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 Plantar Heel Pain: Multisegment Foot Motion and Muscle Function, FFI Translation, and Evaluation of Treatments (NCT03161314), a randomized na study. The primary outcome is Worst Pain.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03161314 |
| Phase | NA |
| Condition | Plantar Fasciitis |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 84 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Mahidol University |
| Results posted | Yes |
2. Clinical Question
Population
The treatment comparison concerns individuals with plantar fasciitis and plantar heel pain. The registry background describes plantar heel pain as a condition associated with pain and functional limitations, and notes particular relevance among active adults aged 25 to 65. It does not report the treatment study’s detailed eligibility criteria or the characteristics of the participants enrolled in each arm.
Intervention
The intervention was strengthening exercises. The registry identifies this as a procedure and describes a Strengthening group of individuals with plantar fasciitis who received the exercises.
Comparator
The comparator was stretching exercises. The registry describes a Stretching group of individuals with plantar fasciitis who received those exercises. Both groups are part of a randomized, parallel design.
Primary question
The primary measure was worst pain over the past 24 hours, assessed with a visual analog scale. The registry planned assessment at baseline, 2 weeks after the intervention, 4 weeks after the intervention, 1-month follow-up, and 2-month follow-up. The registry record does not identify one time point as the sole treatment contrast or report a numerical comparison between the groups.
The registry’s broader description also discusses foot motion during walking and translation of the Foot Function Index (FFI) into Thai. These aims provide context for the record, but the posted primary outcome is worst pain in the exercise comparison. The available record therefore establishes what was compared and what was measured, but it does not provide the results needed to determine how the groups’ pain scores changed or differed.
3. Trial Design
The registry lists NCT03161314 as completed, with a randomized, triple-masked, parallel design. Mahidol University is named as the sponsor. The listed enrollment is 84. The recorded study start date is 2017-08-01, and the primary completion date is 2019-02-01. The phase is listed as NA.
The two treatment groups received strengthening exercises or stretching exercises. The registry describes both as groups of individuals with plantar fasciitis. It does not report the random-sequence method, allocation concealment procedure, details of who was masked, or the practical meaning of triple masking for these exercise interventions. The record also does not report treatment frequency, duration, supervision, adherence, or any co-interventions. Those details should not be inferred from the design labels.
The primary outcome is a continuous pain score, summarized in the registry as a mean with standard deviation. Worst pain was assessed at baseline and at several post-intervention and follow-up time points. Secondary outcomes listed are cadence, stride length, stride time, and gait speed. The registry lists 6 outcome measures and 42 analyses, but does not give the analysis procedures or results for those outcomes in the information available.
The registry’s description also refers to gait and foot-segment motion comparisons and Thai FFI translation and validation. The treatment arms are explicitly described as study 3. The record does not provide enough detail to reconstruct the methods or results for every component. In particular, participant flow, exclusions, analysis populations, and reasons for missing observations are not reported in the registry record.
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.
Baseline
| Stage | Strengthening Group | Stretching Group |
|---|---|---|
| STARTED | 42 | 42 |
| COMPLETED | 42 | 42 |
| NOT COMPLETED | 0 | 0 |
2 Weeks After the Intervention
| Stage | Strengthening Group | Stretching Group |
|---|---|---|
| STARTED | 42 | 42 |
| COMPLETED | 42 | 42 |
| NOT COMPLETED | 0 | 0 |
4 Weeks After the Intervention
| Stage | Strengthening Group | Stretching Group |
|---|---|---|
| STARTED | 42 | 42 |
| COMPLETED | 42 | 42 |
| NOT COMPLETED | 0 | 0 |
1-month Follow-up
| Stage | Strengthening Group | Stretching Group |
|---|---|---|
| STARTED | 42 | 42 |
| COMPLETED | 42 | 42 |
| NOT COMPLETED | 0 | 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 | Strengthening Group | Stretching Group | Total |
|---|---|---|---|---|
| Participants analysed | 42 | 42 | 84 | |
| Age, Continuous | years | 51.95 (SD 10.10) | 52.86 (SD 9.84) | 52.40 (SD 9.97) |
| Sex: Female, Male: Female | Participants | 29 | 33 | 62 |
| Sex: Female, Male: Male | Participants | 13 | 9 | 22 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
| Weight | kg | 65.66 (SD 11.26) | 65.14 (SD 12.52) | 65.40 (SD 11.90) |
| Height | cm | 161.13 (SD 9.18) | 159.45 (SD 8.13) | 160.05 (SD 8.67) |
| Pain at worst intensity | scores | 5.96 (SD 2.3) | 5.74 (SD 2.3) | 5.85 (SD 2.3) |
6. Primary Endpoint
The registry lists the primary outcome as Worst Pain, measured over Baseline, 2 weeks after the intervention, 4 weeks after the intervention, 1-month follow-up, and 2-month follow-up.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | score |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is worst pain during the past 24 hours, measured with a visual analog scale (VAS). The scale is described as running from 0, meaning “no pain,” to 10, meaning “pain as bad as participants can imagine.” Higher scores indicate more severe pain. The unit is scores, and the registry specifies the mean and standard deviation as the summary format.
