Acute Changes in Gastrocnemius Muscle Stiffness

July 30, 2026 updated by: Monira Aldhahi, Princess Nourah Bint Abdulrahman University

Acute Changes in Gastrocnemius Muscle Stiffness Following Different Work-Rest Calf-Raise Protocols and Percussive Therapy: A Randomized Crossover Experimental Study

This study evaluated how different exercise and rest schedules during calf-raise exercise affected the stiffness of the calf muscle in trained volleyball athletes. It also examined how muscle stiffness changed during a five-minute recovery period in which percussive therapy was applied.

Thirty volleyball athletes, including 15 women and 15 men, completed three exercise sessions in a randomized order. During each session, participants performed repeated calf raises for a total period of five minutes using one of three work-to-rest schedules: 30 seconds of exercise followed by 30 seconds of rest, 15 seconds of exercise followed by 45 seconds of rest, or 45 seconds of exercise followed by 15 seconds of rest.

The stiffness of the medial gastrocnemius, one of the main calf muscles, was measured using shear-wave elastography. Measurements were taken before exercise, immediately after exercise, and after the five-minute percussive therapy recovery period.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

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Detailed Description

This randomized, three-period crossover study examined the acute effects of different work-to-rest configurations during a standardized bilateral calf-raise exercise on medial gastrocnemius stiffness in trained volleyball athletes.

Thirty participants, comprising 15 women and 15 men, completed three experimental sessions in a computer-generated randomized order. Sessions were separated by at least 48 hours and were conducted at approximately the same time of day for each participant to reduce the effects of fatigue, carryover, and daily variation. Before data collection, participants completed a familiarization session.

Each experimental session lasted five minutes and included one of the following work-to-rest configurations:

30 seconds of calf raises followed by 30 seconds of rest; 15 seconds of calf raises followed by 45 seconds of rest; or 45 seconds of calf raises followed by 15 seconds of rest.

The exercise cadence was standardized at one repetition per second using a metronome. Participants performed the calf raises barefoot, with their feet approximately shoulder-width apart and their hands placed on their hips. The total session duration was the same for all conditions, while the amount and distribution of exercise and rest differed between protocols.

Medial gastrocnemius stiffness was assessed bilaterally using shear-wave elastography. Measurements were obtained before exercise, immediately after completion of the calf-raise protocol, and after a standardized five-minute recovery period involving percussive therapy. Three elastography acquisitions were recorded for each leg at each assessment and were averaged for analysis.

Percussive therapy was applied to both medial gastrocnemius muscles using a Theragun PRO device with a spherical attachment at approximately 1,750 percussions per minute. Each leg received two 60-second applications separated by 30 seconds of rest. The same experienced researcher administered the intervention and performed the measurements during all sessions.

The primary analysis evaluated changes in shear-wave velocity across the three measurement times and compared those changes among the three exercise protocols. Limb side and participant sex were also examined as exploratory factors.

The primary hypothesis was that the protocol containing 45 seconds of exercise and 15 seconds of rest would produce the greatest immediate increase in gastrocnemius stiffness because it had the highest work density. A secondary objective was to examine whether stiffness decreased toward baseline during the subsequent percussive therapy recovery period.

No sham percussive therapy or passive recovery condition was included. Therefore, changes between the immediate post-exercise and final assessments were interpreted as recovery occurring during the percussive therapy period and not as definitive evidence of an isolated treatment effect

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

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Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Male or female volleyball athlete aged 18 to 30 years.
  • Competing at university or club level.
  • At least 3 years of structured volleyball training experience.
  • Participating in volleyball training at least 3 times per week.
  • Body mass index between 18.5 and 27.0 kg/m².
  • No lower-limb musculoskeletal injury during the previous 6 months.
  • No known neuromuscular or systemic disorder.
  • No use of anti-inflammatory, analgesic, or muscle-relaxant medication during the week before testing.

Exclusion Criteria:

  • Failure to attend or complete any of the three experimental sessions.
  • Performance of vigorous exercise within 24 hours before a testing session.
  • Occurrence of an adverse event that prevented adherence to or completion of the study protocol.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: 30-Second Work / 30-Second Rest Protocol
Participants performed bilateral calf raises for 30 seconds followed by 30 seconds of rest, repeated over a total protocol duration of 5 minutes. Calf raises were performed at one repetition per second. Gastrocnemius shear-wave elastography measurements were obtained before exercise, immediately after exercise, and after the standardized 5-minute percussive therapy recovery period.
Behavioral: 30-Second Work / 30-Second Rest Calf-Raise Protocol
Participants performed bilateral standing calf raises for 30 seconds, followed by 30 seconds of rest. The work-rest cycle was repeated over a total protocol duration of 5 minutes. Calf raises were performed barefoot at a standardized cadence of one repetition per second using a metronome, with the feet shoulder-width apart and the hands positioned on the hips.
Experimental: 15-Second Work / 45-Second Rest Protocol
Participants performed bilateral calf raises for 15 seconds followed by 45 seconds of rest, repeated over a total protocol duration of 5 minutes. Calf raises were performed at one repetition per second. Gastrocnemius shear-wave elastography measurements were obtained before exercise, immediately after exercise, and after the standardized 5-minute percussive therapy recovery period.
Behavioral: 15-Second Work / 45-Second Rest Calf-Raise Protocol
Participants performed bilateral standing calf raises for 15 seconds, followed by 45 seconds of rest. The work-rest cycle was repeated over a total protocol duration of 5 minutes. Calf raises were performed barefoot at a standardized cadence of one repetition per second using a metronome, with the feet shoulder-width apart and the hands positioned on the hips.
Experimental: 45-Second Work / 15-Second Rest Protocol
Participants performed bilateral calf raises for 45 seconds followed by 15 seconds of rest, repeated over a total protocol duration of 5 minutes. Calf raises were performed at one repetition per second. Gastrocnemius shear-wave elastography measurements were obtained before exercise, immediately after exercise, and after the standardized 5-minute percussive therapy recovery period.
Behavioral: 45-Second Work / 15-Second Rest Calf-Raise Protocol
Participants performed bilateral standing calf raises for 45 seconds, followed by 15 seconds of rest. The work-rest cycle was repeated over a total protocol duration of 5 minutes. Calf raises were performed barefoot at a standardized cadence of one repetition per second using a metronome, with the feet shoulder-width apart and the hands positioned on the hips.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Mean Change in Medial Gastrocnemius Shear-Wave Velocity
Time Frame: Baseline, immediately after each 5-minute calf-raise protocol, and after the subsequent 5-minute percussive therapy recovery period, during each of 3 sessions separated by at least 48 hours.
Medial gastrocnemius stiffness was assessed bilaterally using shear-wave elastography and reported as shear-wave velocity in meters per second (m/s), with higher values indicating greater stiffness. Three acquisitions were obtained for each leg at each time point and averaged. Mean changes were evaluated within each work-to-rest protocol from baseline to immediately after exercise, from immediately after exercise to after the percussive therapy recovery period, and from baseline to after recovery.
Baseline, immediately after each 5-minute calf-raise protocol, and after the subsequent 5-minute percussive therapy recovery period, during each of 3 sessions separated by at least 48 hours.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Princess Nourah Bint Abdulrahman University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 24, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 24, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 24, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 30, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 30, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 4, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 4, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 30, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • PNU-14

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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