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Neuromotor Control of Gluteal Muscles in Runners with Achilles Tendinopathy
Abstract
The purpose of this study was to compare the neuromotor control of the Gluteus Medius (GMED) and Gluteus Maximus (GMAX) muscles in runners with Achilles tendinopathy to that of healthy controls.
Fourteen male runners with Achilles tendinopathy and nineteen healthy male runners (Control) ran over-ground whilst electromyography of GMED and GMAX was recorded. Three temporal variables were identified via visual inspection of EMG data: (i) onset of muscle activity (onset), (ii) offset of muscle activity (offset), and (iii) duration of muscle activity (duration). A multivariate analysis of covariance with between subject factor of group (Achilles tendinopathy, Control) and variables of onset, offset, and duration was performed for each muscle. Age, weight and height were included as covariates and alpha level set at 0.05.
The Achilles tendinopathy group demonstrated a delay in the activation of the GMED relative to heel strike (p < 0.001) and a shorter duration of activation (p < 0.001) compared to that of the Control group. GMED offset time relative to heel strike was not different between the groups (p = 0.063). For GMAX the Achilles tendinopathy group demonstrated a delay in its onset (p = 0.008), a shorter duration of activation (p = 0.002), and earlier offset (p < 0.001) compared to the Control group.
This study provides preliminary evidence of altered neuromotor control of the GMED and GMAX muscles in male runners with Achilles tendinopathy. Whilst further prospective studies are required to discern the causal nature of this relationship, this study highlights the importance of considering neuromotor control of the gluteal muscles in the assessment and management of patients with Achilles tendinopathy.
... The final yield was 16 studies investigating biomechanical alterations during running or hopping among people with AT compared to controls, including 14 case-control and cross-sectional, and two prospective studies. 12 (75%) studies investigated participants during running [3,25,26,[37][38][39][40][41][42][43][44][45] and four studies (25%) during hopping [28,[46][47][48]. Two prospective studies (12%) evaluated biomechanics associated with the development of AT [3,41], three cross-sectional studies (19%) investigated asymptomatic people [44,46,48] and eleven cross-sectional studies (69%) investigated symptomatic people [25,26,28,[37][38][39][40]42,43,45,47]. ...
... 12 (75%) studies investigated participants during running [3,25,26,[37][38][39][40][41][42][43][44][45] and four studies (25%) during hopping [28,[46][47][48]. Two prospective studies (12%) evaluated biomechanics associated with the development of AT [3,41], three cross-sectional studies (19%) investigated asymptomatic people [44,46,48] and eleven cross-sectional studies (69%) investigated symptomatic people [25,26,28,[37][38][39][40]42,43,45,47]. Fifteen studies (94%) included active participants (information obtained from the papers or contacting the authors) and one hopping study (6%) included sedentary and active participants [47]. ...
... The mean quality score of the included studies was 57% (33%-89%) with four high quality studies [3,26,28,40] nine moderate quality studies [25,37,39,[43][44][45][46][47][48] and three low quality studies [38,41,42]. Quality assessment of the studies is shown in Table 2. Data extraction is collated in Table 3. ...
... Twenty-three articles met the inclusion criteria and were included in the review. Forward and backward citation of these 23 papers did not identify any further relevant articles; however, PubMed-related article search identified one published paper [25]. Therefore, a total of 24 articles were included in the review (Figure 1). ...
... One study [46] showed that injury status had no effect at all on gluteus medius EMG amplitude. Gluteus medius EMG onset timing was investigated in five research papers [25,27,31,42,43]. Two studies [25,42] found that injury status had a significant effect on gluteus medius EMG timing indicating delayed onset in the injured group. ...
... Gluteus medius EMG onset timing was investigated in five research papers [25,27,31,42,43]. Two studies [25,42] found that injury status had a significant effect on gluteus medius EMG timing indicating delayed onset in the injured group. Beckman and Buchanan [27] also found that injury status had a significant effect on gluteus medius EMG timing, but in this case, the effect was in the opposite direction and indicated an earlier onset of gluteus medius following an unexpected ankle movement. ...
Objectives: Hip control affects movement and muscle firing patterns in the leg, ankle and foot, and may contribute to overuse injuries. Muscle performance can be measured as strength, endurance or muscle activation patterns. Our objective was to systematically review whether hip muscle performance is associated with leg, ankle and foot injuries.
Data Sources: A structured and comprehensive search of six medical literature databases was combined with forward and backward citation tracking (AMED, CINAHL, EMBASE, Medline, Scopus and SportDiscus).
Study Selection: Eligible studies measured hip muscle performance in individuals with musculoskeletal injuries below the tibial tuberosity, using dynamometry or electromyography (EMG). All studies compared an injured group with a control group or compared the injured and non-injured limb in the same individual.
Data Extraction: Data was extracted from each study independently by two authors.
Data Synthesis: Twenty case-control and four prospective studies (n=24) met the inclusion criteria. Injury classifications included chronic ankle instability (n=18), Achilles tendinopathy (n=2), medial tibial stress syndrome and tibial stress fracture (n=1), posterior tibial tendon dysfunction (n=1), and exertional medial tibial pain (n=2). Eleven of the studies revealed differences in hip muscle performance indicating less strength, delayed onset activation and decreased duration of activation in the injured groups. Two studies found evidence for differences between groups only in some of their measurements. Three out of the four prospective studies revealed that hip muscle performance was not a risk factor for leg, ankle and foot injuries.
Conclusions: This review provides limited evidence that hip muscle performance variables are related to leg, ankle and foot injuries. Emerging evidence indicates this might be a result of the injury rather than a contributor to the injury.
... Etiologic factors include overuse, training errors, altered lower limb biomechanics, footwear, postural or leg length imbalances, impaired muscle performance, and direct trauma. [2][3][4][5][6] In addition to etiologic factors, the status of the tendon is important in treatment decisions and prognosis. The continuum model of tendinopathy provides a simple way of estimating tendon status and can be used in parallel with examination findings and treatment (Fig. 1). ...
... Dynamic knee and rearfoot valgus may be owing to altered neuromotor function of the gluteal muscles (ie, hip abductors and external rotators) and can be assessed by performance of single leg squat/ step down or manual muscle tests. 4,5,34 Imaging Tendon heterogeneity, thickening, softening, tearing, and neovascularization have been identified using ultrasound imaging or MRI and may help to indicate the degree of tendon disrepair or degeneration (see Table 1). [8][9][10][11][12] Although imaging results may indicate the degree of pathoanatomic changes, this does not always correlate with symptom severity or improvement. ...
... Impaired gluteal muscle performance has been identified in runners with AT and may be related to the cause or persistence of symptoms. 4,5 Education about expected pain responses and recovery time is essential to the tendon loading program. Increased fear of movement may have a negative effect on exercise effectiveness, 65 although this can be mitigated through appropriate education. ...
Midsubstance Achilles tendinopathy is one of the most common lower leg conditions. Most patients can recover with nonsurgical treatment that focuses on tendon loading exercises and, when necessary, symptom modulating treatments such as topical, oral, or injected medication, ice, shoe inserts, manual therapy, stretching, taping, or low-level laser. If unresponsive to initial management, a small percentage of patients may consider shockwave or sclerosing treatment and possibly surgery.
... There were five studies that compared GMed EMG amplitude of injured runners to healthy controls. Two studies included participants with Achilles tendinopathy (Azevedo et al., 2009;Smith et al., 2014) and the remaining three investigated PFPS (Esculier et al., 2015;Souza and Powers, 2009;Willson et al., 2011). There were no studies that assessed the effect of local hip joint injury on GMed running activity. ...
... All studies used surface electrodes to record activity from GMed, however the placement of electrodes varied across studies. Four studies used the recommended SENIAM location of midway between the iliac crest and greater trochanter (Bartlett et al., 2014;Esculier et al., 2015;Smith et al., 2014;Unfried et al., 2013) and two studies did not report an exact location (Azevedo et al., 2009;Mann et al., 1986). The remaining studies placed the electrode on a line between the iliac crest and the greater trochanter however the exact position was only described in one of these studies (25 mm below the iliac crest; Souza and Powers, 2009). ...
... Two studies compared running related GMed activity in people with Achilles tendinopathy to control participants (Azevedo et al., 2009;Smith et al., 2014) (Tables 2 and 3). Similar diagnostic criteria were reported in each study; gradual onset of mid-portion Achilles pain during functional tasks like running and hopping and tender on palpation. ...
Running is a popular sport and recreational physical activity worldwide. Musculoskeletal injuries in runners are common and may be attributed to the inability to control pelvic equilibrium in the coronal plane. This lack of pelvic control in the frontal plane can stem from dysfunction of the gluteus medius. The aim of this systematic review was therefore to: (i) compile evidence of the activity profile of gluteus medius when running; (ii) identify how gluteus medius activity (electromyography) varies with speed, cadence and gender when running; (iii) compare gluteus medius activity in injured runners to matched controls. Seven electronic databases were search from their earliest date until March 2015. Thirteen studies met our eligibility criteria. The activity profile was mono-phasic with a peak during initial loading (four studies). Gluteus medius amplitude increases with running speed; this is most evident in females. The muscles’ activity has been recorded in injured runners with Achilles tendinopathy (two studies) and patellofemoral pain syndrome (three studies). The strongest evidence indicates a moderate and significant reduction in gluteus medius duration of activity when running in people with patellofemoral pain syndrome. This dysfunction can potentially be mediated with running retraining strategies.
... The strength values that were found in the control group are comparable to hip muscle strength values found in a different study that investigated 253 healthy men with an average age of 49 years.(Stoll, Huber, Seifert, Michel, & Stucki, 2000) Hence, if the strength values found in the AT group of our study are compared to these normative values, differences seemDecreased hip muscle strength found in the AT group is in keeping with findings of previous studies, in which decreased and delayed electromyographic activity of the gluteus medius(Azevedo, Lambert, Vaughan, O'Connor, & Schwellnus, 2009;Franettovich Smith, Honeywill, Wyndow, Crossley, & Creaby, 2014) and maximus(Franettovich Smith et al., 2014) was demonstrated in athletes with AT, indicating altered neuromotor control of the hip musculature. Our study demonstrates decreased isometric hip muscle strength in patients with AT, which (together with appropriate neuromotor control) is considered essential for proper kinetic chain function.(Kibler ...
... The strength values that were found in the control group are comparable to hip muscle strength values found in a different study that investigated 253 healthy men with an average age of 49 years.(Stoll, Huber, Seifert, Michel, & Stucki, 2000) Hence, if the strength values found in the AT group of our study are compared to these normative values, differences seemDecreased hip muscle strength found in the AT group is in keeping with findings of previous studies, in which decreased and delayed electromyographic activity of the gluteus medius(Azevedo, Lambert, Vaughan, O'Connor, & Schwellnus, 2009;Franettovich Smith, Honeywill, Wyndow, Crossley, & Creaby, 2014) and maximus(Franettovich Smith et al., 2014) was demonstrated in athletes with AT, indicating altered neuromotor control of the hip musculature. Our study demonstrates decreased isometric hip muscle strength in patients with AT, which (together with appropriate neuromotor control) is considered essential for proper kinetic chain function.(Kibler ...
Objective:
Investigating differences in hip muscle strength between athletes with Achilles tendinopathy (AT) and asymptomatic controls.
Design:
Cross-sectional case-control study.
Setting:
Sports medical center.
Participants:
Twelve recreational male athletes with mid-portion AT and twelve matched asymptomatic controls.
Outcome measures:
Isometric strength of the hip abductors, external rotators, and extensors was measured using a handheld dynamometer. Functional hip muscle performance was evaluated with the single-leg squat. The Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire was completed to determine clinical severity of symptoms.
Results:
Compared to controls, participants with AT demonstrated 28.9% less isometric hip abduction strength (p = 0.012), 34.2% less hip external rotation strength (p = 0.010), and 28.3% less hip extension strength (p = 0.034) in the injured limb. Similar differences were found for the non-injured limb (26.7-41.8%; p < 0.03). No significant differences were found in functional hip muscle performance between the injured and non-injured limb or between the groups, and no significant correlation was found between hip muscle strength and VISA-A scores.
Conclusion:
Recreational male athletes with chronic mid-portion AT demonstrated bilateral weakness of hip abductors, external rotators, and extensors compared to their asymptomatic counterparts. These findings suggest that hip muscle strength may be important in the assessment and rehabilitation of those with AT.
... There is increasing awareness of the importance of hip muscle function for local and distal joint health (Reiman et al., 2009). Deficits in hip muscle strength, activity or hip joint mechanics have been identified in lower limb pathology (Bolgla et al., 2011;Sims et al., 2002;Smith et al., 2014). It is important then, to understand the function of hip muscles in order to facilitate the clinical assessment and rehabilitation of these conditions. ...
