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OpenTrials
Completed

NCT Number: NCT06924775

Jump Rope Training and Shoulder Isokinetics in CrossFit

The goal of this quasi-experimental clinical trial is to evaluate whether weighted jump rope (WJR) training can improve the isokinetic shoulder strength profile in male and female CrossFit practitioners.

The main questions it aims to answer are:

* Does six weeks of WJR training affect internal and external shoulder rotational peak torque relative to body mass? * Does WJR influence the external/internal shoulder rotation ratio in dominant and non-dominant arms at varying angular velocities? Researchers will compare pre- and post-intervention isokinetic measurements to see if WJR training leads to significant changes in shoulder strength and balance.

Participants will:

* Incorporate WJR sessions three times per week into their usual CrossFit training. * Undergo isokinetic testing of both shoulders at baseline and post-intervention at 60°/s, 180°/s, and 300°/s. * Have their training adherence and technique monitored throughout the study.

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Key information

Conditions

Evaluation of the Effects of Weighted Jump Rope Training on the Isokinetic Shoulder Profile in CrossFit Practitioners

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Human Movement Analysis Laboratory

Viña del Mar, V región/Valparaíso, 2340000, Chile

About this study

Model: Single Group

Model Description:

This study followed a single-arm, quasi-experimental pre-post design in which all participants underwent the same intervention: six weeks of weighted jump rope (WJR) training, integrated into their regular CrossFit routines. The intervention's impact on isokinetic shoulder strength variables was assessed by comparing pre- and post-intervention measures within the same group of participants.

Number of Arms

1, Only one group received the intervention-there was no control or comparator group.

Masking Outcomes Assessor.

Masking Description:

Due to the nature of the physical intervention (WJR training), blinding participants and care providers was not feasible. However, outcome assessors conducting the isokinetic tests were blinded to the study's hypotheses and group allocations to reduce measurement bias.

Allocation N/A. Participants were not randomly assigned but instead enrolled in a single group to undergo the same intervention protocol.

Enrollment 18 participants

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • self-reported CrossFit training experience. Accordingly, participants were classified into one of three categories (Torres-Banduc et al., 2021): advanced level (≥36 months of regular training, defined as ≥3 sessions of ≥120 minutes per week); intermediate level (12 to <36 months); and beginner level (6 to <12 months).
  • no injuries in the three months preceding the study.

Exclusion criteria

  • musculoskeletal issues impacting muscle strength or the ability to undergo isokinetic shoulder evaluation.
  • self-reported use of anabolic steroids or other prohibited substances that might influence the study results.

Treatment and study plan

Weighted jump rope training

Other

Unlike isolated jump rope studies, this intervention was embedded within the participants' habitual CrossFit routine, enhancing ecological validity. Performing the jump rope protocol immediately prior to regular training-rather than as a stand-alone session-was intended to promote warm-up and neuromuscular priming benefits. The use of a weighted rope introduced a resistance stimulus that is rarely incorporated in jump rope interventions.

Primary outcomes

  1. Rotational peak torque relative to body mass

    Time frame: From enrollment to the end of wieghted jump rope training protocol at 6 weeks

    This variable represents the highest muscular force produced during a shoulder rotation movement, normalized to the participant's body mass (expressed in Nm/kg). It was measured using an isokinetic dynamometer, which quantifies muscle torque under controlled speed and resistance conditions. Participants performed maximal effort shoulder rotations to the left and right at a standardized angular velocity, with proper stabilization to isolate shoulder movement. Normalizing torque to body mass allows comparisons between individuals of different sizes and helps assess the relative strength of the shoulder rotator muscles. Higher values indicate greater rotational strength relative to body weight, which is important for upper limb performance and injury prevention.

Sponsors and collaborators

Lead sponsor

University of Americas

Other

Registry information

Official study title

Impact of Jump Rope Training on the Isokinetic Shoulder Profile in CrossFit Practitioners

Important dates

Study start
2022
Primary completion
2023
Study completion
2023
First posted
Apr 11, 2025
Registry last updated
Apr 11, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.