Impaired limb shortening following stroke: what's in a name?

BackgroundDifficulty advancing the paretic limb during the swing phase of gait is a prominent manifestation of walking dysfunction following stroke. This clinically observable sign, frequently referred to as 'foot drop', ostensibly results from dorsiflexor weakness.ObjectiveHere we investigated the extent to which hip, knee, and ankle motions contribute to impaired paretic limb advancement. We hypothesized that neither: 1) minimal toe clearance and maximal limb shortening during swing nor, 2) the pattern of multiple joint contributions to toe clearance and limb shortening would differ between post-stroke and non-disabled control groups.MethodsWe studied 16 individuals post-stroke during overground walking at self-selected speed and nine non-disabled controls who walked at matched speeds using 3D motion analysis.ResultsNo differences were detected with respect to the ankle dorsiflexion contribution to toe clearance post-stroke. Rather, hip flexion had a greater relative influence, while the knee flexion influence on producing toe clearance was reduced.ConclusionsSimilarity in the ankle dorsiflexion, but differences in the hip and knee, contributions to toe clearance between groups argues strongly against dorsiflexion dysfunction as the fundamental impairment of limb advancement post-stroke. Marked reversal in the roles of hip and knee flexion indicates disruption of inter-joint coordination, which most likely results from impairment of the dynamic contribution to knee flexion by the gastrocnemius muscle in preparation for swing. These findings suggest the need to reconsider the notion of foot drop in persons post-stroke. Redirecting the focus of rehabilitation and restoration of hemiparetic walking dysfunction appropriately, towards contributory neuromechanical impairments, will improve outcomes and reduce disability

An Examination of Hip Muscle Activation in those with Hip-Related Groin Pain during Single-Legged and Double-Legged Squats

Approximately 60% of young adults who present with chronic hip pain suffer from hip-related groin pain (HRGP). HRGP causes individuals to experience pain, dysfunction, and have a lower quality of life when compared to healthy individuals. The most severe symptoms in these individuals occur during activities that cause the hip to go through a large range of motion, such as a squat. Hip muscle activation during this task may be altered in these individuals, yet we know little about its role in the disease process and pain level in those with HRGP. Current treatment for these individuals includes surgical and non-surgical interventions; however, the effects of both treatments are not effective, and individuals tend to experience symptoms again within 2 years. Understanding muscle activation during squatting tasks may help us to develop a more effective and long-term solution when treating these patients. Therefore, the purpose of this study was to examine bilateral hip muscle activity of the tensor fascia latae, rectus femoris, gluteus medius, and gluteus maximus during single- and double-legged squats in individuals with HRGP. Specific Aims 1 and 2 were to compare bilateral differences in hip muscle activation during the double-legged and single-legged squats, respectively. Specific Aim 3 examined differences in muscle activation on the symptomatic side between the double-legged and single-legged squats. Methods: Seven individuals (2M/5F, age: 25.83 3.37yrs, BMI: 25.92 4.83kg/m2) with unilateral HRGP were recruited to participate. Following informed consent, surface EMG sensors were placed bilaterally on the four hip muscles. Individuals were asked to perform maximal voluntary isometric contractions (MVICs) for each muscle. Subsequently, two sets of five double-legged squats and five individual single-legged squats were performed. Average RMS value of each muscle (expressed as %MVIC) during the squats were determined. T-tests were performed to compare between the affected and healthy legs (Specific Aims 1 and 2) or between tasks (Specific Aim 3) when the data were normally distributed. Mann-Whitney U tests were performed when the assumptions of normality were violated. The alpha value for all statistical tests was 0.05. Results/Conclusions: No significant differences in hip muscle activation were found bilaterally during double- and single-legged squats for any of the muscles (p\u3e0.05). However, when comparing the symptomatic side muscle activation between squat tasks, the gluteus maximus had higher activation during the single-legged squat (single-legged: 25.0 ± 13.5 %MVIC, double-legged: 12.6 ± 7.3 %MVIC,