Technical application and the level of discomfort associated with an intramuscular electromyographic investigation into gluteus minimus and gluteus medius

Our current theoretical understanding of gluteus minimus (GMin) and gluteus medius (GMed) function is primarily based on cadaveric studies and biomechanical modelling. There is an absence of electromyographic (EMG) research that aims to verify this understanding, particularly in relation to the potentially unique functional roles of structurally distinct segments within GMin (anterior and posterior) and GMed (anterior, middle and posterior). The aim of this paper is to provide a comprehensive technical description for inserting intramuscular EMG electrodes into uniquely oriented segments of GMin and GMed; and to report the levels of discomfort associated with gluteal intramuscular electrode insertions. Fifteen healthy volunteers took part in a series of walking trials after intramuscular EMG electrodes were inserted into segments of GMin (×2) and GMed (×3) according to previously verified guidelines. Visual analogue scores following walking trials at comfortable and fast speed indicate that discomfort levels associated with these insertions were low (2.4. ±. 1.4 and 1.6. ±. 0.7 respectively). The technical descriptions and illustrations provided in this paper will allow trained intramuscular electromyographers to insert electrodes into these muscle segments with confidence

Gluteus minimus: an intramuscular EMG investigation of anterior and posterior segments during gait

Gluteus minimus is believed to consist of two structurally and functionally unique segments (anterior and posterior); however there is a lack of electromyography (EMG) research that attempts to verify current theoretical knowledge of this muscle. The purpose of this study was therefore to evaluate the function of gluteus minimus during gait, and to determine whether anterior and posterior segments are functionally independent. Bipolar fine wire intramuscular EMG electrodes were inserted into anterior and posterior gluteus minimus segments of fifteen healthy volunteers (9 males) according to previously verified guidelines. Participants completed a series of four walking trials, followed by maximum voluntary isometric contractions in five different positions. Temporal and amplitude variables for each segment were compared across the gait cycle with independent t-tests. The relative contribution of each segment to the maximum resisted trials was compared with Mann-Whitney U tests (α=0.05). Anterior and posterior segments were contracting at different relative intensities for three of the five maximum resisted trials (effect size=0.39 to 0.62,

Gluteus medius: an intramuscular EMG investigation of anterior, middle and posterior segments during gait

Previous electromyographic (EMG) studies of gluteus medius (GMed) have not accurately quantified the function of the three proposed structurally and functionally unique segments (anterior, middle and posterior). Therefore this study used anatomically verified locations for intramuscular electrode recordings in three segments of GMed to determine whether the segments are functionally independent. Bipolar fine wire electrodes were inserted into each segment of GMed in 15 healthy individuals. Participants completed a series of four walking trials, followed by maximum voluntary isometric contractions (MVICs) in five different positions. Temporal and amplitude variables for each segment were compared across the gait cycle using ANOVA. The relative contributions of each segment to the MVIC trials were compared with non-parametric tests. All segments showed a biphasic response during the stance phase of gait. There were no differences in amplitude variables (% MVIC) between segments, but the anterior segment had a later peak during both the first and second bursts. For the MVIC trials, there were significant differences in amplitude between segments in four of the five test positions. These data indicate that GMed is composed of three functionally independent segments. This study contributes to the theoretical understanding of the role of GMed

The Assessment, Management and Prevention of Calf Muscle Strain Injuries: A Qualitative Study of the Practices and Perspectives of 20 Expert Sports Clinicians

BackgroundDespite calf muscle strain injuries (CMSI) being problematic in many sports, there is a dearth of research to guide clinicians dealing with these injuries. The aim of this study was to evaluate the current practices and perspectives of a select group of international experts regarding the assessment, management and prevention of CMSI using in-depth semi-structured interviews.ResultsTwenty expert clinicians working in elite sport and/or clinician-researchers specialising in the field completed interviews. A number of key points emerged from the interviews. Characteristics of CMSI were considered unique compared to other muscle strains. Rigor in the clinical approach clarifies the diagnosis, whereas ongoing monitoring of calf capacity and responses to loading exposure provides the most accurate estimate of prognosis. Athlete intrinsic characteristics, injury factors and sport demands shaped rehabilitation across six management phases, which were guided by key principles to optimise performance at return to play (RTP) while avoiding subsequent injury or recurrence. To prevent CMSI, periodic monitoring is common, but practices vary and data are collected to inform load-management and exercise selection rather than predict future CMSI. A universal injury prevention program for CMSI may not exist. Instead, individualised strategies should reflect athlete intrinsic characteristics and sport demands.ConclusionsInformation provided by experts enabled a recommended approach to clinically evaluate CMSI to be outlined, highlighting the injury characteristics considered most important for diagnosis and prognosis. Principles for optimal management after CMSI were also identified, which involved a systematic approach to rehabilitation and the RTP decision. Although CMSI were reportedly difficult to prevent, on- and off-field strategies were implemented by experts to mitigate risk, particularly in susceptible athletes

