Background: Therapeutic exercises are used in clinical practice for patients with low back pain (LBP). Core stabilization exercises can retrain the important function of local trunk muscles and increase the accuracy of the sensory integration process for stability of the spine in individuals with LBP. The aim of this study was to compare the effects of two different exercise regimes, Core stabilization exercises (CSE) and Strengthening exercise (STE), on proprioception, balance, muscle thickness and pain-related outcomes in patients with subacute non-specific low back pain (NSLBP). Methods: Thirty-six subacute NSLBP patients, [mean age, 34.78 ± 9.07 years; BMI, 24.03 ± 3.20 Kg/m²; and duration of current pain, 8.22 ± 1.61 weeks], were included in this study. They were randomly allocated into either CSE (n = 18) or STE groups (n = 18). Exercise training was given for 30 min, three times per week, for up to 4 weeks. Proprioception, standing balance, muscle thickness of transversus abdominis (TrA) and lumbar multifidus (LM), and pain-related outcomes, comprising pain, functional disability and fear of movement, were assessed at baseline and after 4 weeks of intervention. Results: The CSE group demonstrated significantly more improvement than the STE group after 4 weeks of intervention. Improvements were in: proprioception [mean difference (95% CI): − 0.295 (− 0.37 to − 0.2), effect size: 1.38, (p < 0.001)], balance: single leg standing with eyes open and eyes closed on both stable and unstable surfaces (p < 0.05), and percentage change of muscle thickness of TrA and LM (p < 0.01). Although both exercise groups gained relief from pain, the CSE group demonstrated greater reduction of functional disability [effect size: 0.61, (p < 0.05)] and fear of movement [effect size: 0.80, (p < 0.01)]. There were no significant adverse effects in either type of exercise program. Conclusion: Despite both core stabilization and strengthening exercises reducing pain, core stabilization exercise is superior to strengthening exercise. It is effective in improving proprioception, balance, and percentage change of muscle thickness of TrA and LM, and reducing functional disability and fear of movement in patients with subacute NSLBP. Trial registration: Thai Clinical Trial Registry (TCTR20180822001; August 21, 2018).

Background: Exercise is known to be an important component of treatment programs for individuals with neck pain. The study aimed to compare the effects of semispinalis cervicis (extensor) training, deep cervical flexor (flexor) training, and usual care (control) on functional disability, pain intensity, craniovertebral (CV) angle, and neck-muscle strength in chronic mechanical neck pain. Methods: A total of 54 individuals with chronic mechanical neck pain were randomly allocated to three groups: extensor training, flexor training, or control. A Thai version of the Neck Disability Index, numeric pain scale (NPS), CV angle, and neck-muscle strength were measured at baseline, immediately after 6 weeks of training, and at 1- and 3 -month follow-up. Results: Neck Disability Index scores improved significantly more in the exercise groups than in the control group after 6 weeks training and at 1- and 3-month follow-up in both the extensor (P=0.001) and flexor groups (P=0.003, P=0.001, P=0.004, respectively). NPS scores also improved significantly more in the exercise groups than in the control group after 6 weeks’ training in both the extensor (P<0.0001) and flexor groups (P=0.029. In both exercise groups, the CV angle improved significantly compared with the control group at 6 weeks and 3 months (extensor group, P=0.008 and P=0.01, respectively; flexor group, P=0.002 and 0.009, respectively). At 1 month, the CV angle had improved significantly in the flexor group (P=0.006). Muscle strength in both exercise groups had improved significantly more than in the control group at 6 weeks and 1- and 3-month follow-up (extensor group, P=0.04, P=0.02, P=0.002, respectively; flexor group, P=0.002, P=0.001, and 0.001, respectively). The semispinalis group gained extensor strength and the deep cervical flexor group gained flexor strength. Conclusion: The results suggest that 6 weeks of training in both exercise groups can improve neck disability, pain intensity, CV angle, and neck-muscle strength in chronic mechanical neck pain. Trial registration: NCT02656030

BACKGROUND: In our digital society, the use of smartphones has increased rapidly. Parallel with the growing use of smartphones, musculoskeletal problems associated with intensive smartphone use have also increased. Neck flexion is the most commonly a

