Low Load Resistance Training Using Blood Flow Restriction for People With Multiple Sclerosis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Low Load Resistance Training Using Blood Flow Restriction for People With Multiple Sclerosis (NCT04633759), a na na study. The primary outcome is Change in Knee Extension Muscle Strength (More-involved Side).

2. Clinical Question

The registry also lists secondary outcomes concerning sit-to-stand completions, balance, walking, activity, walking-related impact, fatigue, and patient-specific function. Those measures broaden the set of outcomes considered, but their presence does not establish that any particular change occurred. No numerical estimates for these outcomes are reported in the registry record. The design can describe changes observed among the participants, but without a control group it cannot separate changes during the program from changes that might have occurred over the same period for other reasons.

3. Trial Design

This completed study is registered as a single-group intervention study of blood flow restriction exercise for people with multiple sclerosis. Enrollment is listed as 16. The sponsor is the University of Colorado, Denver. The recorded start date is 2021-02-19, and primary completion is listed as 2022-10-05. The registry lists the study status as completed.

The intervention description specifies supervised low-load blood flow restriction exercise twice a week for 8 weeks. The brief summary describes testing before and after the treatment period. For the primary endpoint, the registry specifies measurement at baseline (Week 0) and post-test (Week 9). These are the measurement occasions listed in the record; additional visit details are not reported in the registry record.

The design has no randomized comparator arm. Allocation is listed as NA, masking as NONE, and the model as SINGLE GROUP. Consequently, the main within-study contrast is between measurements over time in the same group. It is not a randomized estimate of the difference between the exercise program and another assigned treatment or control condition. The registry does not report a protocol-level statistical analysis plan, sample-size justification, or interim-analysis plan.

The primary measure is change in knee extension muscle strength on the more-involved side, expressed in kilograms and described as a mean with a 95% confidence interval. The record lists 13 outcome measures and names secondary outcomes for sit-to-stand completions, the Berg Balance Scale, the Timed 25-foot Walk, activity level, the 12-Item MS Walking Scale, the Modified Fatigue Impact Scale, and the MS Patient-Specific Function Scale. The complete set of outcome names and numerical outcome results are not reported in the registry record.

Although enrollment is 16, the adverse-event entry gives 14 participants at risk for the listed group. The reasons for this difference and the analysis populations used for outcome reporting are not reported in the registry record. The record does not describe participant flow, adherence, withdrawals, or how missing measurements were handled.

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: Participants were pre-screened over the telephone prior to baseline testing. Enrollment occurred upon signing of the consent form at the beginning of the baseline testing session. Participants were then fully screened to determine final inclusion status prior to beginning intervention.

Overall Study

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.

Population: Sixteen participants were enrolled in the study. One participant withdrew consent prior to completing baseline information. One participant was screened after consenting, but prior to completing baseline information.

6. Primary Endpoint

The registry lists the primary outcome as Change in Knee Extension Muscle Strength (More-involved Side), measured over Measured at Baseline (Week 0) and Post Test (Week 9).

The primary endpoint is change in knee extension muscle strength on the more-involved side. Strength was measured by hand-held dynamometry. The record defines the more-involved limb using baseline assessment: it is the limb with worse muscle strength. The measure is expressed in kilograms, and the registry describes the result as a mean with a 95% confidence interval. Measurements are specified at baseline (Week 0) and post-test (Week 9).

As a general statistical concept, a strength measure in kilograms provides a quantitative outcome that can be summarized by a mean. A mean describes the central level of measurements in a group, while a confidence interval expresses uncertainty around an estimated quantity under the assumptions of the analysis. A narrower interval generally indicates greater precision than a wider interval, though precision alone does not establish whether a change is important or attributable to an intervention.

