Post-Fatigue Vibration: Impact on Grip and Reaction Time

This randomized controlled study will be conducted with a minimum of 42 participants who meet the inclusion and exclusion criteria. Participants will be randomly assigned to one of three groups: control, 50 Hz local vibration, or 100 Hz local vibration.

• 100 Hz Local Vibration (Other): Participants in this group will receive 100 Hz local vibration along the flexor carpi ulnaris muscle for a duration of 10 minutes.
• 50 Hz Local Vibration (Other): Participants in this group will receive 50 Hz local vibration along the flexor carpi ulnaris muscle for a duration of 10 minutes.
• Sham Local Vibration (Other): Participants in this group will receive sham vibration following the muscle fatigue protocol. The vibration device will be turned on but held near the muscle without making contact for 10 minutes. Participants will be informed that they are being treated with an electromagnetic vibration device.

Primary outcomes

• Hand Grip Strength Measurement [Change in hand grip strength from baseline following intervention or rest]: Grip strength will be assessed using a JAMAR® hydraulic hand dynamometer, which has five grip positions. The test will follow American Society of Hand Therapists guidelines, with the elbow at 90° flexion. Measurements will be taken on the dominant hand. Participants will sit with their head facing forward, shoulders slightly abducted (10-20°), elbows at 90°, and wrists and hands in a neutral position. Both upper extremities will remain relaxed, and feet will be flat on the floor. Fingers will be fully extended and adducted. Participants will be instructed not to allow their hands or forearms to touch the body. The dynamometer will be adjusted to fit the participant's hand size, typically set at the second handle position.
• Upper Extremity Reaction Time Measurement [Change in upper extremity reaction time from baseline following following intervention or rest]: Upper extremity reaction times will be recorded using the BlazePod system (Play Coyotta Ltd., Tel Aviv, Israel). Participants will begin the reaction time test while seated, with both hands placed on a table, palms facing downward, and elbows flexed at 90°, with hands positioned 40 cm apart. The BlazePod unit will be placed centrally, approximately 20 cm away from each hand. When the BlazePod lights up, participants will be instructed to respond as quickly as possible by tapping the light to turn it off. As the lights will activate randomly, participants will be required to react unpredictably and respond accordingly each time the light appears. The total test duration will be recorded at the end of the trial.

Other outcomes

• Fatigue Perception and Relief Sensation After Vibration or Rest [Change in baseline fatigue perception and relief sensation following intervention or rest]: To evaluate the effects of local vibration on fatigue perception and relief sensation, participants will be asked to rate the intensity of these two parameters on a scale from 0 to 10 before and after the application. A score of 0 indicates the lowest intensity, while a score of 10 represents an unbearable level.
• Post-Fatigue Fatigue Rating [Change in baseline fatigue following muscle exhaustion protocol]: To evaluate the perception of fatigue emerging after the fatigue protocol, participants will be asked to rate the intensity of their fatigue on a scale from 0 to 10. A score of 0 indicates no fatigue, while a score of 10 represents an unbearable level of fatigue.

Sex: Female, ages: 18 Years to 25 Years, accepts healthy volunteers

Inclusion Criteria:

1\. Female individuals aged 18-25

Exclusion Criteria:

1. Having an open wound in the area where local vibration is applied
2. A history of previous or current upper extremity injury
3. Use of anti-inflammatory drugs
4. Having a diagnosis of epilepsy

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• ömer dursun, Asst. Prof., Principal investigator, Bitlis Eren University
• merve tunçdemir, Asst. Prof., Principal investigator, Bitlis Eren University