This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Comparison of Lokomat and Aquatic Exercise for Individuals With Chronic Incomplete Spinal Cord Injury (NCT01407354), a randomized na study. The primary outcome is Number of Participants Demonstrating 10% Change: Arm Ergometer and Lokomat Metabolic Cart VO2 Peak.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01407354 |
| Phase | NA |
| Condition | Spinal Cord Injury |
| Allocation | Randomized |
| Design model | Crossover |
| Masking | Single |
| Enrollment | 37 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Maryland, Baltimore |
| Results posted | Yes |
2. Clinical Question
Population
People with chronic motor incomplete spinal cord injury. The study description focuses on individuals whose injury occurred at least 12 months earlier and who retain some ability to move their leg muscles. The registry lists spinal cord injury as the condition and records enrollment of 37 participants.
Intervention
Lokomat treadmill training: robotically assisted walking with body-weight support. The registry identifies it as a device intervention.
Comparator
Aquatic exercise therapy, described as pool-based exercise. The registry identifies it as the comparison intervention.
Primary question
The primary endpoint concerns the number of participants demonstrating a 10% change in peak VO2 measured via arm ergometer and Lokomat with a metabolic cart. The endpoint timeframe is 7 months. The registry record does not provide a single numerical result for this comparison; it notes that the endpoint includes several categories or time points and was not reduced to one comparison.
The underlying research question is whether these rehabilitation approaches are associated with changes in walking-related fitness in people with chronic motor incomplete spinal cord injury. The registry summary describes reduced walking at home and in the community, alongside de-conditioning and reduced endurance or fitness, as concerns motivating the study. Those statements describe the study rationale, not findings from the trial.
A crossover design is recorded, so the study is structured to compare interventions within a crossover framework rather than as a simple parallel-group trial. The record does not describe the intervention sequence, the duration of each treatment period, or whether any washout period was used. Those details matter when interpreting a crossover comparison, because the period and sequence can affect how treatment observations relate to one another.
The endpoint focuses on a threshold change in peak oxygen uptake rather than reporting a continuous group average. Counting participants who meet a threshold can be useful for describing how many cross a specified change criterion, but it does not show the size of changes among participants who do or do not meet it. The numerical participant counts and comparison results are not reported in the registry record.
3. Trial Design
The registry identifies this as a randomized, single-masked crossover study. Enrollment is listed as 37, and the trial status is completed. The record lists the start as 2011-04 and primary completion as 2014-04. The sponsor is University of Maryland, Baltimore. The phase is listed as NA.
The two interventions are Lokomat treadmill training and aquatic exercise therapy. The Lokomat intervention is described as robotic-assisted treadmill training, while aquatic therapy is described as aquatic exercise therapy. The study summary says the investigators examined their impact on walking ability and fitness among people who had experienced motor incomplete spinal cord injury for at least 12 months.
Randomization means assignment to intervention conditions is determined by a chance-based process, rather than being chosen solely by participants or investigators. In a crossover design, participants are intended to receive intervention conditions in sequence, allowing comparisons to draw on observations under more than one condition. These are general descriptions of the design terms. The registry record does not report the randomization sequence, allocation concealment, treatment-period structure, washout arrangements, or how period and sequence effects were addressed.
Single masking is recorded, but the registry record does not identify which participants or study personnel were masked or explain how masking was maintained. It also does not describe adherence, treatment exposure, withdrawals, or the flow of participants through each intervention period. With crossover studies, those details help clarify whether participants contributed observations under each condition and how incomplete treatment sequences were handled.
The primary outcome is stated as the number of participants demonstrating a 10% change in arm ergometer and Lokomat metabolic-cart VO2 peak, with a timeframe of 7 months. A secondary outcome is the number of movement records from an activity monitor. The record lists two outcome measures and two analyses, but does not report the analysis methods or numerical results for these outcomes. It also does not give a sample-size justification or further details of the planned statistical analysis.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: Randomized Controlled Trial (which arm to initiate study) cross over design with no wash out period between arms. Adjusted statistically for change in each arm and arm participation order.
