Comparative Effects of the Neurodynamic Slider and Tensioner Mobilisation Techniques on Sympathetic Nervous System Function: A Randomised Controlled Trial

Ninety healthy volunteer participants were randomly allocated to three groups (sliding neurodynamic techniques (NDT), tension NDT, and control) using the hypothetico-deductive method of theory testing that allows the comparison within the variables. Additionally, a double-blind experimental research strategy was used in this study. The study's participants were not informed on their allocation to the groups in an effort to reduce the likelihood of expectation bias. It is crucial to note that the researcher maintained his or her blindness throughout the data selection process in order to safeguard the study's internal validity. Two people carried out the experiment in order to accomplish this: the "therapist" who applied the NDT and the "data collector" in charge of documenting the outcomes of the intervention.

Any changes in the Sympathetic Nervous System (SNS) were noted and recorded using three valuable outcome measure tools: the Biopac Galvanic skin response 100B electrodermal activity amplifier (MP36 Biopac Systems Incorporation), a thermo-camera © and an ambulatory blood pressure monitor.

The practical room was set up during the experiment so that neither the therapist nor the subjects came in contact with the apparatus. In order to ensure blinding from the results as the experiment was running, the plinth (treatment area) was separated from the data collection table with the computer and equipment (Biopac, blood pressure monitor, environmental thermometer, and thermo-camera) by a screen. Only the data collector has access to the Biopac software, blood pressure monitor, environmental thermometer, and thermo-camera in order to blind the therapist to the results of the experiment completely. Throughout the whole experiment, the therapist stayed hidden behind the screen.

The therapist begins standardising the equipment when the subjects are seated on the plinth. The thermo-camera has to be positioned correctly, pointing at the participant's hold body in the first stage. Second, the therapist placed the blood pressure monitor's cuff on the participant's left arm. The ideal placement of the skin electrodes was the next step. Each participant's second and third toes on both legs received skin electrodes. When the participant finally assumed their position, the therapist asked the data collector to quickly verify SC activity using the thermo-camera, ambulatory blood pressure monitor, and graph readings from the Biopac acquisition programme.

The experiment comprised three phases: (1) Pre-Intervention Phase, (2) Intervention Phase, and (3) Post-Intervention Phase. The experiment started with an 8-minute stabilisation phase aiming to achieve a physiological resting state, followed by the baseline recording period, which lasted 2 minutes. During this phase, the therapist took the body temperature and the blood pressure of each participant, using the blood pressure monitor and the thermo-camera ©. Following, three phases of 1-minute interventions were applied on the 'intervention leg', each separated by a 1-minute rest period. Finally, the experiment concluded with a 5-minute resting period. The SC was recorded through the Biopac software the whole time, and the whole experiment lasted 20 minutes. Throughout the experiment, the data collector indicated the time frame for each phase with the verbal cue 'Intervention Phase 1 or 2 or 3'.

Moreover, the data collector placed markers on the Biopac graph to demonstrate the start and end of each intervention phase. Finally, when the experiment passed into the Post-Intervention Phase, the therapist took the body temperature and the blood pressure from each participant. It must be noted that NDT manoeuvres during the experiment were performed on the participants as described by Shacklock (2005).

Inclusion criteria

• Aged between 18 and 40 years
• Body Mass Index less than 30

Exclusion criteria

• Previous History of Lower Back Pain
• Skin Disorders
• Previous Experience of Spinal Manual Therapy Treatment
• Previous Lower Limb Injuries or Trauma
• Food, Caffeine, Nicotine, or Alcohol consumed 3 hours before the experiment strenuous Activity done 3 hours before the experiment
• Chronic Systemic Health Conditions (for example, diabetes)
• Psychiatric Illnesses or Anxiety Disorders
• Medication that may have an affect on the SNS (for example, anti-depressants, anti-nausea medication, beta-blockers, muscle relaxants)