Prevention of Musculoskeletal Injuries in Slovenian Armed Forces: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Prevention of Musculoskeletal Injuries in Slovenian Armed Forces (NCT03415464), a randomized na study. The primary outcome is Number of Soldiers With Ankle and Knee Injuries.

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group trial with no masking reported. The registry lists an enrollment of 160 and marks the trial as completed. The two groups were functional training and regular army training. The posted primary outcome data include 64 participants in the functional-training group and 41 in the regular-training group. Reasons that these outcome denominators differ from the enrollment figure are not reported in the registry record.

The functional-training program was planned for 15 weeks, using cycles lasting 3 weeks, with two 45-minute sessions per week. The comparator was regular military training. The record does not provide further detail about the comparator’s schedule or about the specific functional exercises, because the intervention description is incomplete. Allocation is identified as randomized, but the method used to generate the allocation sequence, conceal allocation, or implement randomization is not reported in the registry record.

The primary outcome was the number of soldiers with ankle and knee injuries over 1 year. Three secondary outcomes—vertical jump performance, pull-ups performance, and hamstring repetitive strength—were assessed over 15 weeks. The record lists four outcome measures and one reported analysis. The reported primary analysis is identified as a chi-squared test. Details of the original analysis plan, including the intended analysis population and handling of missing outcome data, are not reported in the registry record.

The trial record identifies the study as completed, but does not report the original sample-size justification, planned interim analyses, or whether outcome assessors were masked. Those omissions limit what can be inferred about the design decisions and conduct beyond the recorded randomization, parallel-group structure, intervention, comparator, and outcome timeframes.

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: Initially, there were 160 soldier who approved to participate in initial testing, but prior to assignment of participants to groups 55 of them has declined further participation for different reasons, so only 105 soldiers was later randomised into groups, but the completion rate after this point was 100%.

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Soldiers With Ankle and Knee Injuries, measured over 1 year.

The primary endpoint is the number of soldiers with ankle and knee injuries during a 1-year study period. The registry description frames the outcome as the percentage of soldiers affected; the posted arm results report counts of participants with an event and the numbers assessed. In the functional-training group, 1 of 64 participants had a recorded injury event; in regular army training, 3 of 41 did.

A binary outcome of this kind distinguishes participants who experienced at least one qualifying event from those who did not, according to the trial’s outcome definition. It is useful for summarizing how many participants were affected, but the count alone does not describe the number, severity, timing, or recurrence of injuries. The registry does not report the operational definition of an ankle or knee injury, how events were collected or adjudicated, or whether multiple injuries in one participant were counted separately.

The 1-year timeframe makes the endpoint a measure of injury occurrence over a period that extends beyond the 15-week functional-training program. The record does not explain how injuries after the training period were attributed or how continued exposure to military conditioning was handled. These details matter when interpreting what the endpoint represents: it records participant-level injury occurrence over the stated period, but does not by itself explain the mechanism or timing of any observed difference.

7. Results Posted in the Registry

• Regular Army Training: 7.3% (3/41) versus 1.6% (1/64) on control; risk difference 5.8 percentage points (95% CI -2.8 to 14.3), risk ratio 4.68 (0.50–43.50); unadjusted two-proportion z-test p = 0.133.

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.

Vertical Jump Performance

• 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:
  • Regular Army Training: mean 29.90 versus 35.40 on control; difference -5.50 (95% CI -9.66 to -1.34), standardized effect d = -0.52; z-test p = 0.010.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Regular Army Training than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Pull-ups Performance

• 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:
  • Regular Army Training: mean 4.00 versus 6.00 on control; difference -2.00 (95% CI -3.57 to -0.43), standardized effect d = -0.50; z-test p = 0.012.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Regular Army Training than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Hamstring Repetitive Strength

• 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:
  • Regular Army Training: mean 25.00 versus 25.00 on control; difference 0.00 (95% CI -2.90 to 2.90), standardized effect d = 0.00; z-test p = 1.000.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Regular Army Training and the control. The interval gives the range of effects that remain compatible with the data.

Across the secondary outcomes, the overall pattern is mixed in its specificity: the functional-training group has higher posted averages for two physical-performance measures, while the average for hamstring repetitive strength is the same between groups. These outcomes were measured over 15 weeks, whereas the primary injury endpoint covers 1 year. They describe physical performance and injury occurrence, respectively, so the secondary pattern does not directly confirm or negate the primary comparison.

