Neck static stretching

Control Condition --> participants sat silently on a chair without performing any stretching intervention

The static stretching intervention targeted the right posterolateral region of the neck. The stretching protocol consisted of four sets of 45 seconds each, separated by 45-second rest intervals, for a total intervention time of 3 minutes. Seated in a chair, participants performed the stretch by gently flexing their head forward and to the left in an anterolateral direction, using their contralateral (left) hand to assist the movement and ensure selective stretching of the right posterolateral region of the neck. Participants were asked to achieve a subjective discomfort intensity of at least 8 out of 10 on the Numerical Rating Scale (NRS), where 0 represents "no pain" and 10 indicates "the strongest pain imaginable"

Investigators measured blood pressure while participants were sitting. A reliable blood pressure machine was used. Participants sat and rested for 5-10 minutes to let their blood pressure settle. The cuff was placed on the bare upper arm, about 2 centimeters above the inside of the elbow, with the arm supported at heart level. During the measurement, participants were asked to sit still, stay relaxed, and not talk. Data will be shown as means with standard deviations. To compare baseline values between SS and CC, investigators will first use paired t-tests. Invesigators will then check the data distribution and apply a repeated measures analysis of variance (two conditions × two time points) to look at the effects of time and condition. In the presence of a significant time × condition interaction, post hoc analyses with Scheffé correction will be conducted to locate the differences. Effect sizes will be calculated and reported as partial eta squared (η²p).

MAP was extrapolated from blood pressure using the following formula: MAP = DP + 1/3(SP - DP). Data will be shown as means with standard deviations. To compare baseline values between SS and CC, investigators will first use paired t-tests. Invesigators will then check the data distribution and apply a repeated measures analysis of variance (two conditions × two time points) to look at the effects of time and condition. In the presence of a significant time × condition interaction, post hoc analyses with Scheffé correction will be conducted to locate the differences. Effect sizes will be calculated and reported as partial eta squared (η²p).

Tissue stiffness was measured with a small handheld device (NEUTONE TDM-N1, TRY-ALL Corp., Japan). This device gently pressed into the skin with a fixed pressure to see how deep it could go. The bone at the base of the neck (C7) was used as a reference point. Measurements were taken on both sides of this bone, 2 centimeters to the right and left. Participants lay face down on a medical bed and were asked to stay completely relaxed. Data will be shown as means with standard deviations. To compare baseline values between SS and CC, investigators will first use paired t-tests. Invesigators will then check the data distribution and apply a repeated measures analysis of variance (two conditions × two time points) to look at the effects of time and condition. In the presence of a significant time × condition interaction, post hoc analyses with Scheffé correction will be conducted to locate the differences. Effect sizes will be calculated and reported as partial eta squared (η²p).