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 Blood Flow, Muscle Regeneration and Sarcopenia (NCT01035060), a registered phase not stated study. The primary outcome is Muscle Satellite Cells.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01035060 |
| Phase | Phase not stated |
| Condition | Sarcopenia |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 68 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Florida |
| Results posted | Yes |
2. Clinical Question
Population
Healthy men and women over 70 years of age and healthy men and women aged 18-30 years. Whether participants had diagnosed sarcopenia is not reported in the registry record.
Intervention
The primary outcome description concerns contraction-induced skeletal muscle injury followed by measurement of satellite cells in muscle biopsy samples. An assigned treatment intervention is not reported in the registry record.
Comparator
The registry lists younger and older adult groups. This is not a randomized comparison; allocation is not stated, and the groups are not a like-for-like control comparison.
Primary question
How does the number of Pax7-positive cells per muscle fiber change after injury, assessed at baseline, 2 days post-injury, and 7 days post-injury? Numerical primary outcome results are not reported in the registry record.
The study addresses a proposed biological link between aging and the capacity of skeletal muscle to regenerate. Its description focuses on satellite cells, a type of muscle stem cell, and asks whether blood flow and satellite cell number are associated with muscle function. The registry's stated primary outcome is the change in Pax7-positive cells after contraction-induced injury. It does not report numerical results for that outcome or for the proposed associations.
The age-group structure matters to interpretation. The younger and older groups are observational age cohorts, not randomized treatment arms. Any difference between them could reflect age or other differences between the participants; the registry does not establish that age alone explains a contrast. The outcome description states that data were adjusted for gender, physical activity level, and baseline satellite cell number, but further details of the analysis are not reported in the registry record.
3. Trial Design
The registry describes a completed study sponsored by the University of Florida, titled “Blood Flow, Muscle Regeneration and Sarcopenia.” Its official title is “Role of Skeletal Muscle Blood in Muscle Regeneration and Sarcopenia.” The recorded enrollment is 68. The study start is listed as 2010-06, and primary completion as 2011-12. The registry status is completed.
The listed groups are healthy men and women over 70 years of age and healthy men and women aged 18-30 years. The record explicitly indicates that this is not a randomized comparison. Allocation is not stated, and the groups should not be read as equivalent treatment and control arms. The record does not describe an assigned intervention; the primary outcome concerns muscle responses after contraction-induced injury.
The primary outcome is the number of Pax7-positive cells per muscle fiber, measured at baseline, 2 days post-injury, and 7 days post-injury. The outcome description identifies skeletal muscle biopsy samples and immunohistochemistry as the means of identifying Pax7-positive cells. It also states that the data were adjusted for gender, physical activity level, and baseline satellite cell number.
The registry lists one outcome measure and no analyses. Numerical primary outcome results, group-specific estimates, uncertainty intervals, and statistical test results are not reported in the registry record. Further design details—including the injury procedure, recruitment methods, eligibility criteria beyond the group descriptions, allocation procedures, and analysis population—are not reported in the registry record. The study aims described in the record include examining regeneration in younger and older adults and assessing associations among blood flow, satellite cell number, and muscle function; the posted record does not give numerical findings for those questions.
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.
Overall Study
| Stage | Older Adults | Young Adults |
|---|---|---|
| STARTED | 39 | 29 |
| COMPLETED | 15 | 15 |
| NOT COMPLETED | 24 | 14 |
Reasons for not completing this period:
| Reason | Older Adults | Young Adults |
|---|---|---|
| Lost to Follow-up | 0 | 7 |
| Did not quality after 2nd screening | 14 | 1 |
| Withdrawal by Subject | 8 | 6 |
| Physician Decision | 2 | 0 |
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 | Older Adults | Young Adults | Total |
|---|---|---|---|---|
| Participants analysed | 39 | 29 | 68 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 29 | 29 |
| Age, Categorical: >=65 years | Participants | 39 | 0 | 39 |
| Sex: Female, Male: Female | Participants | 15 | 11 | 26 |
| Sex: Female, Male: Male | Participants | 24 | 18 | 42 |
| Region of Enrollment: United States | participants | 39 | 29 | 68 |
6. Primary Endpoint
The registry lists the primary outcome as Muscle Satellite Cells, measured over Baseline, 2 days post-injury, 7 days post-injury.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Error |
| Unit | Number of Pax7+ cells/muscle fiber |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the number of Pax7-positive cells per muscle fiber, with the outcome description focusing on change following contraction-induced skeletal muscle injury. Pax7-positive cells are identified by immunohistochemistry in skeletal muscle biopsy samples. Measurements are listed at baseline, 2 days post-injury, and 7 days post-injury. The endpoint is continuous and is described using a mean and standard error.