The endpoint is relevant to the study’s stated focus on strengthening exercises, and selecting the more-involved side gives the measure a consistent limb definition based on baseline strength. However, the registry record does not report baseline or post-test strength values, the estimated change, its confidence interval, or a criterion for interpreting the size of a change. It also does not report a minimal important difference or other threshold for judging clinical importance. The endpoint definition therefore explains what was to be measured, but the record does not provide the numerical result needed to describe the observed change or its precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The record defines the primary outcome as a continuous measure: knee extension muscle strength on the more-involved side, measured in kilograms. It identifies the summary as a mean and the accompanying uncertainty measure as a 95% confidence interval. The outcome is assessed at baseline (Week 0) and post-test (Week 9). The record does not include numerical estimates for either measurement occasion or for the change between them, so no estimate can be interpreted from the registry entry.

What does a mean describe?

As a general statistical concept, the mean is a measure of the center of a set of quantitative observations. It can summarize strength measurements across participants at a particular assessment, or summarize participant-level changes if change is defined for each participant. Those are distinct summaries: a difference between two group means is not necessarily the same as the mean of individual changes when the measurements or analysis populations differ. The registry describes the endpoint as change and specifies a mean, but does not report the exact calculation used for the change estimate.

Means can be influenced by unusually high or low observations. The registry does not report the distribution of strength values, individual observations, or a measure of dispersion beyond naming the confidence interval. It is therefore not possible to assess the shape of the outcome distribution or the influence of individual values from the record.

How should a confidence interval be read?

In general, a confidence interval describes uncertainty around an estimated quantity under the statistical model and procedure used to calculate it. It does not show the range of individual participant outcomes, and it is not a guarantee that the true value lies within a particular interval. A 95% confidence interval is the interval type named for this endpoint. Its numerical limits are not reported in the registry record, so the precision of the estimated change cannot be evaluated.

Interpretation of an interval depends on what quantity it surrounds. An interval for a mean at one visit differs from an interval for the mean change between visits. A change interval is most directly relevant to the stated endpoint, but the record does not provide its limits or further analysis details. No claim about statistical significance can be made from the endpoint definition alone.

What does the single-group design contribute?

In general, repeated measurements in one group can describe how measured outcomes differ across assessment times. This design does not include a concurrent randomized group to represent what might have happened without the intervention. As a result, any observed before-and-after difference would be descriptive of the participants and time period; by itself, it would not isolate the effect of blood flow restriction exercise. This is a design limitation, not a statement that change did or did not occur.

The registry lists allocation as NA and the model as SINGLE GROUP. It describes no masking. Further details about measurement procedures, assessor training, or protections against measurement bias are not reported in the registry record. Those details can matter when outcomes rely on measurement, but their absence from the record does not establish how the study team carried them out.

What can the planning illustrations tell readers?

In general, sample-size planning asks how many participants would be needed under specified assumptions to detect a target effect with a chosen error rate and power. The planning assumptions associated with this study describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the target effect is described as a stated fraction of an observed effect. These are planning assumptions, not a description of the registered single-group design. Any such sample sizes are planning illustrations and are not observed power. The registry record does not report a trial-specific sample-size justification or an actual two-arm comparison.

Planning results depend on assumptions about the effect and variability, among other features. An illustration based on an observed effect is not independent evidence that a future study will reproduce that effect. The numerical planning estimates are not reported in the registry record, and the observed primary outcome estimate needed to understand the effect basis is also not reported there.

What can be inferred from the analysis listing?

The record lists 0 analyses. This indicates that analysis entries are not listed in the registry record; it does not establish that no analysis was conducted. The record does not report the statistical model, handling of repeated measurements, adjustment variables, testing procedure, or whether the stated confidence interval was adjusted for any other features. It also does not report an interim-analysis plan. Without those details and numerical results, the statistical analysis cannot be reconstructed from the registry entry.

