The Role of Isometric in Individuals With Rheumatoid Arthritis

Gradual pressure will be applied to the volar (palm side) region of the non-dominant forearm using a pressure gauge (initial intensity-0 kPa, rate-30 kPa/s, 3 repetitions, interval between stimuli-45 seconds). The maximum pressure that participants can tolerate will be recorded as the pressure is increased. The average of 3 consecutive measurements will be taken. The tip of the gauge will be shifted 0.5 cm between repetitions to avoid changes in skin sensitivity. Pain was assessed using the Visual Analog Scale (VAS). The VAS consists of a 10-cm horizontal line ranging from 0 to 10, where 0 indicates "no pain" and 10 indicates "the worst pain imaginable." Total scores range from 0 to 10, with higher scores indicating greater pain severity (worse outcome).

Based on the modified limits method, a pressure algometer will be used to apply gradual pressure to the volar (palm-side) region of the non-dominant forearm (initial intensity-0 kPa, velocity-30 kPa/s, 3 repetitions, interval between stimuli-45 seconds). Participants will inform the investigator when they first perceive pain. The pressure pain threshold will be taken as the average of 3 consecutive measurements. The algometer tip will be shifted 0.5 cm between repetitions to avoid changes in skin sensitivity. Pain was assessed using the Visual Analog Scale (VAS). The VAS consists of a 10-cm horizontal line ranging from 0 to 10, where 0 indicates "no pain" and 10 indicates "the worst pain imaginable." Total scores range from 0 to 10, with higher scores indicating greater pain severity (worse outcome).

Ten stimuli of pressure pain threshold size will be applied to the volar (palm side) region of the non-dominant forearm using a pressure algometer. The difference between the first and tenth stimuli will be recorded. The pain level during the first and tenth stimuli will also be recorded according to GAS. The difference will be calculated.

A conditioning pressure stimulus will be applied to the non-dominant upper extremity, and the pressure pain threshold will be measured in the dominant upper extremity. The non-dominant hand will be immersed up to the wrist in a bucket of water at 37°C for 10 seconds to induce conditioning. The patient will then be asked to immerse their hand in water adjusted to 46°C for 30 seconds. This temperature has been used in many previous studies. During this time, the pressure pain threshold will be measured on the volar portion of the forearm of the contralateral extremity. Pain was assessed using the Visual Analog Scale (VAS). The VAS consists of a 10-cm horizontal line ranging from 0 to 10, where 0 indicates "no pain" and 10 indicates "the worst pain imaginable." Total scores range from 0 to 10, with higher scores indicating greater pain severity (worse outcome).

The VAS is a 10 cm long scale drawn horizontally or vertically, starting with "No pain" and ending with "Unbearable pain." The patient is instructed to mark a point on this line corresponding to the intensity of their pain. The distance from the lowest VAS level to the patient's mark is measured with a ruler and recorded in centimeters.

Current evidence for determining pain phenotypes (Kosek et al.) recommends performing quantitative sensory testing. Quantitative sensory testing is divided into static tactile mechanical fixation threshold, hot-cold pain threshold, static mechanical allodynia, dynamic mechanical allodynia, and vibration assessment All assessments will be performed on the patient's non-dominant upper extremity.

Oxygen saturation measurement will be performed using the MOXY (Fortiori Design LLC., Minnesota, USA) device. MOXY is a medical device measuring 61x44x21mm and weighing 42g. It is an infrared measuring device that measures oxygen saturation and total hemoglobin in muscle capillaries. It has self-adhesive light emitting and reflected light sensors placed a few centimeters apart on the skin. These devices penetrate the tissue a few centimeters using light and various algorithms to provide information about peripheral oxygen saturation in the microcirculation. It is a system that takes infrared measurements with 4 separate LED lights, penetrating to a depth of 12 mm to 25 mm, and provides the average numerically. It is a non-invasive method. In this study, muscle oxygen saturation will be measured over a three-minute period.

The Body Awareness Questionnaire is a questionnaire consisting of 18 statements divided into four subgroups (Changes in body processes, sleep-wake cycle, prediction of disease onset, prediction of body responses) designed to determine the level of sensitivity to normal or abnormal body composition. Participants are asked to rate each statement on a scale of one to seven. The questionnaire uses a total score for the rating. A higher score indicates better body sensitivity.

The ABILHAND-RA questionnaire focuses on functional items that best represent hand activities. Manual dexterity will be assessed using the ABILHAND-RA inventory, which consists of 27 common hand-use-based activities. Each activity will be scored as follows: 0 = impossible, 1 = difficult, 2 = easy. Volunteers will be asked to rate the ease with which they perform daily living activities, regardless of which limb is used or the method employed.

The Pain Catastrophizing Scale was used to assess feelings and thoughts related to pain. This scale consists of 13 items. Each question is scored on a 5-point scale (0: Never, 1: Somewhat, 2: Moderately, 3: Severely, 4: Always). The scale consists of 3 sub-sections: helplessness, magnification, and rumination. The total score ranges from 0 to 52. Higher scores indicate higher pain catastrophizing.

The International Physical Activity Questionnaire - Short Form assesses energy expenditure over the past week in total METs. It consists of seven questions. The total score is calculated by including the total duration (minutes) and frequency (days) of walking, moderate-intensity activity, and vigorous-intensity activity. For an activity to be included in the total score, each activity must have lasted at least 10 minutes. The questionnaire calculates a score in "MET-minutes/week (MET-min/week)" using the minutes spent during the activity, the number of days per week the activity was performed, and the MET value specified in the questionnaire.