When to Pull the Trigger: Conceptual Considerations for Approximating Head Acceleration Events Using Instrumented Mouthguards.

Head acceleration events (HAEs) are acceleration responses of the head following external short-duration collisions. The potential risk of brain injury from a single high-magnitude HAE or repeated occurrences makes them a significant concern in sport. Instrumented mouthguards (iMGs) can approximate HAEs. The distinction between sensor acceleration events, the iMG datum for approximating HAEs and HAEs themselves, which have been defined as the in vivo event, is made to highlight limitations of approximating HAEs using iMGs. This article explores the technical limitations of iMGs that constrain the approximation of HAEs and discusses important conceptual considerations for stakeholders interpreting iMG data. The approximation of HAEs by sensor acceleration events is constrained by false positives and false negatives. False positives occur when a sensor acceleration event is recorded despite no (in vivo) HAE occurring, while false negatives occur when a sensor acceleration event is not recorded after an (in vivo) HAE has occurred. Various mechanisms contribute to false positives and false negatives. Video verification and post-processing algorithms offer effective means for eradicating most false positives, but mitigation for false negatives is less comprehensive. Consequently, current iMG research is likely to underestimate HAE exposures, especially at lower magnitudes. Future research should aim to mitigate false negatives, while current iMG datasets should be interpreted with consideration for false negatives when inferring athlete HAE exposure.

Head Acceleration Events in Male Community Rugby Players: An Observational Cohort Study across Four Playing Grades, from Under-13 to Senior Men.

OBJECTIVES: The aim of this study was to examine the cumulative head acceleration event (HAE) exposure in male rugby players from the Under-13 (U13) to senior club level over 4 weeks of matches and training during the 2021 community rugby season. METHODS: This prospective, observational cohort study involved 328 male rugby players. Players were representative of four playing grades: U13 (N = 60, age 12.5 ± 0.6 years), U15 (N = 100, age 14.8 ± 0.9 years), U19 (N = 78, age 16.9 ± 0.7 years) and Premier senior men (N = 97, age 22.5 ± 3.1 years). HAE exposure was tracked across 48 matches and 113 training sessions. HAEs were recorded using boil-and-bite instrumented mouthguards (iMGs). The study assessed the incidence and prevalence of HAEs by ages, playing positions, and session types (match or training). RESULTS: For all age grades, weekly match HAE incidence was highest at lower magnitudes (10-29 g). Proportionally, younger players experienced higher weekly incidence rates during training. The U19 players had 1.36 times the risk of high-magnitude (> 30 g) events during matches, while the U13 players had the lowest risk compared with all other grades. Tackles and rucks accounted for the largest HAE burden during matches, with forwards having 1.67 times the risk of > 30 g HAEs in rucks compared with backs. CONCLUSIONS: This study provides novel data on head accelerations during rugby matches and training. The findings have important implications for identifying populations at greatest risk of high cumulative and acute head acceleration. Findings may guide training load management and teaching of skill execution in high-risk activities, particularly for younger players who may be exposed to proportionally more contact during training and for older players during matches.

Instrumented Mouthguards in Elite-Level Men's and Women's Rugby Union: The Incidence and Propensity of Head Acceleration Events in Matches.

OBJECTIVES: The aim of this study was to examine head acceleration event (HAE) propensity and incidence during elite-level men's and women's rugby union matches. METHODS: Instrumented mouthguards (iMGs) were fitted in 92 male and 72 female players from nine elite-level clubs and three international teams. Data were collected during 406 player matches (239 male, 167 female) using iMGs and video analysis. Incidence was calculated as the number of HAEs per player hour and propensity as the proportion of contact events resulting in an HAE at a range of linear and angular thresholds. RESULTS: HAE incidence above 10 g was 22.7 and 13.2 per hour in men's forwards and backs and 11.8 and 7.2 per hour in women's forwards and backs, respectively. Propensity varied by contact event, with 35.6% and 35.4% of men's tackles and carries and 23.1% and 19.6% of women's tackles and carries producing HAEs above 1.0 krad/s2. Tackles produced significantly more HAEs than carries, and incidence was greater in forwards compared with backs for both sexes and in men compared with women. Women's forwards were 1.6 times more likely to experience a medium-magnitude HAE from a carry than women's backs. Propensity was similar from tackles and carries, and between positional groups, while significantly higher in men than women. The initial collision stage of the tackle had a higher propensity than other stages. CONCLUSION: This study quantifies HAE exposures in elite rugby union players using iMGs. Most contact events in rugby union resulted in lower-magnitude HAEs, while higher-magnitude HAEs were comparatively rare. An HAE above 40 g occurred once every 60-100 min in men and 200-300 min in women. Future research on mechanisms for HAEs may inform strategies aimed at reducing HAEs.

