Narelle Wyndow

Neuromotor Control of the Lower Limb in Achilles Tendinopathy: Implications for Foot Orthotic Therapy

Achilles tendinopathy (AT) is a common injury in running sports. While the exact aetiology of Achilles injury is still unclear, foot orthoses are often effectively employed in the conservative management of the condition. Foot orthoses have traditionally been provided for people with AT on the basis that they may reduce the rearfoot eversion associated with excessive foot pronation. This increased rearfoot motion is thought to produce excessive Achilles tendon loads. To date, the available literature indicates that foot orthoses have small and unsystematic effects on rearfoot kinematics. However, limitations of foot kinematic measurement currently restrict the ability to conduct truly valid investigations into kinematic responses to foot orthoses. Therefore, the roles of alternate mechanisms, for which orthoses may provide clinical success in pathology such as AT, are now being investigated. One alternative theory is that foot orthoses alter neuromotor recruitment patterns and thus lower limb loads in response to the additional sensory input provided by the device.In AT, altered neuromotor recruitment patterns of the triceps surae have been hypothesized to create differential intratendinous loads. This may lead to pathological changes within the tendon. Furthermore, it is possible that foot orthoses may aid to normalize intratendinous loads via altering neuromotor activity in the triceps surae in AT.This review examines the literature with regard to changes in neuromotor recruitment as an associated aetiological factor in AT and the role foot orthoses may play in the management of this condition.

Neuromotor control of gluteal muscles in runners with achilles tendinopathy

PURPOSE 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. METHODS Fourteen male runners with Achilles tendinopathy and 19 healthy male runners (control) ran overground while EMG 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 α level was set at 0.05. RESULTS 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. CONCLUSIONS This study provides preliminary evidence of altered neuromotor control of the GMED and GMAX muscles in male runners with Achilles tendinopathy. Although 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.

Triceps surae activation is altered in male runners with Achilles tendinopathy

UNLABELLED 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.

The prevalence of radiographic and MRI-defined patellofemoral osteoarthritis and structural pathology: a systematic review and meta-analysis

Background Patellofemoral osteoarthritis (PF OA) is more prevalent than previously thought and contributes to patient’s suffering from knee OA. Synthesis of prevalence data can provide estimates of the burden of PF OA. Objective This study aims to conduct a systematic review and meta-analysis on the prevalence of PF OA and structural damage based on radiography and MRI studies in different populations. Methods We searched six electronic databases and reference lists of relevant cross-sectional and observational studies reporting the prevalence of PF OA. Two independent reviewers appraised methodological quality. Where possible, data were pooled using the following categories: radiography and MRI studies. Results Eighty-five studies that reported the prevalence of patellofemoral OA and structural damage were included in this systematic review. Meta-analysis revealed a high prevalence of radiographic PF OA in knee pain or symptomatic knee OA (43%), radiographic knee OA or at risk of developing OA (48%) and radiographic and symptomatic knee OA (57%) cohorts. The MRI-defined structural PF damage in knee pain or symptomatic population was 32% and 52% based on bone marrow lesion and cartilage defect, respectively. Conclusion One half of people with knee pain or radiographic OA have patellofemoral involvement. Prevalence of MRI findings was high in symptomatic and asymptomatic population. These pooled data and the variability found can provide evidence for future research addressing risk factors and treatments for PF OA. Trial registration number PROSPERO systematic review protocol (CRD42016035649).

The relationship of foot and ankle mobility to the frontal plane projection angle in asymptomatic adults

BackgroundThe frontal plane projection angle (FPPA) is frequently used as a measure of dynamic knee valgus during functional tasks, such as the single leg squat. Increased dynamic knee valgus is observed in people with knee pathologies including patellofemoral pain and anterior cruciate injury. As the foot is the primary interface with the support surface, foot and ankle mobility may affect the FPPA. This study investigated the relationship between foot and ankle mobility and the FPPA in asymptomatic adults.MethodsThirty healthy people (aged 18–50 years) performed 5 single leg squats. Peak FPPA and FPPA excursion were determined from digital video recordings. Foot mobility was quantified as the difference in dorsal midfoot height or midfoot width, between non-weightbearing and bilateral weightbearing positions. Ankle joint dorsiflexion range was measured as the maximum distance in centimetres between the longest toe and the wall during a knee-to-wall lunge. Linear regressions with generalised estimating equations were used to examine relationships between variables.ResultsHigher midfoot width mobility was associated with greater peak FPPA (β 0.90, p < 0.001, odds ratio [OR] 2.5), and FPPA excursion (β 0.67, p < 0.001, OR 1.9). Lower midfoot height mobility was associated with greater peak FPPA (β 0.37, p = 0.030, OR 1.4) and FPPA excursion (β 0.30, p = 0.020, OR 1.3). Lower ankle joint dorsiflexion was also associated with greater peak FPPA (β 0.61, p = 0.008, OR 1.8) and greater FPPA excursion (β 0.56, p < 0.001, OR 1.7).ConclusionsFoot and ankle mobility was significantly related to the FPPA during the single leg squat in healthy individuals. Specifically, higher midfoot width mobility, or lower ankle joint dorsiflexion range and midfoot height mobility, were associated with a greater FPPA. These foot mobility factors should be considered in the clinical management of knee-related disorders that are associated with a high FPPA.

Neuromotor control of the triceps surae during running in people with and without Achilles tendinopathy and the immediate effect of foot orthoses

Background Achilles tendinopathy (AT) is a common injury among physically active populations. It has been proposed that changes in neuromotor control of the triceps surae may increase differential intratendinous forces and thus be associated with the pain and pathology seen in this condition. However, it is not known if neuromotor differences actually exist between those with and without this condition. Thus the primary purpose of this research was to investigate whether neuromotor control of the triceps surae in distance runners with AT is altered compared to controls (Study 1). The secondary purpose of this research was to investigate the immediate effects of foot orthoses on triceps surae neuromotor control in subjects with AT (Study 2).

Foot and ankle mobility and the frontal plane projection angle in asymptomatic controls

The frontal plane projection angle (FPPA) is a measure of the degree of dynamic knee valgus during functional tasks such as the single leg squat. An increased FPPA is associated with patellofemoral pain and is indicative of knee valgus during other tasks such as running. Therefore, it is important to determine factors that can contribute to FPPA in order to develop treatment strategies for people with (or at risk of) PFJ pain.