Myogenic and Osteogenic Responses to eXercise and Ibuprofen: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Myogenic and Osteogenic Responses to eXercise and Ibuprofen (NCT00462722), a randomized na study. The primary outcome is Percentage Change From Baseline in Lumbar Spine Bone Mineral Density (BMD) at 9 Months.

2. Clinical Question

The study title and brief description frame the question around whether ibuprofen use alters exercise-related bone and muscle responses. The primary endpoint addresses bone density at the lumbar spine; the registry also lists bone density at other sites, thigh muscle area, bone turnover markers, and selected muscle-related proteins and genes as secondary outcomes. The posted primary results concern group means and pairwise mean differences. They do not establish a causal mechanism, and the registry record does not report a formal analysis of the overall effect of exercise itself against a non-exercise group.

3. Trial Design

The registry record describes a randomized, parallel-group trial with triple masking. It reports enrollment of 159 and a completed status. The record lists the study start as 2007-07 and primary completion as 2011-12. The phase is recorded as NA, and the sponsor is University of Colorado, Denver.

Three groups are represented in the primary outcome results. One received placebo before and after musculoskeletal-loading exercise. A second received ibuprofen before and placebo after exercise. The third received placebo before and ibuprofen after exercise. Thus, the two comparisons with the reference group concern different timing schedules, not a single interchangeable ibuprofen regimen. The registry record does not report the dose, duration, or detailed exercise protocol.

The primary endpoint is reported as a mean with standard deviation: percentage change from baseline in lumbar spine BMD after 9 months of training. The outcome-specific group counts are 37 for placebo before and after exercise, 50 for ibuprofen before and placebo after exercise, and 42 for placebo before and ibuprofen after exercise. The record notes that one participant in the ibuprofen-before-and-placebo-after group had an uninterpretable spine scan.

The registry record does not report the randomization method, allocation concealment, which parties were masked, the original sample-size justification, or the planned primary statistical model. It also does not report a detailed participant flow or analysis-population definition. Those omissions limit assessment of how assignment was implemented and how the reported outcome sets relate to all enrolled participants.

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

Analysis population for the primary outcome, as defined in the registry: One participant in the "Ibuprofen pre and placebo post exercise" group had an uninterpretable spine scan.

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.

6. Primary Endpoint

The registry lists the primary outcome as Percentage Change From Baseline in Lumbar Spine Bone Mineral Density (BMD) at 9 Months, measured over Baseline and after 9 months of training.

The primary endpoint is percentage change from baseline in lumbar spine bone mineral density (BMD) at 9 months. It describes relative change in the measured density of bone at the lumbar spine over the training period. The registry reports a group mean and standard deviation for each schedule, so the posted comparisons focus on differences between average changes rather than on individual participant responses.

BMD is one measure of bone response, and the lumbar spine is the specified site for the primary outcome. A continuous endpoint preserves information about the amount and direction of change; it is not simply a count of participants who crossed a threshold. The registry also lists BMD outcomes at the femoral neck, trochanter, and sub-trochanter, alongside muscle-related and biological measures. Those outcomes provide related but distinct information and are secondary in the posted record.

The endpoint is defined over baseline and after 9 months of training. The registry does not report the measurement instrument, the timing details for scans, or a clinically important threshold for interpreting a difference. Consequently, the reported means and contrasts describe the observed measurements, while their clinical importance cannot be established from the record alone.

7. Results Posted in the Registry

• Ibuprofen Pre and Placebo Post Exercise: mean 1.50 versus 1.30 on control; difference 0.20 (95% CI -0.94 to 1.34), standardized effect d = 0.08; z-test p = 0.730.
• Placebo Pre and Ibuprofen Post Exercise: mean 0.90 versus 1.30 on control; difference -0.40 (95% CI -1.52 to 0.72), standardized effect d = -0.16; z-test p = 0.484.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Percentage Change From Baseline in Femoral Neck Bone Mineral Density (BMD) at 9 Months

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Ibuprofen Pre and Placebo Post Exercise: mean 0.20 versus 0.20 on control; difference 0.00 (95% CI -1.23 to 1.23), standardized effect d = 0.00; z-test p = 1.000.
  • Placebo Pre and Ibuprofen Post Exercise: mean -0.10 versus 0.20 on control; difference -0.30 (95% CI -1.44 to 0.84), standardized effect d = -0.12; z-test p = 0.606.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Ibuprofen Pre and Placebo Post Exercise and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Placebo Pre and Ibuprofen Post Exercise and the control. The interval gives the range of effects that remain compatible with the data.

