Table 1 Descriptive characteristics of included studies

Falla (2017) UK [46]

Cross-Sectional

To evaluate gait characteristics, including neck and trunk rotation, in patients with nonspecific chronic neck pain and healthy controls walking on a treadmill at 3 different speeds

• n = 14

• Presence of nonspecific, episodic neck pain of more than 3 months in duration

• Periods of symptom aggravation and remission in the last 6 months

• Each episode of neck pain lasting at least 1 week

• Pain of sufficient intensity to limit function

• n = 14

• Convenience sample of healthy individuals

• No relevant history of neck pain or injury that limited function or required treatment from a health care professional

• Presence of major circulatory, neurological, or respiratory disorders; recent or current pregnancies

• Previous spinal surgery

• History of low back or thoracic pain; or neck muscle training in the past 12 months

• Taking pain-related medication, such as opioids, anticonvulsants, antidepressants, or regularly high-dose nonsteroidal anti-inflammatory drugs

• SSWS

• SSWS + R head rotation

• SSWS + L head rotation

• 3 km/hour

• 3 km/hour + L head rotation

• 3 km/hour + R head rotation

• 5 km/hour

• 5 km/hour + L head rotation

• 5 km/hour + R head rotation

• Walk completed on a treadmill

• Head rotation standardized to 30° with custom-made helmet equipped with spherical markers and laser pointers

• Cadence (steps/min)

• Stride length (mm)

Kirmizi (2019) Turkey [26]

Cross-Sectional

To investigate if there was a significant difference in gait speed and gait asymmetry between individuals with CNNP and healthy no-pain controls

• n = 20

• Neck pain persisting longer than 3 months

• NDI score higher than 10/100

• n = 20

• No experience of neck pain for longer than 3 months

• No current presence of neck pain

• Previous history of neck trauma

• Presence of neurological deficits originating from neck disorders

• Musculoskeletal problems that may affect walking performance

• Other diagnosed conditions that may affect balance (inner ear pathology, stroke, history of head injury, diabetes, circulatory and/or vestibular pathologies)

• PS

• PS + head rotation

• FS

• Timing gate system with two gates placed 10 m apart within 16 m walkway

• Gait speed (m/s)

• Gait asymmetry

Kirmizi (2019) Turkey [26]

Cross-Sectional

To compare gait speed, step length, cadence and GSR between individuals

with CNNP and no pain controls in different

walking conditions and determine the

relationship of disability with spatiotemporal

gait variables and GSR in individuals with

CNNP

• n = 25

• Neck pain persisting longer than 3 months

• NDI score higher than 10/100

• n = 25

• Characteristics not described

• Previous history of a neck trauma

• Presence of neurological deficits originating from neck disorders

• Musculoskeletal problems that may affect walking performance

• Other diagnosed conditions that may affect balance (inner ear pathology, stroke, history of head injury, diabetes, circulatory and/or vestibular pathologies)

• PS

• FS

• Timing gate system with two gates placed 10 m apart within 16 m walkway

• Gait speed (m/s)

• Step length (cm)

• Cadence (steps/min)

Kirmizi (2019) Turkey [26]

Cross-Sectional

1. To determine the validity and intra-rater reliability of the video analysis method used to assess spatiotemporal gait variables

2. To investigate the

effects of flat cushioning insole on neck pain severity during walking and spatiotemporal gait variables in individuals with CNP, compared to asymptomatic controls

• n = 21

• Neck pain persisting longer than 3 months

• NDI score higher than 10/100

• n = 21

• No experience of neck pain for longer than 3 months

• No current presence of neck pain

• History of trauma or surgery in the spine or head regions

• Neurological deficits resultant from neck disorders

• Lack of anatomical integrity of the foot

• History of surgery or trauma in the foot region

• Other musculoskeletal or neurological problems which may affect gait performance

• PS

• PS + HR

• FS

• Timing gate system with two gates placed 10 m apart within 16 m walkway

• Gait speed (m/s)

• Step length (cm)

• Cadence (steps/min)

• Gait stability ratio (step/min)

Lee (2022) USA [24]

Cross-Sectional

To compare gait spatiotemporal parameters, such as cadence, speed, stride length, and step width, as well as the normalized similarity index of the kinematic data in the upper and lower limbs during gait between participants with and without NP

• n = 18

• Right upper and lower limb dominant

• Nonspecific chronic neck pain persisting for at least 3 months prior to data collection

• No serious pathology such as neurological or balance disorders, pain, or current injuries in the back and lower limbs

• No conditions that would prevent them from walking

• n = 17

• Selected based on similar characteristics as exposure group (age, BMI, limb dominance)

• Diagnosis of a psychological illness that may interfere with the study protocol

• Pregnant

• PS

• Kinematic data collected from force plates and digital infrared cameras synchronized with reflective markers

• Gait trials utilized a 10 m walkway with force plates

• Speed (cm/s)

• Cadence (steps/min)

• Stride length (cm)

• Step width (cm)

Poole (2008) Australia [49]

Cross-Sectional

To determine if any differences existed in selected standing balance tests and gait speed parameters between elderly subjects with neck pain when compared to elderly subjects without neck pain

