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Abstract Details

Activity Number: 524
Type: Contributed
Date/Time: Wednesday, August 1, 2012 : 10:30 AM to 12:20 PM
Sponsor: IMS
Abstract - #305978
Title: Comparing Two Scales Measuring Perceived Leg Exertion During Exercise in Children
Author(s): Marianne Huebner*+ and Zhen Zhang and Patrick McGrath and Paolo Pianosi
Companies: Mayo Clinic and Michigan State University and Dalhousie University and Mayo Clinic
Address: 200 First Street SW, Rochester, MN, 55905, United States
Keywords: canonical curves ; lag model ; comparing scales

Ratings for leg effort using Borg scale were compared to pictorial Dalhousie scale during incremental cycle ergometer exercise to voluntary exhaustion. Test duration for 79 children ranged from 6-12 minutes. Work was normalized across subjects by expressing it as % of individual maximum work capacity (Wmax). A lag was defined as %Wmax at which point a clear increase in ratings of leg fatigue occurred. We compared two models: a power model with intercept, coefficient, and exponent, and a lag model with intercept, lag time, and slope. The parameters in each model were estimated with a conjugate gradient optimization algorithm. Leg tiredness developed quickly for some children while there was a delay before increasing in heavy exercise for others. The canonical curves of ratings for one scale compared to average ratings of the other scale were similar with deviations at larger ratings. Both lag model and power model can be fitted to each subject's ratings. The exponent in the power coefficient depends on the multiplicative constant to obtain a fit; whereas the lag model allows for interpretability of the model parameters in terms of %Wmax describing different rating patterns.

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