First Intervention
| Stage | Lokomat First Then Aquatic Exercise | Aquatic Therapy First Then Lokomat Intervention |
|---|---|---|
| STARTED | 20 | 17 |
| COMPLETED | 18 | 15 |
| NOT COMPLETED | 2 | 2 |
Reasons for not completing this period:
| Reason | Lokomat First Then Aquatic Exercise | Aquatic Therapy First Then Lokomat Intervention |
|---|---|---|
| Withdrawal by Subject | 0 | 2 |
| Adverse Event | 1 | 0 |
| Physician Decision | 1 | 0 |
Second Intervention
| Stage | Lokomat First Then Aquatic Exercise | Aquatic Therapy First Then Lokomat Intervention |
|---|---|---|
| STARTED | 18 | 15 |
| COMPLETED | 18 | 13 |
| NOT COMPLETED | 0 | 2 |
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | All Study Participants |
|---|---|---|
| Participants analysed | 37 | |
| Age, Continuous | years | 44.7 (SD 12.1) |
| Sex: Female, Male: Female | Participants | 8 |
| Sex: Female, Male: Male | Participants | 29 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 1 |
| Race (NIH/OMB): Asian | Participants | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 1 |
| Race (NIH/OMB): Black or African American | Participants | 11 |
| Race (NIH/OMB): White | Participants | 23 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants Demonstrating 10% Change: Arm Ergometer and Lokomat Metabolic Cart VO2 Peak, measured over 7 months.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is a count: the number of participants demonstrating a 10% change in peak VO2, measured via an arm ergometer and a Lokomat with a metabolic cart. The outcome timeframe is 7 months. Peak VO2 is a measure of peak oxygen uptake during exercise testing; in general, it is used to describe exercise capacity or fitness. Measuring it with specified equipment gives the endpoint a physiological focus, rather than directly measuring walking in daily life.
Using a threshold-change count can make the result easier to express as how many participants met a prespecified criterion. However, this type of outcome does not show the full distribution of individual changes. Participants just meeting the threshold and participants changing by substantially more would both contribute to the count in the same way. The endpoint definition also does not, by itself, establish which intervention is associated with a change or whether any observed change is attributable to treatment.
The registry record says the primary outcome has several categories or time points and was not reduced to one comparison. It therefore does not provide one numerical treatment comparison for this endpoint. The number of participants meeting the 10% change criterion in each relevant category, the estimated contrast between interventions, and a measure of uncertainty are not reported in the registry record. Without those results, the endpoint’s observed magnitude and precision cannot be described.
The registry also lists a movement-activity-monitor outcome, but the available record does not supply a numerical result for it. Neither outcome should be treated as a direct substitute for the other: peak oxygen uptake addresses exercise capacity, while movement recorded by an activity monitor concerns activity as captured by that device.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes the clinical question and trial structure but does not report numerical primary-outcome results. In particular, it does not give the number of participants who demonstrated a 10% change, an estimate comparing Lokomat training with aquatic therapy, or a confidence interval for that comparison. The primary outcome is explicitly noted as having several categories or time points and not being reduced to one comparison. Consequently, no direction, magnitude, or precision of a primary treatment contrast can be inferred from the record.
This absence of a single summarized result is important. A count of participants meeting a threshold could be compared across interventions, but the count alone would not communicate how far participants’ measurements changed or how variable those changes were. An estimated difference or other comparison measure, together with uncertainty, would be needed to describe how compatible the observed data are with a range of possible effects. Such results are not reported in the registry record.
The study is identified as randomized and crossover. In general, randomization helps limit systematic differences in assignment, while a crossover design can allow each participant to contribute information under more than one condition. Those design features do not resolve all interpretive questions. The sequence, period structure, handling of carryover, analysis population, and model are not reported in the registry record. No claim about how these issues were handled is warranted.
The registry records 37 participants enrolled. It also lists adverse-event groups with 37 at risk in each intervention group. Those entries describe the registry’s group-level safety figures; they do not provide the outcome data needed to interpret peak VO2. The figures cannot be used to fill the missing efficacy results.
The record lists a secondary activity-monitor measure, but does not provide its numerical results or an explanation of how it relates to the primary endpoint. The count of listed outcome measures and analyses does not establish which comparisons were prespecified, whether additional analyses were conducted, or how outcome multiplicity was handled.