Digital Technologies for Women's Pelvic Floor Muscle Training to Manage Urinary Incontinence Across Their Life Course: Scoping Review.

BACKGROUND: Women with urinary incontinence (UI) may consider using digital technologies (DTs) to guide pelvic floor muscle training (PFMT) to help manage their symptoms. DTs that deliver PFMT programs are readily available, yet uncertainty exists regarding whether they are scientifically valid, appropriate, and culturally relevant and meet the needs of women at specific life stages. OBJECTIVE: This scoping review aims to provide a narrative synthesis of DTs used for PFMT to manage UI in women across their life course. METHODS: This scoping review was conducted in accordance with the Joanna Briggs Institute methodological framework. A systematic search of 7 electronic databases was conducted, and primary quantitative and qualitative research and gray literature publications were considered. Studies were eligible if they focused on women with or without UI who had engaged with DTs for PFMT, reported on outcomes related to the use of PFMT DTs for managing UI, or explored users' experiences of DTs for PFMT. The identified studies were screened for eligibility. Data on the evidence base for and features of PFMT DTs using the Consensus on Exercise Reporting Template for PFMT, PFMT DT outcomes (eg, UI symptoms, quality of life, adherence, and satisfaction), life stage and culture, and the experiences of women and health care providers (facilitators and barriers) were extracted and synthesized by ≥2 independent reviewers. RESULTS: In total, 89 papers were included (n=45, 51% primary and n=44, 49% supplementary) involving studies from 14 countries. A total of 28 types of DTs were used in 41 primary studies, including mobile apps with or without a portable vaginal biofeedback or accelerometer-based device, a smartphone messaging system, internet-based programs, and videoconferencing. Approximately half (22/41, 54%) of the studies provided evidence for or testing of the DTs, and a similar proportion of PFMT programs were drawn from or adapted from a known evidence base. Although PFMT parameters and program compliance varied, most studies that reported on UI symptoms showed improved outcomes, and women were generally satisfied with this treatment approach. With respect to life stage, pregnancy and the postpartum period were the most common focus, with more evidence needed for women of various age ranges (eg, adolescent and older women), including their cultural context, which is a factor that is rarely considered. Women's perceptions and experiences are often considered in the development of DTs, with qualitative data highlighting factors that are usually both facilitators and barriers. CONCLUSIONS: DTs are a growing mechanism for delivering PFMT, as evidenced by the recent increase in publications. This review highlighted the heterogeneity in types of DTs, PFMT protocols, the lack of cultural adaptations of most of the DTs reviewed, and a paucity in the consideration of the changing needs of women across their life course.

Anticipatory head control mechanisms in response to impact perturbations: An investigation of club rugby players with and without a history of concussion injury.

OBJECTIVES: The primary objective of this study was to examine rugby players anticipatory and compensatory head control during predictable and unpredictable impact events. METHODS: An observational cross-sectional study design. Fifty-one (17_healthy 34_concussion) male rugby players were exposed to external predictable and unpredictable impact perturbations at mid-chest level. Surface EMG of the upper-trapezius (UT), splenius-capitis (Spl) and sternocleidomastoid (Scm) was recorded and analysed across three temporal epochs typical for anticipatory and compensatory postural control. Synchronized sagittal head-kinematics were measured from high-speed video (500 fps). Nonparametric tests were used to examine within and between group effects. RESULTS: Anticipatory head control was evident in predictable conditions, expressed by early posterior head displacement and activation of the Spl. Compared to unpredictable conditions, muscle amplitudes were significantly lower, as was head acceleration. Compared to Healthy, the Concussion athletes lacked early activation of the Spl, exhibited delayed anticipatory head adjustments and experienced higher head accelerations in predictable conditions. CONCLUSION: Rugby players with concussion injuries have significant deficits in cervical spinal motor control. The concussed motor control strategy leads to higher inertial head accelerations and delayed anticipatory head displacements. Effects may persist for two or more years following injury, which may indicate re-injury vulnerability in these athletes.

Influence of the frame of reference on head acceleration events recorded by instrumented mouthguards in community rugby players.

