Erector Spinae Muscle Activation During Forward Movement in Individuals With or Without Chronic Lower Back Pain: A Systematic Review and Meta-analysis.

Objective: To investigate the differences between erector spinae muscle activation in healthy individuals and patients with Chronic Lower Back Pain (CLBP) by conducting (a) systematic review and (b) meta-analysis. Data Sources: PubMed, ScienceDirect, SPORTDiscus, and Google Scholar were used to conduct the searches, which included studies up to the 31st of March 2023 with no start date specified. Study Selection: Any study otherwise meeting eligibility criteria was included if it reported either (1) a standard mean difference effect size; or (2) the means, SDs, and sample sizes for both the patient group and the comparator group. Data Extraction: A total of 7 case control trials were used for the systematic review and meta-analysis. Data Synthesis: The systematic review and meta-analysis revealed that total standardized mean difference in erector spinae muscle activation between healthy individuals vs patients with CLBP expressed in % maximum voluntary isometric contraction was 0.48 (95% confidence interval=0.21-0.74; P<.001) with the heterogeneity being I2=0% (P=.890). The electromyography (EMG) outputs showed significant differences in activation levels between the healthy and CLBP cohorts (P<.001). Conclusions: A small effect size was found in the meta-analysis. The muscle activation levels of the erector spinae during forward propulsion were higher in CLBP individuals compared with healthy cohorts. The findings provide more clarity about the muscles that were the focus of previous research, what procedures were used to evaluate muscular contributions and what speeds the participants were moving at during the test sessions. Given the limited methodological quality of the included studies, the findings should be interpreted with caution. Future research should evaluate the effect of other factors such as walking distance and any changes in walking surfaces and gradients (ie, non-flat surfaces).

An assessment of hand volumetric and temperature changes during office related repetitive activities.

BACKGROUND: Hand usage and movement is routinely performed by all individuals daily irrespective of age. These movements can vary and can be repetitive in nature. Exposure of the hard and soft tissues of the hand to prolonged repetitive activities could contribute to the development of work related upper limb disorders (WRULD). OBJECTIVE: Within the work setting, work related upper limb disorders (WRULDs) rank high in the United Kingdom (UK), second only to back complaints. This paper reports the amount of tendon travel and swelling that occurs in the hand during repetitive office activities associated with WRULDs. PARTICIPANTS: Nine healthy adults (five males; four females) participated in the study. METHODS: A 30-minute laboratory-based simulated office activity that consisted of data entry, mouse clicking and dragging, and mouse scrolling tasks was performed. Participants wore a custom-made cost effective flexible electrogoniometric glove (FEG) as two experimental conditions were tested; namely, FEG - only, and FEG using a Splint (FEG - Splint). RESULTS: The FEG - only condition produced a higher overall tendon travel compared to the FEG - Splint condition. Both hands presented no statistically significant differences in hand temperature (p > 0.05) and hand volume increments (p > 0.05) with respect to the FEG - only and FEG - Splint office activity experiments. All participants that showed a decrease in hand volumetric measurement produced final temperature measurements lower than initial temperature measurements taken at the commencement of the experiment. Based on participants' perception, the mouse scrolling task was deemed as most strenuous. CONCLUSION: The findings can help to advise patients on biomechanical 'risks' associated with repetitive activities.

The evaluation of an inexpensive, 2D, video based gait assessment system for clinical use.

The purpose of this study was to investigate the clinical potential of an augmented-video-based-portable-system (AVPS). The AVPS included a walkway grid mat made of vinyl flooring, flat paper bull's eye markers, four photoswitches mounted on tripods, a light-indicator, a video camera, and a computer with ProTrainer System software. The AVPS output was compared to a "gold standard" 3D Vicon Motion Analysis System both statically and dynamically over a fixed range (-90° to +90°) using a two-segment-goniometric-rig marked with both bull's eye and retroreflective markers. At each segment angle position, three trials of data were captured. The reliability of the AVPS was also tested using three raters. Further twelve, young, healthy subjects participated in a concurrent validity study in which they performed six gait trials which were simultaneously recorded by both systems. Both motion analysis systems showed low levels of intra subject variability in all kinematic variables indicated by the size of the standard deviations across the six trials. There were no significant differences between the motion systems with respect to the kinematic variables (P>0.05). The results showed a high intra- and inter-rater reliability for both the kinematic and temporo-spatial parameters. With respect to gait events the lowest ICC value for the intra-rater reliability test was 0.993 for the kinematic variables, and ranged from 0.941 to 0.956 for the temporo-spatial variables and 0.731 to 0.954 for the tibia inclination angles. The validation data suggest the AVPS is capable of generating highly reliable and repeatable data when applied to normal subjects and could be used within the clinical setting.

