Influence of Elastic Tape on Activation of the Quadriceps Muscle During Selected Resisted and Weight Bearing Exercises: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Influence of Elastic Tape on Activation of the Quadriceps Muscle During Selected Resisted and Weight Bearing Exercises (NCT02318264), a randomized na study. The primary outcome is Vertical Jump Height Immediately Post Tape Administration.

2. Clinical Question

3. Trial Design

This was a randomized, double-masked, crossover study, marked as completed in the registry record. The study concerned elastic kinesiology tape and quadriceps activation during selected resisted and weight-bearing exercises. The listed condition also includes healthy subjects, changes based on duration of tape application, and direction of tape application. The record identifies Kinesio Tape as a device intervention and lists two tape-direction conditions.

In the distal-to-proximal condition, tape was applied from near the knee toward the hip. In the proximal-to-distal condition, application ran from near the hip toward the knee. Enrollment was 15. The outcome summaries list 15 observations for each condition. Since this is a crossover design, conditions are not simply two unrelated groups by design; however, the registry record does not give the sequence assignment, washout procedure, or participant-level pairing details. Those details are not reported in the registry record.

The primary outcome was vertical jump height immediately after tape administration. The record reports the outcome in centimeters as a mean and standard deviation. Other listed outcomes concern electromyographic activity during isokinetic testing at 120 and 60 degrees per second, and isokinetic torque at those speeds, immediately after tape administration. The record lists four secondary outcomes, but it does not provide posted results for them in the registry record presented for this analysis.

The study start is recorded as 2015-02 and primary completion as 2016-05. The sponsor is State University of New York - Upstate Medical University. The phase is listed as NA. Details of the original statistical plan, including how the crossover structure was intended to enter the analysis, 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.

Before assignment: This is a crossover design. There were 15 subjects in total.

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 Vertical Jump Height Immediately Post Tape Administration, measured over Immediate.

Vertical jump height immediately after tape administration is the primary endpoint. It is a continuous measure recorded in centimeters. A vertical jump provides a performance measure related to the study’s interest in quadriceps activity during exercise; it captures an observable task outcome rather than directly measuring electrical muscle activation. The registry record’s stated study aim includes activation speed and amplitude during selected resisted and weight-bearing exercises, while jump height is the posted primary endpoint.

The registry record summarizes jump height using a mean and standard deviation. The mean describes the central value of the measurements, while the standard deviation describes their spread around that mean. These summaries give a sense of both typical observed performance and variation among observations, but they do not show the full distribution or the within-participant pairing that can matter in a crossover study.

The timeframe is immediate after tape administration. This endpoint therefore speaks to the recorded immediate measurement, not to a lasting response or outcomes at later follow-up. The record does not specify a clinically important difference for jump height, nor does it explain how the endpoint was selected or how its measurement was standardized. Those details are not reported in the registry record.

7. Results Posted in the Registry

• Proximal to Distal Tape: mean 41.10 versus 41.60 on control; difference -0.50 (95% CI -13.07 to 12.07), standardized effect d = -0.03; z-test p = 0.938.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is continuous: vertical jump height measured in centimeters. For a continuous outcome, a group mean offers a compact description of the central tendency, and a standard deviation describes the dispersion of individual measurements around that mean. Neither statistic shows the shape of the outcome distribution. The distal-to-proximal mean is 41.6 with a standard deviation of 18.3; the proximal-to-distal mean is 41.1 with a standard deviation of 16.8.

What does the mean difference represent?

The reported contrast is a mean difference of -0.5 centimeters, calculated as the proximal-to-distal mean relative to the distal-to-proximal mean. A negative sign indicates that the first named condition in that contrast has the lower posted mean. The estimate is an unadjusted comparison of summary statistics. It is not an estimate adjusted for other participant characteristics or for features of the crossover design, since such adjustments are not described in the registry record.

A standardized effect expresses the contrast in relation to the variability of the outcome, which can help describe its scale independently of the measurement unit. The recalculated standardized effect is -0.029. This quantity remains a descriptive summary of the observed contrast; it does not add information about participant-level pairing or prove that the underlying effect is exactly zero.