The secondary comparisons are recalculated from group summaries and are not accompanied by sponsor-reported inferential analyses in the registry record. They are unadjusted, and the record does not report a prespecified hierarchy or multiplicity procedure for the three outcomes. When several outcomes are examined, the chance of observing at least one apparently notable result can increase if each is interpreted independently. This is why individual unadjusted secondary p-values should generally carry less confirmatory weight than a prespecified primary analysis.

The secondary findings can be useful for describing what was measured and for identifying patterns that might merit further study, but they cannot establish that the intervention caused a particular performance change. The registry does not report baseline performance values, covariate-adjusted comparisons, or details about missing measurements. It is therefore not possible to determine from the record whether groups differed at baseline or how incomplete measurement may have affected the reported averages.

Interpretation should keep the outcome domains separate. Performance-test averages are not counts of injuries, and the registry does not report an analysis linking changes in performance to subsequent injury risk. Nor does the posted pattern establish that an improvement in a performance measure would translate into fewer injuries. The secondary outcomes provide additional descriptive evidence from the trial, but they do not resolve the uncertainty in the primary endpoint.

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

• Vertical Jump Performance
• Pull-ups Performance
• Hamstring Repetitive Strength

9. Statistical Interpretation

10. Statistical Methods Explained

What is the primary comparison?

The primary endpoint is binary at the participant level: whether a soldier was recorded as having an ankle or knee injury during the 1-year period. The registry reports counts and denominators for each arm. A risk difference compares the proportions with an event by subtracting one group’s event proportion from the other’s. Its sign depends on the order of the groups, so the direction must be read with the stated comparison in mind. In this analysis, the regular-training group is compared with functional training, and the estimated risk difference is positive.

The recalculated comparison is unadjusted: it uses the posted event counts and group sizes without adjusting for other characteristics. The registry identifies a chi-squared test for its reported analysis. A chi-squared test evaluates whether the observed distribution of participants across event and no-event categories is compatible with equal proportions under the test’s assumptions. The record does not describe the specific chi-squared variant, whether a continuity correction was used, or any additional analysis details. With only a few observed events, the test result and effect estimate should be interpreted cautiously; sparse event data can make comparisons less stable.

What does a confidence interval add?

A confidence interval gives a range of values compatible with the observed data under the method’s assumptions. It communicates uncertainty around an estimate, rather than only whether a test crosses a conventional significance threshold. For the primary risk difference, the interval crosses zero, the value representing no difference between groups. This means the data do not rule out no difference at the confidence level used for that interval. The interval also extends in both directions, so the observed point estimate should not be treated as a precise measure of the underlying contrast. The registry does not report a confidence level for its own primary analysis; the posted recalculation includes an interval.

How should p-values be read?

A p-value is calculated under a null hypothesis and the assumptions of the selected statistical test. It describes how compatible the data are with that null model; it does not measure the probability that the treatment effect is absent, nor does it measure the probability that a result will replicate. A p-value also does not describe the magnitude of a group difference. For that reason, the primary p-value is considered alongside the event counts, estimated contrast, and confidence interval.

The registry reports p = 0.134 from a chi-squared analysis, while the unadjusted recalculation is p = 0.133. They are close but are not identical. The record does not explain the small numerical difference, and does not report enough detail to identify the exact computational choices behind the sponsor analysis. The registry’s analysis is the reported trial analysis; the recalculation is a separate unadjusted comparison from the posted summary statistics.

How are the secondary outcomes different?

The three secondary outcomes are continuous performance measures reported as group means and standard deviations at 15 weeks. A mean difference expresses the difference between the group averages in the stated comparison order. The confidence interval for a mean difference describes uncertainty in that estimated contrast. Standard deviations describe variation among participant measurements; they are not the same as confidence intervals around a mean. The registry does not list a reported inferential analysis for these secondary outcomes, so the posted comparisons are unadjusted recalculations rather than documented sponsor analyses.

General statistical context: when outcome counts are sparse, standard approximations may be less reliable than they are with more events. For continuous outcomes, the reliability of a mean-based comparison depends on assumptions about the data and the analysis method. The registry does not report diagnostic checks, transformations, covariate adjustment, or model details for the secondary outcomes. Those methods should not be inferred from the summary statistics alone.

