Validity of one-repetition maximum predictive equations in men with spinal cord injury.

STUDY DESIGN: Cross-sectional study. OBJECTIVES: The study aimed (a) to test the cross-validation of current one-repetition maximum (1RM) predictive equations in men with spinal cord injury (SCI); (b) to compare the current 1RM predictive equations to a newly developed equation based on the 4- to 12-repetition maximum test (4-12RM). SETTING: SARAH Rehabilitation Hospital Network, Brasilia, Brazil. METHODS: Forty-five men aged 28.0 years with SCI between C6 and L2 causing complete motor impairment were enrolled in the study. Volunteers were tested, in a random order, in 1RM test or 4-12RM with 2-3 interval days. Multiple regression analysis was used to generate an equation for predicting 1RM. RESULTS: There were no significant differences between 1RM test and the current predictive equations. ICC values were significant and were classified as excellent for all current predictive equations. The predictive equation of Lombardi presented the best Bland-Altman results (0.5 kg and 12.8 kg for mean difference and interval range around the differences, respectively). The two created equation models for 1RM demonstrated the same and a high adjusted R2 (0.971, P<0.01), but different SEE of measured 1RM (2.88 kg or 5.4% and 2.90 kg or 5.5%). CONCLUSION: All 1RM predictive equations are accurate to assess individuals with SCI at the bench press exercise. However, the predictive equation of Lombardi presented the best associated cross-validity results. A specific 1RM prediction equation was also elaborated for individuals with SCI. The created equation should be tested in order to verify whether it presents better accuracy than the current ones.

Reproducibility and responsiveness of heart rate indexes to assess wheeling efficiency in patients with spinal cord injuries.

STUDY DESIGN: Cross-sectional study. OBJECTIVES: To measure the reproducibility and responsiveness of heart rate indexes in measuring energy expenditure during wheelchair locomotion of adults with spinal cord injury (SCI). SETTING: SARAH Rehabilitation Hospital Network-Brasilia, Brazil. METHODS: The study consecutively enrolled 35 individuals with SCI. Volunteers propelled their wheelchairs at a self-selected and comfortable velocity around a circular track. The first assessment day was a responsiveness study, in which three tests were performed, with the wheelchair weight increased randomly during the last two tests. On the second assessment day, the test was conducted without extra weight (that is, baseline conditions) for reproducibility analyses. RESULTS: All indexes demonstrated reproducibility on all statistical analyses. The Propulsion Cardiac Cost Index (PCCI) had a lower variation coefficient than the Physiological Cost Index (PCI; 8.5%, 95% confidence interval (CI) 5.8-11.2 vs 24.2%, 95% CI 16.0-32.4) and lower effect size than the Total Heart Beat Index (THBI; 0.16 vs 0.26). The PCCI also had the best responsiveness results on all statistical tests. The PCCI correlation was the largest (r=0.63, P<0.01, 95% CI 0.43-0.83, followed by PCI (r=0.53, P<0.01, 95% CI 0.34-0.72) and then the THBI (r=0.50, P<0.01, 95% CI 0.29-0.71). CONCLUSIONS: All three indexes were reproducible and responsive. However, the PCCI gave better statistical results. This index may be useful in functional diagnosis and follow-up of rehabilitation.

Validity of heart rate indexes to assess wheeling efficiency in patients with spinal cord injuries.

STUDY DESIGN: Cross-sectional study. OBJECTIVES: To validate heart rate (HR) indexes for the evaluation of energy expenditure during wheelchair propulsion in people with spinal cord injury (SCI). SETTING: SARAH Rehabilitation Hospital Network-Brasilia, Brazil. METHODS: Forty-eight men aged 29.0±7.8 years with a SCI between C6 and L3 causing complete motor impairment were enrolled in the study. The assessment consisted of 5 min of rest while seated in the wheelchair, followed by 5 min of wheelchair propulsion at a self-selected comfortable speed. The main outcomes measured were oxygen consumption, HR, physiological cost index (PCI), total heart beat index (THBI) and propulsion cardiac cost index (PCCI). RESULTS: Using oxygen uptake as gold standard, the highest correlations were found between this and PCCI (r=0.59, P<0.001, 95% confidence interval (CI) 0.36-0.75) and THBI (r=0.58, P<0.001, 95% CI 0.36-74.0), independently of the injury level. The PCI had the lowest correlation coefficient (r=0.38, P<0.01, 95% CI 0.11-0.60). Spearman correlation analysis showed that the indexes mostly associated with lesion level were PCCI (ρ=-0.531; P<0.001; 95% CI -0.708 to -0.291) and THBI (ρ=-0.524; P<0.001; 95% CI -0.704 to -0.282). CONCLUSIONS: Both THBI and PCCI seem to be valid measures for assessing energy expenditure. Both indexes showed a coherent correlation with the spinal injury level.

Determination of normative values for 20 min exercise of wheelchair propulsion by spinal cord injury patients.

STUDY DESIGN: This was a retrospective observational study. OBJECTIVE: The objective was to determine the normative values for 20 min exercise of wheelchair propulsion in spinal cord injury (SCI) subjects. SETTING: Sarah Rehabilitation Hospitals Network, Brazil. METHODS: A total of 413 medical records for SCI patients at different levels and classifications at the Sarah Rehabilitation Hospitals Network, Brazil, who performed 20 min exercise in a rehabilitation programme between the years 2004 and 2009 were consulted. Information regarding patient and performance characteristics was obtained, including distance travelled, mean velocity, rest and exercising heart rate and perceived exertion. The data were analysed by gender and by injury level group: tetraplegia (TT) or paraplegia (PP). RESULTS: The participants' ages ranged from 18 to 64 years, and the median time since injury was 1.2 years. The men and women had different performances regardless of their level of injury. The distance ranged between 495 and 2106 m for men and between 300 and 1901 m for women. The mean velocity of propulsion ranged from 25 to 105 m min(-1) for men and from 15 to 95 m min(-1) for women. CONCLUSIONS: This study provides normative data for the 20 min exercise that could be used to estimate the resistance capacity by manual wheelchair users with SCI and evaluate the effects of training and other therapeutic interventions.