Percentage Change From Baseline in Trochanter Bone Mineral Density (BMD) at 9 Months

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Ibuprofen Pre and Placebo Post Exercise: mean 0.00 versus 1.10 on control; difference -1.10 (95% CI -2.30 to 0.10), standardized effect d = -0.41; z-test p = 0.072.
  • Placebo Pre and Ibuprofen Post Exercise: mean -0.10 versus 1.10 on control; difference -1.20 (95% CI -2.50 to 0.10), standardized effect d = -0.42; z-test p = 0.071.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Ibuprofen Pre and Placebo Post Exercise and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Placebo Pre and Ibuprofen Post Exercise and the control. The interval gives the range of effects that remain compatible with the data.

Percentage Change From Baseline in Sub-trochanter Bone Mineral Density (BMD) at 9 Months

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Ibuprofen Pre and Placebo Post Exercise: mean 0.00 versus 0.50 on control; difference -0.50 (95% CI -1.78 to 0.78), standardized effect d = -0.18; z-test p = 0.445.
  • Placebo Pre and Ibuprofen Post Exercise: mean -0.30 versus 0.50 on control; difference -0.80 (95% CI -2.14 to 0.54), standardized effect d = -0.27; z-test p = 0.243.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Ibuprofen Pre and Placebo Post Exercise and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Placebo Pre and Ibuprofen Post Exercise and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover BMD at the femoral neck, trochanter, and sub-trochanter, along with thigh cross-sectional muscle area, bone turnover markers, and selected proteins and genes associated with muscle build-up and breakdown. The posted numerical summaries include the three additional BMD sites. The registry lists the other outcome categories but does not post their numerical results in the material recorded.

Across the posted secondary BMD outcomes, the group means and pairwise estimates vary by site and schedule. The contrasts do not show a single uniform pattern across all sites. This broad pattern is compatible with the primary result being uncertain rather than pointing to a clearly consistent difference across skeletal measurements. The secondary outcomes are related to the primary endpoint, but different anatomical sites can reflect distinct measurements and should not be treated as repetitions of the same result.

The secondary comparisons are reported with unadjusted p-values, and the registry record does not report a multiplicity plan. General statistical explanation: when many outcomes or comparisons are examined, the chance of at least one apparently unusual result can rise even if no underlying effects exist. This is one reason isolated secondary findings usually carry less evidential weight than a prespecified primary outcome, particularly when no adjustment or hierarchy is described.

The absence of posted analyses for muscle area and biological markers is also important. Their inclusion in the outcome list does not establish a result in either direction. The registry record does not provide enough information to assess whether all planned secondary outcomes were measured, analyzed, or reported. Secondary findings should therefore be read as supportive or exploratory context only where numerical estimates are posted, not as independent confirmation of a primary conclusion.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Percentage Change From Baseline in Femoral Neck Bone Mineral Density (BMD) at 9 Months
• Percentage Change From Baseline in Trochanter Bone Mineral Density (BMD) at 9 Months
• Percentage Change From Baseline in Sub-trochanter Bone Mineral Density (BMD) at 9 Months
• Change in Thigh Cross-sectional Muscle Area
• Bone Turnover Markers
• Expression of Selected Proteins and Genes Associated With Muscle Build-up and Breakdown

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: it is expressed as percentage change in lumbar spine BMD. The registry reports the mean and standard deviation for each group. A mean describes the central value of the group measurements, while a standard deviation describes their spread around that mean. The standard deviation is not the uncertainty in the mean difference; that uncertainty depends on both the spread and the number of observations in each group.

What does a mean difference represent?

The posted contrasts compare each ibuprofen timing schedule with placebo before and after exercise. A mean difference is the difference between the two group means, with the reference group serving as the comparison. The contrast of 0.2 is for ibuprofen before exercise and placebo after exercise; the contrast of -0.4 is for placebo before exercise and ibuprofen after exercise. The signs indicate the direction relative to the reference group under the posted comparison convention. They do not, by themselves, establish that a difference is reliable or important.