What is not documented?

The registry record does not report the original sample-size justification, a detailed prespecified statistical analysis plan, interim analyses, the randomization procedure, or methods for handling missing outcomes. It also does not state whether all randomized participants were included in the outcome analyses or whether analyses followed an intention-to-treat principle. These details affect how closely the posted results can be linked to a planned analysis and how potential bias can be assessed. The recalculated statistics should therefore be understood as unadjusted summaries of the posted data, not as a reconstruction of unreported protocol decisions.

11. Confidence Intervals and Precision

Precision concerns how narrowly the data estimate a group difference. For the primary endpoint, the event counts are small: 1 participant had a recorded event in functional training and 3 in regular army training. The confidence interval for the unadjusted risk difference spans values below and above no difference. This interval indicates considerable uncertainty about the underlying contrast, even though the point estimate is on the side of a higher observed event proportion in regular training.

The interval should be read as a range of values compatible with the data under the calculation’s assumptions, not as a range containing a fixed proportion of individual outcomes or as a probability statement about the true effect. Its inclusion of zero means that no difference remains among the values compatible with the data at the stated confidence level. It does not demonstrate equivalence, and it does not show that any particular value within the interval is more likely than another.

For the continuous secondary outcomes, the posted recalculated mean-difference intervals provide uncertainty estimates for the differences in group averages. Their widths should be considered alongside the means and standard deviations; an observed difference alone does not indicate how precisely it is estimated. The registry does not report sponsor inferential analyses for these secondary measures, and the record does not give a prespecified multiplicity plan. Their intervals and unadjusted p-values therefore offer exploratory context rather than a complete confirmatory analysis.

In general, confidence intervals tend to be wider when data contain less information, including when the number of observed events is small or the measurements vary substantially. The reported primary data have few events, so the primary interval is broad in practical interpretive terms. Neither the point estimate nor a single p-value removes this uncertainty. The original design assumptions and the trial’s planned precision are not reported in the registry record.

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 estimates are expressed as participants per arm, not as total events. They are illustrations based on the observed effect, not the trial’s original design calculation. The listed assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each planning scenario uses the stated fraction of the observed effect as the effect to detect. The registry does not report the original sample-size justification or the assumptions used when the trial was designed.

The 80% power column gives the estimated participants per arm for a planning scenario designed to have an 80% chance of detecting the selected effect under those assumptions, if that effect were present and the statistical model assumptions held. The 90% power column gives the corresponding per-arm estimate for a higher chance of detection. These are design calculations, not guarantees: realized precision and test results also depend on the data collected and the assumptions being appropriate.

Across the planning scenarios, smaller effects require more participants per arm than larger effects. The estimates are listed for planning at 100%, 75%, and 50% of the observed effect, with per-arm counts for the available outcomes where such estimates are posted. No planning estimates are listed for hamstring repetitive strength. For the primary injury outcome, the posted per-arm planning counts are much larger than the analyzed arm sizes, reflecting the planning calculation based on the observed effect and its assumptions. That comparison is not a statement about the trial’s actual enrollment target or original justification.

This is not observed power. It is a prospective planning illustration computed from the observed effect, and it should not be used to interpret a nonsignificant result as evidence that the trial had a particular chance of finding an effect.

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, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.016; treatment proportion p₁ = 0.073; average p̄ = 0.044.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.2913 = 0.5709.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.2884 = 0.2428.
4. n = (0.5709 + 0.2428)² / (0.0575)² = 199.9, rounded up to 200 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
p0 <- 0.015625                          # control proportion
p1 <- 0.0731707317073171                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^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 (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(3415464)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 200 (80% power), 268 (90% power)
 75% of observed effect: n per arm = 301 (80% power), 403 (90% power)
 50% of observed effect: n per arm = 551 (80% power), 737 (90% power)
power.prop.test: 199.9 
Simulated power at n = 200 per arm: 0.840 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-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. Analyses Reported by the Sponsor

The registry reports a chi-squared analysis of the primary comparison with p = 0.134. The unadjusted recalculation from the posted counts gives p = 0.133. These values are close, and the record marks no discrepancy between the reported analysis and the recalculation. The registry’s result is the trial’s reported analysis; the recalculation is a simple unadjusted analysis based on the arm-level counts and denominators.

