Daniela Aldabe

Pregnancy-related pelvic girdle pain and its relationship with relaxin levels during pregnancy: a systematic review

PurposeThe present systematic review assessed the level of evidence for the association between relaxin levels and pregnancy-related pelvic girdle pain (PPGP) during pregnancy.MethodsPRISMA guidelines were followed to conduct this systematic review. Electronic search was carried out using six different databases. Observational cohorts, cross-sectional or case–control studies focused on the association between relaxin levels and PPGP during pregnancy were included. Studies selection was conducted by two reviewers who screened firstly for titles, then for abstracts and finally for full articles. Risk of bias was assessed using the Newcastle–Ottawa scale and the quality of evidence by the guidelines proposed by the Cochrane back review group.Results731 references were identified. Six articles met the inclusion criteria and were considered for this systematic review. The main reason for the studies exclusion was PPGP related to gynaecological reasons. Five studies were case–control and one study was a prospective cohort. Four studies were ranked as high while two were ranked as low quality. Among the high quality studies, three found no association between PPGP and relaxin levels.ConclusionsBased on these findings, the level of evidence for the association between PPGP and relaxin levels was found to be low. PPGP assessment and controlling for risk factors were found to increase bias leaving uncertainty in interpretation of these findings and a need for further research.

Is pregnancy related pelvic girdle pain associated with altered kinematic, kinetic and motor control of the pelvis? A systematic review

PurposeTo determine the level of evidence for altered mechanical and motor control of the pelvis being associated with pregnancy-related pelvic girdle pain (PPGP).MethodsThis systematic review was undertaken by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Six different databases were used for the electronic search. Observational cohorts, cross sectional or case–control studies focused on the association between altered kinematic/kinetic and motor control of the pelvis and PPGP during pregnancy were included. Study selection was conducted by two reviewers who firstly screened for titles, then for abstracts and finally for full articles. The Newcastle–Ottawa scale and the guidelines proposed by the Cochrane back review group were used to assess risk of bias and quality of evidence, respectively.Results354 references were identified, and after excluding unwanted articles, 10 studies met the final inclusion criteria. Studies not related to motor control or pelvic mobility were the main reason for exclusion. Seven studies were case–control and three were prospective cohort studies. Seven studies were ranked as high while three were ranked as low quality. Among the high quality studies, six found association between PPGP and altered motor control and mobility of the pelvis.ConclusionsThe level of evidence for an association between PPGP and altered motor control and kinematic or kinetic parameters of the pelvis was found to be moderate.

Dose–response relationship between work-related cumulative postural exposure and low back pain: A systematic review

OBJECTIVES To assess the evidence for a dose-response relationship between ROM, duration, and frequency of trunk flexion, and risk of occupational LBP. METHODS An electronic systematic search was conducted using Medline, Cumulative Index to Nursing and Allied Health Literature, EMBASE, and Scopus databases focusing on cohort and case-control studies. Studies were included if they focused on non-specific LBP and postural exposure, considering ROM, duration, or frequency of trunk flexion as independent variables. No language restriction was imposed. Included studies were assessed for risk of bias using the Newcastle-Ottawa Scale for observational studies and a summary of evidence is presented. RESULTS Eight studies were included and all were methodologically rated as high quality. The included studies yielded a total of 7023 subjects who were considered for risk analysis. Different outcome measures for postural exposure were adopted making meta-analysis difficult to perform. CONCLUSIONS We could not find a clear dose-response relationship for work posture exposures and LBP. Limited evidence was found for ROM and duration of sustained flexed posture as risk factor for LBP. We found no evidence for frequency of trunk flexion as a risk factor for LBP.

Shoulder Kinematics Is Not Influenced by External Load During Elevation in the Scapular Plane

The current study aimed to compare the shoulder kinematics (3D scapular orientation, scapular angular displacement and scapulohumeral rhythm) of asymptomatic participants under unloaded and loaded conditions during unilateral shoulder elevation in the scapular plane. We used a repeated-measures design with a convenience sample. Eleven male participants with an age range of 21-28 years with no recent history of shoulder injury participated in the study. The participants performed isometric shoulder elevation from a neutral position to approximately 150 degrees of elevation in the scapular plane in intervals of approximately 30 degrees during unloaded and loaded conditions. Shoulder kinematic data were obtained with videogrammetry. During shoulder elevation, the scapula rotated upwardly and externally, and tilted posteriorly. The addition of an external load did not affect 3D scapular orientation, scapular angular displacement, or scapulohumeral rhythm throughout shoulder elevation (P > .05). In clinical practice, clinicians should expect to observe upward and external rotation and posterior tilt of the scapula during their assessments of shoulder elevation. Such behavior was not influenced by an external load normalized to 5% of body weight when performed in an asymptomatic population.

