Pull-ups and chin-ups both load the lats and biceps heavily; the chin-up (supinated) adds biceps and pec, the pull-up (pronated) adds lower trapezius
A rotating-handle device changed nothing
Participants
n=25 volunteers: 21 men (24.9 ± 2.4 years) and 4 women (23.5 ± 1 years). Training status is not stated in the abstract.
Protocol
Conventional pull-up, chin-up and a rotational exercise on Perfect·Pullup™ twisting handles; surface EMG normalised to MVIC, elbow motion by Vicon; one-factor repeated-measures ANOVA across the 3 exercises.
Key Findings
Mean activation by muscle (%MVIC, range across the exercises): external oblique 31–35%, erector spinae 39–41%, pectoralis major 44–57%, lower trapezius 45–56%, infraspinatus 71–79%, biceps brachii 78–96%, latissimus dorsi 117–130%.
Chin-up vs pull-up: pectoralis major and biceps brachii were significantly more active in the chin-up; the lower trapezius was significantly more active in the pull-up.
The rotating-handle device did not change recruitment: no differences between the Perfect·Pullup™ and the conventional pull-up or chin-up.
Elbow range of motion: 93.4 ± 14.6° (pull-up), 100.6 ± 14.5° (chin-up), 99.8 ± 11.7° (rotational).
Sequence: peak-activation timing showed a broad sequential pattern, suggesting that the lower trapezius and pectoralis major start pull-ups and chin-ups and the biceps brachii and latissimus dorsi finish them.
Practical Application
In 25 young adults, both grips drove the lats above MVIC (117–130%) and the biceps to 78–96%; the supinated chin-up added pec and biceps activation, the pronated pull-up added lower-trapezius activation. Pick the grip for the accessory emphasis — chin-up for arms/chest, pull-up for the lower trap — the lat stimulus is high either way.
Rotating/twisting handles are not a stimulus upgrade over a fixed bar in this study. Inference, not tested: alternating grips across a week spreads the accessory stress, but the paper did not test any training outcome.
Limitations
Single-session EMG (n=25); activation amplitude is not a direct measure of hypertrophy or strength outcome.
Training status of the volunteers is not stated in the abstract; the small female subgroup (4) was pooled with the men.
How this entry was checked and changed
Why this level
regraded 2026-09-27 from C: cross-sectional measurement study, n=25, no performance outcome
Content correction 2026-09-27
"grip and rotation shift the emphasis" -> the rotational (Perfect·Pullup™) exercise showed no difference from the conventional pull-up or chin-up; only grip (pronated vs supinated) shifted activation.
Added the abstract's %MVIC values, the lower-trapezius finding for the pull-up, and the elbow ROM figures; labelled the "rotate grips" advice as untested inference.
Level C -> B (cross-sectional measurement study); Tier "mixed (trained adults)" -> Tier 1-2, training status not stated in the abstract.