The registry does not report the test’s full specification or a numerical effect estimate and confidence interval from the sponsor analysis. Consequently, the recalculated risk difference and its interval provide additional descriptive context, but they should not be presented as though they were reported by the sponsor. The record also does not provide details that would establish whether the sponsor used any other adjustment or analytic choice beyond the identified chi-squared method.

Both p-values indicate that the primary comparison does not provide strong statistical evidence against the null hypothesis under the corresponding test. Neither p-value establishes that the groups are equivalent or that a meaningful difference is absent. The counts and the uncertainty around the recalculated effect remain important: only a few events were recorded, and the interval includes no difference. The sponsor analysis and the recalculation are best read together as consistent descriptions of an uncertain primary comparison, while keeping their distinct sources and methods clear.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome and three secondary outcomes. It reports one primary analysis, identified as a chi-squared test, but does not report a multiplicity adjustment, a testing hierarchy, or a statistical analysis plan describing how the primary and secondary outcomes were to be interpreted together. It is therefore not reported in the registry record whether the secondary outcomes were intended as confirmatory tests, exploratory measures, or part of a prespecified sequence.

Multiplicity is a general statistical issue that arises when several hypotheses are tested. If each test is judged separately without an adjustment or a prespecified strategy, the chance of at least one apparently unusual result can increase. This does not mean that a particular secondary finding is necessarily false; it means that its evidential weight depends in part on how many outcomes and analyses were considered and how they were planned. The record does not supply enough information to evaluate that planning.

The outcome denominators differ from the total enrollment listed in the record. Reasons are not reported in the registry record, and there is no description of missing outcome data, exclusions, withdrawals, or participant flow. The number of participants randomized to each arm is also not reported as a separate allocation count. It is consequently unclear whether the posted outcome analyses include all randomized participants, only those with available data, or a different analysis population. The record does not state whether an intention-to-treat approach was used.

Missing-data methods are also not reported: there is no description of imputation, sensitivity analyses, or assumptions about why measurements might be unavailable. These omissions matter because an analysis limited to participants with observed outcomes can be biased if missingness is related to group assignment or outcome status. No conclusion about the presence or absence of such bias can be drawn from the reported summaries alone.

The original sample-size justification and planned interim analyses are not reported in the registry record. Nor are the detailed randomization sequence and allocation-concealment procedures described. These gaps do not change the posted counts, but they limit assessment of the trial’s planned statistical control, participant flow, and robustness.

16. 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.

The registry reports zero serious adverse events and zero other adverse events in both groups. The safety figures list 64 participants at risk in functional training and 41 in regular military training, matching the denominators reported for the primary outcome. No deaths are recorded in either group, and no serious adverse-event terms are listed.

These figures describe what is recorded in the registry for the listed groups and denominators. They should not be interpreted as proof that no adverse events could occur or that all types of events were captured. The record does not report the methods used to collect or classify adverse events, the observation period for safety reporting, or whether events were actively solicited. It also does not provide event-level detail beyond the zero counts.

In general, an absence of recorded events in a trial does not establish that the risk is zero; the amount of information depends on the number of participants, the duration and completeness of observation, and the event-reporting process. The registry’s safety summary is therefore a description of recorded events, not a comprehensive assessment of every possible harm.

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

The primary comparison describes ankle and knee injury occurrence in the trial’s two groups over 1 year. The recorded counts were low, and the unadjusted confidence interval for the group contrast includes no difference. The results therefore leave substantial uncertainty about the size and direction of the underlying difference. The reported p-value does not provide evidence that the groups are equivalent, and the point estimate alone does not establish a reliable difference.

The trial also reports physical-performance outcomes at 15 weeks. Their overall pattern is not the same as the primary injury result because the outcomes measure different things over different periods. The performance findings can describe group averages, but they do not show whether any performance changes caused, prevented, or predicted injury. The registry does not report an analysis connecting these outcomes.

These results apply directly to the participants and conditions described in the record. Detailed eligibility criteria, participant characteristics, injury definitions, and training exposure are not reported in the registry record, limiting assessment of how well the findings might apply to other settings. The record also does not describe outcome ascertainment in sufficient detail to assess possible differences in injury detection between groups.

In general, randomization is intended to support a fair comparison by reducing systematic differences between groups, but interpretation also depends on how randomization was implemented, how outcomes were measured, and how missing data were handled. Although the record identifies randomized allocation, those operational details are not reported. The posted results should therefore be understood as a randomized comparison with important reporting gaps, rather than as a complete account of every design and analysis decision.