What does the p-value tell us?

The unadjusted p-value is 0.938. In general, a p-value describes how unusual the observed data, or data more extreme, would be under a specified null model and its assumptions. It is not the probability that the null hypothesis is true. It also does not measure clinical importance or the probability that a result will replicate. The registry record does not report the model or full inferential procedure that generated a sponsor analysis; the p-value in this statistical account is an unadjusted recalculation from the posted summaries.

A high p-value does not establish that two conditions are equivalent. Equivalence requires a prespecified margin defining differences small enough to count as practically unimportant, together with an analysis designed to assess that margin. Such a margin and an equivalence analysis are not reported in the registry record.

Why is the crossover structure important?

In general, crossover designs compare conditions within the same participants. When outcomes under two conditions from one participant are correlated, a paired analysis can use that relationship. The variability of within-participant differences can therefore differ from the variability implied by treating condition summaries as independent. The registry record identifies the study as a crossover, but the posted summaries do not include paired differences or their standard deviation. The recalculated contrast is consequently a simple unadjusted summary-based comparison, not a reported crossover-model result.

Potential period, sequence, or carryover effects can also be relevant in crossover studies, depending on the design and conduct. The sequence details, washout information, and analysis of these effects are not reported in the registry record. Their role in this study cannot be determined from the available record.

What does the standard deviation add?

The standard deviations, 18.3 and 16.8 centimeters, describe substantial variation in observed jump heights relative to the small difference between the means. A standard deviation is not the same as a standard error or confidence interval: it describes variation among measurements, while uncertainty in an estimated mean or contrast depends on sample size and analysis design as well. In a crossover design, paired variability is particularly relevant to the contrast, and it is not available in the posted summaries.

In general, over-dispersion means that observed variability exceeds what a chosen statistical model expects. It can make model-based standard errors and tests unreliable if not handled appropriately. The registry record does not report a model diagnostic or an over-dispersion assessment for this continuous endpoint. This concept is therefore relevant as a general statistical consideration, not as a finding about this study.

What is and is not reported?

The registry record reports the endpoint, timeframe, summary means, standard deviations, and sample counts. It does not report the original sample-size justification, statistical analysis plan, primary-outcome analysis population, missing-data method, or details of any interim analysis. It lists four secondary outcomes, while the numerical results for those outcomes are not reported in the registry record. These omissions limit assessment of prespecification, analysis choices, and the completeness of outcome reporting.

10. Confidence Intervals and Precision

The confidence interval for the unadjusted mean difference extends from -13.07 to 12.07 centimeters. It includes zero, so the interval does not isolate a single direction of difference. The point estimate, -0.5 centimeters, lies close to zero, but the interval is much wider than the point estimate. This means the data do not estimate the contrast with high precision.

In general, a confidence interval is a range of values generated by a method that, under its assumptions and repeated use, has a stated coverage property. It conveys uncertainty about the estimated contrast more directly than a p-value alone. It is not a range containing a known proportion of individual participant outcomes, and it does not mean that every value inside it is equally plausible.

The interval is an unadjusted recalculation based on posted summary statistics. The record identifies a crossover design, but does not provide paired observations or a paired standard deviation. The interval therefore should not be interpreted as a crossover-specific interval. If within-participant correlation is important, an analysis using the pairing could have a different estimate of uncertainty. Whether it would be narrower or wider cannot be determined from the registry record.

The record does not give a clinically important difference or an equivalence margin for jump height. As a result, the interval cannot be classified against a registry-defined threshold for a meaningful difference. Its width makes clear that the near-zero point estimate should not be treated as a precise estimate of no difference.

11. 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 events. The planning illustration uses a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It considers effects equal to 100%, 75%, and 50% of the observed effect. These are planning scenarios based on the observed effect, not the original trial’s design assumptions; the original sample-size assumptions are not reported in the registry record.

