Mapping the characteristics of training for vocal conditioning of singers: a scoping review.
Pamela Carvalho, Priscila Oliveira, Denis Batista and 1 others
Eight small studies (1–34 singers) on vocal conditioning all reported positive results, mostly in self-reported measures.
The most common strategies were respiratory muscle exercises and straw/tube phonation, but only one study had a control group, so the evidence base is thin.
Key findings
1Seven of the eight included studies were before-and-after or quasi-experimental designs without a control group; only one used a true experimental design. Sample sizes ranged from a single singer to 34.
2Respiratory muscle strength exercises appeared in five of the eight studies and semi-occluded vocal tract exercises (straws, tubes, humming, lip trills) in four; these were the two most common intervention strategies.
3Self-evaluation was the most common outcome measure (five of eight studies), and positive self-reported results were the most frequent finding across the included studies; no study reported negative results.
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What it does not show
Only eight studies were found, and most had very small samples (one study had a single singer; the largest had 34), making it impossible to generalise results to a broader singing population. Seven of the eight studies were before-and-after or quasi-experimental designs without a control group, so it is not possible to separate the effect of the training from the effect of time, practice, or natural variation. The studies used heterogeneous intervention strategies, dosage parameters, outcome measures, and follow-up periods, which the review itself notes makes synthesis and comparison difficult. Three of the eight studies did not report exercise dosage at all, and only one recorded rest intervals between sets. The most common outcome measure was self-evaluation, which is susceptible to expectation bias, particularly in uncontrolled designs. The review is limited to singers without vocal complaints; it says nothing about singers with existing voice disorders or about other occupational voice users. Most included studies (seven of eight) acknowledged their own methodological limitations, including small sample sizes, absence of laryngeal imaging, and lack of follow-up evaluations.
Declared interests
No funding source was declared and no conflicts of interest were reported.
The easy way to misread this
Do not read 'all eight studies reported positive results' as strong evidence that vocal conditioning works — seven of the eight had no control group, the largest sample was 34 singers, and the most common outcome was the singer's own report of feeling better. The one study with a control group (Sezin et al., 34 religious singers in Turkey) is the only one that can attribute change to the training rather than to time, practice, or expectation, and it is a single data point in a population of professional singers.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →