Musculoskeletal disorder and pain associated with smartphone use: A systematic review of biomechanical evidence.

The number of smartphone users is growing dramatically. Using the smartphone frequently forces the users to adopt an awkward posture leading to an increased risk of musculoskeletal disorders and pain. The objective of this study is to conduct a systematic review of studies that assess the effect of smartphone use on musculoskeletal disorders and pain. A systematic literature search of AMED, CINAHL, PubMed, Proquest, ScienceDirect using specific keywords relating to smartphone, musculoskeletal disorders and pain was conducted. Reference lists of related papers were searched for additional studies. Methodological quality was assessed by two independent reviewers using the modified Downs and Black checklist. From 639 reports identified from electronic databases, 11 were eligible to include in the review. One paper was found from the list of references and added to the review. The quality scores were rated as moderate. The results show that muscle activity of upper trapezius, erector spinae and the neck extensor muscles are increased as well as head flexion angle, head tilt angle and forward head shifting which increased during the smartphone use. Also, smartphone use in a sitting position seems to cause more shift in head-neck angle than in a standing position. Smartphone usage may contribute to musculoskeletal disorders. The findings of the included papers should be interpreted carefully in light of the issues highlighted by the moderate-quality assessment scores.

Multi-segment analysis of spinal kinematics during sit-to-stand in patients with chronic low back pain.

While alterations in spinal kinematics have been frequently reported in patients with chronic low back pain (CLBP), a better characterization of the kinematics during functional activities is needed to improve our understanding and therapeutic solutions for this condition. Recent studies on healthy subjects showed the value of analyzing the spine during sit-to-stand transition (STST) using multi-segment models, suggesting that additional knowledge could be gained by conducting similar assessments in CLBP patients. The objectives of this study were to characterize three dimensional kinematics at the lower lumbar (LLS), upper lumbar (ULS), lower thoracic (LTS) and upper thoracic (UTS) joints during STST, and to test the hypothesis that CLBP patients perform this movement with smaller angle and angular velocity compared to asymptomatic controls. Ten CLBP patients (with minimal to moderate disability) and 11 asymptomatic controls with comparable demographics (52% male, 37.4±5.6 years old, 22.5±2.8kg/m(2)) were tested using a three-dimensional camera-based system following previously proposed protocols. Characteristic patterns of movement were identified at the LLS, ULS and UTS joints in the sagittal plane only. Significant differences in the form of smaller sagittal-plane angle and smaller angular velocity in the patient group compared to the control group were observed at these three joints. This indicated a more rigid spine in the patient group and suggested that CLBP rehabilitation could potentially be enhanced by targeting movement deficits in functional activities. The results further recommended the analysis of STST kinematics using a pelvis-lumbar-thoracic model including lower and upper lumbar and thoracic segments.

Measurement of hand/handrim grip forces in two different one arm drive wheelchairs.

PURPOSE: The aim of this study was to explore the total and regional grip forces in the hand when propelling two different manual one arm drive wheelchairs: the Neater Uni-wheelchair (NUW) and a foot steered Action3 wheelchair. METHODS: 17 nondisabled users were randomly assigned to each wheelchair to drive around an indoor obstacle course. The Grip, a multiple sensor system taking continuous measurement of handgrip force, was attached to the propelling hand. Total grip force in each region of the hand and total grip force across the whole hand were calculated per user per wheelchair. RESULTS: The Action3 with foot steering only generated significantly greater total grip force in straight running compared to the NUW and also in the fingers and thumb in straight running. CONCLUSIONS: The results suggest that the Action3 with foot steering generated greater grip forces which may infer a greater potential for repetitive strain injury in the upper limb. Further work is required to explore whether the difference in grip force is of clinical significance in a disabled population.

A comparison of vertical reaction forces during propulsion of three different one-arm drive wheelchairs by hemiplegic users.

PURPOSE: The aim of this pilot study was to compare the vertical reaction forces (N) generated in three different Action 3 manual one-arm drive wheelchairs: dual handrim, a lever drive and a Neater Uni-wheelchair (NUW). A CONFORmat® Pressure measurement mat, placed on top of the users' prescribed cushion, measured vertical force at the buttock/seat interface on both hemiplegic and non-hemiplegic sides in each wheelchair. METHODS: Fifteen hemiplegic users were randomly assigned each wheelchair to drive around an indoor obstacle course. During propulsion of a multiple sensor, continuous measurement of force was recorded. Time taken to complete the circuit was recorded. Mean force and confidence intervals for each buttock were calculated per user per wheelchair. RESULTS: The dual handrim produced the highest vertical force during propulsion under the right buttock (x= 484.43; SD = 55.4; p < 0.001) and the lever drive produced the least force (x= 368.05; SD = 53.55; p < 0.01). The NUW completed the course quickest (p < 0.01). CONCLUSIONS: The dual-handrim wheelchair requires the greatest vertical force during propulsion. Since increases in this seat vertical reaction force may be related to the propulsive force. Further investigation is indicated as this may be a significant factor for clinicians when prescribing one-arm drive wheelchairs. Implications for Rehabilitation Review of clinical reasoning in prescribing wheelchairs. Addition of the Neater Uni-wheelchair to wheelchair services prescribing lists.