The registry records no serious or other adverse events in either group. That is a report of observed and recorded events in the listed participants, not proof that adverse events are impossible or that safety has been established for other populations or training conditions. Overall, the data describe a small number of injury events, uncertain primary comparison, and additional performance measures that do not resolve the injury question.

18. Why This Trial Matters Statistically

This trial is statistically instructive because the primary outcome is a participant-level event count, and only a few events were recorded. In such settings, a difference in a small number of participants can noticeably affect the estimated contrast. A point estimate may look directional, but its uncertainty can remain substantial. Reading the event counts together with the confidence interval is more informative than treating the p-value as a verdict.

The record also illustrates why outcome choice and timeframe matter. The injury endpoint spans 1 year, while the performance measures are assessed at 15 weeks. The measures address different aspects of the research question, and one set cannot be used as a proxy for the other without an analysis that establishes their relationship. A favorable pattern in performance averages does not resolve uncertainty about injury occurrence.

Another statistical issue is the distinction between a reported trial analysis and a recalculation from summary data. The registry identifies a chi-squared analysis, while the posted recalculation supplies an unadjusted effect estimate and interval. Keeping those sources distinct avoids attributing extra analyses to the trial team and helps readers see both the reported test and the size and precision of the observed contrast.

Finally, the record’s missing information is relevant to statistical interpretation, not merely documentation. Without a reported analysis plan, missing-data approach, original sample-size justification, and multiplicity strategy, it is difficult to judge how the analyses were selected and how fully the posted results represent the intended trial analysis. These limitations make careful, restrained interpretation essential.

19. 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 affect interpretation. The primary endpoint is described as the percentage of soldiers with ankle and knee injuries, but the registry does not report the injury definition, event-verification process, or whether injuries were counted by participant or as repeated events. The posted primary results are participant counts, so recurrence, timing, severity, and anatomical detail cannot be assessed from the record.

The outcome counts are reported for fewer participants than the listed enrollment, but participant flow and reasons for the different denominators are not reported in the registry record. The number randomized to each arm is not separately stated, and the analysis population is not identified. This makes it difficult to assess whether the observed groups represent all randomized participants or only those with available outcomes.

Details of the randomization procedure and allocation concealment are not reported. Masking is listed as none, but the record does not specify whether outcome assessors were masked. Because the primary outcome involves injury reporting, the absence of information about ascertainment and verification leaves uncertainty about how consistently events were identified across groups.

The intervention description is incomplete, and the comparator is described only as regular military training. The record therefore does not provide enough detail to reproduce the programs or compare their full training exposure. Participant characteristics and detailed eligibility criteria are also not reported, limiting assessment of generalizability.

The original sample-size rationale, statistical analysis plan, handling of missing data, interim analyses, and multiplicity approach are not reported in the registry record. The secondary results have no sponsor-reported analyses in the record, and their unadjusted status limits confirmatory interpretation. These gaps do not negate the posted observations, but they restrict assessment of precision, bias, and the degree to which analyses followed a prespecified plan.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Prevention of Musculoskeletal Injuries in Slovenian Armed Forces — NCT03415464.
• Registry record last updated 2023-02-23; status last verified 2023-02.
• Results first posted 2023-02-23.
• 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.

23. Record Summary

The completed randomized, parallel-group trial compared a 15-week functional-training program with regular military training in Slovenian Armed Forces personnel. The primary endpoint was ankle and knee injury occurrence over 1 year. The posted primary counts were 1 of 64 participants in functional training and 3 of 41 in regular army training. The registry reports a chi-squared p-value of 0.134; the unadjusted recalculation gives p = 0.133, with an interval for the risk difference that crosses no difference.

Three secondary physical-performance outcomes were reported at 15 weeks. Their overall pattern includes higher group averages for two measures in functional training and the same average for one measure. No sponsor inferential analyses for these outcomes are reported. The registry also records zero serious and zero other adverse events in both groups.

Important details—including the original sample-size justification, missing-data methods, analysis population, multiplicity strategy, injury ascertainment, and full training descriptions—are not reported in the registry record. The primary comparison is therefore best read as an uncertain estimate based on a small number of recorded injury events, alongside secondary outcomes that do not settle the injury question.