For continuous outcomes, general analysis choices can affect the estimate and its uncertainty. For example, a model that accounts for repeated measurements may use the within-participant relationship between observations, while a simple comparison of assessment means may not. No such method should be attributed to this study without a registry description. The defensible reading is limited to the stated endpoint, summary type, assessment times, and the fact that numerical analysis results are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 13 outcome measures, including a primary strength outcome and named secondary outcomes concerning sit-to-stand completions, balance, walking, activity, fatigue, and patient-specific function. Examining multiple outcomes can raise a general statistical issue: when many hypotheses are tested, the chance of at least one apparently unusual result may increase if each is judged separately without an adjustment. This general concern does not establish that a particular analysis was performed or that a particular finding is spurious.

The registry record does not report a multiplicity strategy, such as a hierarchy of testing, an adjustment method, or a distinction between confirmatory and exploratory analyses. It also does not report the statistical analysis plan or numerical test results. The primary outcome is identified, but that fact alone does not reveal how results across the full set of measures were interpreted.

The record does not report participant-level missingness, the number assessed at each visit, withdrawals, or the method used to handle missing measurements. In general, missing-data methods rely on assumptions about why observations are absent and how that relates to observed or unobserved outcomes. Without counts and methods, it is not possible to evaluate whether missingness could affect the estimated change.

Analysis populations are also not described. Although enrollment is listed as 16, the adverse-event entry identifies 14 participants at risk. The relationship between those counts is not reported in the registry record, and neither number establishes how many participants contributed data to the primary endpoint. The record does not specify whether analyses used all enrolled participants, participants with both assessments, or another defined group. These omissions constrain assessment of both the reliability and scope of the reported findings.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports 0 serious adverse events among 14 participants at risk in the blood flow restriction exercise group. It reports 10 participants with other adverse events among 14 at risk and 0 deaths. These are counts as recorded; no percentages or rates are needed to describe them.

In general, an adverse-event count records events or participants according to the registry’s reporting structure; it does not by itself establish that an event was caused by the intervention. The entry distinguishes serious adverse events from other adverse events, but the serious-event terms are not reported in the registry record. The types of other events, their timing and severity, and the assessment of their relationship to exercise are also not reported there.

The adverse-event denominator is 14, whereas overall enrollment is listed as 16. The reason for this difference is not reported in the registry record. The entry does not give exposure duration for each participant, the number of events per participant, or a comparison group. Therefore, the counts should be read as the registry’s descriptive safety record, not as a comparative estimate of risk or a complete account of event circumstances.

12. What the Result Does, and Does Not, Mean

The registry record establishes that a completed, single-group feasibility study was conducted for supervised low-load resistance exercise using blood flow restriction in people with multiple sclerosis and substantial walking or mobility problems. The planned program lasted 8 weeks, with sessions twice a week. The record specifies a primary strength measure and several secondary functional outcomes. It also reports the adverse-event counts for the intervention group.

Those details describe the question and the measurements, not the study’s numerical efficacy findings. No primary change estimate or confidence interval is reported in the registry record. No numerical results for the named secondary outcomes are reported there either. As a result, the record does not show the direction, magnitude, or precision of changes in strength, walking, balance, fatigue, or other listed measures. The stated primary aim is feasibility, but specific feasibility results or criteria are not reported in the registry record.

The single-group structure also limits what an observed change could mean. In general, a difference between baseline and follow-up within one group does not by itself show that the intervention caused the difference. Without a control group, the study does not provide a randomized contrast against an alternative condition. This limitation remains even if a future or separate report presents a before-and-after estimate.

The safety counts indicate what was entered in the registry, but they do not describe event types, attribution, or comparative safety. The absence of a serious-event count in this record should not be extended into a claim about all possible harms or about other populations and settings.

Overall, the registry supports a careful description of the study design, intended exercise schedule, measurement plan, enrollment, and recorded adverse-event counts. It does not support a conclusion about whether strength or secondary outcomes changed, how precisely they changed, whether any change was clinically important, or whether any change was caused by the exercise program. Those questions require outcome results and analysis details that are not reported in the registry record.

