Step-down Task Research Articles

A preliminary investigation into the impact of shock wave therapy and sonotherapy on postural control of stepping tasks in patients with Achilles tendinopathy.

The outcomes of physical therapy are commonly assessed with subjective scales and questionnaires. Hence, a continuous search to identify diagnostic tests that would facilitate objective assessment of symptom reduction in those patients with Achilles tendinopathy who undergo mechanotherapy. The main aim of this study was to evaluate and compare the effectiveness of shock wave and ultrasound treatments, using objective posturographic assessment during step-up and step-down initiation. The patients with non-insertional Achilles tendinopathy and pain lasting for more than 3 months were randomly assigned to one of the experimental groups, i.e., radial shock wave therapy (RSWT), ultrasound therapy, or placebo ultrasound. All groups also received deep friction massage as the primary therapy. The transitional locomotor task was performed with the affected and unaffected limb in random order, on two force platforms under two conditions (step-up and step-down). The recording of center of foot pressure displacements was divided into three phases: quiet standing before step-up/step-down, transit, and quiet standing until measurement completion. Pre-intervention measurements were performed and then short-term follow-ups at weeks 1 and 6 post-therapy. The three-way repeated measures ANOVA showed few statistically significant two-factor interactions between therapy type, time point of measurement and the type of the locomotor task. Significant increases in postural sway were observed in the entire study population throughout the follow-up period. Three-way ANOVAs revealed a group effect (shock wave vs. ultrasound) on almost all variables of the quiet standing phase prior to step-up/step-down initiation. Overall, postural stability before the step-up and step-down tasks appeared to be more efficient in patients who had undergone RSWT compared to the ultrasound group. Objective posturographic assessment during step-up and step-down initiation did not demonstrate therapeutic superiority of any of the three therapeutic interventions used in patients with non-insertional Achilles tendinopathy.Clinical Trial Registration: The trial was prospectively registered in the Australian and New Zealand Clinical Trials Registry (no. ACTRN12617000860369; registration date: 9.06.2017).

Machine learning full 3-D lower-body kinematics and kinetics on patients with osteoarthritis from electromyography

Osteoarthritis (OA) is a degenerative disease that causes severe pain and reduces the range of motion of the joint, decreasing the quality of life for millions of individuals in the United States. Electromyography (EMG) sensors have been widely studied in biomechanics, showing applications in prosthetics, robotics, and control. While complex musculoskeletal models have been well established, the attempt of directly correlating EMG with kinematics and kinetics is still quite limited. Particularly, little work has been conducted on OA patients. In this work, we propose a method for estimating lower body joint angles (JAs) and ground reaction forces (GRFs) from surface-EMG sensors during a step-down task for individuals diagnosed with OA. The JAs and GRFs were measured by a Vicon motion capture system and force plates, respectively. EMG, JAs, and GRFs were used to train an echo state network (ESN) which afforded JAs with relative errors of 3.78% and 3.71% and the GRFs with relative errors of 3.619% and 4.596% for training and testing datasets, respectively. This study suggests the high fidelity of the ESN in automatically predicting full lower body kinematics and kinetics from the EMG signals. The results of this work promote the development of an EMG-controlled lower limb rehabilitation robot system for patients with OA.

Serial Subtraction Alters Lateral Step-down Tibiofemoral Kinematics in Healthy Adults.

This study evaluated the effects of two types of cognitive dual-tasking on three-dimensional knee kinematics during the lateral step-down. 19 healthy individuals (22.05±1.61 yrs., 173.92±9.21 cm, 67.99±12.65 kg) participated in this study. Participants completed 5 repetitions of a lateral step-down task for each leg and each testing condition (control, Stroop, and serial subtraction by seven). An electromagnetic motion sensor was attached to the femur via compression clamp placed about the medial and lateral epicondyles. Another sensor was attached 2 cm below the ipsilateral tibial tuberosity. A custom MATLAB algorithm located the knee joint axis of rotation from dynamic knee flexion and extension. Discrete kinematics at peak flexion were used in this study. Paired samples t-tests were used to compare average frontal, transverse, and sagittal plane knee position at maximum flexion between conditions for each leg. No significant differences were found for either limb between control and Stroop conditions. Comparisons revealed significant differences in frontal and transverse plane knee angles at peak flexion between the control and serial subtraction by seven conditions. These findings indicate serial subtraction by seven requires different cognitive processing abilities which may cause greater interference with some aspects of motor control.