For 100% of the observed effect, the illustration gives 19,376 participants per arm for 80% power and 25,938 participants per arm for 90% power. For 75% of the observed effect, it gives 34,445 participants per arm for 80% power and 46,112 participants per arm for 90% power. For 50% of the observed effect, it gives 77,501 participants per arm for 80% power and 103,752 participants per arm for 90% power.

In plain terms, the 80% power column describes a planned chance of detecting the specified effect under the calculation’s assumptions if that effect is present; the 90% column uses a higher target chance. Smaller effects require more participants under these assumptions, as reflected by the rising planning counts when the target is a smaller fraction of the observed effect. Because the observed mean difference is close to zero, these illustrations produce very large counts. This is not observed power and does not describe the chance that the completed study detected an effect.

12. 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 = -0.500; pooled standard deviation σ = 17.566.
2. n = 2 × (1.96 + 0.842)² × 17.566² / -0.500² = 19,375.1, rounded up to 19,376 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 <- -0.5                      # observed difference in means
sigma <- 17.5660183308569                     # 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(2318264)
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 = 19,376 (80% power), 25,938 (90% power)
 75% of observed effect: n per arm = 34,445 (80% power), 46,112 (90% power)
 50% of observed effect: n per arm = 77,501 (80% power), 103,752 (90% power)
power.t.test: 19376.1 
Simulated power at n = 19,376 per arm: 0.800 (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.

13. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary endpoint, vertical jump height immediately after tape administration, and four secondary outcomes. The secondary outcomes concern electromyographic activity and isokinetic torque at two testing speeds. Their numerical results are not reported in the registry record. The record does not describe whether outcomes were tested as a family, whether multiplicity adjustment was planned, or how any ordering among outcomes was to be handled.

In general, conducting several statistical tests can increase the chance of obtaining at least one apparently notable result by chance. Prespecified outcome hierarchies or multiplicity adjustments can address that issue, but the record does not state that either approach was used. The p-value discussed for jump height is unadjusted and should not be interpreted as adjusted for the listed secondary outcomes.

The registry record does not report a missing-data method or state how many participants contributed complete primary-outcome measurements beyond the listed observations for each condition. It also does not specify an analysis population, such as whether all randomized participants or only participants with complete measurements were to be analyzed. The enrollment is 15, and each condition summary lists 15 observations, but these counts alone do not describe missingness handling or confirm the intended analysis population.

Although the study is identified as a crossover, the registry record does not state how incomplete participant pairs, period effects, sequence effects, or potential carryover were handled. It also does not report an original statistical analysis plan or interim-analysis plan. These missing details limit assessment of whether the reported outcome summaries follow prespecified methods and whether all relevant uncertainty was accounted for.

14. 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 record reports zero serious adverse events among 15 participants at risk in the distal-to-proximal tape condition and zero among 15 at risk in the proximal-to-distal condition. It also reports zero other adverse events in each condition and zero deaths. No serious adverse-event terms are listed.

These figures describe events recorded in the registry, not proof that no adverse events occurred outside the reporting captured there. With no reported events, the record cannot characterize the type or frequency of uncommon events, and it does not establish safety. The crossover design also means the condition-specific at-risk counts should be read in the context of participants exposed to each condition; they should not be added as if they necessarily represented separate people. The registry record does not provide further detail about adverse-event collection or attribution.

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

The posted results show similar mean vertical jump heights for the two tape directions: 41.6 centimeters for distal-to-proximal application and 41.1 centimeters for proximal-to-distal application. The unadjusted estimated difference is -0.5 centimeters. This describes the observed summaries for the immediate endpoint; it does not establish that the directions are equivalent or that the true difference is zero.

The confidence interval, from -13.07 to 12.07 centimeters, is broad and includes differences in either direction. The result is therefore uncertain in magnitude. The unadjusted p-value of 0.938 does not provide evidence of a difference under the simple comparison, but a non-small p-value is not proof of no effect. Interpretation also depends on the statistical structure of the crossover, for which paired data and analysis details are not reported in the registry record.