... Clinicians and researchers often use walking and running to examine the influence of muscles on stability (Pandy and Andriacchi, 2010), movement (Gazendam and Hof, 2007;Pandy and Andriacchi, 2010) and pathology (Smith et al., 2014). Valuable insights into the role of some hip muscles such as gluteus minimus (Semciw et al., 2014) and the adductors (Green and Morris, 1970) have been provided through EMG analysis of gait. ...
Dysfunction of hip stabilizing muscles such as quadratus femoris (QF) is identified as a potential source of lower extremity injury during functional tasks like running. Despite these assumptions, there are currently no electromyography (EMG) data that establish the burst activity profile of QF during any functional task like walking or running. The objectives of this study were to characterize and compare the EMG activity profile of QF while walking and running (primary aim) and describe the direction specific action of QF (secondary aim). A bipolar fine-wire intramuscular electrode was inserted via ultrasound guidance into the QF of 10 healthy participants (4 females). Ensemble curves were generated from four walking and running trials, and normalized to maximum voluntary isometric contractions (MVICs). Paired t-tests compared the temporal and amplitude EMG variables. The relative activity of QF in the MVICs was calculated. The QF displayed moderate to high amplitude activity in the stance phase of walking and very high activity during stance in running. During swing, there was minimal QF activity recorded during walking and high amplitudes were present while running (run vs walk effect size=4.23, P<0.001). For the MVICs, external rotation and clam produced the greatest QF activity, with the hip in the anatomical position. This study provides an understanding of the activity demands placed on QF while walking and running. The high activity in late swing during running may signify a synergistic role with other posterior thigh muscles to control deceleration of the limb in preparation for stance.
Copyright © 2015 Elsevier Ltd. All rights reserved.
... Our data revealed that hip abduction and extension were decreased compared to controls. These findings are partly consistent with a study that identified impairments in hip abduction, external rotation and extension isometric strength (Habets, Smits, Backx, Van Cingel, & Huisstede, 2017) and could confirm that runners with AT might have altered neuromotor control of the gluteal muscles (MM, Honeywill, Wyndow, Crossley, & Creaby, 2014). Additionally, we also identified decreased dynamic leg extension strength (6RM) in the AT group. ...
Objectives
To confirm what impairments are present in runners with Achilles tendinopathy (AT) and explore the variance of AT severity in an adequately powered study.
Design
Case-control study.
Setting
Two private physiotherapy clinics in Australia and Spain.
Participants
Forty-four recreational male runners with AT and 44 healthy controls matched by age, height, and weight.
Main outcome measures
Demographics, activity (IPAQ-SF), pain and function (VISA-A), pain during hopping (Hop pain VAS), hopping duration, psychological factors (TSK-11, PASS20), and physical tests regarding lower-limb maximal strength and endurance.
Results
Body mass index (BMI), activity, VISA-A, pain, and duration of hopping, TSK-11, PASS20, standing heel raise to failure, seated heel raise and leg extension 6RM, hip extension and abduction isometric torque were significantly different between groups (P < 0.05) with varied effect sizes (V = 0.22, d range = 0.05–4.18). 46% of AT severity variance was explained by higher BMI (β = −0.41; p = 0.001), weaker leg curl 6RM (β = 0.32; p = 0.009), and higher pain during hopping (β = −0.43; p = 0.001).
Conclusion
Runners with AT had lower activity levels, lower soleus strength, and were less tall. BMI, pain during hopping, and leg curl strength explained condition severity. This information, identified with clinically applicable tools, may guide clinical assessment, and inform intervention development.
... We identified 13 studies (twelve retrospective, one prospective) that had analyzed, in total, 123 different potential BRFs for AT (SDC4) through our systematic screening of the literature [20][21][22][23][24][25][26][27][28][29][30][31][32]. Out of these parameters, five BRFs were identified in either two independent retrospective studies or one prospective study, following our predefined relevance criterion. ...
Background
Running overuse injuries (ROIs) occur within a complex, partly injury-specific interplay between training loads and extrinsic and intrinsic risk factors. Biomechanical risk factors (BRFs) are related to the individual running style. While BRFs have been reviewed regarding general ROI risk, no systematic review has addressed BRFs for specific ROIs using a standardized methodology.
Objective
To identify and evaluate the evidence for the most relevant BRFs for ROIs determined during running and to suggest future research directions.
Design
Systematic review considering prospective and retrospective studies. (PROSPERO_ID: 236,832).
Data Sources
PubMed. Connected Papers. The search was performed in February 2021.
Eligibility Criteria
English language. Studies on participants whose primary sport is running addressing the risk for the seven most common ROIs and at least one kinematic, kinetic (including pressure measurements), or electromyographic BRF. A BRF needed to be identified in at least one prospective or two independent retrospective studies. BRFs needed to be determined during running.
Results
Sixty-six articles fulfilled our eligibility criteria. Levels of evidence for specific ROIs ranged from conflicting to moderate evidence. Running populations and methods applied varied considerably between studies. While some BRFs appeared for several ROIs, most BRFs were specific for a particular ROI. Most BRFs derived from lower-extremity joint kinematics and kinetics were located in the frontal and transverse planes of motion. Further, plantar pressure, vertical ground reaction force loading rate and free moment-related parameters were identified as kinetic BRFs.
Conclusion
This study offers a comprehensive overview of BRFs for the most common ROIs, which might serve as a starting point to develop ROI-specific risk profiles of individual runners. We identified limited evidence for most ROI-specific risk factors, highlighting the need for performing further high-quality studies in the future. However, consensus on data collection standards (including the quantification of workload and stress tolerance variables and the reporting of injuries) is warranted.
... We identified twelve studies (eleven retrospective, one prospective) that had analysed, in total, 115 different potential RRRFs for AT (SDC) through our systematic screening of the literature [20][21][22][23][24][25][26][27][28][29][30][31]. Out of these parameters, five RRRFs were identified in either two independent retrospective studies or one prospective study, following our predefined relevance criterion. ...
Objective
To identify and evaluate the evidence of the most relevant running-related risk factors (RRRFs) for running-related overuse injuries (ROIs) and to suggest future research directions.
Design
Systematic review considering prospective and retrospective studies. (PROSPERO_ID: 236832)
Data sources
Pubmed. Connected Papers. The search was performed in February 2021.
Eligibility criteria
English language. Studies on participants whose primary sport is running addressing the risk for the seven most common ROIs and at least one kinematic, kinetic (including pressure measurements), or electromyographic RRRF. An RRRF needed to be identified in at least one prospective or two retrospective studies.
Results
Sixty-two articles fulfilled our eligibility criteria. Levels of evidence for specific ROIs ranged from conflicting to moderate evidence. Running populations and methods applied varied considerably between studies. While some RRRFs appeared for several ROIs, most RRRFs were specific for a particular ROI. The biomechanical measurements performed in many studies would have allowed for consideration of many more RRRFs than have been reported, highlighting a potential for more effective data usage in the future.
Conclusion
This study offers a comprehensive overview of RRRFs for the most common ROIs, which might serve as a starting point to develop ROI-specific risk profiles of individual runners. Future work should use macroscopic (big data) approaches involving long-term data collections in the real world and microscopic approaches involving precise stress calculations using recent developments in biomechanical modelling. However, consensus on data collection standards (including the quantification of workload and stress tolerance variables and the reporting of injuries) is warranted.
... The Single leg Squat (SLS) test assesses the subject's performance as he/she execute a squat on one leg, with the frontal plane projection angle (FPPA) as the main 4 outcome measurement (13,14). It has been demonstrated that women are more prone to display increased femur adduction and internal rotation (i.e., increased FPPA) and greater pelvis and trunk motion during dynamic testing (15)(16)(17), which has been associated with increased risk of patellofemoral pain syndrome (14,18,19), iliotibial band syndrome (20), Achilles tendon pathology (21,22) and ankle injuries (23,24). The abnormal motion of the lower limb may cause compensating movements at the pelvis, such a contralateral pelvis drop (CPD), due to a diminished stability. ...
Background: Chronic non-specific low back pain (CNSLBP) is the leading cause of long-term pain and disability. There is evidence suggesting a relationship between CNSLBP in adult women and altered hip kinematics and gluteus medius (GM) muscle function. However, this association has been less studied in young women.
Objective: To assess the association between lower limb and pelvis kinematics in the frontal plane, and GM strength and electromyographic activity in young women with CNSLBP compared with an age-matched control group of asymptomatic women. Methods: In this cross-sectional study, 32 young women with CNSLBP (>6 months of pain; Oswestry index range: 21-40%) and 20 healthy age-matched women were included. The frontal plane projection angle (FPPA) and contralateral pelvis drop (CPD) at the end point of the Single Leg Squat (SLS) test were measured through photogrammetry. Mean GM muscle activity during the SLS and peak isometric GM strength were measured using surface electromyography (sEMG) and hand-held dynamometry, respectively. Results: The Hotelling’s trace showed no significant differences between groups when the variables were considered as a composite (F=0.69; p=0.76). Also, the univariate
results showed no individual differences between groups considering each variable separately. Conclusions: The results showed no association between CNSLBP, hip and pelvis kinematics, and GM strength and activity in young women.
... It is recommended that such exercises are positioned in final part of a session or performed separately, as pre-fatiguing muscles in isolation is likely to be detrimental to performance in multi-joint tasks (4). Specifically for distance runners, targeted conditioning exercises should focus on the specific structures which are vulnerable to injury, or the muscles that contribute towards controlling the positioning of joints within the lower limb, such as: the intrinsic joints of the feet, the calf-Achilles complex, gluteal and hamstring muscles (2,32,38,55,57,61). In addition, specific exercises that target proximal musculature around the lumbopelvic-hip complex ('core stability') are likely to offset the risk of several types of common overuse injuries in runners (23). ...
For the adolescent athlete who chooses to specialize in endurance running, strength and conditioning (S&C) activities provide a means of enhancing several important determinants of performance and may reduce the risk of overuse injury. It is recommended that adolescent endurance runners include at least 2 S&C sessions per week that comprise movement skills training, plyometric and sprint training, resistance training, plus exercises designed to target specific tissues that are vulnerable to injury. This article describes how these modalities of training can be integrated into the routine of adolescent endurance runners.
... 25,50 One possible explanation for the increased CPD observed in the injured group could be reduced strength or neuromuscular function at the hip. Previous authors have reported the delayed onset of gluteus medius and maximus function in runners with PFP 51 and AT, 15 while others have reported reduced hip abductor strength in runners with ITBS, 16 PFP, 41 AT, 18 and MTSS. 48 The hip abductors, in particular, the gluteus medius, are thought to control frontal plane kinematics of the pelvis and Values are presented as mean 6 SD unless otherwise specified. ...
Background:
Previous research has demonstrated clear associations between specific running injuries and patterns of lower limb kinematics. However, there has been minimal research investigating whether the same kinematic patterns could underlie multiple different soft tissue running injuries. If they do, such kinematic patterns could be considered global contributors to running injuries.
Hypothesis:
Injured runners will demonstrate differences in running kinematics when compared with injury-free controls. These kinematic patterns will be consistent among injured subgroups.
Study design:
Controlled laboratory study.
Methods:
We studied 72 injured runners and 36 healthy controls. The injured group contained 4 subgroups of runners with either patellofemoral pain, iliotibial band syndrome, medial tibial stress syndrome, or Achilles tendinopathy (n = 18 each). Three-dimensional running kinematics were compared between injured and healthy runners and then between the 4 injured subgroups. A logistic regression model was used to determine which parameters could be used to identify injured runners.
Results:
The injured runners demonstrated greater contralateral pelvic drop (CPD) and forward trunk lean at midstance and a more extended knee and dorsiflexed ankle at initial contact. The subgroup analysis of variance found that these kinematic patterns were consistent across each of the 4 injured subgroups. CPD was found to be the most important variable predicting the classification of participants as healthy or injured. Importantly, for every 1° increase in pelvic drop, there was an 80% increase in the odds of being classified as injured.
Conclusion:
This study identified a number of global kinematic contributors to common running injuries. In particular, we found injured runners to run with greater peak CPD and trunk forward lean as well as an extended knee and dorsiflexed ankle at initial contact. CPD appears to be the variable most strongly associated with common running-related injuries.
Clinical relevance:
The identified kinematic patterns may prove beneficial for clinicians when assessing for biomechanical contributors to running injuries.
... As well as controlling muscular activity in the axial skeleton, neuromotor control and the sensorimotor system are important in controlling joint position and loading of the associated soft tissues in the appendicular skeleton. Fatigue 47 as well as injury 48,49 can alter the function of active elements (muscles) as well as sensorimotor inputs and neuromotor control, principally reflected in reduced joint position sense and proprioception. Furthermore, appropriate warm-up can improve joint position sense. ...
