Preacher Curl
The preacher curl places the upper arms against an angled pad with the shoulders flexed approximately 50°. This configuration reduces the available elbow flexion ROM to ~115° (vs 145° for standing curls) and shifts the resistance curve to ascending — the hardest point is at the bottom where the elbow is most extended. The preacher curl emphasizes the lengthened biceps position more than free-standing curls, making it a complementary stimulus rather than a substitute.
Execution
- Adjust the preacher bench so the top of the pad is at armpit height when seated
- Rest the upper arms flat against the pad, shoulder slightly in front of the pad's top edge
- Hold the EZ-bar or barbell at full arm extension (do not lock out completely)
- Curl to the top — do not allow the upper arms to lift off the pad
- Lower slowly and under control; do not bounce at the bottom — this is where distal biceps tendon injury risk is highest
What the EMG Data Shows
| Study | Biceps Activation |
|---|---|
| Porcari 2014 | 88.8% MVIC |
| Oliveira 2009 | 80.0% MVIC |
The preacher curl activates less than concentration curls (97.9%) but more than the barbell curl (76.5%) — a counterintuitive result explained by the ascending strength curve: the harder bottom position demands more muscle force at maximum stretch.
The Ascending Strength Curve
The preacher curl is one of few curl exercises where the ascending curve is pronounced. This is mechanically different from the bell-shaped barbell curl:
- Barbell curl: easiest at bottom and top; hardest at 90° elbow flexion
- Preacher curl: hardest at the bottom; progressively easier through the concentric
The practical implication: preacher curls are uniquely suited for training the biceps under load in the most stretched position, consistent with evidence that lengthened-position loading enhances hypertrophy stimulus.
Injury Warning
The bottom position (full elbow extension against load) concentrates tensile stress on the distal biceps tendon. Do not allow the weight to drop through the eccentric or hyperextend the elbow. Trainees with pre-existing distal biceps tendinopathy should use cable preacher curls, which maintain constant tension without the hard stop at the bottom.
For system-specific training applications, see each system's lens entry.