The primary endpoint is jump height, not a direct measure of electrical activation. The study’s stated aim includes activation during selected exercises, and the registry lists four related secondary outcomes, but their numerical results are not reported in the registry record. No conclusion about those outcomes follows from the primary endpoint summary alone.

The result is limited to the immediate post-application measurement and the two tape directions tested among the healthy subjects described in the registry record. It does not address long-term outcomes, other populations, or comparisons with no tape. No treatment recommendation follows from these data. The record also does not report a threshold for a meaningful difference in jump height, so the practical importance of a difference within the confidence interval cannot be judged against a prespecified criterion.

16. Why This Trial Matters Statistically

This trial illustrates why a point estimate and its uncertainty need to be read together. The mean difference is -0.5 centimeters, close to zero, but the confidence interval extends from -13.07 to 12.07 centimeters. A small point estimate alone can look conclusive when it is not precise enough to exclude meaningfully different values. The interval communicates that uncertainty directly.

The crossover designation is also statistically consequential. In general, measurements from the same person under different conditions may be correlated. A paired analysis can use that dependence, whereas a comparison based only on separate condition summaries cannot reveal it. The registry record’s lack of paired data and crossover-specific analysis details therefore matters for judging the precision of the contrast.

The study also distinguishes the stated scientific interest from the posted primary endpoint. Quadriceps activation is central to the study aim, while vertical jump height is the primary reported measure. The listed activation and torque outcomes could address different aspects of the question, but their numerical results are not reported in the registry record. A reader should avoid treating the jump-height result as a direct result for every listed outcome.

Finally, the planning illustration shows how sample-size requirements depend strongly on the effect targeted. Its large figures arise from planning around a very small observed contrast and should not be confused with the trial’s original design or with observed power. The original sample-size justification is not reported in the registry record. Together, these features underscore the importance of prespecified analysis methods, outcome reporting, and uncertainty intervals when interpreting small clinical studies.

17. 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 registry record describes a crossover design but does not provide the sequence, period structure, washout details, or participant-level paired outcomes. The reported means and standard deviations cannot show the within-participant variability needed to assess a paired contrast. The unadjusted recalculation therefore does not capture all design information that may matter for precision.

The enrollment is 15, with 15 observations reported for each tape direction. This is a limited amount of information for estimating a continuous outcome with the observed variability. The confidence interval is correspondingly broad, and the registry record does not state an original sample-size justification or a clinically important difference for jump height.

The outcome is measured immediately after tape administration. No later primary-outcome timepoint is listed, so the reported result does not address persistence. The registry record does not specify the detailed measurement protocol for jump height, participant characteristics beyond healthy subjects, or whether all randomized participants were included in the analysis.

Four secondary outcomes are listed, but their numerical findings are not reported in the registry record. The record also does not state the multiplicity approach, missing-data method, or full statistical analysis plan. These omissions limit evaluation of outcome completeness and analytic choices. The posted adverse-event counts are zero in both conditions, but details of event ascertainment and attribution are not reported. These limitations constrain how broadly the immediate mean comparison can be interpreted.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Influence of Elastic Tape on Activation of the Quadriceps Muscle During Selected Resisted and Weight Bearing Exercises — NCT02318264.
• Registry record last updated 2022-06-14; status last verified 2022-05.
• Results first posted 2022-05-19.
• 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.

21. Record Summary

NCT02318264 is a completed randomized, double-masked crossover study of Kinesio Tape applied to the quadriceps in distal-to-proximal or proximal-to-distal directions. Enrollment was 15, and the registry record describes healthy subjects. The primary endpoint was vertical jump height immediately after tape administration, measured in centimeters.

The posted means were 41.6 with a standard deviation of 18.3 for distal-to-proximal tape and 41.1 with a standard deviation of 16.8 for proximal-to-distal tape. The unadjusted recalculated mean difference was -0.5 centimeters, with a confidence interval from -13.07 to 12.07 and an unadjusted p-value of 0.938. The record lists four secondary outcomes, but their results, paired crossover analysis details, and original sample-size justification are not reported in the registry record.