Prediction of oxygen uptake during over-ground walking in people with and without Down syndrome

Abstract

The reduced gait stability and aerobic fitness of people with Down syndrome (DS) may increase their rate of gross oxygen uptake (gross-VO(2)) during over-ground walking. If so, the ACSM equation predicting gross-VO(2) from speed may not be appropriate and an equation specifically for these individuals may be needed. This study therefore examined whether the relationship between gross-VO(2) and speed differs between individuals with and without DS during over-ground walking and attempted to develop a gross-VO(2) prediction equation for people with DS. Gross-VO(2) was measured in 18 persons with DS (24.7 ± 6.8 years; 8 men) and 22 persons without DS (25.9 ± 4.8 years; 9 men) at rest and during five over-ground walking trials, each lasting 6 min, at 0.5, 0.75, 1.0, 1.25, and 1.5 m/s. Multi-level modeling with random intercepts and slopes demonstrated significant effects of speed, group, group-by-speed interaction, and speed squared (P < 0.001). In each group, actual gross-VO(2) did not differ from gross-VO(2) predicted by the regression equation across speeds. Bland-Altman plots showed somewhat greater variability in the difference between actual and predicted gross-VO(2) for participants with DS. Mean absolute error of prediction was 10.75 and 10.67% for participants with and without DS, respectively. In participants with DS, the ACSM formula under-estimated gross-VO(2) across speeds, whereas, in participants without DS, only at 1.5 m/s (P < 0.001). Therefore, individuals with DS show altered curvilinear gross-VO(2) to speed relationship during over-ground walking. The present regression equation appears to offer accurate prediction in people with DS and could be used for prescribing over-ground walking intensities.

Prediction of oxygen uptake during walking in ambulatory persons with multiple sclerosis

“…Furthermore, the Bland-Altman plots showed zero mean error of agreement, suggesting that the present equation does not have systematic error across all speeds combined. Furthermore, the 95 percent limits of agreement in the Bland-Altman plots were similar to those found in nondisabled persons and persons with other disabilities [29], but did indicate some variation in individual predictability. Although the reasons for this effect cannot be determined based on the present data, the reasons may relate to the diverse effects of MS between people [2]-ones that cannot be captured fully by the MSWS-12.…”

“…Mean absolute percent error was relatively small-smaller than that reported in other populations [29]. Furthermore, the Bland-Altman plots showed zero mean error of agreement, suggesting that the present equation does not have systematic error across all speeds combined.…”

Reliability and Validity of Physical Fitness Field‐Based Tests in Down Syndrome: A Systematic Review

“…However, with regard to validity, two studies that addressed this issue concluded that the 20‐meter shuttle‐run did not allow for an estimation of maximum oxygen uptake in young people with DS (Agiovlasitis et al, ; Guerra et al, ). In view of this situation, when assessing the aerobic capacity of DS populations it seems that no field‐based test has shown to be valid for this particular aim, with the exception of the half‐mile run‐walk test, whose validity has been regarded as questionable (Fernhall et al, ).…”

Prediction of energy expenditure during walking in adults with down syndrome

“…A widely used formula that estimates VO 2 from walking speed is the one endorsed by the American College of Sports Medicine (ACSM) (American College of Sports Medicine, ). This equation, however, has been developed for people without disabilities and, not surprisingly, underestimates the VO 2 during walking in adults with DS (Agiovlasitis, Motl, Ranadive, et al., ). These individuals have higher VO 2 during walking—especially at faster speeds—than individuals without DS likely because of altered gait patterns (Agiovlasitis, McCubbin, Yun, Widrick, & Pavol, ).…”

“…Past research, with a small number of participants, attempted to develop an equation for predicting VO 2 from walking speed in adults with and without DS (Agiovlasitis, Motl, Ranadive, et al., ). There is a need to develop a prediction equation in larger and more representative samples because DS is a chromosomal disorder that results in wide diversity of physiological complications (Bull & Committee on Genetics, ).…”