Jump Rope Training and Shoulder Isokinetics in CrossFit

NCT06924775 | Completed

• 1 other identifier: 23/2022
• Study Type: interventional
• Target: 18
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

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

Keywords

Isokinetic shoulder profile; Weighted jump rope training; Rotational peak torque; Muscle imbalance; Injury prevention; CrossFit

Outcome Measures

Primary Outcomes (1)

• Rotational peak torque relative to body mass

  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.

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

Study Arms (1)

Weighted jump rope training group

EXPERIMENTAL

A progressive six-week jump rope protocol focusing on simple unders was completed three times per week, individually or in groups, before regular sessions. Training was supervised by final-year kinesiology students. Based on Duzgun et al. (2010), jumps increased weekly: Week 1-D1: 6×25, D2: 3×50, D3: 4×50 (500 total); Week 2-4×50, 4×75, 4×50 (750); Week 3-4×75, 4×75, 4×100 (1000); Week 4-6×75, 6×75, 5×70 (1250); Week 5-5×100, 4×150, 4×100 (1500); Week 6-5×150, 6×100, 4×100 (1750). Rest between sets: 1 min. Participants were advised to avoid prior intense activity, maintain steady pace, and received positive reinforcement as needed.

Other: Weighted jump rope training

Interventions

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.

Weighted jump rope training group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• University of Americas: lead

Study Sites (1)

Human Movement Analysis Laboratory

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

Location

Related Publications (3)

• Torres-Banduc MA, Jerez-Mayorga D, Moran J, Keogh JWL, Ramirez-Campillo R. Isokinetic force-power profile of the shoulder joint in males participating in CrossFit training and competing at different levels. PeerJ. 2021 Sep 17;9:e11643. doi: 10.7717/peerj.11643. eCollection 2021.

  PMID: 34616590 BACKGROUND

• Duzgun I, Baltaci G, Colakoglu F, Tunay VB, Ozer D. The effects of jump-rope training on shoulder isokinetic strength in adolescent volleyball players. J Sport Rehabil. 2010 May;19(2):184-99. doi: 10.1123/jsr.19.2.184.

  PMID: 20543219 BACKGROUND

• Torres-Banduc MA, Thapa RK, Perez MA, Ramirez-Campillo R. Isokinetic shoulder strength adaptations to weighted jump rope training in CrossFit athletes: A pre-post study. Shoulder Elbow. 2025 Dec 30:17585732251409407. doi: 10.1177/17585732251409407. Online ahead of print.

  PMID: 41479676 DERIVED

Study Officials

• Maximiliano A. Torres-Banduc, PhD.

  University of Americas

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: SCREENING
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PhD.

Study Record Dates

• First Submitted: April 4, 2025
• First Posted: April 11, 2025
• Study Start: July 30, 2022
• Primary Completion: January 30, 2023
• Study Completion: March 30, 2023
• Last Updated: April 11, 2025

Record last verified: 2025-04

Locations

CL (1)