The scientific rationale in the registry is that satellite cells may contribute to the regeneration of skeletal muscle fibers. Measuring their number after an injury is intended to characterize one component of the muscle’s regenerative response. This is a biological measure, not a direct measure of strength, daily function, or quality of life. The study description separately raises possible relationships between muscle blood flow, satellite cell number, and muscle function, but numerical results for these relationships are not reported in the registry record.
The outcome description says that the data were adjusted for gender, physical activity level, and baseline satellite cell number. It does not state the model form, the exact contrast used to define change, or how repeated measurements were handled. Nor does the registry give the observed means, adjusted differences, or uncertainty estimates. Without those results, the size, direction, and precision of any change cannot be assessed from the record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the study’s question, its age-group structure, and the intended satellite-cell outcome. It does not report numerical results for the primary outcome. As a result, the posted record does not establish whether the mean number of Pax7-positive cells changed after injury, how any change differed between age groups, or how precisely an estimate was measured. No effect estimate, confidence interval, or p-value for the primary outcome is reported in the registry record.
The group comparison requires particular care. The study lists healthy younger and older adults, but it is not a randomized comparison and allocation is not stated. A difference between these groups would be an association with group membership, not an isolated causal effect of age. Group membership may coincide with other differences among participants. The outcome description notes adjustment for gender, physical activity level, and baseline satellite cell number; the registry does not report enough detail to determine how that adjustment was performed or what potential confounders were considered.
The central biological rationale concerns muscle blood flow, regeneration, and age-related loss of muscle mass. That rationale is not itself a finding. The registry describes aims relating blood flow, satellite cell number, and muscle function, but does not report results for these relationships. It therefore cannot support a conclusion about whether blood flow was associated with regeneration or function in the participants.
The safety counts are descriptive. The registry lists serious adverse events affecting 0 of 29 younger adults at risk and 2 of 39 older adults at risk. It lists other adverse events affecting 6 of 29 younger adults at risk and 7 of 39 older adults at risk. These counts do not by themselves indicate that age caused a difference in event frequency. The groups were not randomized, and the registry does not give event timing, exposure duration, participant-level detail, or a comparative statistical analysis. Myocardial infarction and hospitalization are listed among the serious-event terms at 2.6% each; the record does not clarify whether terms refer to overlapping events or participants.
Overall, interpretation is limited by the absence of posted primary outcome estimates and analysis results. The study’s completion status does not substitute for numerical results. The record supports describing the planned biological question and the reported adverse-event counts, but not quantifying the primary outcome response or drawing a causal conclusion about age, blood flow, or muscle regeneration.
9. Statistical Methods Explained
What does a continuous outcome mean?
General: A continuous outcome can take a range of numerical values rather than representing only a category such as yes or no. The registry describes the satellite-cell measure as a mean of a continuous measure. A mean gives a summary of the measured values, while the standard error describes the sampling precision of that estimated mean. Standard error is not the same as the spread of individual measurements; a standard deviation would describe that spread. The record specifies standard error but does not report observed means or standard errors.
The outcome is measured at baseline, 2 days post-injury, and 7 days post-injury. Repeated measurements can be analyzed in different ways, such as comparing change from baseline or modeling the measurements jointly. General: accounting for repeated observations can be important because observations from the same participant are related rather than independent. The registry does not state which approach was used, how the change was defined, or whether all listed time points were included in a single model.