Objectives: To highlight the need for standardisation in the communication of head impact telemetry from instrumented mouthguards (iMG). The purpose of this study is to examine how the frame of reference for reporting head acceleration events (HAE) may affect the interpretation of head impacts recorded from iMGs in community rugby players. Methods: An analytical investigation of 825 video verified HAEs recorded from male community players during 5 rugby match exposures. HAEs were captured with an iMG, known to be reliable and valid for this purpose. The linear and angular head acceleration at the centre of mass (head_CG) was calculated from filtered iMG accelerometer and gyroscope data, and the location of impact was estimated. The iMG and head_CG data were examined for systematic bias, geometric differences and the degree of concordance. Finally, mixed model analyses were fitted to assess the differences in peak resultant acceleration (PLA) by impact locations and directions of head motion while controlling for intra-athlete correlations. Results: The degree of concordance between the iMG versus head_CG measures varied by impact location. The mixed model confirmed differences in the PLA by location (F(8,819) = 16.55, p<0.001) and by direction of head motion (F(5,417) = 7.78, p<0.001). Conclusion: The head acceleration reported at the iMG is not proportional to measurements that have been transformed to the head_CG. Depending on the impact location and direction of head motion, the acceleration measured at the iMG may overestimate, underestimate or miss entirely the PLA with respect to the head_CG. We recommend standardising the reporting of iMG data within the head_CG frame of reference.

Management of women with pregnancy-related pelvic girdle pain: an international Delphi study.

OBJECTIVES: Pregnancy-related pelvic girdle pain (PPGP) contributes to significant prenatal and postpartum impairments; however, various clinical practices exist around the conservative treatment of this condition. This study sought to reach a consensus on the essential components of PPGP management through an international Delphi survey of experts in women's health. DESIGN AND PARTICIPANTS: Eighty-seven international experts in the field of PPGP were invited to participate and surveyed over three rounds. Round 1 of the survey utilised open-ended questions to gain feedback on 16 components of PPGP management previously identified by a focus group. Feedback from panel members guided modification and refinement of questions for Rounds 2 and 3. A 5-point Likert scale was used to rate level of agreement, with a minimum threshold for consensus of ≥75% agreement set across all survey rounds. RESULTS: Forty-four of the 87 (50%) invited professionals agreed to participate in the panel, with 77% (34/44) of panellists contributing to all three rounds. Of the 16 initial components, 15 were included in Round 2. The final consensus was reached on 10 important components of assessment and management after Round 3: pain education, postural and ergonomic advice, social and lifestyle factors, psychological factors, cultural considerations, strengthening exercise, other exercise, exercise precautions, manual therapy and the use of crutches. CONCLUSION: This study identified 10 key components that should be considered in the management of PPGP. In addition, these components provide a potential framework for future research around the conservative management of PPGP.

External workload intensity in cricket fast bowlers across maximal and submaximal intensities: Modifying PlayerLoad and IMU location.

Workload is a commonly accepted risk factor for injury among fast bowlers, however many methods exist to characterise workload. Recently, automated intensity-sensitive measures like PlayerLoad have been used to improve the estimation of workload in fast bowlers. The purpose of this study was to determine whether similar variables could be extracted from a single inertial measurement unit (IMU) that highly correlate with intensity, according to release speed. Eight elite and pre-elite bowlers participated in the study, with each bowler bowling one over each at 60%, 80% and 100% intensity and repeating this across two sessions (36 balls per participant). IMUs were placed on the upper-back and non-bowling wrist and maximum PlayerLoad from each delivery (PLmax) was compared to the accumulated value across each delivery (PLacc). The strongest correlation with release speed was with PLacc from the non-bowling wrist (R = 0.74), followed by PLacc from the upper-back (R = 0.65) and PLmax from the upper back (R = 0.60). Consequently, an improved estimation of the intensity at which bowlers are working at could be gained by examining accumulated PlayerLoad values from an IMU on the non-bowling wrist.

A multivariate model for predicting PPGP considering postural adjustment parameters.

BACKGROUND: Prospective studies have described evidence about the risk of developing pregnancy-related pelvic girdle pain (PPGP) such as, parity, previous history of low back and pelvic girdle pain. No previous studies have prospectively associated PPGP with postural control. AIM: This study aimed to identify postural control predictors of PPGP during pregnancy. METHODS: Forty-six pregnant women were surveyed throughout their pregnancy for the presence of PPGP. At baseline, participants were evaluated for muscle latencies, mediolateral centre-of-pressure (COP) displacement and velocity during single-leg lift performed with eyes open and closed. PPGP was considered if they presented with one positive clinical assessment as well as pain within the pelvic area. RESULTS: Eighteen (45%) of the participants developed PPGP. This group presented with PPGP around a mean 29th week (SD = 5.7), with mean pelvic pain intensity of 4 mm VAS (SD = 2) on a (0-10 cm VAS) and mean PPGP questionnaire score of 21.5 points (SD = 10.6) out of a possible 100 points with 0 indicating no functional disability. The two factors that were significantly associated with PPGP were the right and left biceps femoris (BF) muscle. For every 50 ms of difference of BF muscles latency between eyes open and closed, the risk of PPGP increases by 20% (right BF) and 30% (left BF) to develop PPGP. CONCLUSION(S): This study shows that BF muscle delay during single-leg lift presented at baseline was a significant predictor for the development of PPGP in late pregnancy.

