Efeito do Dry Needling Plus Vibration em pontos-gatilho miofasciais em indivíduos com dor lombar inespecífica (DryNeed+Vib)

Participants will receive one session of dry needling combined with a mechanical vibratory stimulus, followed by a structured exercise programme (3 sessions/week for 4 weeks).

Participants will receive one session of dry needling combined with vibratory stimulation, plus a structured exercise programme (3 sessions/week for 4 weeks).

A sterile acupuncture needle will be inserted into the affected muscle(s) and, once correctly positioned, will remain stationary throughout the intervention. Vibratory stimulation will then be applied to the needle for 60 seconds at the maximum intensity tolerated by the participant, up to a maximum output of 5 V.

In relation to the exercise program, participants will complete a protocol based on core stabilization and lumbar strengthening.

Participants will receive one session of conventional dry needling, followed by a structured exercise programme (3 sessions/week for 4 weeks).

Participants will receive one session of conventional dry needling, plus the same structured exercise programme as the experimental group (3 sessions/week for 4 weeks).

A sterile acupuncture needle will be inserted into the affected muscle(s), and the intervention will consist of the "fast in-and-out" technique described by Hong (1994), performed at an approximate frequency of one insertion per second (1 Hz) without completely withdrawing the needle from the skin. The technique will be applied for up to 60 seconds with the aim of eliciting local twitch responses. However, the procedure may be discontinued at the participant's request if it becomes intolerably painful. In such cases, the actual duration of the intervention will be recorded.

In relation to the exercise program, participants will complete a protocol based on core stabilization and lumbar strengthening.

This variable refers to the participants' low back pain at the time of the assessment. It does not include the pain caused by the treatment itself. The Numeric Pain Rating Scale (NPRS) will be used. This scale ranges from 0 to 10, where "0" indicates no pain and "10" represents the worst possible pain intensity. Patients will select the number that best reflects the intensity of their pain. The NPRS is a widely used, simple scale that offers good sensitivity and provides suitable data for statistical analysis.

Patient-reported acceptability of the assigned treatment, measured with a purpose-developed Acceptability Scale. This scale is scored as a percentage, with 100% indicating the highest level of acceptability and 0% indicating the lowest.

Pain intensity experienced during the needling procedure, measured with the Numeric Pain Rating Scale (NPRS). This scale ranges from 0 to 10, where "0" indicates no pain and "10" represents the worst possible pain intensity.

It is a highly prevalent adverse effect of dry needling. This pain does not refer to that caused by the MTrPs, but rather to that caused by the needling itself. This variable will be measured with the Numeric Pain Rating Scale (NPRS). This scale ranges from 0 to 10, where "0" indicates no pain and "10" represents the worst possible pain intensity.

Functional disability will be assessed using the Roland-Morris Disability Questionnaire (RMDQ), a tool designed to measure physical disability caused by low back pain. The questionnaire consists of 24 items, with scores ranging from 0 (no limitations) to 24 (maximum possible disability), evaluating limitations in various daily life activities.

The Short Form-36 Questionnaire will be used to assess this variable. This survey comprises 36 questions about general health. The questionnaire consists of eight subscales (physical functioning, physical role, bodily pain, general health, vitality, social functioning, emotional role, and mental health), summarized into two scores: physical and psychological health. Scores range from 0 to 100% and reflect self-perceived health-related quality of life.

PPT will be assessed using a digital algometer (Somedic SenseLab, Suecia) with a 1 cm² rubber tip. The pressure will be applied perpendicularly to the skin at a constant rate of 0.5 kg/s until the participant reports that the pressure sensation changes to pain. To differentiate between peripheral and central mechanisms, measurements will be taken at two locations: 1) Locally, directly over the treated MTrP in the lumbar region (peripheral sensitization), and 2) Distally, at a remote site such as the tibialis anterior muscle (central sensitization). Before the actual tests, the PPT will be familiarized by applying it to the participant's dominant arm until the participant becomes familiar with the test procedure. Three measurements will be taken at each site, but not at precisely the same point to avoid influencing the pain threshold from previous measurements, with a 30-second rest interval, and the mean value will be used for statistical analysis.

It will be recorded using mDurance equipment. For each measurement, the amplitude of the electromyographic activity (measured in microvolts -mV-) of the target musculature at rest will first be recorded for 10 seconds. Then, the muscle activation level during maximal isometric contraction will be recorded to normalize the electromyographic signal. This will follow the same methodology as the maximal isometric strength variable (three maximal isometric contractions of 5 seconds each, with 30 seconds of rest). In this case, the parameter of interest will be the signal's peak amplitude. Lastly, 10 dynamic repetitions of the functional movement "front squat" will be evaluated. This data will determine the percentage of muscle activation relative to maximal isometric contractions, known as the "percentage of maximal voluntary isometric contraction" (%MVIC).

This variable will be measured using the "microFET-2 dynamometer". Muscles assessed will include the lumbar erector spinae, multifidus muscles, and hip abductor musculature. Participants' weight will be recorded to normalize the collected data. Three maximal isometric contractions will be performed, each lasting 5 seconds, with a 1-minute rest period between them. The average of these measurements will be used for statistical analysis.

The Global Rating of Change (GROC) is a simple, single-item patient-reported outcome measure used to quantify a patient's perceived improvement or deterioration in their health condition over time. Patients rate on a scale from -7 to +7, where -7 indicates "a very great deal worse" and +7 indicates "a very great deal better."

We hypothesize that DN+V, being less aggressive than DN, will reduce the risk of adverse effects associated with DN (hematomas, bleeding, pain, dizziness, etc.) Adverse effects will not be included in the statistical analysis; however, these data will provide valuable descriptive information, given that adverse events are often underreported in research despite their clinical relevance.

A local twitch response (LTR) is a brief, involuntary contraction of a tight band of muscle fibers that happens when a trigger point is stimulated with the needle.

When both interventions (dry needling or dry needling + vibration) are applied, it will be noted whether local twitch response has occurred or not. Although this response is not necessary to consider the dry needling treatment applied correctly, and whether or not a local twitch response occurs is not a fundamental aspect of this study, it is deemed appropriate to record this variable for descriptive purposes of the sample and for potential discussion in the findings The physical therapist performing the interventions will be responsible for recording the number of local twitch responses elicited during the intervention.

Both direct and indirect costs related with the two studied interventions will be recorded for future cost-efectiveness analysis