What does adjustment mean in this record?
The outcome description states that data were adjusted for gender, physical activity level, and baseline satellite cell number. General: statistical adjustment estimates an association while accounting for specified variables in a model. Adjustment can help address differences in those measured variables, but it does not automatically remove confounding from unmeasured or incorrectly modeled factors. The registry does not report the model specification, variable coding, interaction terms, diagnostics, or the adjusted estimates. It is therefore not possible to determine from the record how adjustment influenced the result.
How should precision be assessed?
General: A confidence interval expresses a range of estimates compatible with the data and model under the interval’s assumptions. A narrower interval generally indicates greater precision, while a wider interval indicates greater uncertainty. A p-value addresses compatibility with a specified null model; it does not measure the size or practical importance of an effect. Neither confidence intervals nor p-values for the primary outcome are reported in the registry record. Without an estimate and an uncertainty measure, the magnitude and precision of the primary outcome cannot be evaluated.
What can be inferred from the age-group structure?
The registry explicitly states that the comparison is not randomized and that allocation is not stated. General: randomization, when used, is intended to make assigned groups comparable on average with respect to measured and unmeasured characteristics. These age-defined groups do not have that protection. A statistical adjustment for listed covariates may address some measured differences, but it does not turn an observational group contrast into a randomized experiment. The registry does not report a causal analysis or enough detail to assess residual confounding.
What do the planning assumptions represent?
The registry describes sample-size calculations as planning illustrations based on a fraction of the observed effect. Their stated framework uses a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. For non-time-to-event outcomes, the stated quantity is participants per arm for 80% or 90% power. These are planning scenarios, not observed power and not evidence that the study detected an effect. The numerical observed effect and numerical planning outputs are not reported in the registry record, so no such values can be interpreted from the record.
General: A planning calculation depends on assumptions about the effect to detect, variability, allocation, and statistical model. Changing those assumptions can change the sample size needed for a future study. A calculation based on an observed effect can also be unstable when the effect estimate is uncertain. The registry’s description does not report a prospective sample-size justification or enough numerical detail to evaluate the planning scenarios against the study’s actual enrollment.
What analysis results are available?
The registry lists one outcome measure and no analyses. It does not report a statistical analysis plan, a named test, model coefficients, degrees of freedom, missing-data method, or results by time point. Those details are not reported in the registry record and should not be inferred from the fact that an endpoint and adjustment variables are described. In particular, there is no basis in the posted record for reconstructing an adjusted treatment effect or recalculating a significance test.
General: Over-dispersion occurs when observed variability exceeds what a chosen statistical model expects. It can make standard errors and significance tests unreliable if the model fails to account for that extra variability. The registry does not provide the data or model details needed to assess over-dispersion, and no claim that it occurred is warranted. More broadly, model diagnostics and sensitivity analyses can test whether conclusions depend on assumptions, but such analyses are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary outcome measure but no analyses. It does not report a statistical analysis plan, a hierarchy of hypotheses, or a strategy for controlling multiplicity. The study description also names scientific aims concerning muscle blood flow, satellite cell number, and muscle function, but the registry does not state how many statistical tests were planned for those aims or how they would be interpreted alongside the primary outcome.
General: When several outcomes, time points, groups, or hypotheses are tested, the chance of obtaining at least one apparently unusual result can increase. A prespecified hierarchy or multiplicity adjustment can help manage that issue. The record does not report whether any such approach was planned, so it cannot be assumed that the listed time points were treated as a single analysis or that other aims were formally tested.
Missing-data methods are also not reported in the registry record. There is no account of how many participants contributed measurements at each time point, whether any measurements were unavailable, why data might be missing, or how missing observations were handled. The analysis population is not described, and the record does not say whether all enrolled participants were included in each outcome analysis.