Criterion Validity and Reliability of Knee Frontal Plane Projection Angles Measured Using the Technique Application.

Abnormal knee frontal plane projection angles (FPPA) during movement have been associated with patellofemoral pain. As such, clinicians are interested in valid and reliable instruments suitable for broad-based clinical use that allow them to objectively measure such variables. Therefore, the purpose of the current study was to examine the criterion validity and reliability of knee FPPA measures obtained by clinicians using a free tablet application called Technique. Validity/reliability study. To examine validity, the same raters measured 10, two-dimensional criterion reference angles at the first testing session. To examine reliability, the knee FPPA of 16 subjects was measured by 6 raters (3 physical therapists and 3 student physical therapists) on 2 separate occasions while performing a single-limb step-down task. Validity was investigated by calculating the 95% limits of agreement, mean absolute differences, and Bland-Altman plots. Reliability was examined by calculating intraclass correlation coefficients and the SE of measure. For validity, the mean absolute difference between rater and criterion reference angle measures ranged from 0.20° to 0.90°. Ninety-five percent of expected errors between rater and criterion reference angle measures were 2.04° or less. For reliability, the intraclass correlation coefficient values for interrater and intrarater reliability were excellent ranging from .994 to .998 with SE of measure ranging from 0.44° to 0.84°. These findings indicate that knee FPPA measures obtained during a single-limb step-down task using the Technique tablet application are valid and reliable, and suitable for clinical use.

Low-Intensity Focused Ultrasound Stimulation Ameliorates Working Memory Dysfunctions in Vascular Dementia Rats via Improving Neuronal Environment.

Working memory impairment is one of the remarkable cognitive dysfunctions induced by vascular dementia (VD), and it is necessary to explore an effective treatment. Recently, low-intensity focused ultrasound stimulation (LIFUS) has been found notable neuroprotective effects on some neurological diseases, including VD. However, whether it could ameliorate VD-induced working memory impairment was still not been clarified. The purpose of this study was to address this issue and the underlying mechanism. We established VD rat model using the bilateral common carotid artery occlusion (BCCAO) and applied the LIFUS (center frequency = 0.5 MHz; Ispta = 500 mW/cm2, 10 mins/day) to bilateral medial prefrontal cortex (mPFC) for 2 weeks since 2 weeks after the surgery. The main results showed that the LIFUS could significantly improve the performance of VD rats in the specific working memory tasks (delayed nonmatch-to-sample task and step-down task), which might be associated with the improved synaptic function. We also found the improvement in the cerebral blood flow (CBF) and reduced neuroinflammation in mPFC after LIFUS treatment indicated by the inhibition of Toll-like receptor (TLR4)/nuclear factor kappa B (NF-κB) pathway and the decrease of proinflammatory cytokines. The amelioration of CBF and neuroinflammation may promote the living environment of the neurons in VD which then contribute to the survival of neurons and the improvement in synaptic function. Taken together, our findings indicate that LIFUS targeted mPFC can effectively ameliorate reward-based spatial working memory and fear working memory dysfunctions induced by VD via restoring the living environment, survivability, and synaptic functions of the neurons in mPFC of VD rats. This study adds to the evidence that LIFUS could become a promising and non-invasive treatment strategy for the clinical treatment of central nervous system diseases related to cognitive impairments in the future.