The registry reports unadjusted p-values for these comparisons. A p-value describes how compatible the observed data are with a specified null model under the assumptions of the test. It is not the probability that the null hypothesis is true, nor does it quantify the size or clinical importance of an effect. These values are unadjusted, and the registry record does not identify the testing model, any covariate adjustment, or any planned correction for multiple comparisons. Interpretation should therefore consider the estimates and their intervals, not p-values alone.

What does a confidence interval add?

General statistical explanation: a confidence interval gives a range of effect estimates compatible with the data and the procedure used to construct the interval. Its width conveys precision: narrower intervals indicate more precise estimates, while wider intervals indicate greater uncertainty. An interval that includes zero for a mean difference is compatible with no difference as well as with differences in either direction, within the range represented by that interval. It does not prove that the groups are identical.

The registry posts confidence intervals for the primary pairwise mean differences. Both include zero, and each extends to positive and negative values. That pattern is consistent with the small observed contrasts, but the intervals remain important because they also allow effects that are not exactly zero. The registry record does not state a threshold for a clinically meaningful difference, so the ranges cannot be classified against such a threshold.

Why does variability matter?

General statistical explanation: when a continuous outcome varies substantially within groups, it becomes harder to estimate a group difference precisely unless the study has enough observations. Greater variability increases uncertainty in a comparison; more observations can reduce that uncertainty, subject to the design and analysis assumptions. The reported standard deviations describe the observed spread in each group and help readers understand why group means alone are not sufficient.

The posted analyses are pairwise comparisons with a common reference group. They are not a single three-group omnibus test in the information reported. The record does not report whether the original analysis used a model that jointly accounted for all three groups, baseline BMD, or other variables. It also does not describe whether repeated measurements or any clustering features were incorporated. These details are not reported in the registry record.

The sample-size illustrations use a normal approximation, two-sided significance level 0.05, equal allocation between two arms, and an effect specified as a fraction of the observed effect. These are assumptions for the planning illustrations, not reported features of the original trial design. General statistical explanation: power is the chance that a planned test will detect an effect of a specified size under a particular statistical model and design, if that effect is real. Planning calculations depend on assumptions about variability, allocation, significance level, and the effect to detect. A calculation based on an observed effect can be especially unstable when that observed estimate is imprecise.

The registry record does not report whether the primary outcome analysis followed an intention-to-treat principle, whether all randomized participants were included where possible, or how missing values were treated. It also does not report any formal analysis population. Those analysis choices can affect how a mean difference should be interpreted, particularly when outcome availability differs from enrollment. The results are best read as the posted group summaries and unadjusted pairwise estimates, with the unreported analytic details kept in view.

11. Confidence Intervals and Precision

Precision is reflected in the uncertainty around each estimated mean difference, not just in the point estimate. For the primary outcome, both reported confidence intervals cross zero and extend in both directions. This means that the estimates are compatible with no difference, but also with differences favoring either group. The intervals do not support a precise claim that the schedules produce the same mean change.

The observed group means were 1.3, 1.5, and 0.9, and the corresponding standard deviations were 2.8, 2.5, and 2.2. The spread of participant measurements is larger than the observed contrasts between group means. General statistical explanation: when within-group variability is substantial relative to a contrast, that contrast can be estimated imprecisely, especially with limited group sizes. Confidence intervals make that uncertainty visible.

The registry reports 37, 50, and 42 observations for the primary endpoint. These outcome counts and the reported variability contribute to the width of the intervals, but do not alone establish whether the trial was adequately powered for its original purpose. The original sample-size target, its assumptions, and any prespecified meaningful effect are not reported in the registry record.

A confidence interval is not a guarantee that the true effect lies within its particular range. General statistical explanation: in repeated studies using the same procedure, confidence intervals have a specified long-run coverage property under the model assumptions. Here, the interpretation is further limited by the registry's lack of detail about the analysis model and missing-data handling. The intervals should therefore be read as measures of uncertainty around the posted comparisons, rather than as proof of equivalence or proof of no effect.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm, not total participants or total events. They assume a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Each planning row uses the stated fraction of the observed effect as the effect to detect. The registry record does not report whether these assumptions match the trial's original design assumptions.

The 80% power column gives an illustrative number of participants per arm for a design intended to have an 80% chance of detecting the specified effect, under the stated assumptions. The 90% power column gives the corresponding illustration for a 90% chance. General statistical explanation: both are prospective planning probabilities conditional on the assumptions and the effect being considered; they are not probabilities that the observed result is true.

