What New Science Says About Greater Arms (2025) – SET FOR SET

Plus 3 coaching purposes to maximise hypertrophy 

The hunt for one of the best workouts to maximise muscle progress is endless. You possibly can simply discover articles titled “Prime 5 Workouts For (any muscle you need)”. However what if we have it unsuitable? What if one of the best ways to maximise muscle hypertrophy is not utilizing one of the best train, however through the use of a number of workouts? That is what new analysis printed in Sport Sciences for Well being suggests, including to the rising stack of literature selling train variation over utilizing a single train.

The Examine: Acute and power regional adjustments in elbow flexor thickness after resistance coaching with dumbbell curl or dumbbell row workouts (2025)

A 2025 examine in Sport Sciences for Well being (Leitão et al., 2025) wished to reply a few questions regarding bicep progress:

• Are there variations between acute and long-term muscle progress from resistance coaching?
• Do dumbbell curls or rows produce larger muscle hypertrophy? 
• Does utilizing a number of workouts produce larger muscle progress than a single train?

To do that, they in contrast single-joint dumbbell curls (DC) and multi-joint dumbbell rows (DR) to see how every train impacts muscle progress within the biceps.

How Did Researchers Examine Variations within the Biceps’ Muscle Development? 

Because the researchers had been taking a look at each power and acute results, they used two research. 

Every examine used an analogous protocol with a within-subject experimental design. Every participant carried out a dumbbell curl with one arm and a single-arm row with the opposite.

Muscle hypertrophy was measured at proximal (25%) and distal (75%) areas of the biceps.

Experiment 1 (Acute response): To find out acute response, 16 educated males carried out a single session of dumbbell curls and single arm dumbbell rows utilizing a 4×8–12RM rep scheme. 

Ultrasound was used to measure muscle swelling instantly after coaching (a brief enhance in thickness).

Experiment 2 (Continual adaptation): To take a look at long-term progress, 9 untrained males educated for 8 weeks, twice per week, performing curls with one arm and rows with the opposite. Muscle thickness was measured earlier than and after coaching at two factors alongside the biceps (proximal = close to the shoulder; distal = close to the elbow).

What’s The Distinction Between Acute And Continual Muscle Development?

Let’s contact on “acute” and “power” muscle hypertrophy and why that issues.

• Acute Results was the quick swelling of the biceps measured proper after a exercise. This is casually known as “the pump,” brought on by blood circulate and water accumulation. 
• Continual Results had been measured after eight weeks of coaching, reflecting true muscle hypertrophy from long-term adaptation. That is “precise progress” that may stick round.

The acute swelling can spotlight which areas of a muscle are most burdened throughout an train in actual time. Nonetheless, solely power measurements affirm whether or not that stress truly interprets into lasting progress.

This distinction is essential in immediately’s fitness center, the place many lifters are chasing the pump. They confuse their bigger muscle groups after an intense session with precise progress, however a number of days later, they discover out their muscle groups have “shrunk”.

Now, this doesn’t suggest the pump has no worth, as there is a relationship with muscle progress, and it will be anabolic. Nonetheless, it is vital to differentiate the distinction and that coaching for a pump would not robotically translate into actual muscle progress.

What Did The Researchers Discover?

Alright, so what occurred? This is a rundown of the outcomes.

Acute (single session):

• Each curls and rows prompted swelling alongside the biceps.
• Curls produced larger swelling proximally (nearer the shoulder) than rows (19% vs 13%).
• Distal swelling (close to the elbow) was related between workouts.

Continual (8 weeks of coaching):

• Dumbbell curls elevated muscle thickness each proximal (≈5%) and distal (≈11%).
• Dumbbell rows elevated solely proximal thickness (≈5%), with no important distal progress (≈1%).
• General, curls produced extra whole hypertrophy, particularly within the decrease (distal) biceps area.

Within the acute experiment, the dumbbell curls produced larger progress in the complete biceps. Of curiosity, this progress was considerably larger within the proximal area of the biceps (close to the shoulders).

Within the power experiment, the dumbbell curls once more produced larger total progress. Of curiosity, each teams produced related will increase within the proximal area of the biceps. Nonetheless, within the distal area (close to the elbow), the row noticed minimal progress whereas the bicep curls produced an 11% enhance in muscle.

Why Would possibly This Occur?

So, why would these two workouts trigger such variations? Effectively, there are 3 issues to contemplate.

1. Vary of movement: Vary of movement (ROM) performs a big half in muscle progress, with greater ROM generally being superb for progress. This is largely due to:

• The quantity of stress positioned on the muscle 
• A extra even distribution of stress all through the muscle stomach

Curls practice the biceps by means of a bigger vary of movement, leading to larger stretch and extra direct stress alongside the size of the muscle.

2. Train mechanics: In rows, the biceps help the again and shoulder muscle groups slightly than being the prime mover. This may restrict their hypertrophic stimulus and even focus.

When a person performs a curl, their focus is probably going directed extra to the biceps muscle. Theoretically, this might invoke the mind-muscle connection, which has been discovered to be a determinant in muscle progress (Calatayud et. al, 2017)

3. Regional variations: Proof now reveals {that a} muscle (just like the biceps or rectus femoris) can develop extra in particular areas relying on the train mechanics. 