A wrist tendon travel assessment of hand movements associated with industrial repetitive activities.

OBJECTIVE: To investigate slow and fast paced industrial activity hand repetitive movements associated with carpal tunnel syndrome where movements are evaluated based on finger and wrist tendon travel measurements. METHODS: Nine healthy subjects were recruited for the study aged between 23 and 33 years. Participants mimicked an industrial repetitive task by performing the following activities: wrist flexion and extension task, palm open and close task; and pinch task. Each task was performed for a period of 5 minutes at a slow (0.33 Hz) and fast (1 Hz) pace for a duration of 3 minutes and 2 minutes respectively. RESULTS: Tendon displacement produced higher flexor digitorum superficialis (FDS) tendon travel when compared to the flexor digitorum profundus (FDP) tendons. The left hand mean (SD) tendon travel for the FDS tendon and FDP tendon were 11108 (5188) mm and 9244 (4328) mm while the right hand mean tendon travel (SD) for the FDS tendon and FDP tendon were 9225 (3441) mm and 7670 (2856) mm respectively. Of the three tasks mimicking an industrial repetitive activity, the wrist flexion and extension task produced the most tendon travel. CONCLUSION: The findings may be useful to researchers in classifying the level of strenuous activity in relation to tendon travel.

A comparison of two interventions designed to promote neutral wrist postures during simple computer operations.

OBJECTIVE: To compare two postural interventions, a wrist splint and a Wrist Alignment Device (WAD) with a biofeedback mechanism. PARTICIPANTS: Nine right-handed healthy individuals participated in the study. METHODS: Using both hands independently a 30-minute office-activity-experiment was performed that consisted of data entry, mouse clicking, text dragging, and mouse scrolling executed one after the other. Joint motion, tendon travel and productivity levels were measured. Participants wore a custom-made flexible electrogoniometric glove (FEG) as three scenarios were tested; namely FEG-only, FEG-Splint, and FEG-WAD. Data analysis was performed using descriptive statistics and ANOVA. RESULTS: The joint motion results produced insignificant differences (p>0.05) between hands. Both hands showed larger overall tendon travel for the FEG-only when compared with either FEG-Splint or FEG-WAD experiments. Wearing the splint reduced the overall tendon travel by 24% and 10% for the left and right hands while using the WAD further reduced the overall tendon travel for the left and right hands by 51% and 42%. Productivity levels were similar across participants with respect to experiment task and type. CONCLUSION: The WAD intervention is the most suitable device to promote a comfortable and non-restrictive neutral wrist posture.

Tendon and nerve displacement at the wrist during finger movements.

BACKGROUND: Repetitive motion of the hand has been suggested as a major factor of pathogenesis of cumulative trauma disorders (e.g., carpal tunnel syndrome). The purpose of this study was to investigate the 3D displacement of the median nerve and extrinsic finger flexor tendons (flexor digitorum superficialis; flexor digitorum profundus) as a function of flexion/extension of metacarpophalangeal joints of the index and middle fingers. METHODS: Shim markers were placed on the median nerve, flexor digitorum superficialis, and flexor digitorum profundus tendons at the wrist region of seven cadaveric specimens for the purpose of digitization of tendon and nerve locations. The metacarpophalangeal joint of the index or middle finger was moved from 15 degrees extension to 75 degrees of flexion while the markers were digitized at increments of 15 degrees. Marker displacements were determined in the longitudinal, radial-ulnar, and dorsal-palmar directions. FINDINGS: Movement of metacarpophalangeal joint of the index or middle finger caused tendon and nerve displacements in the longitudinal, radial-ulnar, and dorsal-palmar directions. The longitudinal displacements of the median nerve and the flexor tendons were linearly correlated with angular movement of the metacarpophalangeal joint. The maximum longitudinal displacements of the flexor digitorum superficialis tendon, flexor digitorum profundus tendon, and median nerve were, on average, 14.7 mm, 11.9 mm, and 3.0 mm, respectively, for the index finger; and 18.4 mm, 14.5 mm, and 4.0 mm, respectively, for the middle finger. The radial-ulnar and dorsal-palmar displacements were irregular and relatively small. The maximum displacements in these transverse directions fell in the range of 1.4-5.1 mm for the median nerve and 1.9-7.3 mm for the flexor tendons. INTERPRETATIONS: Finger flexor tendons and median nerve move not only concurrently, but also differentially, in all anatomical directions. Tendon and nerve movement during prolonged repetitive hand movement may cause hand disorders such as carpal tunnel syndrome.