Biomechanical measures of clinician-defined unsteadiness during a forward stepdown task in individuals post-arthroscopy for femoroacetabular impingement syndrome

BackgroundPatients with femoroacetabular impingement syndrome can present with aberrant movement patterns including unsteady balance. Balance training is included in rehabilitation after hip arthroscopy and may improve quality of movement; however, specific biomechanical measures associated with clinician-defined balance impairments are unknown. We aimed to understand these associations as they may inform targeted rehabilitative interventions. MethodsThe forward stepdown is a clinical test used to evaluate movement quality, including balance. 23 individuals at least one-year post-arthroscopy for femoroacetabular impingement syndrome and 15 healthy comparisons performed the forward stepdown, recorded by 3-dimensional motion capture and 2-dimensional video. Three physical therapists graded the 2-dimensional video for steadiness. Two-way analyses of variance were used to evaluate the interaction of group (post-arthroscopy/healthy comparison) by steadiness (steady/unsteady), for center of pressure medial-lateral excursion, center of pressure path length, and lateral trunk, pelvis, and lower extremity joint excursions. FindingsSix (26.1%) participants post-arthroscopy and five (33.3%) healthy comparisons were categorized as unsteady. The odds of being categorized as unsteady were not greater for participants post-arthroscopy (P = 0.72). There were no significant interactions; however, participants with clinician-defined unsteady balance, regardless of group, had significantly greater frontal plane trunk excursion, greater hip excursion, and greater center of pressure path length than those with steady balance (P ≤ 0.006). InterpretationThe odds of being categorized as unsteady were not greater for individuals post-arthroscopy for femoroacetabular impingement syndrome. Clinician-defined unsteadiness was associated with greater frontal plane trunk and hip motion which may be rehabilitation targets to improve balance during a dynamic single-leg task.

Does forward step-down task frontal kinematics differ in women with and without patellofemoral pain? A cross-sectional study

Does forward step-down task frontal kinematics differ in women with and without patellofemoral pain? A cross-sectional study

The effect of URB597, exercise or their combination on the performance of 6-OHDA mouse model of Parkinson disease in the elevated plus maze, tail suspension test and step-down task.

Parkinson disease (PD) is a progressive neurodegenerative disorder that is often accompanied by motor and psychiatric symptoms. Various approaches have been proposed for the treatment of PD. Here, we investigated the effect of a low dose of fatty acid amide hydrolase inhibitor URB597 (as an enhancer of endocannabinoid anandamide levels), exercise or their combination on some behavior alterations in PD mice lesioned by 6-hydroxydopamine (6-OHDA). The impact of swimming exercise (5×/week for 4weeks) and URB597 (0.1mg/kg, 2×/week for 4weeks) on the anxiety-related behavior (elevated plus maze; EPM), depression-related behavior (tail suspension test; TST), and passive avoidance memory (step-down task) was examined in the sham and male NMRI mouse of PD model. The results show that URB597 prevented memory deficits and elicited antidepressant- and anxiolytic-like effects but did not affect hypolocomotion in the PD mice. However, URB597 did not have a significant effect on the performance of the sham mice in the performed tests. Moreover, swimming training abolished depressive- and anxiogenic-like behaviors and increased locomotion without affecting memory deficits in the PD mice. Meanwhile, swimming decreased immobility time and increased locomotion in the sham mice. Furthermore, URB597 in association with swimming training prevented all deficits induced in the PD mice, while this combination impaired memory and produced the positive effects on depression- and anxiety-related behaviors and locomotion of the sham mice. It is concluded that although URB597 or exercise alone had positive effects on most behavioral tests, their combination improved all parameters in the PD mice.