In general, a confidence interval conveys the range of effect estimates that remain reasonably compatible with the observed data under the analysis assumptions. A narrow interval indicates greater statistical precision than a wide interval, but neither width nor location can be assessed without the estimate and interval. Because neither is reported for the primary comparison, its precision cannot be characterized.
The registry record supports a description of the study’s intended comparison, design labels, endpoint definition, and selected safety counts. It does not support a conclusion about which intervention produced a larger change, whether a difference was statistically distinguishable from no difference, or how clinically important any difference might be. Those questions require outcome estimates and analysis details that are not reported in the registry record.
9. Statistical Methods Explained
What does a randomized crossover design mean?
In general, randomization assigns participants to intervention conditions using chance. It can reduce the risk that treatment groups differ systematically at the outset, although it does not guarantee balance in every characteristic. A crossover design organizes treatment conditions in sequence, so the comparison can use measurements from participants under more than one condition. The registry labels this trial randomized and crossover, but does not describe the specific sequence or assignment procedure.
Analysis of crossover data must account for the fact that observations from the same participant are related. Treating those observations as if they came from unrelated people can misstate uncertainty. Period effects are also relevant: outcome measurements may change over time for reasons unrelated to the intervention. Carryover is another general concern, because effects of an earlier treatment could persist into a later period. The registry record does not state whether or how these features were considered in the analysis.
What does the primary endpoint measure?
The endpoint is a count of participants demonstrating a 10% change in peak VO2 measured via arm ergometer and Lokomat with a metabolic cart. In general, peak VO2 describes peak oxygen uptake during exercise testing and is used as an indicator of exercise capacity. A threshold-based count conveys how many participants cross the stated criterion, rather than the average size of change or the distribution of individual changes.
Counts can be analyzed using methods suited to categorical or binary outcomes, depending on the exact structure of the data and comparison. For a crossover trial, an appropriate analysis may also need to account for repeated observations within each participant and the intervention sequence. These are general methodological considerations, not a description of the analysis used in this trial. The registry record does not provide the model, effect measure, or analysis assumptions.
How should uncertainty be understood?
In general, an estimate describes the observed comparison, while a confidence interval expresses uncertainty around that estimate under a stated statistical model. A p-value addresses how compatible the data are with a particular null hypothesis under the model; it does not measure the size or importance of an effect. Neither an estimate, a confidence interval, nor a p-value for the primary comparison is reported in the registry record. Statistical significance therefore cannot be evaluated from this record.
Precision depends in part on how much information the analysis contains and on the variability of the outcome. For a count-based endpoint, the number of participants in each outcome category and the dependence between crossover observations can affect uncertainty. The enrollment figure alone is not enough to reconstruct an effect estimate or its precision. No recalculated comparison is available in the registry record.
Why does over-dispersion matter in general?
For count outcomes, some statistical models assume that variation follows a particular relationship to the expected count. Over-dispersion occurs when the observed variation is greater than the model expects. If ignored, uncertainty can be understated and intervals or tests can become too optimistic. Whether over-dispersion is relevant depends on the outcome and analysis model. The registry record does not report a count model or diagnostic checks, so no claim about over-dispersion in this trial can be made.
How does the endpoint structure affect interpretation?
The registry notes several categories or time points for the primary outcome and does not reduce them to one comparison. When outcomes include multiple categories, time points, or contrasts, interpretation depends on which comparisons were planned and how their results are presented. Multiple testing can increase the chance of a chance finding if many comparisons are examined without an appropriate strategy. In general, multiplicity procedures may control that risk, but the selected approach should follow the analysis plan. The registry record does not report such a procedure or enough result detail to evaluate it.
The record identifies a secondary measure based on movement recorded by an activity monitor. In general, different outcome types capture different aspects of a study question and may require different statistical models. The monitor measure should not be assumed to validate or replace the primary endpoint. Its exact analysis and numerical findings are not reported in the registry record.
What can sample-size planning illustrations tell readers?