Physical therapy (physiotherapy, or PT) can be broadly defined as the restoration of movement and function and includes assessment, treatment, and rehabilitation. This review outlines the history, definition, and regulation of PT, followed by the core scientific principles of PT. Because musculoskeletal physiotherapy is the predominant subdiscipline in equine PT, encompassing poor performance, back pain syndromes, other musculoskeletal disorders, and some neuromuscular disorders, the sciences of functional biomechanics, neuromotor control, and the sensorimotor system in the spine, pelvis, and peripheral joints are reviewed. Equine PT also may involve PT assessment and treatment of riders.
... Prospective studies have shown that increased hip adduction during overground running [46] and increased hip internal rotation when landing from a drop jump [22] are risk factors for the development of patellofemoral pain. Furthermore , cross-sectional studies have reported deficits in neuromuscular control of the hip in those with patellofemoral pain55565758596061 and Achilles tendinopathy [62,63]. Further research is required to better understand the relationship between proximal and distal mechanics during gait, and risk of overuse injury development. ...
Dynamic foot function is considered a risk factor for lower limb overuse injuries including Achilles tendinopathy, shin pain, patellofemoral pain and stress fractures. However, no single source has systematically appraised and summarised the literature to evaluate this proposed relationship. The aim of this systematic review was to investigate dynamic foot function as a risk factor for lower limb overuse injury.
A systematic search was performed using Medline, CINAHL, Embase and SportDiscus in April 2014 to identify prospective cohort studies that utilised dynamic methods of foot assessment. Included studies underwent methodological quality appraisal by two independent reviewers using an adapted version of the Epidemiological Appraisal Instrument (EAI). Effects were expressed as standardised mean differences (SMD) for continuous scaled data, and risk ratios (RR) for nominal scaled data.
Twelve studies were included (total n = 3,773; EAI 0.44 to 1.20 out of 2.00, representing low to moderate quality). There was limited to very limited evidence for forefoot, midfoot and rearfoot plantar loading variables (SMD 0.47 to 0.85) and rearfoot kinematic variables (RR 2.67 to 3.43) as risk factors for patellofemoral pain; and plantar loading variables (forefoot, midfoot, rearfoot) as risk factors for Achilles tendinopathy (SMD 0.81 to 1.08). While there were significant findings from individual studies for plantar loading variables (SMD 0.3 to 0.84) and rearfoot kinematic variables (SMD 0.29 to 0.62) as risk factors for 'non-specific lower limb overuse injuries', these were often conflicting regarding different anatomical regions of the foot. Findings from three studies indicated no evidence that dynamic foot function is a risk factor for iliotibial band syndrome or lower limb stress fractures.
This systematic review identified very limited evidence that dynamic foot function during walking and running is a risk factor for patellofemoral pain, Achilles tendinopathy, and non-specific lower limb overuse injuries. It is unclear whether these risk factors can be identified clinically (without sophisticated equipment), or modified to prevent or manage these injuries. Future prospective cohort studies should address methodological limitations, avoid grouping different lower limb overuse injuries, and explore clinically meaningful representations of dynamic foot function.
Background
There is conflicting data on which kinetic variables are important to consider with running injuries. Furthermore, less is understood regarding differences in these variables when considering demographics such as age, sex, weight, and running speed. The primary question was what joint power kinetic variables were different between non-injured and injured runners.
Purpose
The purpose of this study was to identify if there were differences in joint power kinetic variables between non-injured runners and injured runners.
Study Design
Case-Control Study
Methods
Kinetic data were collected on 122 runners (26 non-injured and 96 injured) over three years with a Bertec force plated treadmill and Qualisys 3D motion capture. The subjects were considered eligible if they self-identified themselves as runners or had running as a key component of their activity. The subjects ran at a comfortable, self-selected pace while two 10-second trials of recordings were used to calculate the means of peak power generated at the hips, knees, and ankles of each gait cycle. Foot strike was categorized by kinematic data. Two sample T-tests were used to compare peak power variables at the hips, knees, and ankles between non-injured and injured runners. Logistic regression analyses examined how a combination of demographics and peak power variables were associated with injuries.
Results
No peak power variable at the hip, knee, or ankle was significantly different between injured and non-injured runners (p=0.07-0.87). However, higher hip power absorbed was found to be protective against injuries (odds ratio, .16; 95% CI .025-.88) when considering demographics using a logistic regression model including sex, foot strike, BMI, speed, age, and power variables from the hip, knee, and ankle. The area under the ROC curve was .74, which is acceptable discrimination.
Conclusion
When controlling for age, sex, BMI, foot strike, and speed; higher hip power absorbed was found to be protective against injury. This could be due to the hip muscles’ unique role in absorbing force during early stance phase.
Level of Evidence
3b
©The Author(s)
Achilles tendinopathy (AT) is a debilitating injury in athletes, especially for those engaged in repetitive stretch-shortening cycle activities. Clinical risk factors are numerous, but it has been suggested that altered biomechanics might be associated with AT. No systematic review has been conducted investigating these biomechanical alterations in specifically athletic populations. Therefore, the aim of this systematic review was to compare the lower-limb biomechanics of athletes with AT to athletically matched asymptomatic controls. Databases were searched for relevant studies investigating biomechanics during gait activities and other motor tasks such as hopping, isolated strength tasks, and reflex responses. Inclusion criteria for studies were an AT diagnosis in at least one group, cross-sectional or prospective data, at least one outcome comparing biomechanical data between an AT and healthy group, and athletic populations. Studies were excluded if patients had Achilles tendon rupture/surgery, participants reported injuries other than AT, and when only within-subject data was available.. Effect sizes (Cohen's d) with 95% confidence intervals were calculated for relevant outcomes. The initial search yielded 4,442 studies. After screening, twenty studies (775 total participants) were synthesised, reporting on a wide range of biomechanical outcomes. Females were under-represented and patients in the AT group were three years older on average. Biomechanical alterations were identified in some studies during running, hopping, jumping, strength tasks and reflex activity. Equally, several biomechanical variables studied were not associated with AT in included studies, indicating a conflicting picture. Kinematics in AT patients appeared to be altered in the lower limb, potentially indicating a pattern of "medial collapse". Muscular activity of the calf and hips was different between groups, whereby AT patients exhibited greater calf electromyographic amplitudes despite lower plantar flexor strength. Overall, dynamic maximal strength of the plantar flexors, and isometric strength of the hips might be reduced in the AT group. This systematic review reports on several biomechanical alterations in athletes Frontiers in Sports and Active Living 01 frontiersin.org with AT. With further research, these factors could potentially form treatment targets for clinicians, although clinical approaches should take other contributing health factors into account. The studies included were of low quality, and currently no solid conclusions can be drawn.
Background
Achilles tendinopathy (AT) is a common overuse injury in runners. While the mainstay of treatment for AT is tendon loading exercises (physical therapy and exercise programme (EXER)), some patients have refractory symptoms. Extracorporeal shockwave therapy (ESWT) and photobiomodulation therapy (PBMT) have each been evaluated to facilitate tendon healing; the influence of combining treatments is unknown and limited studies have been completed in runners. This randomised control study, with an elective cross-over at 3 months, will evaluate the efficacy of three forms of treatment of non-insertional AT: (1) EXER (loading programme specific to Achilles tendon combined with physical therapy); (2) EXER and ESWT; (3) EXER, ESWT and PBMT. Sixty runners will be assigned using block randomisation into one of three treatment groups (n=20). After 3 months, each participant may elect a different treatment than previously assigned and will be followed for an additional 3 months. The EXER Achilles loading programme will be standardised using the Silbernagel at-home programme. The primary outcome of interest is treatment group responses using the Victorian Institute of Sports Assessment—Achilles (VISA-A) Score. Secondary outcomes include the Patient-Reported Outcomes Measurement Information System—29 questions, the University of Wisconsin Running Injury and Recovery Index, heel raise to fatigue test, hopping test and ultrasound measurements. We will also capture patient preference and satisfaction with treatment. We hypothesise that the cohorts assigned EXER+ESWT+PBMT and EXER+ESWT will see greater improvements in VISA-A than the EXER cohort, and the largest gains are anticipated in combining ESWT+PBMT. The elective cross-over phase will be an exploratory study and will inform us whether patient preference for treatment will impact the treatment response.
Trial registration number
NCT04725513 .
Background:
Achilles tendinopathy (AT) may affect ground reaction force (GRF) and muscle synergy (MS) during walking due to pain, biological integrity changes in the tendon and neuroplastic adaptations. The objective of this study was to compare GRF asymmetries and MS attributes between symptomatic and asymptomatic lower limbs (LL) during walking at natural and fast speeds in adults with unilateral AT.
Methods:
A convenience sample consisting of twenty-eight participants walked on an instrumented treadmill at natural (1.3 m/s) and fast (1.6 m/s) speeds. Peak GRF were measured in mediolateral, anteroposterior and vertical directions. Individualized electromyography (EMG) activation profiles were time- and amplitude-normalized for three consecutive gait cycles and MS were extracted using non-negative matrix factorization algorithms. MS were characterized by the number, composition (i.e., weighting of each muscle) and temporal profiles (i.e., duration and amplitude) of the MS extracted during walking. Paired Student's t-tests assessed peak GRF and MS muscle weighting differences between sides whereas Pearson correlation coefficients characterized the similarities of the individualized EMG and MS activation temporal profiles within sides.
Results:
AT had limited effects on peak GRF asymmetries and the number, composition and temporal profiles of MS between symptomatic and asymptomatic LL while walking on a level treadmill at natural and fast speeds. In most participants, four MS with a specific set of predominantly activated muscles were extracted across natural (71 and 61%) and fast (54 and 50%) walking speeds for the symptomatic and asymptomatic side respectively. Individualized EMG activation profiles were relatively similar between sides (r = 0.970 to 0.999). As for MS attributes, relatively similar temporal activation profiles (r = 0.988 to 0.998) and muscle weightings (p < 0.05) were found between sides for all four MS and the most solicited muscles. Although the faster walking speed increased the number of merged MS for both sides, it did not significantly alter MS symmetry.
Conclusion:
Faster walking speed increased peak GRF values but had limited effects on GRF symmetries and MS attribute differences between the LL. Corticospinal neuroplastic adaptations associated with chronic unilateral AT may explain the preserved quasi-symmetric LL motor control strategy observed during natural and fast walking among adults with chronic unilateral AT.
Background
Achilles tendinopathy (AT) is associated with severe pain and is the cause of dysfunction and disability that are associated with significant reduction in social and economic benefits. Several potential risk factors have been proposed to be responsible for AT development; however, the results of observational epidemiological studies remain controversial, presumably because the designs of these studies are subject to residual confounding and reverse causality. Mendelian randomization (MR) can infer the causality between exposure and disease outcomes using genetic variants as instrumental variables, and identification of the causal risk factors for AT is beneficial for early intervention. Thus, we employed the MR strategy to evaluate the causal associations between previously reported risk factors (anthropometric parameters, lifestyle factors, blood biomarkers, and systemic diseases) and the risk of AT.
Methods
Univariable MR was performed to screen for potential causal associations between the putative risk factors and AT. Bidirectional MR was used to infer reverse causality. Multivariable MR was conducted to investigate the body mass index (BMI)-independent causal effect of other obesity-related traits, such as the waist-hip ratio, on AT.
Results
Univariable MR analyses with the inverse-variance weighted method indicated that the genetically predicted BMI was significantly associated with the risk of AT (P=2.0×10⁻³), and the odds ratios (95% confidence intervals) is 1.44 (1.14−1.81) per 1-SD increase in BMI. For the other tested risk factors, no causality with AT was identified using any of the MR methods. Bidirectional MR suggested that AT was not causally associated with BMI, and multivariable MR indicated that other anthropometric parameters included in this study were not likely to causally associate with the risk of AT after adjusting for BMI.
Conclusions
The causal association between BMI and AT risk suggests that weight control is a promising strategy for preventing AT and alleviating the corresponding disease burden.
Achilles tendon injury is one of the most common musculoskeletal conditions in athletes. The majority of Achilles tendon injuries are managed non-surgically. However, a subset of athletes can experience chronic symptoms that interfere with sports. Achilles tendinopathy is a failed healing response with a clinical syndrome of pain, with or without swelling, and impaired performance. This condition ultimately results from excessive load on the tendon often accompanied by other factors predisposing to tendon disease. Achilles tendinopathy is usually diagnosed using history and physical examination alone, with pain being the primary symptom resulting in a patient seeking medical treatment. Both musculoskeletal ultrasound and magnetic resonance imaging can be used in the diagnostic workup and guide treatment, especially if there is consideration for interventional treatment. Conservative measures are typically utilized for 3–6 months in the treatment of Achilles tendinopathy. Choice of treatment if conservative measures fail is patient specific, with newer interventional treatments serving as an alternative to surgery.
