Early strength gains carry an important neural component
More neural drive, motor-unit firing changes and a strong practice effect — before noticeable hypertrophy
Key Findings
Strength increasing without noticeable hypertrophy is the first line of evidence for neural involvement; early-phase strength gains come with higher surface-EMG amplitude, read as increased neural drive.
Motor-unit changes: some studies report a transient rise in firing rate; faster rate of tension development has been linked to more doublet firing. Motor-unit synchronisation is possible but not definitely demonstrated.
Central evidence: imagined contractions raise cortical excitability (but are unlikely to match physical training); strength retained after physiological effects fade shows a strong practice effect; training can reverse the bilateral deficit and the lower EMG of eccentric contractions; unilateral training produces cross-education in the untrained limb.
Antagonist co-activation has been shown both to decrease and to increase with training — it is unclear whether the CNS optimises force or joint integrity. Peripheral contributions (e.g. Golgi tendon organ disinhibition) are much more uncertain.
Authors' recommendations: use motor-learning principles and imagined contractions; static contractions at longer muscle lengths transfer across more joint angles; submaximal eccentrics for pain, detraining or immobilisation; always record antagonist EMG when assessing neural change.
Practical Application
This narrative review holds that neural factors play an important role in early strength gains — more drive to the muscle, motor-unit firing changes and a strong practice effect — and arrive before visible hypertrophy, so expect quick early strength gains and treat the lift as a skill to practise.
Inference, not tested here: because part of the early gain is practice, train the specific movement you want to get stronger in.
Limitations
Narrative review; much of the evidence is surface EMG, a global measure.
The neural-vs-hypertrophic contribution shifts over a training career.
How this entry was checked and changed
Why this level
regraded 2026-09-27 from C: narrative review of human training studies without systematic method
Content correction 2026-09-27
"Reduced antagonist co-activation" as an established neural adaptation -> the abstract says both decreases and increases have been shown.
"Task- and velocity-specific" -> velocity specificity is not in the abstract; replaced with the abstract's evidence (practice effect, cross-education, bilateral/eccentric changes). Specificity advice labelled inference.
Level C -> C+ (narrative review).