Assessment of maximum inspiratory pressure. Prior submaximal respiratory muscle activity ('warm-up') enhances maximum inspiratory activity and attenuates the learning effect of repeated measurement.
BACKGROUND
The variability of maximal inspiratory pressure (PImax) in response to repeated measurement affects its reliability; published studies have used between three and twenty PImax measurements on a single occasion.


OBJECTIVE
This study investigated the influence of a specific respiratory 'warm-up' upon the repeated measurement of inspiratory muscle strength and attempts to establish a procedure by which PImax can be assessed with maximum reliability using the smallest number of manoeuvres.


METHODS
Fourteen healthy subjects, familiar with the Mueller manoeuvre, were studied. The influence of repeated testing on a single occasion was assessed using an 18-measurement protocol. Using a randomised cross-over design, subjects performed the protocol, preceded by a specific respiratory warm-up (RWU) and on another occasion, without any preliminary activity (control). Comparisons were made amongst 'baseline' (best of the first 3 measurements), 'short' series (best of 7th to 9th measurement) and 'long' series (best of the last 3 measurements).


RESULTS
Under control conditions, the mean increase ('baseline' vs. 'long' series) was 11.4 (5.8)%; following the RWU, the increase (post RWU 'baseline' vs. 'long' series) was 3.2 (10.0)%. There were statistically significant differences between measurements made at all 3 protocol stages ('baseline', 'short' and 'long' series) under control conditions, but none following the RWU.


CONCLUSIONS
The present data suggest that a specific RWU may attenuate the 'learning effect' during repeated PImax measurements, which is one of the main contributors of the test variability. The use of a RWU may provide a means of obtaining reliable values of PImax following just 3 measurements.
School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham, UK. S.Volianitis@Bham.ac.uk
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Volianitis
A K
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McConnell
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DA
Jones
D000328:Adult; D000704:Analysis of Variance; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007320:Inspiratory Capacity / Q000502:physiology*; D008297:Male; D010809:Physical Fitness / Q000502:physiology*; D011336:Probability; D012016:Reference Values; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D012132:Respiratory Muscles / Q000502:physiology*; D012680:Sensitivity and Specificity