Anterior cruciate ligament (ACL) injuries are one of the most serious injuries of the lower limb and can result in a relatively low rate of return to sport and decreased quality of life in later years, as well as to the psychological attitude towards sports among young people. Previous research has investigated the interaction between the hip muscles and knee valgus moments where some studies have concluded that decreased hip abductor and external rotator strength is a risk factor for ACL injury, but no research has been conducted on preadolescent population. Data from 271 students (174 girls), age 9-12 where collected while performing cutting manoeuvre and the isometric maximal voluntary contraction of hip external rotators and abductors. Our results show that no significant correlation where found between the hip strength does not influence the knee VM during the cutting manoeuvre in this age group which is in line with many previous studies conducted on older population.
Objectives
To investigate if the temporal characteristics of hamstring and gluteal muscle activation are altered during high speed overground running in professional Australian Football players following hamstring muscle injury.
Design
Cohort study.
Setting
Field-based testing.
Participants
Elite professional Australian Football players who had sustained a hamstring muscle injury in the six months prior to testing (n = 7) and a group of players from the same club who had no history of hamstring muscle injury (n = 8).
Main outcome measures
Muscle onset timing, muscle offset timing and muscle onset duration of the medial hamstrings, biceps femoris and gluteus maximus muscles during high-speed running using electromyographic data.
Results
No significant differences in any of the temporal aspects of muscle activation were found between groups for any of the muscles tested (p > 0.05).
Conclusions
Persistent alterations to the timing of muscle activation following hamstring muscle injury that have been reported in recreational athletes were not observed during high speed running in professional athletes who have completed comprehensive rehabilitation programs.
ACHILLES TENDINOPATHY (AT) IS A CONDITION WHEREBY INDIVIDUALS EXPERIENCE PAIN AND IMPAIRMENTS AS A RESULT OF PATHOLOGICAL CHANGES AT THE ACHILLES TENDON AND NEIGHBORING TISSUES. THIS ARTICLE PROVIDES AN EVIDENCE-BASED OVERVIEW OF THE STRUCTURAL PATHOLOGY AND CLINICAL SEQUELA ASSOCIATED WITH AT. THE EVIDENCE UNDERPINNING MORE COMMON TREATMENTS, WITH AN EMPHASIS ON EXERCISE INTERVENTIONS, IS PRESENTED IN AN EFFORT TO MITIGATE THE IMPAIRMENT SEQUELA AND GUIDE SPORTS MEDICINE PROFESSIONALS IN THEIR CHOICE OF TREATMENTS FOR AT.
Objective
To determine the immediate effects of a varus unloader knee brace on lower-limb electromyographic activity in individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction.
Methods
Electromyographic data were recorded in 19 individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction during walking under three conditions: (i) no brace, (ii) unadjusted brace (no varus adjustment), and adjusted brace (varus adjustment). Variables of interest were statistically analyzed using repeated measures analysis of variance.
Results
There were no significant differences in muscle co-contraction between the three test conditions. The adjusted brace resulted in delayed offset of gluteus maximus (mean difference [95% CI]: 72 ms [24–119]), and earlier onset of gluteus medius (59 ms [21–97]) compared to no brace. The adjusted brace delayed onset of lateral gastrocnemius compared to no brace (53 ms [28–78]) and the unadjusted brace (39 ms [7–71]) and reduced average activation amplitude of gluteus maximus (−4 mV [−6 to −1]) and lateral gastrocnemius (−9 mV [−16 to −2]) compared to no brace.
Conclusions
The unloader brace did not produce significant changes in muscle co-contraction in individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction. Significant changes in gluteal and gastrocnemius muscle activation timing and amplitude were observed, however, it is not clear whether these changes are of clinical importance.
Achilles tendinopathy is a common problem and often difficult to treat. The best-known and best-researched treatment is mechanical loading, either with eccentric or concentric-eccentric exercises or with a heavy-load, slow-speed (concentric-eccentric) rehabilitation program. To experience a favorable outcome from exercise, the exercises are allowed to cause pain. Therefore, the use of a pain-monitoring model together with a training log will help the patient and the clinician in the balance between overloading and loading enough to achieve a positive response to the exercises. The exercise program needs to continue for at least 12 weeks, and often it needs to be continued for up to a year. It might also be beneficial to combine the exercise treatment with other treatments, such as shock wave therapy, laser therapy, and the use of orthotics. Surgery is considered to be the last option. Patients with insertional Achilles tendinopathy are more likely to need surgery compared with patients with midportion Achilles tendinopathy.
Background
Achilles tendinopathy is a common problem, but its exact aetiology remains unclear.
Objective
To evaluate the association between potential clinical risk factors and Achilles tendinopathy.
Design
Systematic review.
Data sources
The databases Embase, MEDLINE Ovid, Web of Science, Cochrane Library and Google Scholar were searched up to February 2018.
Eligibility criteria
To answer our research question, cohort studies investigating risk factors for Achilles tendinopathy in humans were included. We restricted our search to potential clinical risk factors (imaging studies were excluded).
Results
We included 10 cohort studies, all with a high risk of bias, from 5111 publications identified. There is limited evidence for nine risk factors: (1) prior lower limb tendinopathy or fracture, (2) use of ofloxacin (quinolone) antibiotics, (3) an increased time between heart transplantation and initiation of quinolone treatment for infectious disease, (4) moderate alcohol use, (5) training during cold weather, (6) decreased isokinetic plantar flexor strength, (7) abnormal gait pattern with decreased forward progression of propulsion, (8) more lateral foot roll-over at the forefoot flat phase and (9) creatinine clearance of <60 mL/min in heart transplant patients. Twenty-six other putative risk factors were not associated with Achilles tendinopathy, including being overweight, static foot posture and physical activity level.
Conclusion
From an ocean of studies with high levels of bias, we extracted nine clinical risk factors that may increase a person’s risk of Achilles tendinopathy. Clinicians may consider ofloxacin use, alcohol consumption and a reduced plantar flexor strength as modifiable risk factors when treating patients with Achilles tendinopathy.
Trial registration number
CRD42017053258.
Research to date suggests that the relationship between hip muscle strength and dynamic knee valgus is conflicting. But on closer inspection the relationship may be task dependent. Future research methods may need to come closer to reproducing the demands of sport to establish whether a relationship exists
Objective:
To systematically review literature investigating the relationship between hip muscle strength and dynamic lower extremity valgus during movement tasks in asymptomatic females.
Methods:
Four databases (CINAHL, SPORTDiscus, Embase and Ovid MEDLINE) were searched in February 2017. Studies investigating the relationship between hip muscle strength and dynamic knee or lower extremity valgus during movement tasks among asymptomatic females over 18 years old were included. Meta-analyses were performed where two or more studies used similar tasks.
Results:
Five studies reported no relationship between hip strength and dynamic lower extremity valgus. Greater peak lower extremity valgus was associated with reduced hip strength in eight studies, and greater hip strength in three studies. In the meta-analysis, a relationship between weaker hip strength and greater dynamic lower extremity valgus was found for ballistic single leg landing, but not double leg landing or single leg squat tasks.
Conclusions:
Although the relationship between hip strength and dynamic lower extremity valgus is conflicting, meta-analysis revealed lower extremity dynamic valgus was consistently associated with hip strength in single leg ballistic tasks, but not double leg ballistic or single leg squat tasks. The relationship between hip strength and dynamic lower extremity valgus may be conditional to task demand.
The Orthopaedic Section of the American Physical Therapy Association (APTA) has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). The purpose of these revised clinical practice guidelines is to review recent peer-reviewed literature and make recommendations related to midportion Achilles tendinopathy.
J Orthop Sports Phys Ther 2018;48(5):A1–A38. doi:10.2519/jospt.2018.0302
El propósito de este estudio es el de valorar si existe relación entre una inestabilidad pélvica en dinámica con la cinética y cinemática del miembro inferior. También se relaciona la limitación de la flexión de tobillo con las presiones plantares.
En una muestra de 47 corredores varones sanos se grabó la ejecución del test “single leg squat” para posteriormente ser valorado por un comité de expertos. Los participantes corrieron calzados sobre una pista de atletismo a 3,3m/s llevando puestos 2 acelerómetros en tibia y cabeza. También se tomaron las presiones plantares en dinámica. El rango articular de flexión de tobillo también ha sido valorado mediante el test de flexión de tobillo.
Los resultados obtenidos muestran mayor presión máxima en M1 (7.9 vs 14.7N/cm2) p=0.003 y M2 (10.3 vs 16.8 N/cm2) p=0.008 en el pie derecho, entre los grupos de buena y mala estabilidad dinámica de la pelvis. Por otro lado, el grupo con limitación de la flexión de tobillo presentaron menor tiempo máximo de presión en talón medial (26.8 vs 29.8 ms) p=0.046 y M4 (117.6 vs 125.7 ms) p=0.042 del pie derecho y menor ratio de carga en M4 (0.18 vs 0.25 N/cm2s) p= 0.041 del pie izquierdo. La acelerometría no mostró resultados estadísticamente significativos asociada a la inestabilidad pélvica.
La inestabilidad dinámica de pelvis produce mayor presión en la zona medial del antepié (M1 y M2) que se ha asociado con mayor pronación del pie. La limitación a la flexión de tobillo provoca menos tiempo de presión en talón medial y M4, lo que sugiere cambios en el tiempo de las presiones plantares. La acelerometría no mostró resultados significativos, esto apoya la hipótesis de que el cuerpo tiene un sistema de ajuste neuromuscular para controlar las alteraciones biomecánicas y que no modifiquen el impacto del pie contra el suelo.
Blagrove, RC, Brown, N, Howatson, G, and Hayes, PR. Strength and conditioning habits of competitive distance runners. J Strength Cond Res XX(X): 000-000, 2017-Targeted strength and conditioning (S&C) programs can potentially improve performance and reduce injury risk factors in competitive runners. However, S&C practices of distance runners are unknown. This study aimed to explore S&C practices of competitive middle- and long-distance runners and examined whether reported frequency of injuries was influenced by training behaviors. One thousand eight hundred eighty-three distance runners (≥15 years old) completed an online survey. All runners who raced competitively were included in data analysis (n = 667). Distance runners mainly engaged with S&C activities to lower risk of injury (63.1%) and improve performance (53.8%). The most common activities used were stretching (86.2%) and core stability exercises (70.2%). Resistance training (RT) and plyometric training (PT) were used by 62.5 and 35.1% of runners, respectively. Junior (under-20) runners include PT, running drills, and circuit training more so than masters runners. Significantly more international standard runners engaged in RT, PT, and fundamental movement skills training compared with competitive club runners. Middle-distance (800-3,000 m) specialists were more likely to include RT, PT, running drills, circuit training, and barefoot exercises in their program than longer-distance runners. Injury frequency was associated with typical weekly running volume and run frequency. Strength and conditioning did not seem to confer a protection against the number of injuries the runners experienced. Practitioners working with distance runners should critically evaluate the current S&C practices of their athletes, to ensure that activities prescribed have a sound evidence-based rationale.
Study Design
Controlled laboratory study, repeated-measures design.
Background
Previous studies have reported that the superior and inferior portions of the gluteus maximus have different functional roles. Knowledge of how the different portions of the gluteus maximus are activated during therapeutic exercise may lead to more specific exercise prescription.
Objective
To compare muscle activation of the superior and inferior portions of the gluteus maximus during commonly used therapeutic exercises.
Methods
Twenty healthy persons participated. Electromyographic (EMG) signals were obtained from the superior and inferior portions of the gluteus maximus using fine-wire electrodes. Normalized EMG signal amplitudes were compared between the superior and inferior gluteus maximus across 11 exercises using a 2-way repeated-measures analysis of variance.
Results
The superior portion of the gluteus maximus had significantly greater relative EMG activity than the inferior portion of the gluteus maximus during exercises that incorporated elements of hip abduction and/or external rotation (5 of 11 exercises evaluated). There was no significant difference in activation between the superior and inferior portions of the gluteus maximus during the remaining 6 exercises.
Conclusion
The results of the present study demonstrate preferential activation of the superior portion of the gluteus maximus during exercises that incorporate elements of hip abduction and/or external rotation. In contrast, exercises that primarily involve hip extension target both portions of the gluteus maximus to a similar extent. J Orthop Sports Phys Ther 2016;46(9):794–799. Epub 5 Aug 2016. doi:10.2519/jospt.2016.6493
Foot and ankle injuries account for nearly one-third of running injuries. Achilles tendinopathy, plantar fasciopathy, and ankle sprains are 3 of the most common types of injuries sustained in runners. Other common injuries include other tendinopathies of the foot and ankle, bone stress injuries, nerve conditions including neuromas, and joint disease including osteoarthritis. This review provides an evidence-based framework for the evaluation and optimal management of these conditions to ensure safe return to running participation and reduce risk for future injury.
