Comparison of training methods to improve walking in persons with chronic spinal cord injury: a randomized clinical trial

Abstract

Objective: To compare two forms of device-specific training - body-weight-supported (BWS) ambulation on a fixed track (TRK) and BWS ambulation on a treadmill (TM) - to comprehensive physical therapy (PT) for improving walking speed in persons with chronic, motor-incomplete spinal cord injury (SCI).

Methods: Thirty-five adult subjects with a history of chronic SCI (>1 year; AIS 'C' or 'D') participated in a 13-week (1 hour/day; 3 days per week) training program. Subjects were randomized into one of the three training groups. Subjects in the two BWS groups trained without the benefit of additional input from a physical therapist or gait expert. For each training session, performance values and heart rate were monitored. Pre- and post-training maximal 10-m walking speed, balance, muscle strength, fitness, and quality of life were assessed in each subject.

Results: All three training groups showed significant improvement in maximal walking speed, muscle strength, and psychological well-being. A significant improvement in balance was seen for PT and TRK groups but not for subjects in the TM group. In all groups, post-training measures of fitness, functional independence, and perceived health and vitality were unchanged.

Conclusions: Our results demonstrate that persons with chronic, motor-incomplete SCI can improve walking ability and psychological well-being following a concentrated period of ambulation therapy, regardless of training method. Improvement in walking speed was associated with improved balance and muscle strength. In spite of the fact that we withheld any formal input of a physical therapist or gait expert from subjects in the device-specific training groups, these subjects did just as well as subjects receiving comprehensive PT for improving walking speed and strength. It is likely that further modest benefits would accrue to those subjects receiving a combination of device-specific training with input from a physical therapist or gait expert to guide that training.

Figure 1

CONSORT diagram summarizing numbers of subjects recruited and randomized to each of the three study arms.

Figure 2

Summary of training parameters and heart-rate data for training sessions #1, 13, 26 and 39 for subjects in the TRK (filled bars), TM (diagonal bars), and PT (open bars) groups. Values are the group averages (±SD) of the total duration of ambulation (A; in minutes), total distance of ambulation (B; in meters), total number of heart beats while training (C), and average heart-rate (D) during the time spent in training. Note that duration and distance measures are provided for the TRK and TM groups only, since subjects in the PT group routinely trained for 1 hour each session, and walking distances within each PT training session were not tallied.

Figure 3

Results of the 10-m maximal walking speed test in subjects of three training groups before and after completion of training. Individual results for each subject in the PT (○), TRK (∇), and TM (□) groups are plotted in ‘A’, where each data point is positioned at the intersection of each individual's post-training (ordinate) and pre-training (abscissa) values. The dashed line shows where data points would lie if there was no difference between pre-training and post-training values. In ‘B’, each subject's post-training measure was expressed as a percentage of his/her pre-training data, then averaged within each training group and plotted as group averages (±SD). All three groups showed a significant (*) post-training increase in walking speed over this 10 m distance.

Figure 4

Maximal 10-m walking speeds before and after training for all 35 subjects studied. Data are arranged from the slowest to the fastest pre-training walking speed (i.e. independent of training group). The pre-training walking speed is shown by black bars. Gray bars show the amount by which the final walking speed changed from the pre-training value. Thus most gray bars are stacked above the black bars, showing that final walking speeds were higher than initial values for most subjects. This was not the case for three subjects, who had slower walking speeds after training compared to pre-training values; these are shown where the gray-filled bar lies below the zero-value line. A few subjects had improvements in final walking speed that were too small (≤0.005 m/second) to be resolved in this figure; these cases are indicated with an ‘*’. The dashed horizontal line represents a widely cited ‘Most-limited community’ walking speed of 0.4 m/second, considered the minimum necessary to be functional in the community (30). Eight subjects in this study (indicated by ‘+’) began training with a walking speed below this 0.4 m/second value, but reached or exceeded this value by the end of training. Finally, the arrow (↑) symbols indicate those subjects who were wheelchair-independent ambulators at the beginning of training.

Figure 5

Results of the Tinetti balance test for the three training groups. Description as for Fig. 3. Note that the difference in balance scores was not significant for the TM group. Note also that one subject in the TM group (□) was unable to maintain standing balance prior to training onset (thereby scoring a ‘zero’), but scored a ‘3’ in this measure following training. Since normalization was not possible for this measure, it was not included in the average for the TM group.

Figure 6

Results of aggregate muscle strength testing (upper-limbs + lower-limbs) in subjects of three training groups before and after completion of training. Description as for Fig. 3. All three groups showed a significant (*) post-training increase in muscle strength after training, and there were no differences between groups.

Figure 7

Results of the graded maximum arm-ergometry test showing averaged peak VO₂ test for the three training groups. Description as for Fig. 3. None of the differences were significant within- or between-groups.

Figure 8

Percent change in individual post-training score relative to pre-training score for walking speed (‘A’; ordinate) versus Satisfaction with Abilities and Well-Being Scale (SAWS; abscissa) and for balance score (‘B’) versus SAWS score. For most subjects, both speed and balance scores showed improvement, as did SAWS scores. However, there were subjects who showed improvement in walking speed (n = 6) and/or balance (n = 3) compared to their pre-training value (i.e. data points above the x-axis), yet they reported no change or a decrease in satisfaction with their abilities and/or well-being (i.e. data points to the left of the y-axis).