Comparative Study of Two Ultrasound-guided Percutaneous Neuromodulation Protocols on Maximal Handgrip Strength.

Study Design:

This is a randomized, controlled, double-blinded clinical trial. Both the evaluator and the participants will be blinded to group allocation. A total of 86 volunteers (aged 18-40 years) will be randomly assigned to one of two intervention groups.

Eligibility Criteria:

Inclusion:

Healthy adults aged 18-40 years No musculoskeletal, neurological, or upper limb conditions Informed consent provided

Exclusion:

Recent physical activity (within 48 hours) Electrotherapy contraindications (e.g., pregnancy, epilepsy, needle phobia) Pain or functional limitations at the time of assessment

Blinding Procedures:

Participants will be unaware of the specific stimulation frequency applied. Since both protocols involve similar sensations and durations, distinguishing between them is unlikely. Evaluations will be performed by a separate physiotherapist who is not informed of the group assignments.

Sample Size Justification:

Based on prior research, a sample size of 43 participants per group (86 in total) is needed to detect statistically significant differences between groups with 80% power and a 5% significance level. Calculations are based on previously reported standard deviations and an expected moderate effect size.

Data Handling and Confidentiality:

All participant data will be pseudonymized using unique identification codes. Only the principal investigator will have access to the code-key linking participants' identities. Data will be stored securely, and all procedures will comply with current data protection regulations.

Potential Risks and Safety Measures:

As an invasive physiotherapy technique, PNM may involve minimal risks such as mild discomfort from the needle insertion, transient pain during electrical stimulation, or minor hematoma formation. However, all interventions will be performed by trained professionals following strict aseptic protocols, using sterile gloves, probe covers, and appropriate skin disinfection procedures. The technique has been previously validated in both healthy and clinical populations, further supporting its safety.

Inclusion criteria

• Healthy adults aged 18-40 years
• No musculoskeletal, neurological, or upper limb conditions
• Informed consent provided

Exclusion criteria

• Recent physical activity (within 48 hours)
• Electrotherapy contraindications (e.g., pregnancy, epilepsy, needle phobia)
• Pain or functional limitations at the time of assessment