significant difference between the two methods, indicating that muscle growth is similar regardless of whether peak torque is applied at shorter or longer muscle lengths.
Original Statement
“For biceps brachii thickness, significant increases were observed for both CAB (pre = 25 ± 5 mm, post = 27 ± 6 mm; ES = 0.37; +7%) and BAR (pre = 24 ± 4 mm, post = 26 ± 4 mm; ES = 0.35; +8%), without significant difference between them (p = 0.346).”
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 direct measurements and statistical analysis, allowing definitive causal claims within the studied population and intervention.
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.
Systematic Review & Meta-AnalysisLevel 1aWhether the equivalence in biceps hypertrophy between cable and barbell preacher curls holds across diverse populations, training volumes, and durations.
Whether the equivalence in biceps hypertrophy between cable and barbell preacher curls holds across diverse populations, training volumes, and durations.
What This Would Prove
Whether the equivalence in biceps hypertrophy between cable and barbell preacher curls holds across diverse populations, training volumes, and durations.
Ideal Study Design
A meta-analysis of all RCTs comparing cable vs. barbell preacher curls (or equivalent torque-positioned exercises) in untrained adults, with standardized ultrasound measurements of biceps thickness at mid-belly, training for 8–12 weeks, 3x/week, 3 sets of 8–12 reps, and reporting effect sizes with 95% CIs.
Limitation: Cannot establish causation in new populations — only synthesizes existing evidence.
Randomized Controlled TrialLevel 1bIn EvidenceWhether the equivalence in hypertrophy persists when controlling for total training volume, muscle activation patterns, and recovery variables.
Whether the equivalence in hypertrophy persists when controlling for total training volume, muscle activation patterns, and recovery variables.
What This Would Prove
Whether the equivalence in hypertrophy persists when controlling for total training volume, muscle activation patterns, and recovery variables.
Ideal Study Design
A double-blind RCT with 100+ young untrained adults randomized to cable or barbell preacher curls, using EMG to confirm similar muscle activation, matching total work, and measuring biceps thickness via DXA and ultrasound at proximal, mid, and distal sites pre- and post-12 weeks.
Limitation: Limited to young, untrained adults; cannot generalize to trained individuals or other muscle groups.
Prospective Cohort StudyLevel 2bWhether long-term hypertrophy differences emerge over years of habitual use of one method over the other in real-world settings.
Whether long-term hypertrophy differences emerge over years of habitual use of one method over the other in real-world settings.
What This Would Prove
Whether long-term hypertrophy differences emerge over years of habitual use of one method over the other in real-world settings.
Ideal Study Design
A 3-year prospective cohort tracking 200 young adults who self-select either cable or barbell preacher curls as their primary biceps exercise, measuring biceps thickness annually via ultrasound while controlling for diet, other training, and adherence.
Limitation: Cannot control for confounding variables like diet or other exercises; prone to selection bias.
Evidence from Studies
Supporting (1)
Placing Greater Torque at Shorter or Longer Muscle Lengths? Effects of Cable vs. Barbell Preacher Curl Training on Muscular Strength and Hypertrophy in Young Adults
Both ways of doing preacher curls—using a cable machine or a barbell—made people’s biceps grow about the same amount after 10 weeks, even though the exercises felt different. So, it doesn’t matter which one you pick if you just want bigger biceps.