For example, planning for 100% of the observed primary contrast gives 2,718 participants per arm for 80% power and 3,638 for 90% power for the ibuprofen-before-and-placebo-after comparison. For the placebo-before-and-ibuprofen-after comparison, the corresponding figures are 613 and 820 participants per arm. The larger figures in some rows reflect the different observed contrasts used as planning inputs; they should not be treated as a ranking of treatment value.

Planning for 75% or 50% of an observed effect entails a smaller target effect, and smaller effects need more participants to detect under otherwise unchanged assumptions. These figures are illustrations based on observed estimates, not the original trial's reported sample-size justification. This is not observed power.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 0.200; pooled standard deviation σ = 2.631.
2. n = 2 × (1.96 + 0.842)² × 2.631² / 0.200² = 2,717.1, rounded up to 2,718 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 0.2                      # observed difference in means
sigma <- 2.63123768685117                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(462722)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 2,718 (80% power), 3,638 (90% power)
 75% of observed effect: n per arm = 4,831 (80% power), 6,467 (90% power)
 50% of observed effect: n per arm = 10,869 (80% power), 14,550 (90% power)
power.t.test: 2718 
Simulated power at n = 2,718 per arm: 0.799 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome and several secondary outcome categories, with multiple pairwise comparisons for the posted BMD outcomes. It does not report a multiplicity strategy, such as a prespecified hierarchy or adjustment across outcomes and comparisons. The listed p-values are unadjusted. Consequently, they should not be interpreted as though the many statistical tests formed a single controlled family with a known overall error rate.

General statistical explanation: as the number of statistical tests increases, the chance of at least one small p-value arising by chance can increase. Adjustments and prespecified testing plans address this issue in different ways, but the appropriate approach depends on the trial question and design. Because the registry record does not report such a plan, the unadjusted secondary comparisons deserve cautious interpretation and should not be used to select a preferred result after the fact.

Missing-data information is limited. The primary outcome description notes that one participant in the ibuprofen-before-and-placebo-after group had an uninterpretable spine scan. The registry does not report a missing-data method, imputation procedure, sensitivity analysis, or reason for any other differences between enrollment and endpoint-specific counts. It also does not state whether the primary analysis included all randomized participants or only participants with an interpretable measurement.

The record does not define an intention-to-treat, per-protocol, or other analysis population. This matters because the interpretation of a randomized comparison depends partly on how participants are retained in the analysis after randomization. The available group summaries describe the posted endpoint data, but they do not resolve possible effects of missingness or exclusions.

The registry also does not report the original sample-size rationale, a detailed statistical analysis plan, or interim analyses. These are not evidence that a particular procedure was or was not used; they are simply not reported in the registry record. Without those details, it is not possible to determine whether the primary analysis was prespecified in the form shown or how multiplicity and missing data were addressed outside the registry entry.

15. Safety Results

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

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 serious adverse events for 0 participants in each group: 0 of 37 in the placebo-before-and-after group, 0 of 51 in the ibuprofen-before-and-placebo-after group, and 0 of 42 in the placebo-before-and-ibuprofen-after group. These are the numbers at risk listed for the serious-event summaries. The at-risk count of 51 in the second group differs from the primary endpoint count of 50; the record does not explain that difference.

These figures describe the posted serious-event counts during the period covered by the registry record. A zero count does not establish that an event is impossible or that the groups have identical safety profiles; it means no serious adverse events were recorded in these group summaries. The record does not list serious adverse-event terms. Death counts are not reported in the registry record.

For other adverse events, the record reports 0 of 37, 1 of 51, and 0 of 42 across the same respective groups. The record does not provide further detail about that event in the information available. Safety findings should be interpreted in the context of the reported counts and the limited detail, without treating them as a comprehensive assessment of risk.

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

The results describe average percentage change in lumbar spine BMD after 9 months among the three reported schedules. The observed means were 1.3 for placebo before and after exercise, 1.5 for ibuprofen before and placebo after, and 0.9 for placebo before and ibuprofen after. The estimated differences from the reference group were 0.2 and -0.4, and both confidence intervals include zero.

These findings do not establish that the schedules are equivalent. A non-significant or imprecise difference is not the same as evidence that two groups have the same outcome. Equivalence or non-inferiority conclusions require a defined margin and a suitable design and analysis; those details are not reported in the registry record. The intervals permit a range of possible effects, so the estimates should be interpreted with their uncertainty.

