Reliability of Ultrasound Imaging of the Trunk Musculature in Athletes with and without Hamstring Injuries.

BACKGROUND: Trunk muscles play an important role in providing both mobility and stability during dynamic tasks in athletes. The purpose of this study was to evaluate the within-day and between-day reliability of ultrasound (US) in measuring abdominal and lumbar multifidus muscle (MF) thickness in athletes with and without hamstring strain injury (HSI). METHODS: Fifteen male soccer players (18-30 years old) with and without HSI were evaluated using two US probes (50 mm linear 7.5 MHZ and 70 mm curvilinear 5 MHz). The abdominal muscle thickness as well as the cross sectional area (CSA) of the MF was measured. To determine within and between days reliabilities, the second and third measurements were repeated with two hours and one week intervals, respectively. RESULTS: Intraclass correlation coefficients for athletes with and without HSI demonstrated good to high reliability for the abdominal muscle thickness (0.82 and 0.93) and CSA of the MF muscle (0.84 and 0.89, respectively). CONCLUSION: Our results indicated that US seemed to be a reliable instrument to measure abdominal and lumbar multifidus muscle thickness in soccer players with and without HSI. However, further studies are recommended to support the present study findings in other athletes.

Reliability of Real-time Ultrasound Imaging for the Assessment of Trunk Stabilizer Muscles: A Systematic Review of the Literature.

Rehabilitative ultrasound (US) imaging is one of the popular methods for investigating muscle morphologic characteristics and dimensions in recent years. The reliability of this method has been investigated in different studies. As studies have been performed with different designs and quality, reported values of rehabilitative US have a wide range. The objective of this study was to systematically review the literature conducted on the reliability of rehabilitative US imaging for the assessment of deep abdominal and lumbar trunk muscle dimensions. The PubMed/MEDLINE, Scopus, Google Scholar, Science Direct, Embase, Physiotherapy Evidence, Ovid, and CINAHL databases were searched to identify original research articles conducted on the reliability of rehabilitative US imaging published from June 2007 to August 2017. The articles were qualitatively assessed; reliability data were extracted; and the methodological quality was evaluated by 2 independent reviewers. Of the 26 included studies, 16 were considered of high methodological quality. Except for 2 studies, all high-quality studies reported intraclass correlation coefficients (ICCs) for intra-rater reliability of 0.70 or greater. Also, ICCs reported for inter-rater reliability in high-quality studies were generally greater than 0.70. Among low-quality studies, reported ICCs ranged from 0.26 to 0.99 and 0.68 to 0.97 for intra- and inter-rater reliability, respectively. Also, the reported standard error of measurement and minimal detectable change for rehabilitative US were generally in an acceptable range. Generally, the results of the reviewed studies indicate that rehabilitative US imaging has good levels of both inter- and intra-rater reliability.

The activity pattern of the lumbo-pelvic muscles during prone hip extension in athletes with and without hamstring strain injury.

BACKGROUND: Altered muscular activation pattern has been associated with musculoskeletal disorders. Some previous studies have demonstrated muscle weakness or tightness in athletes who have sustained hamstring (HAM) injuries. However, no study has clinically investigated the muscular activity pattern in subjects with HAM strain injuries. OBJECTIVE: To investigate the activity pattern of the ipsilateral erector spinae (IES), contralateral erector spinae (CES), gluteus maximus (GM), and medial and lateral HAM muscles during the prone hip extension (PHE) test in athletes with and without history of HAM strain injury. DESIGN: Cross-sectional non-experimental study design. PARTICIPANTS: A convenience sample of 20 soccer athletes participated in the study. Subjects were categorized into two groups: those with history of HAM strain injury (n=10, mean age = 22.6 ± 3.74) and without history of HAM strain (n =10, mean age = 22.45 ± 3.77). METHODS: Three repetitions of the PHE were performed by each subject, and the electromyographic (EMG) outputs of the IES, CES, GM, and HAM muscles were recorded, processed and normalized to maximum voluntary electrical activity (MVE). Independent t-tests were used for comparing activation means of each muscle between athletes with and without history of HAM strain injury. RESULTS: There were significant differences in EMG activity of the GM (p= 0.04) and medial HAM (p = 0.01) between two groups. No significant difference was found in EMG signals of the IES (p= 0.26), CES (= 0.33) and lateral HAM (p= 0.58) between the two groups. Greater although non-significant normalized EMG outputes of IES, CES and lateral HAM were seen in athletes with history of HAM strain compared to those without HAM strain. CONCLUSION: The findings of this study demonstrated greater normalized EMG activity of GM and medial HAM tested in athletes with history of HAM strain compared to those without HAM strain (altered activation pattern). LEVEL OF EVIDENCE: 3a.

Application of rehabilitative ultrasound in the assessment of low back pain: a literature review.

Low back pain (LBP) is one of the most common work-related conditions affecting all populations both in industrialized and non-industrialized countries, with reported high prevalence and incidence rates and huge direct and indirect costs. Among various suggested causes of LBP, dysfunction of back muscles, particularly lumbar multifidus and transverse abdominis, has been the subject of considerable research during last decades. Of the available imaging techniques, ultrasound (US) imaging technique is increasingly used to assess muscle dimensions and function as a valid, reliable and non-invasive approach. The purpose of the present study was to review the previously published studies (1990-2009) concerning the merit of US imaging of lumbar and abdominal muscles with particular attention to its clinical application in patients with LBP. Studies showed wide variation in terms of methodology, sample size, procedure, definition of LBP, heterogeneous sample, method of analyzing US imaging, US imaging parameters, etc. However, a convincing body of evidence was identified that supports US imaging as a reliable and valid tool both to differentiate patients with LBP from normal subjects and to monitor the effect of rehabilitation programs.

Altered muscular activation during prone hip extension in women with and without low back pain.

BACKGROUND: Altered movement pattern has been associated with the development of low back pain (LBP). The purpose of this study was to investigate the activity pattern of the ipsilateral erector spinae (IES) and contralateral erectorspinae (CES), gluteus maximus (GM) and hamstring (HAM) muscles during prone hip extension (PHE) test in women with and without LBP. A cross-sectional non-experimental design was used. METHODS: Convenience sample of 20 female participated in the study. Subjects were categorized into two groups: with LBP (n = 10) and without LBP (n = 10). The electromyography (EMG) signal amplitude of the tested muscles during PHE (normalized to maximum voluntary electrical activity (MVE)) was measured in the dominant lower extremity in all subjects. RESULTS: Statistical analysis revealed greater normalized EMG signal amplitude in women with LBP compared to non-LBP women. There was significant difference in EMG activity of the IES (P = 0.03) and CES (P = 0.03) between two groups. However, no significant difference was found in EMG signals of the GM (P = 0.11) and HAM (P = 0.14) among two groups. CONCLUSION: The findings of this study demonstrated altered activation pattern of the lumbo-pelvic muscles during PHE in the women with chronic LBP. This information is important for investigators using PHE as either an evaluation tool or a rehabilitation exercise.