Pain is a patient-reported symptom and is directly relevant to the condition described in the record. Asking about the worst pain experienced over the past 24 hours focuses the measure on a recent period rather than asking participants to recall an unspecified long interval. Repeated assessment can describe how scores vary over the intervention and follow-up schedule. This is a general explanation of the measure’s role; it does not establish that the treatment groups differed or that scores changed.
The stated time frame includes baseline, 2 weeks after the intervention, 4 weeks after the intervention, 1-month follow-up, and 2-month follow-up. Because the registry presents several time points, interpretation depends on the comparison made at each time and on whether the analysis accounts for repeated observations. The registry record does not report the group means, standard deviations, between-group estimates, confidence intervals, or p-values. It also does not specify a single time point as the only primary comparison. Thus, the endpoint definition is available, but the numerical treatment effect and its precision are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a randomized comparison and defines worst pain as the primary measure, but it does not report the results for that measure. No group means, standard deviations, changes from baseline, between-group contrasts, confidence intervals, or p-values are stated in the record. Consequently, the direction and size of any observed difference cannot be described from this information. The completed status does not itself reveal the result.
The repeated assessment schedule matters. A difference at one time point would not automatically describe the pattern at the other assessments, and a within-group change would not by itself establish a difference between the exercise groups. A comparative interpretation ordinarily relies on an estimate of the difference between groups, together with a measure of uncertainty. Neither is reported. It is therefore not possible to assess the precision of an effect or whether the posted results are compatible with a range of materially different effects.
In general, a confidence interval expresses uncertainty around an estimated effect under the assumptions of the analysis. A narrow interval indicates greater precision than a wide interval, but precision alone does not determine clinical importance. No confidence interval or clinical-importance threshold is reported in the registry record, so neither can be discussed for this comparison. Likewise, no numerical test result is reported from which to describe statistical evidence.
The record lists cadence, stride length, stride time, and gait speed as secondary outcomes, and it lists 6 outcome measures and 42 analyses. These listings indicate that the research record covers multiple measurements and analyses; they do not, without the results and analysis details, establish how many comparisons were tested, which were prespecified, or how multiplicity was handled. The registry record does not report a multiplicity adjustment or a hierarchy of outcomes.
The sample-size material is described as a planning illustration based on an observed effect, not as the trial’s own design justification. Its assumptions include a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such illustrations can show how a hypothetical future study’s required size changes with the effect chosen for detection. They are not observed power, and they do not supply missing estimates of the treatment effect or its uncertainty in this trial.
Overall, the record supports a description of the study question, design labels, outcome scale, and assessment schedule. It does not support a quantitative conclusion about the comparative pain results. The sponsor’s analysis cannot be evaluated or contrasted with a recalculation because no posted summary statistics or sponsor estimates are reported in the registry record.
9. Statistical Methods Explained
The registry identifies a randomized, parallel-group study. In general, random assignment is intended to reduce systematic differences between treatment groups at the point of allocation. A parallel design means participants are assigned to one of the intervention groups rather than receiving both interventions in sequence. These design features describe the planned comparison; they do not guarantee that groups were similar in every observed or unobserved characteristic, and they do not replace reporting of the analysis.
What does a mean and standard deviation describe?
The primary outcome is continuous and is recorded as a VAS score. The registry specifies a mean and standard deviation. In general, the mean describes the central level of scores, while the standard deviation describes how spread out the individual scores are around that mean. These summaries can help characterize each group, but they do not alone quantify the uncertainty in a between-group treatment effect. The record does not report the means or standard deviations at the stated assessment times.
How should repeated measurements be understood?
Worst pain was scheduled for measurement at baseline, 2 weeks after the intervention, 4 weeks after the intervention, 1-month follow-up, and 2-month follow-up. Repeated measurements on the same participant are generally related: a participant’s score at one assessment may be associated with that participant’s score at another. Statistical methods for repeated outcomes can account for this dependence and use the pattern across time, but the appropriate method depends on the design and data. The registry record does not report whether the analysis used a repeated-measures model, separate comparisons at each time, change scores, or another approach.
Baseline adjustment can be useful in randomized trials when estimating a follow-up difference, but the registry record does not specify whether baseline scores were included in the model. Nor does it report how any treatment-by-time pattern was evaluated. Without these details and the numerical results, the size and uncertainty of the comparison cannot be reconstructed.
What do confidence intervals and p-values contribute?