Sex differences in anticipatory postural adjustments during rapid single leg lift

The aim of this study was to assess the influence of sex on the kinetic, kinematic and neuromuscular correlates of anticipatory postural adjustments (APAs) during a single leg lift task performed by healthy participants. Fifty healthy age and body mass index matched participants (25 women and 25 men) performed 20 single leg lift task (hip flexion to 90 ° as quickly as possible) with their dominant and their non-dominant lower limbs. A force plate was used to determine the medial-lateral displacement of the center of pressure (COPML), and the initiation of weight shift (T0); kinematics was used to determine leg lift (T1); and electromyography was used to determine onset times from eight muscles: bilateral external oblique, internal oblique and lumbar multifidus, and unilateral (stance limb) gluteus maximus and biceps femoris. Movement control limb dominance was included in the analysis. Statistically significant interactions between sex and limb dominance (p < .001) were observed for T1, COPML, and muscle onsets. Also, statistically significant main effect of sex on T0 was observed. Women showed increased APA time (T1) and magnitude (COPML) in their dominant limbs compared to men. Such differences between sexes did not occur in the non-dominant limb. Women recruited proximal muscles later than their man counterparts. Overall, women appear to have a stronger effect of limb dominance on their anticipatory postural control strategy which requires further investigation. The findings of the current study indicate that women and men differ in their anticipatory postural control strategy for rapid single leg lift.

Reliability of surface electromyography activity of gluteal and hamstring muscles during sub-maximal and maximal voluntary isometric contractions

BACKGROUND Normalizing to a reference signal is essential when analysing and comparing electromyography signals across or within individuals. However, studies have shown that MVC testing may not be as reliable in persons with acute and chronic pain. OBJECTIVES The purpose of this study was to compare the test-retest reliability of the muscle activity in the biceps femoris and gluteus maximus between a novel sub-MVC and standard MVC protocols. METHODS This study utilized a single individual repeated measures design with 12 participants performing multiple trials of both the sub-MVC and MVC tasks on two separate days. The participant position in the prone leg raise task was standardised with an ultrasonic sensor to improve task precession between trials/days. Day-to-day and trial-to-trial reliability of the maximal muscle activity was examined using ICC and SEM. FINDINGS Day-to-day and trial-to-trial reliability of the EMG activity in the BF and GM were high (0.70-0.89) to very high (≥0.90) for both test procedures. %SEM was <5-10% for both tests on a given day but higher in the day-to-day comparisons. The lower amplitude of the sub-MVC is a likely contributor to increased %SEM (8-13%) in the day-to-day comparison. CONCLUSIONS The findings show that the sub-MVC modified prone double leg raise results in GM and BF EMG measures similar in reliability and precision to the standard MVC tasks. Therefore, the modified prone double leg raise may be a useful substitute for traditional MVC testing for normalizing EMG signals of the BF and GM.

Concurrent validity and reliability of using ground reaction force and center of pressure parameters in the determination of leg movement initiation during single leg lift

Postural adjustment evaluations during single leg lift requires the initiation of heel lift (T1) identification. T1 measured by means of motion analyses system is the most reliable approach. However, this method involves considerable workspace, expensive cameras, and time processing data and setting up laboratory. The use of ground reaction forces (GRF) and centre of pressure (COP) data is an alternative method as its data processing and setting up is less time consuming. Further, kinetic data is normally collected using frequency samples higher than 1000Hz whereas kinematic data are commonly captured using 50-200Hz. This study describes the concurrent-validity and reliability of GRF and COP measurements in determining T1, using a motion analysis system as reference standard. Kinematic and kinetic data during single leg lift were collected from ten participants. GRF and COP data were collected using one and two force plates. Displacement of a single heel marker was captured by means of ten Vicon(©) cameras. Kinetic and kinematic data were collected using a sample frequency of 1000Hz. Data were analysed in two stages: identification of key events in the kinetic data, and assessing concurrent validity of T1 based on the chosen key events with T1 provided by the kinematic data. The key event presenting the least systematic bias, along with a narrow 95% CI and limits of agreement against the reference standard T1, was the Baseline COPy event. Baseline COPy event was obtained using one force plate and presented excellent between-tester reliability.