General: Missing observations can affect estimates when the likelihood of missingness is related to participant characteristics or outcomes. Complete-case analysis, imputation, and model-based approaches rely on different assumptions; the appropriate interpretation depends on the method and missingness pattern. No method can be attributed to this study from the registry record. Without analysis-set and missing-data information, the extent to which the reported population might differ from participants with outcome measurements cannot be assessed.
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 |
|---|---|---|---|
| Younger Adults | 0 | 29 | 0.0% |
| Older Adults | 2 | 39 | 5.1% |
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 |
|---|---|
| Younger Adults | 6 of 29 |
| Older Adults | 7 of 39 |
Most frequent serious adverse event terms
| Event term | Organ system | Younger Adults | Older Adults |
|---|---|---|---|
| Myocardial Infarction | Cardiac disorders | 0 of 29 | 1 of 39 |
| Hospitalization | Blood and lymphatic system disorders | 0 of 29 | 1 of 39 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Younger Adults | Older Adults |
|---|---|---|---|
| Pain/Bruising | General disorders | 4 of 29 | 1 of 39 |
| Skeletal Muscle Soreness | Musculoskeletal and connective tissue disorders | 0 of 29 | 4 of 39 |
| Dermatitis | Skin and subcutaneous tissue disorders | 1 of 29 | 0 of 39 |
| Broken Toe | Musculoskeletal and connective tissue disorders | 1 of 29 | 0 of 39 |
| Muscle Spasms | Musculoskeletal and connective tissue disorders | 0 of 29 | 1 of 39 |
| Mild swelling | General disorders | 1 of 29 | 0 of 39 |
| Atrial Fibrillation | Cardiac disorders | 0 of 29 | 1 of 39 |
| Minor Rash | Skin and subcutaneous tissue disorders | 0 of 29 | 1 of 39 |
Serious events with the highest arm-level rate: myocardial infarction (2.6%), hospitalization (2.6%).
The registry lists serious adverse events for younger and older adults separately. Among younger adults, 0 of 29 at risk were recorded with a serious adverse event; among older adults, 2 of 39 at risk were recorded with a serious adverse event. For other adverse events, the record lists 6 of 29 younger adults at risk and 7 of 39 older adults at risk. These are descriptive counts, not evidence of a causal difference between age groups.
Myocardial infarction and hospitalization are listed as serious-event terms, each at 2.6%. The registry does not state whether these terms describe the same event, whether a participant could contribute more than one term, or which group each term concerns. Deaths are not reported in the registry record.
General: Adverse-event counts are easier to interpret when the observation period, event definitions, exposure time, severity criteria, and completeness of reporting are known. Those details are not reported in the registry record. The groups are age-defined and not randomized, so differences in event counts should not be treated as effects of an assigned treatment. The posted figures also do not provide a formal comparison or uncertainty estimate. They describe what the registry records, without establishing the cause, timing, or clinical context of each event.
12. What the Result Does, and Does Not, Mean
The record documents a completed study designed to examine muscle regeneration in healthy younger and older adults. Its primary outcome concerns the number of Pax7-positive cells per muscle fiber after contraction-induced skeletal muscle injury, with measurements listed at baseline, 2 days post-injury, and 7 days post-injury. The scientific rationale links muscle blood flow and satellite cells to regeneration and age-related loss of muscle mass.
However, the registry does not report numerical primary outcome results. It therefore does not show the observed mean change, a contrast between age groups, or the precision of either estimate. The absence of those figures means the biological question cannot be answered from the posted record alone. Completion status indicates that the study is marked completed in the registry; it is not evidence about the direction or size of an outcome.
The study’s nonrandomized age-group design also limits causal interpretation. The groups are not like-for-like randomized arms, and allocation is not stated. Even if numerical group differences were available, they could not automatically be attributed to age without considering other differences and the adequacy of adjustment. The outcome description names adjustment for gender, physical activity level, and baseline satellite cell number, but does not report the model or results.
