Neck muscle vibration produces diverse responses in balance and gait speed between individuals with and without neck pain

Neck muscle vibration can influence cervical proprioception and sensorimotor function. It is hypothesized to affect motor performance differently in persons with and without neck pain.Cross-sectional study.To clarify the extent to which vibration-induced motor responses of neck muscles affect static standing balance and gait speed in persons with and without neck pain.Thirty participants with chronic neck pain and 30 healthy controls were recruited. Balance and gait were measured before and after 30 s of suboccipital neck muscle vibration. Balance was measured in a confortable stance with eyes closed using a swaymeter and gait using the timed 10 m walk test.At baseline, neck pain participants had greater postural sway, particularly in the anterior-posterior direction and slower gait speed than healthy controls (p

3D measurement of clavicular and scapular orientations: the association with clinical characteristics and responsiveness to scapular repositioning in patients with neck pain

Background: Clavicular and scapular orientations vary between neck pain patients as do clinical features and responses (changes in pain and rotation range) to scapular repositioning. Associations between these factors are unknown. Objectives: To identify subgroups of neck pain patients based on three-dimensional (3D) measures of clavicular and scapular orientations and differences between subgroups in clinical characteristics and responses to scapular repositioning. Design: Cross-sectional study. Methods: Eligible participants were recruited as part of a larger study. The 3D clavicular and scapular orientations were analyzed on the more painful side of the neck using a hierarchical cluster analysis. Clinical characteristics were neck pain location, intensity, duration, disability and presence of headache. Responses to scapular repositioning were classified as “yes and no”. Results: Fifty-eight participants (29 responsive; 29 non-responsive to scapular repositioning) participated in the study. Analysis identified two distinct subgroups: subgroup1 had greater clavicular retraction and scapular downward rotation (n = 26) and subgroup2 had greater clavicular elevation and scapular internal rotation and anterior tilt (n = 32). Headache and dominant pain in the upper neck were more frequent in subgroup 1 while dominant pain in the lower neck was frequent in subgroup 2 (p &lt; 0.01). Most participants who responded positively to scapular repositioning (88.5%) were in subgroup1 and most non-responsive participants (81.2%) in subgroup2. Conclusions: The 3D clavicular and scapular orientations identified two subgroups of neck pain patients. Participants with predominantly downward scapular rotation were distinguished by pain in the upper neck, presence of headache and a positive response to scapular repositioning.</p

Axioscapular and neck extensor muscle behavior during isometric shoulder exertions in patients with nonspecific neck pain with and without a scapular downward rotation posture

Background: A common observation in persons with neck pain is scapular downward rotation (SDR) with altered muscle behavior. Evidence of changes in axioscapular muscles in neck pain patients remains inconclusive, which may reflect population heterogeneity in previous studies. Research question: Are there differences in behavior of the axioscapular (upper trapezius: UT, lower trapezius: LT and serratus anterior: SA) and neck extensor (NE) muscles during isometric shoulder tasks in patients with neck pain with SDR, patients with no scapular dysfunction and healthy controls? Methods: Sixty participants with nonspecific neck pain (30 with SDR and 30 without scapular dysfunction) and 30 controls were recruited. Electromyographic signals were recorded unilaterally from the UT, LT, SA and NE during different isometric shoulder tasks (30° flexion, 30°abduction and 30°external rotation) at 20%, 50% and 100% maximal voluntary contraction (MVC). Activity of UT, LT, SA and NE was normalized with respect to reference contractions. The UT/LT, UT/SA and LT/SA ratios were calculated for each task. Results: The neck pain group with SDR had increased UT activity in 30°flexion (20%MVC) and 30°abduction (20% and 50%MVC) compared to the neck pain and control groups without scapular dysfunction (p &lt; 0.05). There were no between group differences in LT and SA activity (p &gt; 0.05). The neck pain groups had greater NE activity in all tasks (p &lt; 0.001). Finally, the neck pain group with SDR had higher UT/LT and UT/SA ratios in a few tasks at low force levels (p ≤ 0.01). Significance: Greater UT activity and UT/LT and UT/SA ratios during particularly low force isometric shoulder tasks suggest that SDR is associated with altered axioscapular motor control. Greater NE activity in both neck pain groups suggests altered motor control related to neck pain. Changes in the NE and UT behavior should be considered in management of patients with neck pain with observable SDR.</p

Clavicular and scapular, but not spinal kinematics vary with scapular dyskinesis type during arm elevation and lowering in persons with neck pain

Background: Scapular dyskinesis is often observed in patients with neck pain. However, it is unknown whether clavicular, scapular and spinal kinematics vary with different types of scapular dyskinesis during arm movement. Research question: Are there differences in clavicular, scapular and spinal kinematics during unilateral arm elevation and lowering among neck pain patients presenting with (i) scapular winging, (ii) with dysrhythmia, (iii) with no scapular abnormality and (iv) healthy controls? Methods: Sixty participants with neck pain (20 in each group) and 20 asymptomatic controls were recruited. The 3D kinematic data were measured during unilateral arm elevation and lowering at 30°, 60°, 90°, and 120° in the scapular plane. A three-way mixed-effects ANOVA was used to determine the main effects (group, phase and angle) and the interactions between three independent variables on the kinematic data. Results: The neck pain group with scapular winging had decreased clavicular retraction and increased scapular internal rotation and anterior tilt compared to the other neck pain and control groups at all angles during both phases of arm movement (p &lt; 0.01). The neck pain group with scapular dysrhythmia had decreased scapular upward rotation compared to all other groups (p &lt; 0.01). Some alterations in the kinematics existed during the lowering phase compared to the raising phase for all groups (p &lt; 0.05). Spinal kinematics were similar across all groups (p &gt; 0.05). Significance: Specific patterns of clavicular and scapular kinematics were identified during arm movement relevant to the type of observed scapular dyskinesis in patients with neck pain. Such findings stand to inform more precise and relevant motor training in rehabilitation and improve understanding of the association between altered scapular kinematics and neck pain.</p