You only need 2 arm exercises max per workout! Do a curl for the biceps, which hits other large arm flexors like the brachialis & brachioradialis too. The triceps require elbow extension. To get full development though, these must be single-joint exercises done right.
Why So Few Arm Exercises?
A typical biceps workout includes a standing barbell curl for the muscle belly, concentration curls for the peak, and preacher curls for the lower biceps near the elbow.
For the triceps, you may do lying skull crushers for the middle region, kickbacks for the lateral head or upper triceps (or lower?), and finally a close-grip press for the lower portion (upper maybe?) or the medial head.
Doing all of these is redundant. The benefit from so many exercises may come from the volume alone, yet many natural trainees burn out with this approach.
The rationale for more exercises comes from a desire for balance and pattern seeking. Since 3 exercises per muscle group is a bodybuilding standard, biceps & triceps are treated the same.
2-3 exercises can be justified for big muscles with greater deviations in fiber orientation. For the biceps & triceps, all fibers orient nearly the same direction or the force vectors are balanced. This is also supported by these muscles acting through the elbow, a simple hinge joint.
Unlike the calves, where the gastrocnemius & soleus exhibit reciprocal activation (meaning heel raises with both straight & bent knees have value), neural conflicts seem minimal for either the arm flexors or extensors. All the muscles involved can and will produce high forces.
You can’t develop both the upper and lower biceps. What happens is the whole muscle fiber adapts to the average length where stimulation occurs.
For long lengths or eccentric contractions, more growth happens in-series near the attachments for stretch adaptation. More growth happens in-parallel, or for the muscle cross-section, at shorter lengths or concentric contractions.
With various grips or when keeping the elbows in vs. out, you just stretch a certain head. EMG may then decrease since force requirements are lower due to more passive tension. More passive tension leads to soreness.
You get similar development either way in the end, though DOMS felt the next day creates the illusion of focus.
Which Arm Exercises Are Best?
We do need single-joint exercises to fully develop the biceps & triceps.
The biceps and the long head of the triceps attach to both the elbow and the shoulder. This means that compound exercises, like underhand pull-ups & upright dips, do not activate these muscles intensely. They facilitate smooth movement since they change little in length.
The moment arms are weak for both the biceps & triceps at the shoulder, so front raises & pull-overs have little value for them.
For the biceps, you must perform elbow flexion with a nearly-supinated or underhand grip. This unwraps the biceps from the radius bone in the forearm, preventing inhibition.
Pure supination during elbow flexion is harsh on the elbows though, so a cambered or E-Z bar works great, or dumbbells, instead of a straight barbell.
For triceps, you can perform arm extension with any grip, though pronated & neutral grips are more stable to ensure activation.
Many trainees find that overhead & lying arm extensions can be harsh on the elbow, due to the stretch on the tendon, so keep this mind.
What are the best exercises then?
Any exercise that lets you have consistent endpoints and works with your equipment is fine. How low or high your elbows are within reasonable limits, for either a biceps or triceps exercise, won’t matter.
Both very stretched & very shortened positions (passive & active insufficiency), especially through long levers that overload these points, are not ideal since they limit passive & active tension. Think behind-the-neck cable curls or cable kickbacks overloading the lockout.
The body may adapt eventually but perhaps not fully. Yet conventional exercises, say even preacher curls & overhead arm extensions, still overload a normal range of motion.
Can Arm Exercise Selection Be Complicated?
Yes. Bodybuilding only gets complicated though when you want to develop specific areas while limiting growth elsewhere. This applies to few trainees… most need all the muscle they can get!
On curls, supinating with dumbbells may favor the biceps compared to other arm flexors. The body prefers to emphasize a multi-joint muscle if 2+ actions are required from it.
A pronated or neutral grip would emphasize the brachialis & brachioradialis since the biceps is disabled.
A mostly-underhand curl would balance growth for all elbow flexors, making it best overall.
You would only consider the earlier options if you had an unusual structure. For example, you may try to limit brachialis growth by supinating during the motion.
Regional differences within the muscles likely don’t matter here. Supination for the biceps is unlikely to hit the medial fibers more than elbow flexion once you approach MVC. Selective motor unit recruitment is for precision, not moving heavy weights!
Regarding the stretch, I’m unsure if say incline curls lead to fuller biceps visually, due to distal muscle development. Do concentration curls lead to a greater peak?
Both Steve Reeves & Vince Gironda believed in the concept… they recommended hack squats to develop lower thighs, and not just the vastus medialis, for instance.
While I’ve never seen parallel vs. in-series growth quantified through a study, I suspect a slight difference. Unfortunately, we are mostly prisoners to our genetic makeups for muscle shape.
Some research hypothesizes that 90° or greater at the elbow is required to fully involve the medial head of the triceps. Anecdotal evidence and some biomechanical models support that an underhand grip emphasizes the medial triceps. I doubt these make a big difference.
How Many Arm Exercises Per Workout?
You often notice bodybuilding sources encouraging variety without any real support. Furthermore, you notice countless discrepancies among these experts describing what area an exercise targets. Arms are no exception!
I feel things are likely simpler than many believe, though it took me a long time to reach this viewpoint.
Do know that most great bodybuilders recommend variety, so you would be wise to not conclude your search for truth here.
Nonetheless, the evidence seems to shows that you only need 1 exercise for the biceps & triceps each. Use a nearly-underhand grip on the curl selected, and choose a strong grip for arm extension. Avoid very weird positions.
I suggest that most trainees do at least 3 sets each, performed at least once weekly, for 6-12 reps closely approaching failure on each working set.
I personally like standing cambered barbell curls for the biceps with cheating allowed.
For the triceps, I do arm extensions with a long dumbbell.
I use an odd technique where I start from the ground then place my feet high on a wall. This places my elbows near my sides to reduce tendon stress. It feels like a cable push-down made possible while training with free weights at home.
Instead of more senseless arm exercises, consider:
- doing neck & forearm work.
- balancing exercises for antagonists. For example, leg raises offsetting stiff-legged dead-lifts.
- addressing different fiber orientations for large muscle groups like the lats & shoulders.
- trying unusual exercises like toe raises for the tibialis anterior.
- performing additional sets, if needed, on whichever good exercises you choose!