Patient-reported outcome measures for hip-related pain: A review of the available evidence and a consensus statement from the International Hip-related Pain Research Network, Zurich 2018

Hip-related pain is a well-recognised complaint among active young and middle-aged active adults. People experiencing hip-related disorders commonly report pain and reduced functional capacity, including difficulties in executing activities of daily living. Patient-reported outcome measures (PROMs) are essential to accurately examine and compare the effects of different treatments on disability in those with hip pain. In November 2018, 38 researchers and clinicians working in the field of hip-related pain met in Zurich, Switzerland for the first International Hip-related Pain Research Network meeting. Prior to the meeting, evidence summaries were developed relating to four prioritised themes. This paper discusses the available evidence and consensus process from which recommendations were made regarding the appropriate use of PROMs to assess disability in young and middle-aged active adults with hip-related pain. Our process to gain consensus had five steps: (1) systematic review of systematic reviews; (2) preliminary discussion within the working group; (3) update of the more recent high-quality systematic review and examination of the psychometric properties of PROMs according to established guidelines; (4) formulation of the recommendations considering the limitations of the PROMs derived from the examination of their quality; and (5

Targeted gluteal exercise versus sham exercise on self-reported physical function for people with hip osteoarthritis (the GHOst trial - Gluteal exercise for Hip Osteoarthritis): a protocol for a randomised clinical trial

Clinical practice guidelines recommend exercise as the first line of management for hip osteoarthritis, yet high-quality evidence from Cochrane reviews suggest only slight benefits for pain and physical function; and no benefit on quality of life (low-quality evidence). However, the scope of physical impairments identified in people with hip osteoarthritis may not have been adequately addressed with targeted rehabilitation options in previous randomised controlled trials (RCTs). Potential targeted options include gait retraining to address spatio-temporal impairments in walking; motor control training to address deep gluteal (gluteus minimus) dysfunction; and progressive, high-intensity resistance exercises to address atrophy of the gluteal muscles. The aim of this study is to investigate the effect of a targeted gluteal rehabilitation programme that incorporates gait retraining, motor control and progressive, high-intensity resistance-strength training, to address physical activity levels and self-reported physical function in people with mild to moderate disability from hip osteoarthritis.Ninety people diagnosed with mild to moderately disabling hip osteoarthritis will be recruited and randomised to receive one of two exercise programmes (sham or GHOst programme). Interventions will be 12 weeks in duration, with weekly, supervised physiotherapy sessions, and daily home exercises. Both groups will receive standardised education. Outcomes will be assessed at baseline, 7 weeks, 13 weeks (primary time-point) and 25 weeks. The primary outcome will be self-reported physical function measured with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcomes include physical activity measured with a tri-axial accelerometer, physical function tests, self-reported physical activity, isometric hip-muscle strength tests, hip-related patient-reported outcome measures, pain thoughts and depressive symptoms, quality of life, global rating of change, gluteal-muscle activity (electromyography (EMG)) and gluteal-muscle size and adiposity (magnetic resonance imaging (MRI)).This will be the first study to compare a targeted gluteal rehabilitation programme to a sham exercise programme. The targeted GHOst programme includes exercises designed to address gait impairments as well as gluteal-muscle atrophy and dysfunction.Australian New Zealand Clinical Trials Registry, ID: ACTRN12617000970347 . Registered retrospectively on 5 July 2017. Protocol version 3.0

Gluteus medius and minimus activity during stepping tasks: comparisons between people with hip osteoarthritis and matched control participants

Background: Altered gluteus minimus (GMin) activity has been identified in people with hip osteoarthritis (OA) during gait with some evidence of altered gluteus medius (GMed) activity in patients with advanced OA. It is not known whether these muscles also exhibit altered activity during other functional tasks. Research question: Does gluteal muscle activity during stepping tasks differ between people with hip OA and healthy older adults? Methods: Participants included 20 people with unilateral hip OA and 20 age-and sex-matched controls. Muscle activity in the three segments within GMed and two segments of GMin were examined using intramuscular electromyography during step-up, step-down and side-step tasks. Results: Participants in the OA group demonstrated reduced muscle activity early in the step-up task and a later time to peak activity in most muscle segments. Greater activity was identified in anterior GMin in people with hip OA during the side-step task. A delay in time to peak activity was identified in most muscle segments in people with OA during the side-step task. Significance: For participants with OA, reduced activity in most muscle segments and increased time spent in double limb stance during the step-up task could reflect the decreased strength and pain associated with single limb stance on the affected limb. This study provides further evidence of altered function of the deep gluteal muscles in people with hip OA and highlights the importance of addressing these muscles in rehabilitation