RUNNERS WITH PATELLOFEMORAL PAIN HAVE ALTERED BIOMECHANICS, WHICH INTERVENTIONS CAN ALTER:
A SYSTEMATIC REVIEW AND META-ANALYSIS.
Neal BS 1-2, Gallie R 1, Barton CB 1-4, Morrissey D 1,5*.
1. Centre for Sports and Exercise Medicine, Queen Mary University of London, United Kingdom.
2. Pure Sports Medicine, London, United Kingdom.
3. Complete Sports Care, Melbourne, Australia.
4. Lower Extremity and Gait Studies Program, Faculty of Health Sciences, La Trobe University, Melbourne, Australia.
5. Physiotherapy Department, Bart’s Health NHS Trust, London, United Kingdom
* NIHR Disclaimer: Dr Morrissey is part funded by the NIHR/HEE Senior Clinical Lecturer scheme. This abstract presents independent research part-funded by the National Institute for Health Research (NIHR). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.
Introduction: Patellofemoral pain (PFP) in runners is reported to be asscoiated with several biomechanical (kinetic, kinematic, muscle function) factors. This review (i) synthesises biomechanical studies of individuals with and without PFP in runners and (ii) defines the outcomes of interventions targetting observed biomechanical deficits.
Methods: Medline, CINAHL, Embase and SportDiscus were searched for case-control and intervention studies of runners with PFP. Two assessors graded study quality and data was pooled where possible to aid in determination of levels of evidence.
Results: 27 studies were included (20 case-control and 7 intervention). PFP was moderately associated with increased peak hip adduction (standardized mean difference (SMD), confidence interval (CI) for all) (0.41, 0.13-0.70), increased peak hip internal rotation (0.44, 0.18-0.69) and increased peak contralateral pelvic drop (0.85, 0.50-1.19). Very limited evidence also identified a prospective link between increased peak hip adduction and PFP development (0.90, 0.38-1.42). No association was identified for increased peak rearfoot eversion (0.03, -0.41-0.35), which matches significant but very limited prospective findings (-0.53, -1.05 to -0.01). Intervention studies showed significant but limited evidence that orthoses reduced peak rearfoot eversion (0.78, 0.08-1.48) and running gait re-education reduced peak hip adduction (2.10, 1.30-2.91).
Conclusion: The strong association between PFP and both greater peak hip adduction and internal rotation suggests interventions should address kinematics of the hip in runners with PFP, supported by very limited evidence of increased hip adduction as a risk factor. Limited evidence indicates running gait re-education can induce favorable kinematic change at the hip and longer tem studies are recommended.
Electromyographic (EMG) studies into gluteus medius (GMed) typically involve surface EMG electrodes. Previous comparisons of surface and fine wire electrode recordings in other muscles during high load isometric tasks suggest that recordings between electrodes are comparable when the muscle is contracting at a high intensity, however, surface electrodes record additional activity when the muscle is contracting at a low intensity. The purpose of this study was to compare surface and fine wire recordings of GMed at high and low intensities of muscle contractions, under high load conditions (maximum voluntary isometric contractions, MVICs). Mann-Whitney U tests compared median electrode recordings during three MVIC hip actions; abduction, internal rotation and external rotation, in nine healthy adults. There were no significant differences between electrode recordings in positions that evoked a high intensity contraction (internal rotation and abduction, fine wire activity >77% MVIC; effect size, ES<0.42; p>0.277). During external rotation, the intensity of muscle activity was low (4.2% MVIC), and surface electrodes recorded additional myoelectric activity (ES=0.67, p=0.002). At low levels of muscle activity during high load isometric tasks, the use of surface electrodes may result in additional myoelectric recordings of GMed, potentially reflective of cross-talk from surrounding muscles.
Objectives
Australian Football League (AFL) players have a high incidence of back injuries. Motor control training to increase lumbopelvic neuromuscular control has been effective in reducing low back pain (LBP) and lower limb injuries in elite athletes. Control of pelvic and femoral alignment during functional activity involves the piriformis muscle. This study investigated a) the effect of motor control training on piriformis muscle size in AFL players, with and without LBP, during the playing season, and b) whether there is a relationship between lower limb injury and piriformis muscle size.
Design
Stepped-Wedge Intervention
Methods
46 AFL players participated in a motor control training program consisting of two 30 minute sessions per week over 7-8 weeks, delivered across the season as a randomised 3 group single-blinded stepped-wedge design. Assessment of piriformis muscle cross-sectional area (CSA) involved magnetic resonance imaging (MRI) at 3 time points during the season. Assessment of LBP consisted of player interview and physical examination. Injury data were obtained from club records.
Results
An interaction effect for Time, Intervention Group and LBP group (F = 3.7, p = 0.03) was found. Piriformis muscle CSA showed significant increases between Times 1 and 2 (F = 4.24, p = 0.046), and Times 2 and 3 (F = 8.59, p = 0.006). Players with a smaller increase in piriformis muscle CSA across the season had higher odds of sustaining an injury (OR = 1.08).
Conclusion
Piriformis muscle size increases across the season in elite AFL players and is affected by the presence of LBP and lower limb injury. Motor control training positively affects piriformis muscle size in players with LBP.
Objective: Provide a current review of the literature concerning the epidemiology and risk factors for injuries in runners. Data sources: The information in this paper is taken from a review of articles and book chapters (Source: PubMed and MEDLINE, years covered 1966-2006). Conclusions: Understanding the precise causative nature of risk factors in running populations remains a challenging task. Comparison of various works in the literature is impeded by large variations in injury definition, subject population and study design. Weekly running volume continues to be considered a strong risk factor, however more work is needed to determine whether it is the absolute volume, or the increase in volume that is deleterious. Recent research has provided greater insight into the risks that previous injury and lack of full rehabilitation may play in recreational runners starting a training program. Variables related to excessive rear-foot eversion and pronation are frequently sited in combination with the incidence of specific injuries; however, the role of impact characteristics remains in debate. Isokinetic research of hip muscle function is helping to link our understanding of lower extremity kinematics, but requires more research to be proven as a causative factor. Future research in joint coupling and functional training of the complete lower extremity will be beneficial in implementing preventative interventions for running populations.
Background
Achilles tendinopathy (AT) is a common condition, causing considerable morbidity in athletes and non-athletes alike. Conservative or physical therapies are accepted as first-line management of AT; however, despite a growing volume of research, there remains a lack of high quality studies evaluating their efficacy. Previous systematic reviews provide preliminary evidence for non-surgical interventions for AT, but lack key quality components as outlined in the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Statement. The aim of this study was to conduct a systematic review and meta-analysis (where possible) of the evidence for physical therapies for AT management.
Methods
A comprehensive strategy was used to search 11 electronic databases from inception to September 2011. Search terms included Achilles, tendinopathy, pain, physical therapies, electrotherapy and exercise (English language full-text publications, human studies). Reference lists of eligible papers were hand-searched. Randomised controlled trials (RCTs) were included if they evaluated at least one non-pharmacological, non-surgical intervention for AT using at least one outcome of pain and/or function. Two independent reviewers screened 2852 search results, identifying 23 suitable studies, and assessed methodological quality and risk of bias using a modified PEDro scale. Effect size calculation and meta-analyses were based on fixed and random effects models respectively.
Results
Methodological quality ranged from 2 to 12 (/14). Four studies were excluded due to high risk of bias, leaving 19 studies, the majority of which evaluated midportion AT. Effect sizes from individual RCTs support the use of eccentric exercise. Meta-analyses identified significant effects favouring the addition of laser therapy to eccentric exercise at 12 weeks (pain VAS: standardised mean difference −0.59, 95% confidence interval −1.11 to −0.07), as well as no differences in effect between eccentric exercise and shock wave therapy at 16 weeks (VISA-A:–0.55,–2.21 to 1.11). Pooled data did not support the addition of night splints to eccentric exercise at 12 weeks (VISA-A:–0.35,–1.44 to 0.74). Limited evidence from an individual RCT suggests microcurrent therapy to be an effective intervention.
Conclusions
Practitioners can consider eccentric exercise as an initial intervention for AT, with the addition of laser therapy as appropriate. Shock wave therapy may represent an effective alternative. High-quality RCTs following CONSORT guidelines are required to further evaluate the efficacy of physical therapies and determine optimal clinical pathways for AT.
Excessive flexion and internal rotation of the hip is a common gait abnormality among individuals with cerebral palsy. The purpose of this study was to examine the influence of hip flexion on the rotational moment arms of the hip muscles. We hypothesized that flexion of the hip would increase internal rotation moment arms and decrease external rotation moment arms of the primary hip rotators. To test this hypothesis we measured rotational moment arms of the gluteus maximus (six compartments), gluteus medius (four compartments), gluteus minimus (three compartments) iliopsoas, piriformis, quadratus femoris, obturator internus, and obturator externus. Moment arms were measured at hip flexion angles of 0, 20, 45, 60, and 90° in four cadavers. A three-dimensional computer model of the hip muscles was developed and compared to the experimental measurements. The experimental results and the computer model showed that the internal rotation moment arms of some muscles increase with flexion; the external rotation moment arms of other muscles decrease, and some muscles switch from external rotation to internal rotation as the hip is flexed. This trend toward internal rotation with hip flexion was apparent in 15 of the 18 muscle compartments we examined, suggesting that excessive hip flexion may exacerbate internal rotation of the hip. The gluteus maximus was found to have a large capacity for external rotation. Enhancing the activation of the gluteus maximus, a muscle that is frequently underactive in persons with cerebral palsy, may help correct excessive flexion and internal rotation of the hip.
Abnormal lower limb biomechanics is speculated to be a risk factor for Achilles tendinopathy. This study systematically reviewed the existing literature to identify, critique and summarise lower limb biomechanical factors associated with Achilles tendinopathy.
We searched electronic bibliographic databases (Medline, EMBASE, Current contents, CINAHL and SPORTDiscus) in November 2010. All prospective cohort and case-control studies that evaluated biomechanical factors (temporospatial parameters, lower limb kinematics, dynamic plantar pressures, kinetics [ground reaction forces and joint moments] and muscle activity) associated with mid-portion Achilles tendinopathy were included. Quality of included studies was evaluated using the Quality Index. The magnitude of differences (effect sizes) between cases and controls was calculated using Cohen's d (with 95% CIs).
Nine studies were identified; two were prospective and the remaining seven case-control study designs. The quality of 9 identified studies was varied, with Quality Index scores ranging from 4 to 15 out of 17. All studies analysed running biomechanics. Cases displayed increased eversion range of motion of the rearfoot (d = 0.92 and 0.67 in two studies), reduced maximum lower leg abduction (d = -1.16), reduced ankle joint dorsiflexion velocity (d = -0.62) and reduced knee flexion during gait (d = -0.90). Cases also demonstrated a number of differences in dynamic plantar pressures (primarily the distribution of the centre of force), ground reaction forces (large effects for timing variables) and also showed reduced peak tibial external rotation moment (d = -1.29). Cases also displayed differences in the timing and amplitude of a number of lower limb muscles but many differences were equivocal.
There are differences in lower limb biomechanics between those with and without Achilles tendinopathy that may have implications for the prevention and management of the condition. However, the findings need to be interpreted with caution due to the limited quality of a number of the included studies. Future well-designed prospective studies are required to confirm these findings.
Despite anecdotal evidence linking overpronation to the onset of Achilles tendinopathy (AT), there is little conclusive evidence of a particular movement pattern of the lower extremity associated with this injury. Therefore, the objective of the present study was to observe differences in the kinematic profiles of healthy runners (CON) and runners with mid-portion Achilles tendinopathy (ATG).
In this cross-sectional analysis, 48 male height and weight matched subjects were invited to participate: 27 with mid-portion Achilles tendon pain and 21 asymptomatic controls. Subjects underwent lower extremity clinical examination, then ran barefoot for 10-trials at a self-selected pace. A 3D motion capture system analysed tri-plane kinematic data for the lower extremity.
The ATG displayed significantly greater sub-talar joint eversion displacement during mid-stance of the running gait (13 +/- 3 degrees vs. 11 +/- 3 degrees; p = 0.04). Trends were observed such that the ATG showed lower peak dorsiflexion velocity (300 +/- 39 degrees/s vs. 330 +/- 59 degrees/s; p = 0.08) and greater overall frontal plane ankle joint range of motion (45 degrees +/- 7 vs. 41 degrees +/- 7; p = 0.09).