In general, a confidence interval gives a range of effect values compatible with the observed data under the model’s assumptions. It communicates precision and can help readers judge whether the data remain consistent with effects of different magnitudes. A p-value describes how unusual the data would be under a specified null hypothesis and statistical model; it is not the probability that the null hypothesis is true, nor a measure of clinical importance. Neither confidence intervals nor p-values for the primary outcome are reported in the registry record.
Why does multiplicity matter?
When many outcomes, assessment times, or statistical comparisons are considered, the chance of at least one apparently unusual result can increase if each is assessed separately at a conventional threshold. General approaches include prespecifying a primary comparison, adjusting for a family of tests, or clearly distinguishing confirmatory from exploratory analyses. The record lists 6 outcome measures and 42 analyses, but it does not describe the testing families, which analyses were primary, or any adjustment. The count alone cannot establish that all analyses were independent tests or that a particular correction was necessary.
How should the planning illustration be read?
The planning assumptions are described as an illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. For non-time-to-event outcomes, the illustration is expressed as participants per arm for 80% power or another stated power target when available. These are planning quantities, not observed trial results and not observed power. The record explicitly distinguishes this illustration from the trial’s own design. It does not report a sample-size justification from the investigators, and no particular planning result should be treated as the enrollment target or as evidence that the study was adequately powered.
For a continuous outcome, a planning calculation depends on assumptions about the effect to detect, variation in the outcome, the significance level, allocation, and the statistical model. General sample-size calculations can inform future study planning, but they do not answer whether a treatment effect was observed. The registry record does not report the numerical assumptions or resulting planning values in the information available for this explanation.
What information is needed to reproduce an analysis?
Reproduction would require details such as the analysis population, handling of missing observations, model specification, covariates, and the exact contrast of interest. For repeated outcomes, it would also require the model’s treatment of within-participant dependence and time. These items are not reported in the registry record. Accordingly, no recalculated estimate can be made from the available summary information, and no inference about a treatment effect should be substituted for the absent results.
10. Multiplicity, Missing Data and Analysis Populations
The primary pain measure is scheduled at multiple assessment times, and the registry also lists secondary gait outcomes. It records 6 outcome measures and 42 analyses. This breadth raises a general interpretive issue: when many comparisons are considered, an isolated result can be harder to interpret unless the analysis plan distinguishes the primary question from secondary or exploratory questions and explains how multiplicity was addressed.
The registry record does not report a multiplicity strategy, a hierarchy among outcomes, or which time-point comparison was designated as the principal treatment contrast. It also does not report whether adjustment was applied. The number of listed analyses is not enough to infer the number of independent statistical tests or the consequences of any testing strategy.
Missing-data handling and analysis populations are also not reported in the registry record. The available information does not state how many participants contributed outcome data at each assessment, whether all randomized participants were included in the primary analysis, how withdrawals or missed visits were handled, or whether any imputation was used. These details matter because incomplete follow-up can affect both the precision and interpretation of repeated outcome comparisons.
The record’s enrollment and adverse-event entries do not establish the completeness of the pain outcome data. No assumption about intention-to-treat analysis, per-protocol analysis, or missingness mechanism is justified by the information reported. These omissions limit independent assessment of the analysis and its susceptibility to selective reporting or bias.
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 |
|---|---|---|---|
| Strengthening Group | 0 | 42 | 0.0% |
| Stretching Group | 0 | 42 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Strengthening Group | 0 of 42 |
| Stretching Group | 0 of 42 |
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 |
|---|---|
| Strengthening Group | 0 of 42 |
| Stretching Group | 0 of 42 |
The registry records serious adverse events, other adverse events, and deaths separately for the Strengthening and Stretching groups. For each group, the number at risk is listed as 42 for serious adverse events and 42 for other adverse events. The recorded number affected is 0 for serious adverse events, 0 for other adverse events, and 0 for deaths in each group. No serious adverse-event terms are listed.
These entries describe what the registry reports; they should not be read as proof that no unwanted experiences occurred in every participant or that the interventions carry no risk. The record does not provide event definitions, ascertainment procedures, reporting windows, severity details beyond the serious/other categories, or a narrative explaining whether events were actively solicited. It also does not describe how missing safety information was handled.
Zero recorded events in these categories means that the posted registry counts do not show an affected participant in either group for the listed categories. It does not permit a precise estimate of the risk of uncommon events, and it does not resolve whether all events were captured. The adverse-event information is distinct from the primary pain outcome and does not establish the comparative pain result.
12. What the Result Does, and Does Not, Mean
The registry record establishes that NCT03161314 was listed as a completed, randomized, triple-masked, parallel study of strengthening and stretching exercises, with worst pain as the primary outcome. It defines the pain scale, identifies the scheduled assessment times, lists secondary gait measures, and records adverse-event counts. This is useful for understanding the intended comparison and the scope of the registered outcomes.