Comparison of gluteus medius and minimus activity during gait in people with hip osteoarthritis and matched controls

The gluteal muscles act as stabilizers of the hip joint and are important for the maintenance of hip function. Atrophy and weakness of the gluteal muscles have been identified in people with hip OA, but it is not known whether these muscles also exhibit altered activity patterns. The aim of this study was to compare gluteal muscle activity in people with hip OA and healthy older adults. Fine-wire intramuscular electrodes were inserted into the three segments of gluteus medius (GMed) and two segments of gluteus minimus (GMin) in 20 participants with unilateral hip OA and 20 age- and gender-matched controls. Electromyographic activity of these muscle segments was examined during walking along a 10\ua0m walkway. Peak amplitude, average amplitude, and time to peak were compared between groups during the stance phase of the gait cycle. During early stance, the OA group demonstrated a higher burst of activity in posterior GMin (P\ua0=\ua00.02) and trends toward a higher peak in anterior GMin. Both groups displayed peak activity in anterior GMin in the early stance phase in contrast to previous reports in young adults. This early burst of muscle activity was more pronounced with increasing severity of OA. No differences were identified in GMed activity. While altered GMin activity is associated with aging, these changes were more pronounced in participants with hip OA. To reduce disability associated with hip OA, future rehabilitation programs should consider targeted gait strategies and exercises for GMin

Calf muscle strain injuries in elite Australian Football players: A descriptive epidemiological evaluation

Background: Calf muscle strain injuries (CMSI) show consistent rates of prevalence and re-injury in elite Australian Football players. An epidemiological evaluation is warranted to better understand the clinical presentation and recovery of CMSI. Purpose: First, to describe the epidemiology of CMSI in elite Australian Football players. Second, to determine if recovery following injury is different according to: (a) injury type (index vs re-injury); (b) muscle injured (soleus vs gastrocnemius); and (c) mechanism of injury (running-related activity vs non running-related activity). Study design: Descriptive epidemiological. Methods: Data retrieved from the Soft Tissue injury Registry of the Australian Football League were analyzed. Sixteen clubs submitted data on CMSI from 2014 to 2017. Data included: player characteristics, training and match history at the time of injury, MRI, and the time to reach recovery milestones. Results: One hundred and eighty-four CMSI were included (149 index injuries; 35 re-injuries). Soleus injuries were most prevalent (84.6%). Soleus injuries took 25.4\ua0±\ua016.2\ua0days to return to play, whereas gastrocnemius injuries took 19.1\ua0±\ua014.1\ua0days (P\ua0=.097). CMSI sustained during running-related activities took approximately 12\ua0days longer to recover than injuries sustained during non running-related activities (P\ua0=.001). Compared to index injuries, re-injuries involved older players (P\ua0=.03) and significantly more time was taken to run at >90% of maximum speed, return to full training, and return to play (P\ua0≤.001). Almost all of the observed re-injuries involved soleus (91.4%). Conclusion: Soleus injuries are more prevalent than gastrocnemius injuries in elite Australian Football players. Prognosis appears to be influenced by clinical factors, with CMSI sustained during running-related activities and re-injuries needing more time to recover

Return to Play and Recurrence After Calf Muscle Strain Injuries in Elite Australian Football Players

Background: Calf muscle strain injuries (CMSI) are prevalent in sport, but information about factors associated with time to return to play (RTP) and recurrence is limited. Purpose: To determine whether clinical and magnetic resonance imaging (MRI) data are associated with RTP and recurrence after CMSI. Study Design: Case-control study; Level of evidence, 3. Methods: Data of 149 CMSI reported to the Soft Tissue injury Registry of the Australian Football League were explored to evaluate the impact of clinical data and index injury MRI findings on RTP and recurrence. Clinical data included age, previous injury history, ethnicity, and the mechanism of injury. Results: Irrespective of the anatomical location, players with CMSI with severe aponeurotic disruption (AD) took longer to RTP than players with CMSI with no AD: 31.3 ± 12.6 days vs 19.4 ± 10.8 days (mean ± SD; P =.003). A running-related mechanism of injury was associated with a longer RTP period for CMSI overall (adjusted hazard ratio [AHR], 0.59; P =.02). The presence of AD was associated with a longer RTP period for soleus injuries (AHR, 0.6; P =.025). Early recurrence (ie, ≤2 months of the index injury) was associated with older age (AHR, 1.3; P =.001) and a history of ankle injury (AHR, 3.9; P =.032). Older age (AHR, 1.1; P =.013) and a history of CMSI (AHR, 6.7; P =.002) increased the risk of recurrence within 2 seasons. The index injury MRI findings were not associated with risk of recurrence. Conclusion: A running-related mechanism of injury and the presence of AD on MRI were associated with a longer RTP period. Clinical rather than MRI data best indicate the risk of recurrent CMSI