In untrained young men, adding isolated arm exercises to a full-body weight training program for 8 weeks led to a slightly larger increase in arm size compared to full-body training alone, but there...

Pro

Against

Mechanism

Synthesis from 1 study

How it works

Adding arm-specific exercises like curls and extensions to a full-body workout makes the upper arms grow a little more because those exercises squeeze and stretch the biceps and triceps more directly than big lifts like bench presses do — this extra stress triggers more muscle growth in that one...

Most probable mechanism

In Simple Terms

When untrained men do arm-specific exercises like bicep curls and tricep extensions in addition to big lifts like bench presses, the muscles in their upper arms get stretched and squeezed more directly, which triggers more muscle growth in that area — this is why their arms get slightly bigger, even though their overall strength doesn't improve more than those who only do big lifts (10.4081/ejtm.2018.7827).

Causal chain

Single-joint exercises (elbow flexion and extension) apply direct mechanical tension to the biceps brachii and triceps brachii, increasing muscle fiber activation beyond what occurs during secondary recruitment in multi-joint movements (10.4081/ejtm.2018.7827)

Supported by evidence

which leads to

This increased mechanical load and localized metabolic stress (e.g., metabolite accumulation, muscle cell swelling) enhances intracellular signaling pathways such as mTOR, which upregulate muscle protein synthesis specifically in the elbow flexors and extensors (10.4081/ejtm.2018.7827)

Supported by evidence

which leads to

Differential regional hypertrophy occurs in the triceps brachii due to distinct loading patterns between single-joint and multi-joint exercises, and combining both exercise types optimizes whole-muscle growth in the upper arm (10.4081/ejtm.2018.7827)

Supported by evidence

which leads to

Accumulated muscle fiber growth increases the cross-sectional area of the upper arm, which is measured as a greater increase in flexed arm circumference (10.4081/ejtm.2018.7827)

Verified by multiple studies

Evidence from Studies

Supporting (1)

Community contributions welcome

Does the addition of single joint exercises to a resistance training program improve changes in performance and anthropometric measures in untrained men?

Randomized Controlled Trial

Human

2018 Nov 2

Contradicting (0)

Community contributions welcome

No contradicting evidence found

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.

Source Study

Does the addition of single joint exercises to a resistance training program improve changes in performance and anthropometric measures in untrained men?

Score: 52

DOI: 10.4081/ejtm.2018.7827

Similar Assertions

For untrained young men, adding isolated arm exercises like bicep curls to a workout routine that already includes compound movements like bench presses and rows does not lead to bigger arm muscles or stronger elbow flexion after 10 weeks of training.

90%

For untrained young men, adding isolated arm exercises to a full-body strength routine does not result in bigger or stronger biceps after 10 weeks compared to doing only compound exercises.

88%

When young men who haven't trained before do either multi-joint exercises (like curls) or single-joint exercises (like bicep curls) for 10 weeks, their arm muscles grow by about the same amount - there's no meaningful difference between the two types of workouts.

88%

If young men who haven't exercised before do either multi-joint exercises (like pull-ups) or single-joint exercises (like bicep curls) for 10 weeks, their arm strength increases by about the same amount - neither type of exercise is clearly better than the other.

87%

Doing extra arm exercises along with big compound lifts like squats and presses makes arms a little bigger, but doesn’t make you stronger than doing just the big lifts alone.

87%