Upper-limb muscle fatigue during digital handwriting in healthy adults (musculoskeletal / biomechanical study) trunk stretching
Conditions
Interventions
A trunk stretching program targeting the back, lower back, and mid-trunk, approximately 15 minutes, delivered by a single trained researcher to standardize force and technique. Five poses: (1) Seated
(2) Seated spinal twist, 30 seconds per side, 2 reps, 3 sets
(3) Child pose, 60 seconds for 3 sets
(4) Seated side stretch, 30 seconds per side, 2 reps, 3 sets
(5) Supine spinal twist, 30 seconds per side, 2 reps, 3 sets. No upper limb stretching in this condition.,An upper limb stretching program targeting the shoulder, arm, and wrist, approximately 15 minu
(2) Cross-body shoulder stretch
(3) Overhead triceps stretch
(4) Forearm extensor stretch
(5) Forearm flexor stretch, each 30 seconds per side, 2 reps, 3 sets. No trunk stretching in this condition.,Seated rest for 15 minutes in a standard chair with backrest and armrests, in a controlled
Trunk stretching,Upper limb stretching,Control (seated rest)
Sponsors
Chulabhorn Royal Academy
Eligibility
Sex/Gender
All
Age
18 Years to 24 Years
Inclusion criteria
Inclusion criteria: 1. University students, male or female 2. Age 18 to 24 years 3. Good general health 4. Regular use of a tablet or digital device for writing at least 3 times per week for at least 6 months 5. No neurological or musculoskeletal disease affecting motor control 6. Right-handed
Exclusion criteria
Exclusion criteria: 1. History of injury to the upper limb, neck, shoulder, or back within the past 6 months 2. Pain or discomfort in the neck, shoulder, or upper limb during the experiment 3. Use of analgesics, muscle relaxants, or drugs affecting the neuromuscular system within 24 hours before testing
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Upper-limb muscle fatigue indexed by surface EMG median frequency Before and after the 10-minute digital handwriting task, in each condition Median frequency of surface EMG (Cometa) from six upper-limb muscles, electrodes per SENIAM, normalised to MVC. Compared before vs after writing. | — |
Secondary
| Measure | Time frame |
|---|---|
| Motor strategy - EMG RMS and %MVC before and after writing, each condition RMS of surface EMG normalised to maximal voluntary contraction (%MVC) for the six target muscles. Compared before vs after writing.,Handwriting performance during the writing task Tablet metrics (stylus position, coordinates, speed) captured by the writing app on iPad with Apple Pencil during the 10-minute writing task.,2D motion analysis during writing, each condition Joint range of motion and angular velocity of trunk, shoulder, elbow, and wrist analysed with Kinovea from frontal and lateral video.,Perceived fatigue (VAS 0 to 10) before and after writing, each condition Visual Analog Scale 0 to 10. | — |
Countries
Thailand
Contacts
Public ContactThanyaporn Wongwatcharanon
Faculty of Health Science Technology, Chulabhorn Royal Academy
Outcome results
None listed