The record does not report the observed pain scores or a between-group treatment estimate. It therefore cannot show from the information available whether the groups’ scores were similar or different, how large any difference was, how scores changed over time, or how precise an estimate might be. No conclusion about the treatment effect should be drawn from the study’s completed status, enrollment, or design labels alone.
Even when numerical results are available, a statistical difference does not by itself establish that a difference is important to participants. Interpretation generally considers the effect’s size, its uncertainty, the outcome’s meaning, and the credibility of the analysis. Here, the numerical effect and its uncertainty are absent, and the registry record does not report a threshold for a clinically important difference.
The planning illustration is not a substitute for trial findings. Its stated assumptions concern hypothetical planning, and its description explicitly distinguishes it from the trial’s own design. It should not be interpreted as observed power or as evidence for or against an intervention. Similarly, the zero adverse-event entries are registry counts within the stated categories; they do not establish absence of all possible harms.
The appropriate reading is therefore bounded: the record documents a treatment question and a measurement plan, but does not provide enough outcome information to judge the comparative result. Further conclusions would require numerical results and analysis details that are not reported in the registry record.
13. Why This Trial Matters Statistically
This record is statistically relevant because it brings together several kinds of research questions around plantar heel pain: foot motion during walking, use of a translated foot-function questionnaire, and evaluation of physical therapy exercises. Those questions involve different outcomes and study aims. Keeping them distinct helps prevent results from one component from being treated as evidence for another.
For the exercise comparison, worst pain is a continuous patient-reported outcome observed repeatedly. A careful analysis needs to make clear whether the target is a single follow-up difference, a change from baseline, or a pattern across assessments. It also needs to report the estimate and its uncertainty. The registry gives the measure and time frame but does not report those numerical results or the analysis specification.
The record also highlights why multiplicity and transparency matter. Multiple outcome measures and analyses can create more than one route to a potentially notable result. Prespecification and clear reporting help readers distinguish the main question from secondary exploration. The registry lists outcome and analysis counts, but does not describe how comparisons were prioritized or multiplicity was addressed.
Finally, planning illustrations and trial results answer different questions. A planning calculation describes the sample size associated with assumptions about a future target effect and statistical procedure. An observed estimate describes what the study data indicate. The former cannot fill in missing results for the latter. Here, the registry record supports discussion of design and measurement, while leaving the comparative treatment effect unreported.
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 principal limitation for interpretation is the absence of numerical primary-outcome results in the registry record. The group means, standard deviations, changes, between-group estimates, confidence intervals, and p-values are not reported. Without them, neither the direction nor the precision of a pain comparison can be assessed.
The record specifies several assessment times but does not identify one as the sole primary contrast or describe how repeated measurements were analyzed. It does not report the statistical model, baseline adjustment, covariates, analysis population, missing-data approach, or participant flow. These omissions prevent independent assessment of the analysis and the extent to which incomplete follow-up could affect interpretation.
Details of the interventions and masking are limited. The record names strengthening and stretching exercises and labels the study triple-masked, but does not describe the exercise protocols, masking roles, adherence, or treatment fidelity. Eligibility criteria and detailed participant characteristics for the treatment groups are also not reported in the information available.
The broader record mentions gait and foot-segment motion research and Thai FFI translation, but the available description does not establish how those components were conducted or what they found. The secondary outcome list and analysis count do not clarify which analyses were prespecified or how multiplicity was handled. Finally, the sample-size material is described as a planning illustration rather than the trial’s own design justification; it cannot establish the study’s intended detectable effect or observed precision.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Plantar Heel Pain: Multisegment Foot Motion and Muscle Function, FFI Translation, and Evaluation of Treatments — NCT03161314.
- Registry record last updated 2025-07-04; status last verified 2025-06.
- Results first posted 2025-07-04.
- 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
NCT03161314 is listed as a completed, randomized, triple-masked, parallel study sponsored by Mahidol University. Enrollment is listed as 84. The study start date is 2017-08-01, and the primary completion date is 2019-02-01. The phase is listed as NA.
The treatment comparison is between strengthening exercises and stretching exercises for individuals with plantar fasciitis. The primary outcome is worst pain over the past 24 hours on a visual analog scale, with higher scores indicating more severe pain. Assessments were scheduled at baseline, 2 weeks after the intervention, 4 weeks after the intervention, 1-month follow-up, and 2-month follow-up. Secondary outcomes include cadence, stride length, stride time, and gait speed.
The registry also describes gait and foot-motion research and Thai translation of the FFI. It records 0 serious adverse events, 0 other adverse events, and 0 deaths in each treatment group. Numerical primary-outcome results, analysis details, missing-data handling, and a multiplicity plan are not reported in the registry record.