Quite a few research have proven that when utilizing a single train, the working muscle will expertise completely different quantities of progress in areas that have extra stress (Antonio, 2000).

How This Compares To Different Analysis

The outcomes of this examine align with different analysis, however they have to be thought of in context.

1. The impact of muscle swelling and its relationship to long-term muscle progress is surprisingly largely understudied.

There was an attention-grabbing examine in 2022 printed within the Journal of Energy and Conditioning Analysis that checked out the affiliation between the muscle swelling after the primary coaching session of a 6-week program and muscle progress on the finish. In contrast to this examine, they did discover a direct relationship.

Whereas attention-grabbing, that is mechanistic and should not have an effect on our coaching considerably.

2. By way of the non-uniform progress seen in a muscle, there was a number of analysis up to now that strains up with these findings. A lot in order that we might say, to optimize progress, it is important to make use of train variation.

This opinion is echoed by Dr. Jose Antonio, who printed a examine within the Journal of Energy and Conditioning Analysis. He performed a examine researching the impact of a number of workouts on muscle activation and progress. Attributable to non-uniform muscle progress from a single train, he concluded;

One other examine from de Vasconcelos et. al (2021) printed within the Worldwide Journal of Sports activities Drugs examined utilizing a single train to coach the biceps and quadriceps or a spread (3 workouts).  In it, each the biceps and quadriceps noticed fuller muscle progress throughout the total muscle in comparison with utilizing a single train.

We’ve got written about this before in a dedicated article, so be sure you test that out!

What Does This Imply For Your Coaching?

When taking a look at the takeaways, it is vital to notice that the muscle swelling is mechanistic in nature, whereas utilizing train variation is immediately relevant to our coaching. 

So, whereas searching for the connection between acute swelling and long-term progress is unquestionably attention-grabbing, “chasing the pump” in all probability is not one of the best take-away.

Moderately, this examine reveals the vital roles that train choice and train variation alternative can play in our total coaching technique.

Now, since just one isolation and one compound train had been examined, we clearly cannot apply this to all actions. For instance, chin-ups and close-grip lat pulldowns are glorious bicep workouts.

Essentially the most sensible conclusion is that variation of workouts that combine compounds and isolations is probably going wanted to optimize muscle progress. 

With that stated, be sure you embrace train variation in your coaching following these 3 tips.

1. Do not use workouts with related biomechanics in the identical session. This can grow to be redundant because the muscle groups are being labored in the identical approach.

• Do not Use: Bench press and push-ups
• Use: Incline bench press, dips, chest flies

2. In the event you practice the identical muscle twice per week, use completely different workouts. This can range relying on the person and coaching objectives, however here is an instance of the way it may look.

• Session 1: Incline barbell bench press, chest flies 
• Session 2: Dumbbell flat bench, dips

3. Alter workouts in a scientific strategy. You continue to want to focus on making use of progressive overload, which requires utilizing the identical workouts. The time-frame can range significantly relying in your coaching age, however listed below are some normal suggestions;

• Massive workouts: Swap each 6-12 weeks
• Accent workouts: Swap each 2-4 weeks
• Isolations: You possibly can alter each session or two in order for you

Bear in mind these are normal tips, and specifics rely on the individual. Regardless, keep in mind to at all times practice smarter, not more durable!

References

1. Antonio, J. (2000). Nonuniform response of skeletal muscle to heavy resistance coaching: Can bodybuilders induce regional muscle hypertrophy? Journal of Energy and Conditioning Analysis, 14(1), 102–113. https://doi.org/10.1519/00124278-200002000-00017
2. Calatayud, J., Vinstrup, J., Jakobsen, M. D., Sundstrup, E., Brandt, M., Jay, Okay., … Andersen, L. L. (2017). Thoughts–muscle connection coaching precept: Affect of muscle energy and coaching expertise throughout a pushing motion. European Journal of Utilized Physiology, 117(7), 1445–1452. https://doi.org/10.1007/s00421-017-3637-6
3. de Vasconcelos Costa, B. D., Kassiano, W., Nunes, J. P., Kunevaliki, G., Castro-E-Souza, P., Rodacki, A., Cyrino, L. T., Cyrino, E. S., & de Sousa Fortes, L. (2021). Does performing completely different resistance workouts for a similar muscle group induce non-homogeneous hypertrophy? Worldwide Journal of Sports activities Drugs, 42(9), 803–811. https://doi.org/10.1055/a-1308-3674
4. Hirono, T., et al. (2022). Relationship between muscle swelling and hypertrophy induced by resistance coaching. Journal of Energy and Conditioning Analysis, 36(2), 359-364. https://doi.org/10.1519/JSC.0000000000003478 
5. Leitão B. F. M., Albarello J. C. S., Halmenschlager G. H., Mannarino P., Nunes J. P., De Salles B. F., & Matta T. T. (2025). Acute and power regional adjustments in elbow flexor thickness after resistance coaching with dumbbell curl or dumbbell row workouts. Sport Sciences for Well being. https://doi.org/10.1007/s11332-025-01530-7