13. Why This Trial Matters Statistically

This study is statistically informative as an example of the distinction between a feasibility question and an efficacy estimate. The registry identifies feasibility as the primary aim and specifies a strength endpoint, but it does not report feasibility criteria or numerical findings. Without those details, readers cannot determine from the record how feasibility was defined or whether the study met a prespecified threshold.

The single-group design also makes the interpretation of change especially important. Repeated measurements can describe trajectories among enrolled participants, but without a concurrent comparison group, they do not isolate what would have happened in the absence of the intervention. This is a general causal-inference limitation. It does not erase the descriptive value of measuring participants before and after a program, but it narrows the conclusions that can be drawn.

The registry’s choice of a mean and 95% confidence interval for the continuous primary outcome points to two distinct statistical questions: the average change and the precision of its estimate. Neither numerical result is reported in the registry record. Thus, readers cannot assess whether the estimate is precise, whether it is compatible with a range of changes, or how it relates to a threshold of importance. A measure can be clearly defined while its result remains unavailable.

The record lists numerous outcomes, so reporting and interpretation across outcomes matter. In general, a prespecified approach to multiple outcomes helps distinguish a primary analysis from supportive or exploratory analyses. The relevant analysis plan and multiplicity approach are not reported in the registry record. Likewise, missing-data handling and analysis populations are not specified, restricting the ability to evaluate the completeness of the outcome evidence.

These features matter because statistical interpretation depends on more than a point estimate. Design, uncertainty, missingness, and transparent analysis plans all affect what readers can infer. The registry offers useful information on the intended intervention and endpoint, but its missing numerical results prevent assessment of observed effects and their precision.

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.

Several limitations specific to this trial constrain interpretation of the registry record. First, the study is listed as single-group, with no randomized comparator. This design can describe change over time but cannot provide a randomized estimate of the intervention’s effect relative to a control condition.

Second, the registry does not report numerical outcome results. The primary endpoint is described, including its measurement method, unit, assessment times, and summary type, but its mean change and 95% confidence interval are absent. Numerical results for the listed secondary outcomes are also not reported. Consequently, the direction and size of changes, and their precision, cannot be assessed.

Third, the record identifies feasibility as the primary aim but does not report specific feasibility criteria or numerical feasibility outcomes. It is therefore not possible to judge from the registry record how feasibility was operationalized or what findings supported that aim.

Fourth, important analysis details are not reported: the statistical analysis plan, analysis populations, participant flow, missing-data handling, and approach to multiple outcomes. The reason the adverse-event entry lists 14 participants at risk when enrollment is 16 is also not reported. These gaps prevent readers from determining which participants contributed to each endpoint and how incomplete measurements may have affected results.

Finally, the adverse-event record gives counts but not event descriptions, timing, severity details, or attribution. It does not include a comparison group. These limitations apply to what can be learned from the registry record; they do not establish what may appear in other records or reports.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Low Load Resistance Training Using Blood Flow Restriction for People With Multiple Sclerosis — NCT04633759.
• Registry record last updated 2026-06-09; status last verified 2026-05.
• Results first posted 2026-06-09.
• 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.

18. Record Summary

This completed, single-group study examined supervised low-load resistance exercise using blood flow restriction for people with multiple sclerosis and marked mobility restriction. Enrollment is listed as 16. The intervention description specifies sessions twice a week for 8 weeks, with testing before and after the treatment period. The primary outcome is change in knee extension muscle strength on the more-involved side, measured by hand-held dynamometry and summarized as a mean with a 95% confidence interval.

The registry lists 13 outcome measures and names several secondary functional outcomes. It does not report numerical outcome results, the statistical analysis plan, missing-data methods, analysis populations, or specific feasibility criteria. The adverse-event entry reports 0 serious adverse events among 14 at risk, 10 participants with other adverse events among 14 at risk, and 0 deaths. The record does not describe event types or the reason the adverse-event denominator differs from enrollment.