An exploratory, in-field, multimodal assessment of cervical function in adults following to high-altitude trekking with light backpack.

Hours-lasting walks with backpacks can trigger or worsen musculoskeletal dysfunctions of the neck, and high-altitude hypoxia adds to the stress. To delve deeper into this topic, this study analyzed the functional and neuromuscular alterations at the head-and-neck region during high-altitude trekking by combining thermal imaging, electromyography, and kinematics. Fifteen adults who took part in a Himalayan expedition were tested for cervical range of motion (RoM) at 1400 m, at peak altitude staying (5000 meters), and once back at 1400 m, during a trek lasting 14 days. The 8 males were also tested for surface electromyography (sEMG) and infrared thermography. The maximum RoM of flexion-extension along the sagittal plane increased in response to trekking. Surface electromyography revealed greater activation at the end of the trek in right side for rotation and the left side for bending. Thermography revealed a general reduction of skin temperature over the target muscles during side bending. This study highlights the feasibility and usefulness of multimodal analysis through inertial measurement unit-registered kinematics, thermography, and electromyography in monitoring neck function in a demanding real-world environment. The high-altitude trek, with a backpack weighing less than 10% of one's body weight, triggers asymmetrical adaptations in the neck muscles, increasing measured RoM.