Effect of the Ultrasound-guided Percutaneous Neuromodulation on the Mean Velocity in Crossfit Practitioners.

EFFECT OF ULTRASOUND-GUIDED PERCUTANEOUS NEUROMODULATION OF THE TRANSVERSUS ABDOMINIS ON THE FORCE-VELOCITY PROFILE DURING THE SQUAT PERFORMANCE IN CROSSFIT PRACTITIONERS

This randomized controlled blinded clinical trial aims to evaluate the effect of ultrasound-guided percutaneous neuromodulation (US-guided PNM) targeting the innervation of the transversus abdominis muscle on squat performance in CrossFit practitioners.

The transversus abdominis is a deep trunk muscle that contributes to lumbopelvic stability and force transmission during functional and athletic movements. Previous research suggests that improving neuromuscular activation of the trunk musculature may enhance movement efficiency and performance during resistance exercises. Ultrasound-guided percutaneous neuromodulation is a minimally invasive technique that applies electrical stimulation through a needle placed close to a peripheral nerve under ultrasound guidance, with the aim of modulating neuromuscular function.

Healthy male and female CrossFit practitioners aged 18 to 60 years, with at least one year of training experience, will participate in the study. Participants will undergo an initial ultrasound assessment of transversus abdominis activation to classify and distribute the sample into groups. In a second session, mean velocity, mean propulsive velocity, and velocity loss during squat performance will be assessed using a linear velocity transducer. Participants will perform 3 sets of 2 repetitions of the squat exercise at 80% of their one-repetition maximum (1RM).

Following baseline assessment, participants will be randomly assigned to either an experimental group receiving ultrasound-guided percutaneous neuromodulation of the iliohypogastric and ilioinguinal nerves, or a sham group receiving needle insertion without electrical stimulation. The intervention will consist of a TENS-type current applied at 10 Hz for 10 cycles of 10 seconds. Squat performance variables will be reassessed immediately after the intervention.

The purpose of this study is to determine whether US-guided percutaneous neuromodulation can acutely improve squat performance in trained CrossFit practitioners. The study hypothesis is that participants receiving active neuromodulation will demonstrate greater improvements in squat execution velocity and lower velocity loss compared with participants receiving the sham intervention.

Study Overview

• Status: Not yet recruiting
• Conditions: Healthy Adult Participants; Crossfit
• Intervention / Treatment: Other: ultrasound-guided percutaneous neuromodulation; Other: ultrasound-guided percutaneous neuromodulation (sham)

Detailed Description

CrossFit training requires the integration of strength, power, trunk stability, and efficient force transmission during complex multi-joint movements. The back squat is one of the most frequently used exercises in CrossFit and is commonly applied to assess lower-limb performance through force-velocity profiling. Variables such as mean velocity, mean propulsive velocity, and velocity loss between sets provide relevant information regarding neuromuscular performance and fatigue resistance.

The transversus abdominis is a deep abdominal muscle involved in trunk stabilization and lumbopelvic control. Adequate activation of this muscle may contribute to improved force transmission between the lower and upper extremities during strength exercises. Ultrasound-guided percutaneous neuromodulation (UGPNM) is an invasive physiotherapy technique that delivers electrical stimulation through a needle placed near a peripheral nerve under ultrasound guidance. This intervention has been proposed as a method to modulate neuromuscular function and potentially enhance motor performance.

Despite the increasing use of ultrasound-guided percutaneous neuromodulation in clinical and sports settings, evidence regarding its immediate effects on sport performance variables remains limited. In particular, the influence of neuromodulation targeting the innervation of the transversus abdominis on force-velocity profile characteristics during the squat has not been thoroughly investigated.

The objective of this randomized controlled trial is to evaluate the immediate effects of ultrasound-guided percutaneous neuromodulation of the nerves supplying the transversus abdominis on mean velocity during the back squat in CrossFit practitioners. Secondary outcomes include mean propulsive velocity, fatigue resistance assessed through velocity loss between sets, perceived exertion, and potential differences in response according to baseline transversus abdominis activation capacity.

A total of 42 healthy CrossFit practitioners, both male and female, aged 18 to 60 years with at least one year of training experience, will be recruited. During baseline assessment, participants will undergo ultrasound evaluation of the transversus abdominis muscle at rest and during voluntary contraction. Muscle thickness will be measured in both conditions, and the percentage of activation will be calculated based on the relative change in thickness. Participants will then be classified into higher and lower activation subgroups according to the median value of transversus abdominis activation.

Following this classification, participants will be randomly allocated to either the experimental or sham group using block randomization performed with R statistical software, ensuring balanced distribution of activation levels between groups.

A blinded randomized controlled design with third-party outcome assessment will be used. Outcome assessments will be performed by a blinded evaluator responsible for ultrasound measurements of transversus abdominis thickness and for collecting squat performance variables obtained via a linear velocity transducer. The evaluator will not be involved in the randomization process and will remain unaware of group allocation throughout the study.

A separate clinician, not involved in outcome assessment, will administer either the active ultrasound-guided percutaneous neuromodulation intervention or the sham procedure. Participants will remain blinded to treatment allocation throughout the study.

The baseline performance assessment will include squat testing using a linear velocity transducer. Participants will perform three sets of two repetitions at 80% of their individual one-repetition maximum (1RM), following a standardized warm-up. Mean velocity, mean propulsive velocity, velocity loss, and rating of perceived exertion will be recorded.