In general, sample-size planning uses assumptions about the effect to detect, variability, allocation, and acceptable error rates. A planning illustration is conditional on those assumptions and is not a statement about the probability that a completed trial found an effect. It is also distinct from observed power, which should not be used to reinterpret a completed study’s results. The registry record does not report the trial’s own sample-size justification or planning assumptions.
Any planning illustration based on an observed effect would depend on the effect estimate used and on the specified assumptions. Without a reported primary effect estimate, such an illustration cannot establish the result or compensate for the missing comparison. The sample-size rationale and analysis plan are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome is described as having several categories or time points, and the registry record says it was not reduced to one comparison. The record lists two outcome measures and two analyses, but does not identify all comparisons, define a testing hierarchy, or explain whether any multiplicity adjustment was used. The number of listed measures does not establish the number of statistical tests actually performed.
In general, multiplicity matters when investigators assess several outcomes, time points, categories, or treatment contrasts. Without an analysis strategy, readers cannot tell whether a particular result was designated as primary for inference, whether other findings were exploratory, or how the possibility of chance-positive results was handled. No such strategy is reported in the registry record.
Missing-data methods are also not described. The record does not report how many participants completed each intervention period, whether outcome measurements were missing, why any data were unavailable, or how missing observations were handled. In a crossover study, incomplete treatment sequences can affect which within-participant comparisons contribute information. The registry record does not say whether an intention-to-treat, per-protocol, or other analysis population was used.
These omissions limit assessment of whether the outcome analysis included all randomized participants, how robust the results might be to missing observations, and how the reported comparisons were selected. Since numerical primary and secondary outcome results are not reported in the registry record, neither the effects of missing data nor the consequences of multiplicity can be evaluated from the posted results.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Lokomat Training | 0 | 37 | 0.0% |
| Aquatic Therapy | 0 | 37 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Lokomat Training | 2 of 37 |
| Aquatic Therapy | 1 of 37 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Lokomat Training | Aquatic Therapy |
|---|---|---|---|
| Autonomic Dysreflexia | Nervous system disorders | 1 of 37 | 0 of 37 |
| parasthesia | Nervous system disorders | 1 of 37 | 0 of 37 |
| medical instability | Blood and lymphatic system disorders | 0 of 37 | 1 of 37 |
The registry lists zero serious adverse events among 37 participants at risk in the Lokomat Training group and zero among 37 at risk in the Aquatic Therapy group. It lists two other adverse events in the Lokomat group and one in the Aquatic Therapy group, with 37 at risk in each group. These are the registry’s recorded counts, not a complete description of event timing, type, severity, or relationship to an intervention.
No serious adverse-event terms are listed. Death counts are not reported in the registry record. The entries do not state whether participants could contribute to both intervention groups because of the crossover design, or how events were attributed when treatment periods overlapped with follow-up. Therefore, the group counts should be read as recorded, without assuming that they represent independent groups or that they allow a direct risk comparison.
In general, a count of zero recorded serious events does not establish that an intervention has no safety risks. Safety interpretation depends on how events were defined, collected, monitored, and attributed, as well as the amount and duration of observation. Those details are not reported in the registry record. The adverse-event figures also do not provide evidence about the primary peak VO2 endpoint.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a completed randomized crossover study compared Lokomat treadmill training with aquatic exercise therapy in people with chronic motor incomplete spinal cord injury. It describes a primary endpoint based on the number of participants demonstrating a 10% change in peak VO2 and lists a 7-month timeframe. It also identifies an activity-monitor measure as a secondary outcome.
The record does not establish the direction or size of any difference between interventions. It does not report participant counts for the primary endpoint, an effect estimate, a confidence interval, or a p-value. The endpoint is noted as having several categories or time points and is not summarized as one comparison. The numerical result and its statistical precision are therefore not available for interpretation.
In general, a threshold-based count describes whether participants meet a defined change criterion, but it does not reveal the amount of change across all participants. Even a reported difference in threshold counts would need to be interpreted alongside the analysis method, uncertainty, outcome definition, and study conduct. Those details are not available in the registry record.
The design labels of randomized and crossover describe important features of how the comparison was organized, but they do not alone answer whether the analysis accounted for repeated participant observations, treatment sequence, period effects, or carryover. The registry record does not report those analysis details, nor does it describe missing-data handling or the analysis population.