The results also do not directly answer whether exercise itself increases bone or muscle mass relative to no exercise. Each listed primary group took part in musculoskeletal-loading exercise, and the comparisons concern different medication timing schedules around that exercise. There is no no-exercise comparator in the posted primary group results. The findings therefore speak to the reported comparisons, not to every component of the study's motivating question.

The primary outcome concerns lumbar spine BMD, while other BMD sites and biological measures are distinct outcomes. The available results do not establish changes in muscle mass or the mechanisms underlying bone or muscle responses. The registry lists additional outcome categories, but numerical results are not reported for all of them.

Finally, the registry record does not report enough information about the analysis model, missing-data handling, multiplicity, or original design assumptions to support stronger claims. These limitations do not erase the posted estimates; they define what can reasonably be inferred from them. The most direct reading is that the observed primary group means were close, but the comparisons remain uncertain and do not demonstrate either a clear difference or equivalence.

17. Why This Trial Matters Statistically

This trial illustrates why a clinical result should be read through its estimate and uncertainty, rather than through a p-value alone. The primary contrasts are modest in the posted units, but their confidence intervals include both positive and negative values. That combination communicates that the data do not precisely identify the direction or size of a difference between the medication-timing schedules.

The design question is also specific: the comparisons distinguish when ibuprofen was given relative to exercise, against a group receiving placebo at both time points. A broader question about exercise effects would require a comparison that isolates exercise from no exercise; that is not among the posted primary groups. Keeping the estimand—the precise comparison being made—in view prevents an overextension from these results to the broader motivation.

Multiple related endpoints create another statistical challenge. BMD was assessed at several sites, and the registry lists muscle and biological measures as well. Without a reported analysis hierarchy or multiplicity plan, findings across outcomes should be interpreted as a pattern of evidence rather than as independent confirmatory tests. This trial therefore offers a practical example of why prespecification and transparent reporting matter.

Finally, registry summaries can communicate useful group estimates while leaving key design and analysis details unreported. The available record gives group means, standard deviations, comparisons, and some adverse-event counts, but not the original sample-size rationale, detailed analysis plan, or complete missing-data approach. Recognizing both the information that is posted and the information that is absent is central to sound statistical interpretation.

18. 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 are specific to the information recorded for this trial. The registry does not report the exercise protocol in enough detail to characterize the loading regimen, nor does it report the ibuprofen dose or duration. The three schedules establish timing differences, but the available record is insufficient to assess adherence or the exact exposure participants received.

The primary endpoint counts differ across groups, and the record notes one uninterpretable spine scan in the ibuprofen-before-and-placebo-after group. It does not explain the full relationship between enrollment and endpoint availability or state how missing measurements were handled. The difference between the primary outcome count and the serious-event at-risk count for that group is also unexplained.

The analysis model, adjustment for baseline values or other factors, analysis population, and multiplicity strategy are not reported in the registry record. The original sample-size justification and any interim analyses are also not reported. These absences limit assessment of prespecification, precision goals, and the robustness of the results.

The posted primary outcome concerns lumbar spine BMD, and numerical results for all listed secondary outcomes are not present in the record. The trial results therefore provide a limited view of the broader bone and muscle question. The findings should be interpreted as registry-reported comparisons rather than as a complete account of all trial analyses.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Myogenic and Osteogenic Responses to eXercise and Ibuprofen — NCT00462722.
• Registry record last updated 2015-11-02; status last verified 2015-10.
• Results first posted 2015-08-10.
• 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.

22. Record Summary

NCT00462722 is a completed randomized, triple-masked, parallel-group study sponsored by University of Colorado, Denver. The registry lists enrollment of 159, a start of 2007-07, and primary completion in 2011-12. The study compared placebo or ibuprofen schedules around musculoskeletal-loading exercise.

The primary outcome was percentage change from baseline in lumbar spine BMD after 9 months. The posted means were 1.3, 1.5, and 0.9 across the three groups. The pairwise mean differences versus placebo before and after exercise were 0.2 and -0.4; both confidence intervals include zero. The record also lists secondary bone, muscle, and biological outcomes, but does not post numerical analyses for all listed outcomes.

The registry reports zero serious adverse events in each group and limited additional safety detail. The original sample-size rationale, full statistical analysis plan, multiplicity approach, and missing-data methods are not reported in the registry record.