Abstract
Oxygen consumption (VO2) has been used as a measure of walking economy to establish efficacy of various interventions, with little evidence of reproducibility in children with CP. Attainment of steady-state reach VO2 is critical to assess walking economy. From the onset of a submaximal constant workload, adults reach steady-state VO2 in about 3 min. AB children have shorter time constants (τVO2), representing faster VO2 kinetics (steady-state < 2 min). However, τVO2 has not been assessed in children with CP.
PURPOSE1) establish test-retest reliability of VO2 in the CP grp; 2) compare τVO2 between the CP & AB grps.
METHODSVO2 was initially measured with a metabolic cart for 12 AB children (age = 10.5 ± 4.3 yrs) & 11 independent ambulators with spastic diplegia CP (age = 9.8 ± 4.1 yrs), who were ≥ 6 yrs. The children performed 4 min of low intensity treadmill walking (AB = 0.49 ± 0.04 m/s, CP = 0.33 ± 0.13 m/s). Testing was repeated at 6 weeks for 7 children with CP. A monoexponential model was used to calculate phase II τVO2. VO2 scores were also calculated for min 2, 3 & 4 to assess steady-state. Mean VO2 & τVO2 scores were compared using between- & within-subject ANOVAs, as appropriate. Reliability was assessed with intraclass correlation coefficients (ICC).
RESULTSFor the CP group, initial & 6 week VO2 values were not significantly different (13.99 ± 3.05 ml/[kg*min] & 14.26 ± 4.37 ml/[kg*min], p = 0.75) & had high ICC = 0.91 [95% CI = 0.50–0.99]. There were no significant differences in τVO2 between the groups (AB = 11.92 ± 6.56 s, CP = 13.69 ± 6.95 s, p = 0.54). There were no significant differences between the mean VO2 scores obtained during min 2, 3 & 4, which also showed high ICC, min 2 to 4 = 0.88 & min 3 to 4 = 0.98 [95% CI = 0.90–1.00].
CONCLUSIONThere was a high correlation between initial & 6 week visits, indicating good reliability of this measure. The time constant (τVO2) showed no significant differences between groups. Similar to their AB peers, most children with CP were capable of reaching steady-state in < 2 min.
PURPOSE1) establish test-retest reliability of VO2 in the CP grp; 2) compare τVO2 between the CP & AB grps.
METHODSVO2 was initially measured with a metabolic cart for 12 AB children (age = 10.5 ± 4.3 yrs) & 11 independent ambulators with spastic diplegia CP (age = 9.8 ± 4.1 yrs), who were ≥ 6 yrs. The children performed 4 min of low intensity treadmill walking (AB = 0.49 ± 0.04 m/s, CP = 0.33 ± 0.13 m/s). Testing was repeated at 6 weeks for 7 children with CP. A monoexponential model was used to calculate phase II τVO2. VO2 scores were also calculated for min 2, 3 & 4 to assess steady-state. Mean VO2 & τVO2 scores were compared using between- & within-subject ANOVAs, as appropriate. Reliability was assessed with intraclass correlation coefficients (ICC).
RESULTSFor the CP group, initial & 6 week VO2 values were not significantly different (13.99 ± 3.05 ml/[kg*min] & 14.26 ± 4.37 ml/[kg*min], p = 0.75) & had high ICC = 0.91 [95% CI = 0.50–0.99]. There were no significant differences in τVO2 between the groups (AB = 11.92 ± 6.56 s, CP = 13.69 ± 6.95 s, p = 0.54). There were no significant differences between the mean VO2 scores obtained during min 2, 3 & 4, which also showed high ICC, min 2 to 4 = 0.88 & min 3 to 4 = 0.98 [95% CI = 0.90–1.00].
CONCLUSIONThere was a high correlation between initial & 6 week visits, indicating good reliability of this measure. The time constant (τVO2) showed no significant differences between groups. Similar to their AB peers, most children with CP were capable of reaching steady-state in < 2 min.
| Original language | English |
|---|---|
| Pages (from-to) | S46-S46 |
| Number of pages | 1 |
| Journal | Medicine & Science in Sports & Exercise |
| Volume | 35 |
| Issue number | 5 |
| Publication status | Published - May 2003 |
| Externally published | Yes |