We found an increase in eversion displacement of the sub-talar joint in runners with Achilles mid-portion tendinopathy. Based on the findings from this study, there is evidence that devices used to control sub-talar eversion may be warranted in patients with Achilles mid-portion tendinopathy who demonstrate over-pronation during mid-stance of the running gait.
G*Power is a free power analysis program for a variety of statistical tests. We present extensions and improvements of the version introduced by Faul, Erdfelder, Lang, and Buchner (2007) in the domain of correlation and regression analyses. In the new version, we have added procedures to analyze the power of tests based on (1) single-sample tetrachoric correlations, (2) comparisons of dependent correlations, (3) bivariate linear regression, (4) multiple linear regression based on the random predictor model, (5) logistic regression, and (6) Poisson regression. We describe these new features and provide a brief introduction to their scope and handling.
The aim of this study was to investigate the kinetics, kinematics and muscle activity in runners with Achilles tendinopathy.
Case-control study.
Biomechanics laboratory.
21 runners free from injury and 21 runners with Achilles tendinopathy performed 10 running trials with standardised running shoes. Injured runners were diagnosed clinically according to established diagnostic criteria. Uninjured runners had been injury-free for at least 2 years. Main outcome measurements: During each trial, kinetic and lower limb kinematic data were measured using a strain gauge force plate and six infrared cameras respectively. Electromyographic (EMG) data from six muscles (tibialis anterior (TA), peroneus longus (PE), lateral gastrocnemius (LG), rectus femoris (RF), biceps femoris (BF) and gluteus medius (GM)) were measured with a telemetric EMG system.
Knee range of motion (heel strike to midstance) was significantly lower in injured runners than in uninjured runners. Similarly, preactivation (integrated EMG (IEMG) in 100 ms before heel strike) of TA was lower for injured runners than uninjured runners. RF and GM IEMG activity 100 ms after heel strike was also lower in the injured group. However, impact forces were not different between the two groups.
Altered knee kinematics and reduced muscle activity are associated with Achilles tendinopathy in runners. Rehabilitation exercises or other mechanisms (e.g. footwear) that affect kinematics and muscle activity may therefore be beneficial in the treatment of runners with Achilles tendinopathy.
Limb movement imparts a perturbation to the body. The impact of that perturbation is limited via anticipatory postural adjustments. The strategy by which the CNS controls anticipatory postural adjustments of the trunk muscles during limb movement is altered during acute back pain and in people with recurrent back pain, even when they are pain free. The altered postural strategy probably serves to protect the spine in the short term, but it is associated with a cost and is thought to predispose spinal structures to injury in the long term. It is not known why this protective strategy might occur even when people are pain free, but one possibility is that it is caused by the anticipation of back pain. In eight healthy subjects, recordings of intramuscular EMG were made from the trunk muscles during single and repetitive arm movements. Anticipation of experimental back pain and anticipation of experimental elbow pain were elicited by the threat of painful cutaneous stimulation. There was no effect of anticipated experimental elbow pain on postural adjustments. During anticipated experimental back pain, for single arm movements there was delayed activation of the deep trunk muscles and augmentation of at least one superficial trunk muscle. For repetitive arm movements, there was decreased activity and a shift from biphasic to monophasic activation of the deep trunk muscles and increased activity of superficial trunk muscles during anticipation of back pain. In both instances, the changes were consistent with adoption of an altered strategy for postural control and were similar to those observed in patients with recurrent back pain. We conclude that anticipation of experimental back pain evokes a protective postural strategy that stiffens the spine. This protective strategy is associated with compressive cost and is thought to predispose to spinal injury if maintained long term.
This study examined the kinematic differences between subjects who had a history of chronic Achilles tendon (AT) injury and matched controls during running. Eleven subjects from each group ran barefoot (BF) and shod at self-selected speeds on a treadmill. Three-dimensional angles describing rearfoot and lower limb motion were calculated throughout stance. Five footfalls were obtained for each subject and condition. Pairwise comparisons revealed greater eversion, ankle dorsiflexion and less leg abduction during stance in the AT group compared with controls. Running kinematics were exaggerated in shod compared with BF conditions, as expected from previous research. The differences between conditions were more exaggerated in AT subjects compared with control subjects. Further analysis using a curve-based approach is recommended.
Background —There is no disease specific, reliable, and valid clinical measure of Achilles tendinopathy.
Objective —To develop and test a questionnaire based instrument that would serve as an index of severity of Achilles tendinopathy.
Methods —Item generation, item reduction, item scaling, and pretesting were used to develop a questionnaire to assess the severity of Achilles tendinopathy. The final version consisted of eight questions that measured the domains of pain, function in daily living, and sporting activity. Results range from 0 to 100, where 100 represents the perfect score. Its validity and reliability were then tested in a population of non-surgical patients with Achilles tendinopathy (n = 45), presurgical patients with Achilles tendinopathy (n = 14), and two normal control populations (total n = 87).
Results —The VISA-A questionnaire had good test-retest ( r = 0.93), intrarater (three tests, r = 0.90), and interrater ( r = 0.90) reliability as well as good stability when compared one week apart ( r = 0.81). The mean (95% confidence interval) VISA-A score in the non-surgical patients was 64 (59–69), in presurgical patients 44 (28–60), and in control subjects it exceeded 96 (94–99). Thus the VISA-A score was higher in non-surgical than presurgical patients (p = 0.02) and higher in control subjects than in both patient populations (p<0.001).
Conclusions —The VISA-A questionnaire is reliable and displayed construct validity when means were compared in patients with a range of severity of Achilles tendinopathy and control subjects. The continuous numerical result of the VISA-A questionnaire has the potential to provide utility in both the clinical setting and research. The test is not designed to be diagnostic. Further studies are needed to determine whether the VISA-A score predicts prognosis.
G*Power (Erdfelder, Faul, & Buchner, 1996) was designed as a general stand-alone power analysis program for statistical tests commonly used in social and behavioral research. G*Power 3 is a major extension of, and improvement over, the previous versions. It runs on widely used computer platforms (i.e., Windows XP, Windows Vista, and Mac OS X 10.4) and covers many different statistical tests of the t, F, and chi2 test families. In addition, it includes power analyses for z tests and some exact tests. G*Power 3 provides improved effect size calculators and graphic options, supports both distribution-based and design-based input modes, and offers all types of power analyses in which users might be interested. Like its predecessors, G*Power 3 is free.
Objective: To examine the effect of the application of tape over the patella on the onset of electromyographic (EMG) activity of vastus medialis obliquus (VMO) relative to vastus lateralis (VL) in participants with and without patellofemoral pain syndrome (PFPS). Design: Randomised within subject. Settings: University laboratory. Participants: Ten participants with PFPS and 12 asymptom-atic controls. Interventions: Three experimental taping conditions: no tape, therapeutic tape, and placebo tape. Main Outcome Measures: Electromyographic onset of VMO and VL assessed during the concentric and eccentric phases of a stair stepping task. Results: When participants with PFPS completed the stair stepping task, the application of therapeutic patellar tape was found to alter the temporal characteristics of VMO and VL activation, whereas placebo tape had no effect. In contrast, there was no change in the EMG onset of VMO and VL with the application of placebo or therapeutic tape to the knee in the asymptomatic participants. Conclusions: These data support the use of patellar taping as an adjunct to rehabilitation in people with PFPS.
Achilles tendinopathy is a common injury in running sports however the exact etiology of Achilles injury is still unclear. In recent years, altered neuromotor recruitment patterns of the triceps surae have been hypothesized to create differential intra-tendinous loads leading to pathology; however, this hypothesis has not been investigated. Further, the effect foot orthoses may have on neuromotor recruitment of the triceps surae in Achilles tendinopathy has not been investigated. Methods: The electromyographic activity of the triceps surae was recorded during an over-ground running task. Fifteen Achilles injured participants and 19 asymptomatic controls were assessed in a footwear only condition. The Achilles injured participants were also assessed running in a pre-fabricated foot orthoses. Results: In Achilles injured participants, there was a significant difference between soleus and lateral gastrocnemius offset times during running compared to the asymptomatic controls (p<0.05). There were no significant differences in triceps surae muscle activity between the footwear only and footwear and orthoses condition in the Achilles injured participants. Conclusions: The finding that triceps surae activity is altered in participants with Achilles tendinopathy may have clinical importance as it suggests that intra-tendinous loads are altered which may contribute to pathological changes. Further, foot orthoses have no immediate effect on the neuromotor control of the triceps surae.
Excessive rearfoot eversion is thought to be a risk factor for patellofemoral pain syndrome development, based on theoretical rationale linking it to greater tibial internal rotation and hip adduction. This study aimed to establish the relationship of rearfoot eversion with tibial internal rotation and hip adduction during walking in individuals with and without patellofemoral pain syndrome.
Twenty-six individuals with patellofemoral pain syndrome and 20 controls (18-35years) participated. Each underwent instrumented three-dimensional motion analysis during over-ground walking. Pearson's correlation coefficients (r) were calculated to establish the relationship of rearfoot eversion with tibial internal rotation and hip adduction (peak and range of motion).
Greater peak rearfoot eversion was associated with greater peak tibial internal rotation in the patellofemoral pain syndrome group (r=0.394, P=0.046). Greater rearfoot eversion range of motion was associated with greater hip adduction range of motion in the patellofemoral pain syndrome (r=0.573, P=0.002) and control (r=0.460, P=0.041) groups; and greater peak hip adduction in the control group (r=0.477, P=0.033).
Associations between greater rearfoot eversion and greater hip adduction indicate that interventions targeted at the foot or hip in individuals with patellofemoral pain syndrome may have similar overall effects on lower limb motion and clinical outcomes. The relationship between rearfoot eversion and tibial internal rotation identified in the patellofemoral pain syndrome group may be related to aetiology. However, additional prospective research is needed to confirm this.
During the past decade, our understanding of biomechanics and its importance in rehabilitation has advanced significantly. The kinetic chain, a concept borrowed from engineering, has helped us better understand the underlying physiology of human movement. This understanding, in turn, has facilitated the development of new and more rational rehabilitation strategies. The kinetic chain concept has application in a wide spectrum of clinical conditions, including musculoskeletal medicine, sports medicine, and neurorehabilitation, as well as prosthetics and orthotics. The purpose of this review is to provide insights into the biomechanics related to the concept of kinetic chains, with a specific focus on closed kinetic chains and its clinical applications in rehabilitation.
Residual hip impairments, such as decreased hip muscle moment and power during walking, have been reported in patients with total hip arthroplasty (THA). Meanwhile, greater ankle power has also been reported in these patients. We investigated the interaction between hip and ankle joints during walking to determine the effects of different ankle pushoff instructions on hip biomechanics in patients with THA. Twenty-four women (age, 60.8±5.5 years) were randomly assigned to walking exercise groups with either decreased pushoff or increased pushoff. Patients in the decreased pushoff group and increased pushoff group were given the instructions "push less with your foot when you walk" and "push more with your foot when you walk," respectively. Exercises lasted approximately 10-15 min. A series of gait-related parameters were analyzed during pre-exercise, exercise, and post-exercise session. In the decreased ankle pushoff group, hip flexor power absorption and hip/ankle power ratio were higher during post-exercise than during pre-exercise. An increase in hip power from -9.8% to 32.1% was identified. The effect of increase in the hip power by the decreasing ankle pushoff was higher in the patients with greater ankle pushoff in their natural gaits. The patients in the increased ankle pushoff group showed decreased hip flexion angle and hip muscle moment and power after the walking exercise, although ankle pushoff was not increased. Walking exercise with decreased ankle pushoff may help improve the distribution of muscle power between hip flexors and ankle plantarflexors during walking in patients with THA.
Walking is a complex dynamic task that requires the regulation of whole-body angular momentum to maintain dynamic balance while performing walking subtasks such as propelling the body forward and accelerating the leg into swing. In human walking, the primary mechanism to regulate angular momentum is muscle force generation. Muscles accelerate body segments and generate ground reaction forces that alter angular momentum about the body's center-of-mass to restore and maintain dynamic stability. In addition, gravity contributes to whole-body angular momentum through its contribution to the ground reaction forces. The purpose of this study was to generate a muscle-actuated forward dynamics simulation of normal walking to quantify how individual muscles and gravity contribute to whole-body angular momentum in the sagittal plane. In early stance, the uniarticular hip and knee extensors (GMAX and VAS), biarticular hamstrings (HAM) and ankle dorsiflexors (TA) generated backward angular momentum while the ankle plantar flexors (SOL and GAS) generated forward momentum. In late stance, SOL and GAS were the primary contributors and generated angular momentum in opposite directions. SOL generated primarily forward angular momentum while GAS generated backward angular momentum. The difference between muscles was due to their relative contributions to the horizontal and vertical ground reaction forces. Gravity contributed to the body's angular momentum in early stance and to a lesser extent in late stance, which was counteracted primarily by the plantar flexors. These results may provide insight into balance and movement disorders and provide a basis for developing locomotor therapies that target specific muscle groups.