Is there an association between external workload and lower-back injuries in cricket fast bowlers? A systematic review.

OBJECTIVE: To examine the level of evidence for an association between external bowling workload and lower-back injuries in cricket fast bowlers. METHODS: Six online databases were searched using four sets of keywords (relating to cricket, bowler, lumbar, workload). Risk of bias was assessed using the NIH quality assessment tool, while quality of evidence was assessed according to the Cochrane Back and Neck (CBN) group guidelines. RESULTS: Eight articles were found to fit the inclusion/exclusion criteria. It was found that overall, there was a low quality of evidence amongst the included studies. A high risk of bias was present - both in the measurement of external workload and lower-back injuries. CONCLUSION: The association between external workload and lower-back injuries has minimal strength. Technological advancements that allow total workload to be measured accurately would potentially allow the association between workload and lower-back injury to be examined more precisely, possibly leading to effective injury prevention interventions in fast bowlers.

Anticipatory postural control differs between low back pain and pelvic girdle pain patients in the absence of visual feedback.

PURPOSE: The aim of this study was to examine the effect of vision on anticipatory postural control (APA) responses in two groups of clinically diagnosed chronic low back pain patients, those with Posterior Pelvic Girdle pain and those with Non-Specific Low Back Pain compared to a matched group of healthy controls during the modified Trendelenburg task. METHODS: Seventy-eight volunteer participants (60 females and 18 males) gave informed consent to take part in this study. 39 with confirmed LBP or PGP lasting longer than 12 weeks and 39 healthy matched controls performed 40 single leg lift tasks (hip flexion to 90° as quickly as possible) with their non-dominant lower limb. A force plate was used to determine the medial-lateral displacement of the center of pressure, and the initiation of weight shift; kinematics was used to determine initiation of leg lift; and electromyography was used to determine onset times from the external oblique (EO), internal oblique (IO) and lumbar multifidus (MF), gluteus maximus (GM) and biceps femoris (BF). RESULTS: The PGP group showed significantly longer muscle onset latencies in the BF, EO MF with visual occlusion (F2,746 = 4.51, p < .0001). CONCLUSION: The muscle onset delays identified between the two LBP sub-groups suggests that pain may not be the primary factor in alteration of APA response. The PGP group show a greater reliance on vision which may signal impairment in multiple feedback channels.

Is Pelvic Floor Dysfunction Associated With Development of Transient Low Back Pain During Prolonged Standing? A Protocol.

BACKGROUND: Prolonged standing has been associated with an increased prevalence of low back pain (LBP) and is recognized as a potential workplace hazard for employees such as retail staff, assembly line workers, and healthcare personnel. Low back pain is more prevalent in women than in men, and disability due to LBP is worse in women with severe urinary incontinence. However, it is unclear whether pelvic floor dysfunction observed in stress urinary incontinence is a risk factor for LBP. The main purpose of this study is to determine whether co-activation patterns between the pelvic floor and abdominal muscles during a 2-hour prolonged standing task predict transient LBP in women with and without stress urinary incontinence. METHODS: In this is prospective cohort study, 60 female volunteers will stand in a confined area for 2 hours (120 minutes) while performing tasks such as, 'computer work' and 'small object assembly'. The primary outcome measure is transient LBP, which will be monitored every 10 minutes using a numeric pain rating scale. Surface electromyography (EMG) will be collected from the gluteus medius and internal oblique/transverse abdominis muscles, and an intravaginal electrode will be used to monitor pelvic floor muscle activity. The EMG signals will be divided into 12 10-minute blocks to assess changes in co-activation over time. Cross-correlation analyses will be used to quantify co-activation between the muscle pairs (e.g. pelvic floor and internal oblique/transverse abdominis), and the coefficient of co-activation will be expressed as a percentage for each block. A mixed-model regression analysis will be used to determine whether co-activation patterns can predict transient LBP during the prolonged standing task. DISCUSSION: The primary objective of this research is to improve current understanding regarding the role of pelvic floor muscles in the onset of LBP and the potential association between stress urinary incontinence and LBP. These findings have the potential to inform prevention and rehabilitation programmes for women with stress urinary incontinence and LBP. TRIAL REGISTRATION: ACTRN12618000446268 [Protocol Version 2].