• n = 16

• Neck pain greater than 3 months duration

• NDI score higher than 10/100

• n = 16

• No inclusion criteria specified

• Taking more than 4 medications

• History of falls

• Recent orthopedic surgery (hip/knee/ankle problems)

• Inner ear pathology

• Stroke

• Head injury

• Diabetes

• Neurological or vestibular pathology

• Arthritis requiring active management, pain management

• Acute injuries (such as ankle/knee sprains)

• PS

• PS + HR

• 10MWT with stride analyser

• Time (s)

• Strides

• Cadence (steps/s)

• Stride length (cm)

• Gait cycle duration (s)

Shehab (2021) Egypt [53]

Case control

To evaluate if there a significant correlation between neck pain and gait parameters in people suffering from neck pain

• n = 26

• Presence of chronic mechanical neck pain for more than three months

• Possessed the requisite cognitive abilities to comprehend the study's requirements

• n = 26

• No inclusion criteria specified

• History of cervical spine surgery

• Orthopedic problems affecting the cervical spine

• Vision or hearing problems

• Cervical radiculopathy or myelopathy

• PS

• Biodex Gait Trainer 2 for 3 min

• Walking velocity (m/s)

• R step length (cm)

• L step length (cm)

• Time on R foot (%)

• Time on L foot (%)

Sremakaew (2021) Thailand [50]

Cross-Sectional

To investigate the effect of challenging walking tasks (i.e., tandem walk, and cognitive and motor dual-task walks) on gait speed in persons with neck pain compared with asymptomatic controls

• n = 30

• Presence of idiopathic neck pain had neck pain for more than 3 months

• Scored ≥ 10/100 on the Thai version of the Neck Disability Index (NDI-TH)

• n = 30

• No presence of neck pain, headache, and dizziness for at least the past 6 months

• History of traumatic neck injury/surgery

• Known or suspected vestibular pathology

• Neurological deficits

• Visual problem

• Cognitive impairment

• Musculoskeletal injury/disorders that could interfere with gait speed tests

• Taking more than four medications

• PS

• Tandem walk

• Cognitive DT

• Motor DT

• 10MWT using digital stopwatch

• Gait speed (m/s)

Stokell(2011) Australia [51]

Cross-Sectional

To determine whether postural stability differed between subjects with persistent whiplash and

healthy controls in selected clinical dynamic and functional balance

measures

• n = 20

• Persistent neck pain associated with whiplash (at least three months post injury and still suffering from pain)

• NDI score higher than 10/100

• n = 20

• No history of whiplash, neck pain, headache, or dizziness

• Cervical fracture or dislocation

• Reported period of unconsciousness, post-traumatic amnesia or concurrent head injury with the whiplash injury

• Known or suspected vestibular pathology such as benign paroxysmal positional vertigo

• History of dizziness prior to the whiplash injury

• Neurological deficits, lower limb problems, and additional medical problems that might affect performance

• PS

• PS + HR

• PS + HN

• 10MWT with stopwatch

• Seconds

• Steps

Uthaikhup (2012) Thailand [52]

Cross-Sectional

To investigate eye movement control, cervical proprioception, postural stability and gait parameters in elders with neck pain to determine if there were any deficits in sensorimotor function above those which could be attributed to aging

• n = 20

• Presence of neck pain as a predominant complaint

• Neck pain no less than 3 months duration

• NDI score higher than 10/100

• n = 20

• No inclusion criteria specified

• History of orthopedic surgery

• Current acute musculoskeletal injury

• Lumbar spine or lower limb arthritis for which they had sought active management

• Neurological problems (e.g. stroke, Parkinson’s disease)

• Diabetes

• Cognitive impairment

• PS

• PS + HR

• PS + HN

• 10MWT with stopwatch

• Gait speed (cm/s)

• Cadence (steps/min)

Uthaikhup (2014) Thailand [23]

Cross-Sectional

1. To determine temporospatial gait parameters during walking with different head movements and at different walking speeds in patients with chronic

idiopathic neck pain compared to asymptomatic individuals

2. To determine the relationships between gait speed and pain intensity and disability

• n = 20

• Neck pain no less than 3 months duration

• NDI score higher than 10/100

• n = 20

• No inclusion criteria specified

• Previous history of neck injury

• Known or suspected vestibular pathology

• Neurological deficits

• Musculoskeletal problem/s that could affect gait performance

• Cognitive impairment

• Taking more than four medications

• PS

• PS + HR

• PS + HN

• FS

• 12 m GAITRite walkway

• R/L step length (cm)

• R/L stride length (cm)

• R/L step width (cm)

• R/L step time (s)

• R/L stride time (s)

• Gait speed (cm/s)

• Cadence (steps/min)

Wannaprom (2018) Thailand [54]

Cohort

To clarify the extent of vibration-induced motor responses of neck muscles on both static standing balance and gait speed in persons with and without neck pain

• n = 30

• Neck pain for more than 3 months

• No radicular pain

• NDI-TH score higher than 10/100

• n = 30

• No history of either neck pain, frequent intermittent headache or dizziness in the past 6 months

• Previous history of neck injury

• Known or suspected vestibular pathology, neurological deficit, musculoskeletal problem(s) that could affect balance and gait speed tests

• Taking more than four medications

• FS

• 10MWT with stopwatch

• Gait speed (m/s)