Rearfoot pronation-supination and hip internal-external rotation are commonly assumed to be temporally coupled. Many mechanisms of musculoskeletal injury are proposed based on this assumption. Previous studies suggested that this theoretical coupling does not exist. However, recent experimental studies observed relationships consistent with foot-hip mechanical interdependence.
Three-dimensional kinematics of the lower extremity of 18 healthy subjects, wearing flat trekking sandals, was measured during the stance phase of normal walking. Rearfoot-shank complex motion in the transverse plane (shank internal-external rotation) and frontal plane (rearfoot eversion-inversion) and hip motion in the transverse plane were analyzed. Cross-correlation coefficients were calculated to investigate temporal similarities between curves of rearfoot-shank and hip motions. Pearson correlations were used to investigate relationships between the timings of the peaks of these motions.
Cross-correlations revealed a strong mean temporal coupling (mean r=0.77, range 0.56 to 0.92) between shank internal-external rotation and hip internal-external rotation and a moderate mean temporal coupling (mean r=0.56, range 0.37 to 0.78) between rearfoot eversion-inversion and hip internal-external rotation. Pearson correlations revealed significant (P</=0.031) moderate relationships of timing of peak shank internal rotation (r=0.45) and timing of peak rearfoot eversion (r=0.62) with timing of peak hip internal rotation.
The findings suggest a temporal coupling of rearfoot pronation with hip internal rotation and rearfoot supination with hip external rotation during walking stance. The between-subjects variability of curves' temporal similarities and the moderate relationships between timings of motion peaks indicate that coupling strength should be clinically addressed on an individual basis.
Achilles tendinopathy is a considerable problem for active people. The degenerative processes associated with tendinopathy may be associated with changes in the inherent mechanical properties of the musculotendinous unit.
The purpose of this study was to compare Achilles tendon-aponeurosis strain between male athletes with and without Achilles tendinopathy.
Cross-sectional study; Level of evidence, 3.
Fifteen healthy men (age, 35 +/- 9 years; height, 1.78 +/- 0.05 m; mass, 79 +/- 11 kg) and 14 men with midportion Achilles tendinopathy (age, 40 +/- 8 years; height, 1.77 +/- 0.06 m; mass, 80 +/- 9 kg) who were all running over 20 km per week participated in the study. Each participant was tested in a single session that involved maximal isometric plantar flexion efforts being performed on a calf-raise apparatus while synchronous real-time ultrasonography of the triceps surae aponeurosis was recorded. Achilles tendon-aponeurosis strain (%) was calculated by dividing tendon displacement during plantar flexion by resting tendon length (intrarater reliability: intraclass correlation coefficient = .92).
Participants in the Achilles tendinopathy group (5.2% +/- 2.6%) had significantly (P = .039) higher Achilles tendon-aponeurosis strain compared with the control group (3.4% +/- 1.8%). In contrast, there were no significant between-group differences for maximal isometric plantar flexion force.
Achilles tendon-aponeurosis strain is higher in male athletes with tendinopathy than those without. The results of this study provide a rationale for current clinical approaches to management of Achilles tendinopathy, whereby repetitive mechanical loading may impart a positive benefit through reduced compliance of the musculotendinous unit.
Synopsis
The 21 muscles that cross the hip provide both triplanar movement and stability between the femur and acetabulum. The primary intent of this clinical commentary is to review and discuss the current understanding of the specific actions of the hip muscles. Analysis of their actions is based primarily on the spatial orientation of the muscles relative to the axes of rotation at the hip. The discussion of muscle actions is organized according to the 3 cardinal planes of motion. Actions are considered from both femoral-on-pelvic and pelvic-on-femoral perspectives, with particular attention to the role of coactivation of trunk muscles. Additional attention is paid to the biomechanical variables that alter the effectiveness, force, and torque of a given muscle action. The role of certain muscles in generating compression force at the hip is also presented. Throughout the commentary, the kinesiology of the muscles of the hip are considered primarily from normal but also pathological perspectives, supplemented with several clinically relevant scenarios. This overview should serve as a foundation for understanding the assessment and treatment of musculoskeletal impairments that involve not only the hip, but also the adjacent low back and knee regions. J Orthop Sports Phys Ther 2010;40(2):82–94. doi:10.2519/jospt.2010.3025
Chronic tendinopathy is difficult to treat. Nonsurgical management is the most conservative approach. Switching to another sport (swimming, weight training, rowing, cycling) allows the tendon time to rest. Eccentric exercise therapy (exercises that cause stretching combined with contraction of a muscle) is increasingly prescribed for patients with chronic Achilles tendinopathy. Although scientific evidence does not support many traditional treatments, they are still often used and include nonsteroidal anti-inflammatory medication (eg, ibuprofen), orthoses (devices to support the muscle and relieve tendon stress; eg, heel pads), stretching, massage, ultrasound, taping the back of the leg, and plaster casting. Steroid injection directly into the tendon is sometimes used but not generally recommended because some specialists believe this increases the risk of tendon rupture. Surgery is often a last resort because recovery is slow. Although not proven, preventive measures often include choosing running shoes that provide sufficient cushion for heel strike, using a prescribed orthotic, walking and stretching to warm up calf muscles before running, gradually increasing running distance and speed by not greater than 10% per week, avoiding unaccustomed sprinting and hill running, and cooling down properly after exercise.
To compare the effects of vastus medialis oblique (VMO) motor control retraining (MCR) and quadriceps strengthening (QS) exercises on the onset timing of the medial (VMO) and lateral (vastus lateralis, VL) quadriceps muscle.
This single-blind randomized controlled trial involved 60 currently pain-free individuals with a history of anterior knee pain and delayed (>10 ms) onset of VMO relative to VL during stair stepping. A blinded assessor took measures at baseline, immediately after 6 wk of treatment, and after an 8-wk follow-up. Both exercise programs involved weekly individual physiotherapy sessions with home exercises. The MCR program comprised specific VMO exercises incorporating EMG biofeedback, mostly in functional weight-bearing positions. The QS program comprised progressive-resistance inner range open kinetic chain exercises. The primary outcome was the latency between the onset of VMO EMG activity relative to that of VL during stair stepping measured using surface electrodes.
During stair ascent, there was a significant change immediately after the intervention in VMO-VL timing in the MCR group only (P = 0.04), but there was no significant difference in the change between groups. During stair descent, VMO-VL timing changed in both groups (P < 0.01), with the MCR group showing a greater change than the QS group (P = 0.02). At the completion of training, quadriceps strength was only improved in the QS group (all P < 0.001). At follow-up, VMO timing and quadriceps strength had improved in both groups compared with baseline (P < 0.01), but there was no difference between groups.
Although greater changes in motor control during stair descent and strength are induced by interventions that target each of these parameters in the short term, both parameters are similarly improved after the cessation of training, regardless of the target of the intervention.
To compare neuromuscular control ofthe lower limb during gait between individuals with and without a history of exercise-related leg pain (ERLP).
Fourteen females with a history of ERLP and 14 age-, height-, and weight-matched asymptomatic female controls participated in the study.Electromyographic activity, normalized to maximum voluntary contraction (MVC), from 12 lower limb muscles during walking gait was the primary outcome. Secondary outcomes were three-dimensional kinematics of the lower limb during gait, measurements of static foot posture (arch height and midfoot width in weight bearing and non-weight bearing), and foot mobility (difference in arch height and midfoot width from non-weight bearing to weight bearing and foot mobility magnitude).
Individuals with a history of ERLP demonstrated lower peak activation (13.7% MVC, 95% confidence interval (CI) = 3.2%-24.3% MVC) and lower average activation of gluteus medius (2.3% MVC, 95% CI = 0.3%-4.3% MVC) when compared with controls (P G 0.05). This reduction in gluteus medius activation was moderately determined (57.1%, P = 0.01) by the duration (beta = 0.555) and severity of pain (beta = -0.516). Peak and average activation of lateral gastrocnemius were also lower than controls (20.5% MVC, 95% CI = 0.6%-40.5% MVC and 1.7% MVC, 95% CI = 0.2%-3.1% MVC, respectively) but were not explained by pain duration or severity. No differences in kinematics at the ankle, knee, hip and pelvis, or differences in static foot posture and mobility were observed between groups (P > 0.05).
This study provides evidence of altered neuromuscular control of gait in females with a history of ERLP. Further work is required to discern the clinical relevance of this finding.
Sagittal bending moments acting on the lower leg during running may play a role in tibial stress fracture development. The purpose of this study was to evaluate these moments at nine equidistant points along the length of the lower leg (10% point-90% point) during running. Kinematic and ground reaction force data were collected for 20 male runners, who each performed 10 running trials. Inverse dynamics and musculoskeletal modelling techniques were used to estimate sagittal bending moments due to reaction forces and muscle contraction. The muscle moment was typically positive during stance, except at the most proximal location (10% point) on the lower leg. The reaction moment was predominantly negative throughout stance and greater in magnitude than the muscle moment. Hence, the net sagittal bending moment acting on the lower leg was principally negative (indicating tensile loads on the posterior tibia). Peak moments typically occurred around mid-stance, and were greater in magnitude at the distal, compared with proximal, lower leg. For example, the peak reaction moment at the most distal point was -9.61+ or - 2.07%Bw.Ht., and -2.73 + or - 1.18%Bw.Ht. at the most proximal point. These data suggest that tensile loads on the posterior tibia are likely to be higher toward the distal end of the bone. This finding may explain the higher incidence of stress fracture in the distal aspect of the tibia, observed by some authors. Stress fracture susceptibility will also be influenced by bone strength and this should also be accounted for in future studies.
Statistical guidelines and expert statements are now available to assist in the analysis and reporting of studies in some biomedical disciplines. We present here a more progressive resource for sample-based studies, meta-analyses, and case studies in sports medicine and exercise science. We offer forthright advice on the following controversial or novel issues: using precision of estimation for inferences about population effects in preference to null-hypothesis testing, which is inadequate for assessing clinical or practical importance; justifying sample size via acceptable precision or confidence for clinical decisions rather than via adequate power for statistical significance; showing SD rather than SEM, to better communicate the magnitude of differences in means and nonuniformity of error; avoiding purely nonparametric analyses, which cannot provide inferences about magnitude and are unnecessary; using regression statistics in validity studies, in preference to the impractical and biased limits of agreement; making greater use of qualitative methods to enrich sample-based quantitative projects; and seeking ethics approval for public access to the depersonalized raw data of a study, to address the need for more scrutiny of research and better meta-analyses. Advice on less contentious issues includes the following: using covariates in linear models to adjust for confounders, to account for individual differences, and to identify potential mechanisms of an effect; using log transformation to deal with nonuniformity of effects and error; identifying and deleting outliers; presenting descriptive, effect, and inferential statistics in appropriate formats; and contending with bias arising from problems with sampling, assignment, blinding, measurement error, and researchers' prejudices. This article should advance the field by stimulating debate, promoting innovative approaches, and serving as a useful checklist for authors, reviewers, and editors.
This paper presents a general statistical methodology for the analysis of multivariate categorical data arising from observer reliability studies. The procedure essentially involves the construction of functions of the observed proportions which are directed at the extent to which the observers agree among themselves and the construction of test statistics for hypotheses involving these functions. Tests for interobserver bias are presented in terms of first-order marginal homogeneity and measures of interobserver agreement are developed as generalized kappa-type statistics. These procedures are illustrated with a clinical diagnosis example from the epidemiological literature.
During 1976-1986, 3,336 athletes consulted the Turku Sports Medical Research Unit, 455 (14%) of these for Achilles tendon injuries. Achilles tendon problems were more frequent among joggers (66%), tennis players (32%) and runners (24%), which emphasizes the aetiological role of running. Achilles tendon complaints (n = 698) consisted of paratenonitis (including tendinopathies) (66%), insertional (23%) and myotendineal (8%) pain syndromes and total tendon ruptures (3%). The mean age of Achilles tendon injury patients was 26.1 years; among other sport injury patients it was 21.9 years (P < 0.001). Surgery was performed in 24% of the subjects with paratenonitis and insertional pains. Different structural faults were found in 60% of the athletes with Achilles tendon overuse injuries. Forefoot varus correlated (r = P < 0.001) with paratenonitis. A markedly limited total passive subtalar joint mobility and/or ankle joint dorsiflexion with knee extended was found in 6% of the conscripts, in 44% of the control athletes and in 58% and 70% of athletes with Achilles tendon paratenonitis and insertional pains, respectively. The range of motion of the ankle and subtalar joints was much lower in athletes than conscripts (P < 0.001).