The adverse-event counts provide a separate descriptive account. They do not establish that age caused the observed event pattern, and the registry lacks context needed for a fuller safety comparison. The findings also should not be generalized beyond the listed healthy adult groups without further evidence. The registry does not report whether participants had diagnosed sarcopenia or provide clinical outcome results. Thus the record defines a relevant mechanistic research question but does not establish a clinical benefit, a treatment effect, or a conclusion about prevention or management of sarcopenia.
13. Why This Trial Matters Statistically
This study is statistically interesting because it connects a biological measurement to an age-related research question while comparing age-defined cohorts rather than randomized groups. That distinction shapes what any estimate could mean. A randomized intervention comparison can, under its assumptions, support causal interpretation of an assigned treatment contrast. An observational contrast between younger and older adults instead describes differences between groups whose other characteristics may also differ.
The endpoint is measured repeatedly around an injury stimulus, making the analysis dependent on how change over time is defined and modeled. The registry gives the time points and identifies adjustment variables, but it does not state the repeated-measures model or provide numerical results. Without those details, readers cannot assess whether the analysis captures the time course, how baseline values enter the estimate, or how uncertainty was calculated.
Precision is central in a pilot study. General: An estimate can be compatible with a wide range of effects when data are limited, and a non-significant test would not by itself demonstrate absence of an effect. Conversely, a nominally unusual result would not settle a biological question if the estimate were imprecise or the analysis exploratory. The record does not report the estimates or uncertainty needed to make these distinctions.
The described planning framework is also distinct from evidence about what the study found. Planning calculations use assumptions about effect size and variability; they are not observed power. The record’s sample-size description does not substitute for reporting the primary outcome estimate, its uncertainty, or the analysis plan. These statistical considerations matter because a mechanistic study can motivate further research, but the reliability and scope of its evidence depend on transparent reporting of design, analysis, and results.
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 study are apparent from the registry record. First, numerical results for the primary satellite-cell outcome are not reported in the registry record. Without group estimates, contrasts, or uncertainty intervals, the principal biological question cannot be evaluated quantitatively. The record also lists no analyses, so there are no reported model results to interpret.
Second, the age groups are not randomized comparison arms. Allocation is not stated, and the registry explicitly cautions that the groups are not a like-for-like control comparison. The endpoint description identifies adjustment for gender, physical activity level, and baseline satellite cell number, but the model and its assumptions are not described. Residual differences between groups therefore remain a concern for interpretation.
Third, the listed population consists of healthy men and women in specified age ranges. Whether participants had diagnosed sarcopenia is not reported in the registry record. The results, even if available, would not automatically represent people with sarcopenia or other clinical populations. Recruitment and eligibility details beyond the group descriptions are also not reported.
Fourth, the endpoint description names biopsy-based Pax7-positive cell counts and several measurement times, but the registry does not report the injury procedure, missing measurements, analysis population, repeated-measures approach, or missing-data method. It also does not describe multiplicity handling for the time points or the broader aims. Finally, safety reporting lacks event timing and context, and deaths are not reported in the registry record. These omissions constrain both reproducibility and assessment of the scope and precision of the findings.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Blood Flow, Muscle Regeneration and Sarcopenia — NCT01035060.
- Registry record last updated 2013-01-09; status last verified 2012-10.
- Results first posted 2013-01-09.
- 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.
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18. Record Summary
The University of Florida-sponsored study “Blood Flow, Muscle Regeneration and Sarcopenia” is marked completed, with enrollment of 68. The registry lists healthy younger adults aged 18-30 years and healthy older adults over 70 years of age. The study is not a randomized comparison, and allocation is not stated.
The primary outcome is the number of Pax7-positive cells per muscle fiber after contraction-induced skeletal muscle injury, assessed at baseline, 2 days post-injury, and 7 days post-injury. The outcome description says data were adjusted for gender, physical activity level, and baseline satellite cell number. Numerical primary outcome results and statistical analyses are not reported in the registry record.
Safety counts are recorded separately for the age groups. The registry does not provide enough context to interpret those counts as a causal comparison. Overall, the record describes a mechanistic study question but does not report the outcome estimates needed to assess the primary result.