This study examined the differences in neck muscle activity at various neck flexion angles in smartphone users with and without neck pain. Forty-four participants performed texting tasks for 1 minute and 30 seconds. Neck muscle activity and pain in the neck were measured at different neck flexion angles. There was a difference in neck muscle activity for each of the neck flexion angles; the Cervical Erector Spinae (CES) muscle activity increased while the Upper Trapezius (UT) muscle activity decreased when at increased neck flexion angles. At neck flexion angle of 0°-15°, the activity of both CES and UT muscles were acceptably low. Smartphone users with neck pain had slightly higher muscle activity levels than smartphone users without neck pain. In conclusion, smartphone users should consider adopting neck flexion angles between 0-15 degrees during smartphone use as there is an association between this neck flexion angle range and reduced CES muscle activity. Practitioner Summary: This study demonstrated that both smartphone users with and without neck pain should try to keep their neck flexion angle between 0°-15° when using their smartphone. This would reduce neck muscle activity and the risk of developing neck disorders associated with smartphone use.

The number of smartphone users globally is rapidly increasing. This study aimed to assess the level of ergonomic risk to smartphone users, and to evaluate the correlation between any self-reported musculoskeletal disorders and the level of ergonomic risk. Thirty participants completed a questionnaire, tailored specifically for smartphone users, to determine any musculoskeletal disorders. Participants were given a seated smartphone texting task and their postures were video recorded during the task. The video scenarios were evaluated by three independent researchers to determine the level of ergonomic risk using the Rapid Upper Limb Assessment (RULA) tool. RULA is an observation-based screening tool which has been widely used to assess the postural risk of IT device users. However, it has not yet been specifically utilized with smartphone users. The RULA tool scores identified ergonomics risks from using smartphones to text. Most smartphone users had a total RULA Grand Score of 6 for both sides (left side: 80.00%, right side: 90.00%), indicating the need for further investigation and changes (Action Level 3). Notably, no participants had acceptable RULA Grand Scores of 1 or 2. The correlation between musculoskeletal disorders and the ergonomic risk among smartphone users was determined using the Chi-Square test and Fisher's exact test; p<0.05 was considered statistically significant. There was a significant correlation between right RULA Grand Score and neck musculoskeletal disorder (χ2 = 9.424 at p value = 0.009) and right RULA Grand Score and upper back musculoskeletal disorder (χ2 = 31.717 at p value <0.001). RULA Score B (combination of neck, trunk and leg postures) and RULA Score D (combination of Score B, muscle use and force scores for group B) were also significantly correlated with neck musculoskeletal disorders (χ2 = 19.286 at p value<0.001 and χ2 = 9.310 at p value = 0.002 respectively). The RULA results identified the high ergonomics risk of smartphone users, this resulted from two key risk factors: posture and muscle use. The neck, trunk and leg postures had a combined effect on neck musculoskeletal disorders. Future investigations should consider these factors when designing ergonomic interventions for smartphone users.

This study compares the effects of different neck flexion angles on neck gravitational moment and muscle activity of users that stand and operate a smartphone. Thirty-two healthy young adult smartphone users performed texting tasks for three minutes at four different neck flexion angles (0°, 15°, 30°, and 45°) while standing. Neck gravitational moment and cervical erector spinae (CES) and upper trapezius (UT) activity were investigated. When the neck flexion angle increased, the gravitational moment of the neck increased significantly. The muscle activity of CES significantly increased when the neck flexion angle increased, whereas that of UT decreased. The lowest gravitational moment of the neck at 0° flexion was consistent with the lowest CES muscle activity and the lowest neck discomfort score. In conclusion, for texting while standing, adults should maintain their neck posture at 0° flexion to reduce the gravitational force acting on the cervical spine and alleviate neck discomfort. Practitioner Summary: During smartphone use when standing, excessive neck flexion (30° and 45° flexion) should be avoided. The suggested neck posture when operating a smartphone while standing is 0° flexion. Abbreviations: CES: cervical erector spinae; UT: upper trapezius; COG: centre of gravity; MSDs: musculoskeletal disorders; CROM: cervical range of motion; sEMG: surface electromyography; VAS: visual analogue scale; MVCs: maximum voluntary contractions.