People with acute neck pain commonly present with restricted neck movement. However, it is unknown whether the presence of acute pain affects the quality of neck movement, specifically neck movement variability. We examined the effects of acute neck muscle soreness induced via eccentric exercise in healthy volunteers, on the variability of neck movement by examining changes in parameters of the helical axis during active neck movements.

An experimental, single-arm repeated measures study recruited 32 healthy participants, male and female, aged between 18 and 55 years. Repetitive active neck movements (flexion–extension, bilateral lateral flexion and bilateral rotation) were performed at different speeds, either at full range of motion (RoM) or restricted to 45° RoM at baseline, pre-exercise (T0), immediately following eccentric neck exercise (T1), 24 h (T2) and 48 h post-exercise (T3). The mean distance (MD) and mean angle (MA) parameters of the helical axis were extracted to quantify movement variability.

MD, measured during movements performed at full RoM, reduced significantly at T2 compared to T0 (P = 0.001) regardless of direction or speed of movement. MA was significantly lower at T2 and T3 compared to T1 (P = 0.029 and P = 0.033, respectively). When RoM was restricted to 45°, significantly lower MD values were observed at T3 compared to T1 (P = 0.034), and significantly lower MA values were measured at T3 compared to T0, T1 and T2 (all P < 0.0001).

This study uniquely demonstrates that neck movement variability is reduced immediately after, 24 h and 48 h after eccentric exercise, indicating that acute neck muscle soreness modifies the quality of neck movement.

患有急性颈部疼痛的人通常表现为颈部活动受限。然而，尚不清楚急性疼痛的存在是否会影响颈部运动的质量，特别是颈部运动的变异性。我们通过检查活跃的颈部运动过程中螺旋轴参数的变化，检查了健康志愿者中通过离心运动诱发的急性颈部肌肉酸痛对颈部运动变异性的影响。

一项实验性单臂重复测量研究招募了32位男性和女性健康参与者，年龄在18至55岁之间。反复主动颈部运动（屈伸，双侧向屈和双侧旋转）以不同的速度进行，无论是在全范围运动（RoM）还是在基线，运动前（T0），偏心后立即限制在45°RoM颈部锻炼（T1），运动后24小时（T2）和运动后48小时（T3）。提取螺旋轴的平均距离（MD）和平均角度（MA）参数以量化运动的可变性。

相对于T0（P = 0.001），无论运动方向或速度如何，在完全RoM下运动期间测得的MD值在T2时均显着降低（P = 0.001）。与T1相比，MA在T2和T3时显着降低（分别为P = 0.029和P = 0.033）。当RoM限制在45°时，与T1相比，T3处的MD值显着降低（P = 0.034），与T0，T1和T2相比，在T3处的MA值显着降低（所有P <0.0001）。

这项研究独特地证明了在离心运动后，运动后24小时和48小时立即降低了颈部运动的变异性，这表明急性颈部肌肉酸痛改变了颈部运动的质量。