Predictors of energy cost during stair ascent and descent in individuals with chronic stroke

Development of a prediction model for ascent and descent staircase independence during the sub-acute rehabilitation phase in individuals post-stroke

BACKGROUND

Nearly half of individuals post-stroke are dependent in their daily activities. The ability to ascend and descend stairs is an important component of independence in the community.

OBJECTIVE

To predict the future ability of post-stroke individuals at the beginning of the sub-acute rehabilitation phase to achieve ascending and descending staircase independence.

METHODS

36 participants were recruited for the study.

OUTCOME MEASURES

independence in ascending and descending stairs up to the end of the sub-acute rehabilitation phase. Predictive measures included the knee extensors Muscles Strength (MS), the seated Modified Functional Reach (MFR) test, and Heart Rate Variability (HRV) measures. Logistic and Cox regression were used.

RESULTS

Twenty-four participants (66.7%) completed the sub-acute rehabilitation phase being independent in ascending and descending stairs. MFR was the best predictor (R2 = 0.18), and with MS the best predictors for the time (days) to achieve this goal during the sub-acute rehabilitation. HRV measure was found to be the main predictor of the staircase ascent model (R2 = 0.32), and MFR the best predictor for the descent model (R2 = 0.24).

CONCLUSIONS

Balance performance is the main predictor of independence in ascending and descending stairs. Improving this component during the sub-acute rehabilitation phase might be reflected in achieving staircase independence.

The relationship between the physical cost index and knee extensor strength in children with hemiplegic cerebral palsy

[Purpose] Lower extremity strength is a contributing factor to energy efficiency of gait. However, this contribution has not previously been evaluated in children with hemiplegic cerebral palsy (CP). The aim of this study was to evaluate the association between energy consumption, measured by the physical cost index (PCI), and strength of lower extremity, measured by the maximum knee extensor strength (MKES), in children with hemiplegic CP. [Subjects and Methods] Subjects were 10 children (4 males and 6 females; age, 7–17 years) with hemiplegic CP, but no history of orthopedic intervention or botulinum toxin treatment over the 1 year prior to the assessment. The PCI was measured during a 6-min walk test, and MKES using hand-held dynamometry, with the highest of two measures used for analysis. [Results] A negative correlation was identified between the PCI and MKES (R-value, −0.81 (affected) and −0.83 (unaffected) lower limb). [Conclusion] Higher lower extremity strength was associated with lower fatigability during a 6-min walk test in children with hemiplegic CP, providing evidence for the inclusion of strengthening exercises for both the affected and unaffected extremities in the rehabilitation of these children.

Relationship between oxygen cost of walking and level of walking disability after stroke: An experimental study

BACKGROUND AND PURPOSE

Since physical inactivity is the major risk factor for recurrent stroke, it is important to understand how level of disability impacts oxygen uptake by people after stroke. This study investigated the nature of the relationship between level of disability and oxygen cost in people with chronic stroke.

METHODS

Level of walking disability was measured as comfortable walking speed using the 10-m Walk Test reported in m/s with 55 ambulatory people 2 years after stroke. Oxygen cost was measured during 3 walking tasks: overground walking at comfortable speed, overground walking at fast speed, and stair walking at comfortable speed. Oxygen cost was calculated from oxygen uptake divided by distance covered during walking and reported in ml∙kg^-1 ∙m^-1 .

RESULTS

The relationship between level of walking disability and oxygen cost was curvilinear for all 3 walking tasks. One quadratic model accounted for 81% (95% CI [74, 88]) of the variance in oxygen cost during the 3 walking tasks: [Formula: see text] DISCUSSION: The oxygen cost of walking was related the level of walking disability in people with chronic stroke, such that the more disabled the individual, the higher the oxygen cost of walking; with oxygen cost rising sharply as disability became severe. An equation that relates oxygen cost during different walking tasks according to the level of walking disability allows clinicians to determine oxygen cost indirectly without the difficulty of measuring oxygen uptake directly.

Energy expenditure and cost of walking and stair climbing in individuals with chronic stroke

•

Stroke subjects had lower EE during the 6MWT and SCT compared to the healthy subjects.

•

Stroke subjects had higher EC during the 6MWT and SCT compared to the healthy subjects.

•

Walking speed differentiated healthy from stroke subjects gait.

•

The stroke subjects who walked faster showed better energy efficiency.

•

Evidence-based interventions to improve walking speed should be implemented.

Background

Subjects with stroke show higher energy cost (EC) during walking, when compared to healthy individuals, but the mechanisms are not fully understood. Additionally, the behavior of physiological variables during other activities has not been investigated.

Objectives

To investigate energy expenditure (EE) and EC during the six-minute walking test (6MWT) and stair climb test (SCT) in chronic stroke subjects compared to healthy controls.

Methods

Cross-sectional study in which stroke subjects (n = 18) (community-walking speed ≥0.8 m/s) or limited-community <0.8 m/s walkers and matched healthy controls (n = 18) had their EE and EC assessed during the 6MWT and SCT with a portable monitoring system.

Results

Significant differences in EE were observed for both the 6MWT (MD 7.29; 95%CI 4.08–10.50) and SCT (MD 8.53; 95%CI 5.07–12.00) between the stroke and control groups, but not between the stroke subgroups. Significant between-group differences in EC were found for both the 6MWT and SCT. For the 6MWT, differences were significant between the limited-community and the community walkers (MD 0.19; 95%CI 0.05–0.33) and controls (MD 0.17; 95%CI 0.04–0.29). No significant differences were found between the community walkers and controls (MD 0.02; 95%CI −0.09 to 0.13). For the SCT, the limited-community walkers showed highest EC, followed by the community walkers, and controls.

Conclusions

Both stroke subgroups demonstrated lower EE compared to healthy controls. During the 6MWT, the limited-community walkers demonstrated higher EC compared to the community walkers and controls. During the SCT, the limited-community walkers demonstrated higher EC, followed by the community walkers, and controls.

Relationships between self-reported and performance-based measures of functional capacity in individuals with chronic stroke

[Purpose] The aim of this study was to investigate the associations between self-reported and valid performance-based measures of functional capacity in individuals with chronic stroke. [Subjects and Methods] Self-reported measures of functional capacity of 31 individuals with chronic stroke were assessed by the Duke Activity Status Index scores, whereas performance-based measures were assessed by the distance covered (in meters) and oxygen consumption (relative oxygen consumption, in ml·kg⁻¹·min⁻¹) during the six-minute walking test. [Results] The subjects had a mean age of 58.6±13 years and a mean time since the onset of stroke of 28.3±15.1 months. They had a mean Duke Activity Status Index of 27.3±14.4, mean distance covered of 325.2±140.2 m, and mean relative oxygen consumption of 9.6±2.3 ml·kg⁻¹·min⁻¹. Significant, positive, and moderate to good correlation coefficients were found between the Duke Activity Status Index scores and the distance covered during the six-minute walking test (r=0.68). Significant, positive, and fair associations were also found between the Duke Activity Status Index scores and relative oxygen consumption values obtained during the six-minute walking test (r=0.45). [Conclusion] The findings of the present study support the clinical use of the Duke Activity Status Index as a tool to assist in clinical evaluations of functional capacity of individuals with chronic stroke.