The experimental intervention will consist of ultrasound-guided percutaneous neuromodulation applied to the iliohypogastric and ilioinguinal nerves using electrical stimulation at 10 Hz in 10-second cycles. The sham condition will involve identical needle insertion without electrical stimulation. Immediately after the intervention, all performance variables will be reassessed under identical testing conditions.

This study aims to determine whether ultrasound-guided percutaneous neuromodulation can produce immediate improvements in squat performance variables and whether baseline transversus abdominis activation capacity influences the response to the intervention.

• Study Type: Interventional
• Enrollment (Estimated): 42
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Paco N Navarro Pastor, Physiotherapist; Phone Number: +34 685536102; Email: navarropastorpaco@gmail.com

Study Locations

• Spain
  • Murcia
    • Murcia, Murcia, Spain, 30007
      • Fisiosport premium SL
      • Contact: Francisco N Navarro Pastor, Physiotherapist; Phone Number: +34 685536102; Email: navarropastorpaco@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age between 18 and 60 years
• At least 1 year of CrossFit training experience
• Training frequency between 2 and 6 sessions per week

Exclusion Criteria:

• Belonephobia (fear of needles)
• Presence of cardiac conditions or implanted cardiac devices (e.g., pacemaker)
• Pregnancy
• Active oncological process
• Skin conditions or lesions in the intervention area
• Neurological or neurosensory disorders
• Epilepsy
• Current febrile condition
• Recent use of antibiotics
• Treatment with anticoagulant medication
• Use of medications that may affect physical performance
• Autoimmune diseases or use of immunosuppressive therapy
• Active lumbar or abdominal pathology
• Recent lumbar surgery or operations related to the intervention area
• Active musculoskeletal injury or pain affecting squat technique or -performance
• Undiagnosed pain affecting execution of the sporting movement.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: ultrasound-guided percutaneous neuromodulation; The patients will receive ultrasound-guided percutaneous neuromodulation of the iliohypogastric and ilioinguinal nerves using electrical stimulation at 10 Hz in 10-second cycles.	Other: ultrasound-guided percutaneous neuromodulation; The intervention will be applied using ultrasound-guided percutaneous neuromodulation of the iliohypogastric and ilioinguinal nerves. The procedure will be performed under ultrasound guidance using a sterile percutaneous needle. In the experimental group, electrical stimulation will be delivered through the needle at a frequency of 10 Hz in 10-second cycles. Stimulation intensity will be adjusted according to participant tolerance, without exceeding the pain threshold.
Sham Comparator: Ultrasound-guided percutaneous neuromodulation (sham); The patients will receive a sham ultrasound-guided percutaneous neuromodulation procedure involving identical needle insertion under ultrasound guidance without electrical stimulation	Other: ultrasound-guided percutaneous neuromodulation (sham); The sham intervention consists of an ultrasound-guided percutaneous needle insertion performed in the same anatomical region as the experimental procedure (iliohypogastric and ilioinguinal nerves), using identical positioning and procedural setup. No electrical stimulation is delivered through the needle at any point during the procedure. The duration and handling of the procedure are matched to the experimental condition to ensure participant blinding.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean Velocity during Back Squat (Linear Velocity Transducer)	Mean velocity will be measured using a linear position transducer attached to the barbell during the back squat exercise. This device records bar displacement over time and allows calculation of bar velocity during the concentric phase of each repetition. The mean velocity of each repetition will be recorded, and the average across repetitions and sets will be used for analysis.	Baseline assessment (pre-intervention) and immediately after the intervention (post-intervention, same session).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean Propulsive Velocity during Back Squat (Linear Velocity Transducer)	Mean propulsive velocity will be measured using a linear position transducer attached to the barbell during the back squat exercise. Mean propulsive velocity corresponds to the average bar velocity during the propulsive phase of the concentric movement, from the start of the upward movement until bar acceleration falls below gravitational acceleration. The average value across repetitions and sets will be used for analysis.	Baseline assessment (pre-intervention) and immediately after the intervention (post-intervention, same session).
Velocity Loss Between Sets during Back Squat (Linear Velocity Transducer)	Velocity loss between sets will be calculated from the mean velocity recorded by the linear position transducer during the back squat exercise. This variable will be expressed as the percentage reduction in movement velocity between sets and will be used as an indicator of fatigue resistance.	Baseline assessment (pre-intervention) and immediately after the intervention (post-intervention, same session).
Rating of Perceived Exertion (RPE)	Perceived exertion during the back squat exercise will be assessed using a rating of perceived exertion (RPE) scale. Participants will rate the perceived intensity of the exercise after completing the squat protocol. Higher scores indicate greater perceived effort.	Baseline assessment (pre-intervention), immediately after the intervention (post-intervention, same session), 1 week after the intervention, and 2 weeks after the intervention.
Activation of the transverse abdominal muscle	We measure the resting and activation thicknesses. We calculate the activation ratio.	Baseline assessment (pre-intervention) and immediately after the intervention (post-intervention, same session).

Collaborators and Investigators

• Sponsor: CEU San Pablo University
• Investigators: Principal Investigator: Francisco N Navarro Pastor, Physiotherapist, CEU San Pablo University

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): October 1, 2026
• Study Completion (Estimated): November 1, 2026

Study Registration Dates

• First Submitted: June 29, 2026
• First Submitted That Met QC Criteria: June 29, 2026
• First Posted (Actual): July 6, 2026

Study Record Updates

• Last Update Posted (Actual): July 6, 2026
• Last Update Submitted That Met QC Criteria: June 29, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: salicylhydroxamic acid
• Other Study ID Numbers: CdEi94

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Anonymized study data will be made available to other researchers upon reasonable request and following consultation with the principal investigator

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No