The adverse-event entries record zero serious events in each listed group, alongside other adverse-event counts of two and one. They are limited registry counts and should not be read as proof of safety or as a direct comparison of intervention risks. Death counts are not reported in the registry record.
Overall, the available information supports understanding the study question, design labels, endpoint definition, and recorded safety counts. It does not support a conclusion that either intervention was superior, that the interventions had equivalent outcomes, or that any particular effect was clinically meaningful. Those conclusions require posted outcome estimates and fuller statistical and methodological details.
13. Why This Trial Matters Statistically
This trial raises statistical issues that are common in rehabilitation research: how to compare interventions when participants are studied in a crossover framework, how to interpret threshold-based outcomes, and how to report uncertainty for outcomes with several categories or time points. These issues matter because the design and endpoint determine what a result can mean, while the analysis determines how reliably the comparison is estimated.
A crossover framework can make within-participant comparisons informative, but observations from the same participant are related. Appropriate analysis needs to reflect that dependence and consider the intervention sequence and time period. The registry identifies the crossover model but does not report its analysis details, illustrating why a design label alone is not enough to assess statistical validity.
The primary endpoint is a participant count based on a 10% change threshold in peak VO2. Thresholds can make outcomes easier to communicate, but they reduce information about the range of individual responses. Reporting both the threshold count and a fuller description of measured changes can help readers understand whether a result reflects a broad shift, a subset crossing a cutoff, or another pattern. The registry record does not provide those results.
Outcome categories and time points also affect interpretation. A single headline comparison may conceal a broader set of analyses, while multiple comparisons raise questions about how results were selected and how chance findings were addressed. Since the registry does not provide one reduced primary comparison or a multiplicity strategy, readers cannot determine how its various outcome components were interpreted.
Finally, transparent reporting of estimates, uncertainty, missing-data handling, and analysis populations is essential for evaluating what a completed clinical trial contributes. The absence of those details limits statistical interpretation even though the trial’s central comparison and endpoint are described.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main limitation for statistical interpretation is that the registry record does not report numerical results for the primary endpoint. It identifies a threshold-change count and a timeframe, but the outcome has several categories or time points and is not reduced to one comparison. The participant counts, estimated contrast, and uncertainty are not reported in the registry record.
The record also provides little detail about how the crossover design was implemented. The intervention sequence, treatment-period structure, washout arrangements, and handling of period or carryover effects are not reported. Single masking is recorded, but which people were masked and how masking was maintained are not described.
Analysis details are unavailable, including the statistical model, analysis population, handling of missing observations, and any approach to multiplicity. The registry does not report a sample-size justification. It is therefore not possible to assess whether the analysis accounted for the dependence between observations from the same participant or how the outcome categories and time points were handled.
The registry lists an activity-monitor secondary outcome but does not give its numerical results. Its relationship to the primary endpoint and its analysis are not described. The safety entries provide counts, but the event definitions, observation details, and attribution to intervention periods are not reported. These limitations concern what can be inferred from the registry record and do not establish that the underlying trial lacked methods or results beyond those recorded.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Comparison of Lokomat and Aquatic Exercise for Individuals With Chronic Incomplete Spinal Cord Injury — NCT01407354.
- Registry record last updated 2021-05-26; status last verified 2021-05.
- Results first posted 2016-04-08.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry record describes a completed randomized, single-masked crossover study sponsored by University of Maryland, Baltimore. Enrollment was 37. The record lists the start as 2011-04 and primary completion as 2014-04, and identifies spinal cord injury as the condition.
The comparison was between Lokomat treadmill training and aquatic exercise therapy. The primary outcome was the number of participants demonstrating a 10% change in peak VO2 via arm ergometer and Lokomat with a metabolic cart, with a 7-month timeframe. The outcome is noted as having several categories or time points, with no single comparison reported. A movement-activity-monitor measure is listed as secondary.
Numerical efficacy results, analysis details, missing-data procedures, and a sample-size justification are not reported in the registry record. The listed safety counts include zero serious adverse events in each group and other adverse-event counts of two and one. Death counts are not reported.