Assessing the construct validity of clinical tests to identify sacroiliac joint inflammation in patients with non-radiographic axial spondyloarthritis.

AIM: Magnetic resonance imaging (MRI) can be used to identify sacroiliac joint (SIJ) inflammation and provide an earlier diagnosis of nonradiographic axial spondyloarthritis (nrAxSpA). However, MRI is frequently a resource-limited examination. Our aim was to assess if a set of physical clinical tests can identify SIJ inflammation in patients with nrAxSpA. METHODS: Twenty participants with nrAxSpA underwent two functional tests (active straight leg raise, and stork test on the support side) and four pain provocation tests (Gaenslen's, posterior pelvic pain provocation, Patrick's Faber and palpation of the long dorsal SIJ ligament) for the SIJ, and then proceeded to a contemporaneous reference standard MRI. The Spondyloarthritis Research Consortium of Canada scoring system (SPARCC) was used to score MRI. Specificity, sensitivity, and likelihood ratios (LR) were calculated for individual clinical tests, and for the composite of tests. RESULTS: Pain provocation tests were superior to functional tests, which showed poor accuracy. The Patrick's Faber test was the best performing procedure (sensitivity 71%, specificity 75%, positive LR 2.9, negative LR 0.4). When combining the provocation tests, a positive test in one out of two tests demonstrated the strongest predictive value (sensitivity 86%, specificity 62%, positive LR 2.2, negative LR 0.2). CONCLUSIONS: Sacroiliac joint pain provocation tests correlate modestly with inflammation. The Patrick's Faber test showed the greater LR to identify SIJ inflammation in patients with nrAxSpA. SIJ pain provocation tests may offer a simple and cost-effective way of identifying patients with nrAxSpA who are most likely to have MRI evidence of inflammation.

A Retrospective Study Investigating Injury Incidence and Factors Associated with Injury Among Belly Dancers.

Belly dance is an appreciably under researched dance form. As such, little is known of the injury prevalence and risk factors for injury among this dance population. Therefore, the primary objective of this study was to examine the most common injury sites and to identify potential factors associated with injury risk within the belly dance community of New Zealand over a 12-month retrospective period. Dancers who had practiced or performed belly dance during that time span were surveyed using an online or paper-based questionnaire. One hundred and nine injury questionnaires (all from female dancers) qualified for the final analysis. The participants had a median age of 44.3 years and danced a median of 3.0 hours per week. The injury rate was 37% (40 injuries in 109 dancers surveyed), the injury incidence proportion was 24.8% (27 dancers reporting at least one injury), and the per hour injury incidence rate was 1.69 per 1,000 dance hours. Of the two most recently sustained injuries reported, lower limb injuries were the most common, followed by trunk injuries. Age, total dance hours per week, and participation in a non-dance exercise regimen of any kind were associated with a decreased risk of injury; performing regularly was associated with an increased injury rate. It is concluded that an understanding of the incidence and sites of injuries may help create awareness that belly dance can be injurious, and subsequently lead to the development of future interventions.

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.

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.

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.

Innominate segment deformation during passive hip abduction and external rotation.

BACKGROUND: Electromagnetic palpation-digitization technique for measurement of innominate motion involves calculation of innominate rotation using the innominate vector length in the neutral (NEUT) and combined hip abduction and external rotation (HABER) test positions. The innominate vector length [i.e., the segment between anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS)] is not a rigid structure and its deformation could introduce an error influencing the final innominate rotation measurement. OBJECTIVES: The aim of this study is to determine if there is significant deformation occurring in innominate vector length when the hip is loaded into the HABER test position. METHOD: A cross sectional study using sixteen healthy individuals and a single tester was conducted. Four pelvic landmarks, left and right PSIS and ASIS, were palpated and digitized using 3D digitizing stylus of Polhemus electromagnetic tracking device, in two hip test positions, NEUT and 50° HABER. The innominate vector lengths were calculated from the 3D coordinates of pelvic landmarks, for each hip test positions. RESULTS AND CONCLUSION: Paired t-tests demonstrated no significant differences (p > 0.05) in the innominate vector lengths at the side of the load as well as the opposite innominate when either the right or left hip was loaded; thus indicating no significant bone deformation in innominate segment during the HABER test position.