The purpose of this study was to determine whether relationships exist between selected training, anthropometric, isokinetic muscular strength, and endurance, ground reaction force, and rearfoot movement variables in runners afflicted with Achilles tendinitis.
Specifically, we examined differences in selected measures between a noninjured cohort of runners (N = 58) and a cohort of injured runners with Achilles tendinitis (N = 31). Isokinetic, kinetic, and kinematic measures were collected using a Cybex II+ isokinetic dynamometer (Medway, MA), AMTI force plate (500 Hz), and Motion Analysis high-speed videography (200 Hz), respectively. Separate discriminant function analyses were performed on each of the five sets of variables to identify the factors that best discriminate between the injured and control groups.
Years running, training pace, stretching habits (injured runners were less likely to incorporate stretching into their training routine), touchdown angle, plantar flexion peak torque at 180 degrees x s(-1) and arch index were found to be significant discriminators.
A combined discriminant analysis using the above mentioned significant variables revealed that plantar flexion peak torque, touchdown angle, and years running were the strongest discriminators between runners afflicted with Achilles tendinitis and runners who had no history of overuse injury.
The knowledge of surface electromyography (SEMG) and the number of applications have increased considerably during the past ten years. However, most methodological developments have taken place locally, resulting in different methodologies among the different groups of users.A specific objective of the European concerted action SENIAM (surface EMG for a non-invasive assessment of muscles) was, besides creating more collaboration among the various European groups, to develop recommendations on sensors, sensor placement, signal processing and modeling. This paper will present the process and the results of the development of the recommendations for the SEMG sensors and sensor placement procedures. Execution of the SENIAM sensor tasks, in the period 1996-1999, has been handled in a number of partly parallel and partly sequential activities. A literature scan was carried out on the use of sensors and sensor placement procedures in European laboratories. In total, 144 peer-reviewed papers were scanned on the applied SEMG sensor properties and sensor placement procedures. This showed a large variability of methodology as well as a rather insufficient description. A special workshop provided an overview on the scientific and clinical knowledge of the effects of sensor properties and sensor placement procedures on the SEMG characteristics. Based on the inventory, the results of the topical workshop and generally accepted state-of-the-art knowledge, a first proposal for sensors and sensor placement procedures was defined. Besides containing a general procedure and recommendations for sensor placement, this was worked out in detail for 27 different muscles. This proposal was evaluated in several European laboratories with respect to technical and practical aspects and also sent to all members of the SENIAM club (>100 members) together with a questionnaire to obtain their comments. Based on this evaluation the final recommendations of SENIAM were made and published (SENIAM 8: European recommendations for surface electromyography, 1999), both as a booklet and as a CD-ROM. In this way a common body of knowledge has been created on SEMG sensors and sensor placement properties as well as practical guidelines for the proper use of SEMG.
The main objectives of this study on able-bodied gait were (a) to identify the main functions of the ankle and hip muscle moments and their contribution to support and propulsion tasks, and (b) to illustrate the interaction between the ankle and hip moment activities.
Twenty young, able-bodied male subjects walked along a 13 m path at a freely chosen speed.
Functional contributions of the ankle and hip muscles and their interactions in achieving support and propulsion tasks during gait are still subject to controversy.
Principal component analysis was applied as a curve structure detection method to identify the main functional characteristics of the ankle and hip muscle moments. The first two principal components which contained over 70% and 85%, respectively, of the information in the ankle and hip moment curves revealed their functional tasks. Ankle versus hip moment plots was used to illustrate the interactions between muscles acting at the hip and ankle in the sagittal plane. Correlation coefficient and covariance calculations quantified the interaction between the ankle and hip moments.
The first principal component revealed that the main role of the ankle and hip is to keep the body from collapsing. The second principal component is associated with the functional contribution of both ankle plantarflexors and hip flexors during the propulsion phase (50-60% of the gait cycle). High coordination (r=0.82) between the ankle and hip moments was observed.
Maintaining body support against gravity was identified as the first functional task of the ankle plantarflexors and hip extensors, while contribution to propulsion was recognised as the second major role for the ankle plantarflexors and hip flexors.
Identifying the main roles of the muscles acting at the hip and ankle during able-bodied walking provides better insight into how pathological gait should be evaluated.
There is no disease specific, reliable, and valid clinical measure of Achilles tendinopathy.
To develop and test a questionnaire based instrument that would serve as an index of severity of Achilles tendinopathy.
Item generation, item reduction, item scaling, and pretesting were used to develop a questionnaire to assess the severity of Achilles tendinopathy. The final version consisted of eight questions that measured the domains of pain, function in daily living, and sporting activity. Results range from 0 to 100, where 100 represents the perfect score. Its validity and reliability were then tested in a population of non-surgical patients with Achilles tendinopathy (n = 45), presurgical patients with Achilles tendinopathy (n = 14), and two normal control populations (total n = 87).
The VISA-A questionnaire had good test-retest (r = 0.93), intrarater (three tests, r = 0.90), and interrater (r = 0.90) reliability as well as good stability when compared one week apart (r = 0.81). The mean (95% confidence interval) VISA-A score in the non-surgical patients was 64 (59-69), in presurgical patients 44 (28-60), and in control subjects it exceeded 96 (94-99). Thus the VISA-A score was higher in non-surgical than presurgical patients (p = 0.02) and higher in control subjects than in both patient populations (p<0.001).
The VISA-A questionnaire is reliable and displayed construct validity when means were compared in patients with a range of severity of Achilles tendinopathy and control subjects. The continuous numerical result of the VISA-A questionnaire has the potential to provide utility in both the clinical setting and research. The test is not designed to be diagnostic. Further studies are needed to determine whether the VISA-A score predicts prognosis.
This study describes the types and frequencies of musculoskeletal injuries among a cohort of adults with above average activity levels who were enrolled in the Aerobics Center Longitudinal Study (Dallas, TX).
Participants were adults aged 20-85 yr who completed a baseline clinical examination (1970-1982) and returned a mailed follow-up survey in 1986. Participants (5,028 men, 1,285 women) were measured for aerobic fitness, height, and body weight during the baseline examination. They reported detailed information about their physical activity levels and injury experiences on the follow-up survey (1986). An injury was defined as any self-reported soft tissue or bone injury that occurred within the previous 12 months. Activity-related injuries were those injuries participants attributed to participation in a formal exercise program.
A quarter of all participants reported a musculoskeletal injury. Of these, 83% were activity-related. More than 66% of activity-related injuries occurred in the lower extremity; the knee was listed as the joint most often affected. There were no significant sex differences in the prevalence of injury, regardless of cause. Sport participants had the highest proportion of all-cause and activity-related musculoskeletal injuries among both men and women. Self-perceived severe injuries had a significant negative impact on physical activity levels since almost 1/3 of subjects reported permanently stopping their exercise program after injury.
These results suggest the need for developing and implementing injury prevention programs targeted toward moderately active adults.
To examine the effect of the application of tape over the patella on the onset of electromyographic (EMG) activity of vastus medialis obliquus (VMO) relative to vastus lateralis (VL) in participants with and without patellofemoral pain syndrome (PFPS).
Randomised within subject.
University laboratory.
Ten participants with PFPS and 12 asymptomatic controls.
Three experimental taping conditions: no tape, therapeutic tape, and placebo tape.
Electromyographic onset of VMO and VL assessed during the concentric and eccentric phases of a stair stepping task.
When participants with PFPS completed the stair stepping task, the application of therapeutic patellar tape was found to alter the temporal characteristics of VMO and VL activation, whereas placebo tape had no effect. In contrast, there was no change in the EMG onset of VMO and VL with the application of placebo or therapeutic tape to the knee in the asymptomatic participants.
These data support the use of patellar taping as an adjunct to rehabilitation in people with PFPS.
Augmentation of the Achilles tendon with flexor hallucis longus is an established method to treat neglected ruptures and severe cases of chronic tendinopathy. After transfer of the muscle/tendon, good pain reduction and improved plantar flexion have been reported. To date, only one study has investigated the effect of FHL transfer on forefoot biomechanics. Theoretically, there should be a partial transfer of forefoot loading towards the lateral metatarsal heads during push-off, resulting in an asymmetric gait.
13 patients were examined clinically and using pedobarography with a mean follow-up of 46 months (minimum 24) after Achilles tendon augmentation with flexor hallucis longus. Parameters of the forefoot were investigated to detect differences in pressure and force distribution, load transfer to other areas of the forefoot, and asymmetries compared to the non-operated leg. The results are discussed with regard to clinical relevance.
Clinically, there were no subjective or objective gait asymmetries. All patients were free of pain and without restrictions during normal walking. In general, pedobarography showed an unloading of the first toe with a load transfer to the metatarsal heads on the operated side. All results featured high inter-subject and within-subject variability.
Due to the high within-subject variability, there is inconsistency within the results making interpretation difficult. However, the results confirm the hypothesis that unloading of the first toe during push-off and an asymmetrical loading pattern can be measured after harvesting of the flexor hallucis longus. The clinical situation of the patients did not reflect a visible amount of gait asymmetry. Differences in loading patterns 2 years after flexor hallucis longus transfer for Achilles tendon augmentation appear to be well compensated.
: To evaluate the initial effects of antipronation taping (APT) on foot posture and electromyographic (EMG) activity of tibialis anterior (TA), tibialis posterior (TP), and peroneus longus (PL) muscles during walking.
: Five asymptomatic individuals who exhibited lower medial longitudinal arch height on a clinical assessment of gait walked on a treadmill for 10 min before and after the application of an APT technique-specifically, the augmented low-Dye. Arch height (AH) in standing as well as peak and average amplitude, duration, time of onset, and time of offset of recorded EMG activity during walking were analyzed for each condition.
: APT produced a mean (95% confidence interval (CI)) increase in AH of 12.9% (6.5-19.3; P = 0.005). Mean (95% CI) reductions in peak and average EMG activation of TA (peak: -23.9% (-34.0 to -13.9); average: -7.8% (-13.6 to -2.0)) and TP (peak: -45.5% (-77.3 to -13.7); average: -21.1% (-41.6 to -0.6)) were observed when walking with APT (P < 0.05). The APT also produced a small increase in duration of TA EMG activity of 3.7% (0.9-6.5) of the stride cycle duration, largely because of an earlier onset of EMG activity (4.4%; -8.1 to -0.8 of a stride cycle; P < 0.05).
: APT reduces activity of the TA and TP muscles during walking while increasing AH, which provides preliminary evidence of its role in reducing the load of these key extrinsic muscles of the ankle and the foot. Follow-up study is required to evaluate these findings.
In a simple bipedal walking model, an impulsive push along the trailing limb (similar to ankle plantar flexion) or a torque at the hip can power level walking. This suggests a tradeoff between ankle and hip muscle requirements during human gait. People with anterior hip pain may benefit from walking with increased ankle pushoff if it reduces hip muscle forces. The purpose of our study was to determine if simple instructions to alter ankle pushoff can modify gait dynamics and if resulting changes in ankle pushoff have an effect on hip muscle requirements during gait. We hypothesized that changes in ankle kinetics would be inversely related to hip muscle kinetics. Ten healthy subjects walked on a custom split-belt force-measuring treadmill at 1.25m/s. We recorded ground reaction forces and lower extremity kinematic data to calculate joint angles and internal muscle moments, powers and angular impulses. Subjects walked under three conditions: natural pushoff, decreased pushoff and increased pushoff. For the decreased pushoff condition, subjects were instructed to push less with their feet as they walked. Conversely, for the increased pushoff condition, subjects were instructed to push more with their feet. As predicted, walking with increased ankle pushoff resulted in lower peak hip flexion moment, power and angular impulse as well as lower peak hip extension moment and angular impulse (p<0.05). Our results emphasize the interchange between hip and ankle kinetics in human walking and suggest that increased ankle pushoff during gait may help to compensate for hip muscle weakness or injury and reduce hip joint forces.
Achilles tendinopathy.
- Chang
Chang HJ, Burke AE, Glass RM. Achilles Tendinopathy. J Am Podiatr Med Assoc.
2010;303(2):188.
Kinematic analysis of runners with Achilles mid-portion tendinopathy A review of anthropometric, biomechanical, neuromuscular and training related factors associated with injury in runners
- M Ryan
- S Grau
- I Krauss
- C Maiwald
- J Taunton
- T Horstmann
- Mb Ryan
- Cl Maclean
- Je Taunton
Ryan M, Grau S, Krauss I, Maiwald C, Taunton J, Horstmann T. Kinematic analysis
of runners with Achilles mid-portion tendinopathy. Foot Ankle Int. 2009;30(12):1190.
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Ryan MB, MacLean CL, Taunton JE. A review of anthropometric, biomechanical,
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