Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Reliability and Validity

Reliability and Validity

Reliability and validity are two important considerations that must be made with any type of data collection. Reliability refers to the ability to consistently produce a given result. In the context of psychological research, this would mean that any instruments or tools used to collect data do so in consistent, reproducible ways.

Standing Waves

Standing Waves

Sometimes waves do not seem to move; rather, they just vibrate in place. Unmoving waves can be seen on the surface of a glass of milk kept in a refrigerator, which is one example of standing waves. Vibrations from the refrigerator motor create waves on the milk that oscillate up and down but do not seem to move across the surface. These waves are formed or created by the superposition of two or more identical moving waves in opposite directions. The waves move through each other, with their...

Standing Electromagnetic Waves

Standing Electromagnetic Waves

Electromagnetic waves can be reflected; the surface of a conductor or a dielectric can act as a reflector. As electric and magnetic fields obey the superposition principle, so do electromagnetic waves. The superposition of an incident wave and a reflected electromagnetic wave produces a standing wave analogous to the standing waves created on a stretched string.
Suppose a sheet of a perfect conductor is placed in the yz-plane, and a linearly polarized electromagnetic wave traveling in the...

Standing Waves in a Cavity

Standing Waves in a Cavity

A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:

Modes of Standing Waves: II

Modes of Standing Waves: II

The starting point for expressing the modes of standing waves is understanding the boundary conditions that the waves must follow. The boundary conditions are derived from the physical understanding of how the standing waves are sustained, that is, how the vibrating particles of the medium behave at the boundaries imposed on them.
For a tube open at one end and closed at the other filled with air, the modes are such that there is always an antinode at the open end and a node at the closed end....

Modes of Standing Waves - I

Modes of Standing Waves - I

A close look at earthquakes provides evidence for the conditions appropriate for resonance, standing waves, and constructive and destructive interference. A building may vibrate for several seconds with a driving frequency matching the building's natural frequency of vibration; this produces a resonance that results in one building collapsing while the neighboring buildings do not. Often, buildings of a certain height are devastated, while other taller buildings remain intact. This...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Blood Flow at Different Occlusion Pressures Using Multichambered Blood Flow Restriction Cuffs in the Arm and Leg.

Journal of strength and conditioning research·2026

Same author

Sex differences in brachial and superficial femoral artery occlusion pressure.

Current research in physiology·2026

Same author

Measuring Arterial Occlusion Pressure Using Pulse Wave and Continuous Wave Doppler Ultrasound and 2 Methods of Cuff Inflation.

Journal of sport rehabilitation·2025

Same author

Variability Among Individual Male Runners Influences Cumulative Loading More Than Foot Strike Type.

Sports health·2025

Same author

Sticking the landing: A comparison of shod vs barefoot landing kinetics and foot muscle characteristics in gymnasts, cheerleaders, and non-athletes.

PloS one·2024

Same author

Local and non-local effects (on the posterior chain) of four weeks of foot exercises: a randomized controlled trial.

Scientific reports·2024

Search research articles

Related Experiment Video

Updated: Jan 26, 2026

An Instrumented Pull Test to Characterize Postural Responses

An Instrumented Pull Test to Characterize Postural Responses

Published on: April 6, 2019

Validity and Reliability of Standing Posture Measurements Using a Mobile Application.

Breanna Berry Hopkins¹, Pat R Vehrs¹, Gilbert W Fellingham²

¹Department of Exercise Sciences, Brigham Young University, Provo, Utah.

Journal of Manipulative and Physiological Therapeutics

|April 20, 2019

Summary

The PostureScreen Mobile (PSM) app shows bias in assessing standing posture compared to 3D analysis. Head shift measurements were comparable, but caution is advised for accurate postural assessments.

Keywords:

Mobile Applications Posture Standing Position

More Related Videos

Experimental Methods to Study Human Postural Control

Experimental Methods to Study Human Postural Control

Published on: September 11, 2019

Sit-to-stand-and-walk from 120% Knee Height: A Novel Approach to Assess Dynamic Postural Control Independent of Lead-limb

Sit-to-stand-and-walk from 120% Knee Height: A Novel Approach to Assess Dynamic Postural Control Independent of Lead-limb

Published on: August 30, 2016

Related Experiment Videos

Last Updated: Jan 26, 2026

An Instrumented Pull Test to Characterize Postural Responses

An Instrumented Pull Test to Characterize Postural Responses

Published on: April 6, 2019

Experimental Methods to Study Human Postural Control

Experimental Methods to Study Human Postural Control

Published on: September 11, 2019

Sit-to-stand-and-walk from 120% Knee Height: A Novel Approach to Assess Dynamic Postural Control Independent of Lead-limb

Sit-to-stand-and-walk from 120% Knee Height: A Novel Approach to Assess Dynamic Postural Control Independent of Lead-limb

Published on: August 30, 2016

Area of Science:

Biomechanics
Kinesiology
Digital Health

Background:

Accurate standing posture assessment is crucial in clinical settings.
Mobile applications offer potential for accessible postural analysis.
Evaluating the validity of digital tools is essential for reliable data collection.

Purpose of the Study:

To assess the validity and reliability of the PostureScreen Mobile (PSM) iOS application for standing posture evaluation.
To compare PSM measurements against a criterion 3-dimensional analysis system (VICON).

Main Methods:

50 asymptomatic men underwent 3 standing posture trials on the same day.
PostureScreen Mobile (PSM) measurements were compared with VICON 3D analysis.
Bayesian statistical methods were employed for data analysis.

Main Results:

PSM demonstrated bias in frontal plane measurements (head, shoulder, hip tilt/shift) and sagittal plane measurements (shoulder, hip, knee shift).
Head shift in both frontal and sagittal planes showed comparability between PSM and VICON.
Intraclass correlations were similar for 6 out of 10 measurements; PSM showed lower reliability for sagittal head/shoulder measurements.

Conclusions:

The PSM app introduces significant bias in standing postural measurements.
Caution is recommended when using the PSM app for highly accurate postural assessments pending further research.