Three-dimensional joint kinematic and two-dimensional quality of movement comparison between lateral and forward step-downs

ObjectivesWhile lateral and forward step-down tasks are commonly used, they may have different kinematic and performance demands that could influence clinical assessment and rehabilitation. Therefore, the purpose of this study was to compare 3D lower extremity kinematics and 2D quality of movement between the tasks. DesignCross-sectional comparative study. SettingResearch laboratory. ParticipantsThirty healthy adults (18 females, age = 23.2 ± 1.4 years, BMI = 23.9 ± 2.2 kg/m2). Main outcome measuresParticipants underwent 3D and 2D motion analysis. 3D variables were peak hip, knee, and ankle angles. Dichotomous clinical criteria were used for 2D assessment. An alpha level of 0.05 was used for statistical analyses. ResultsIn the sagittal plane, the forward step-down averaged 7° more knee flexion (p < 0.001, d = 2.30) and 4° more ankle dorsiflexion (p < 0.001, d = 1.72), but 2° less hip flexion (p = 0.001, d = 0.64). In the frontal plane, forward step-downs averaged 1° more hip adduction (p = 0.006, d = 0.54) and 1° more ankle eversion (p < 0.001, d = 1.04). The forward step-down elicited 2D movement faults more often (p = 0.003). ConclusionsThe increased knee flexion and ankle dorsiflexion demands of the forward step-down were accompanied by increases in frontal plane aberrations. The forward step-down may be more challenging for individuals with reduced tolerance to loaded knee flexion and/or limited ankle mobility.

The influence of step-down technique on lower extremity mechanics during curb descent

When stepping down from a curb, individuals typically make initial ground contact with either their rearfoot or forefoot. The purpose of this study was to compare vertical ground reaction forces, lower extremity mechanics, and intra-limb work distribution when individuals adopt a rearfoot technique vs. a forefoot technique, during simulated curb descent. Sixteen subjects stepped down from a platform with both a rearfoot and a forefoot technique. Vertical ground reaction forces and sagittal plane joint kinematics and kinetics were examined for the lead limb during the step-down task. Paired t-tests were used for comparison. Subjects demonstrated greater ankle joint power and negative work, and less hip joint power and negative work, with the forefoot technique vs. the rearfoot technique. Total lower extremity negative work was greater for the forefoot technique vs. the rearfoot technique. The percent contribution to the total negative work was greater for the ankle joint, and less for the hip and knee joints, with the forefoot technique vs. the rearfoot technique. The results of this study may provide insight into how curb descent technique can be modified to alter lower extremity loading.

Influence of foam thickness on the control of EMG activity during a step-down task in females

Compliant foams can be used to mitigate ground reaction forces. However, it is unknown how foam surfaces influence the modulation of leg muscle activity. Thus, the current study aimed to investigate how the neuromuscular system managed changes in expected loading due to various thickness of foam placed on the landing surface during a step down task. The surface electromyographic signal (sEMG) pre-activation duration and the root mean square (RMS) amplitude of tibialis anterior (TA), lateral gastrocnemius (LG), and vastus medialis (VM) of 10 active females were measured as they stepped-down with a single leg onto polyurethane foam slabs of varying thickness (0–50 mm). Pre-activation duration was not affected by the thickness of the foam padding. LG RMS amplitude was less in the foam conditions than the control (no– foam) condition, with the greatest reduction observed for the 50 mm foam condition. In some trials, the muscles remained active throughout the step-down task. In such instances, a sEMG onset time and thus a pre-activation duration could not be determined. All foam conditions significantly increased the odds of continuous muscle activity above that of the no-foam condition. The results indicate that foam surfaces may alter the modulation of muscle activity during step-down tasks.

The Influence of Step Direction and Step Height on Lower Extremity Joint Kinematics During Step-Down Tasks

The Influence of Step Direction and Step Height on Lower Extremity Joint Kinematics During Step-Down Tasks

Coupled Gluteus Maximus and Gluteus Medius Recruitment Patterns Modulate Hip Adduction Variability During Single-Limb Step-Downs: A Cross-Sectional Study.

Examining the coordinated coupling of muscle recruitment patterns may provide insight into movement variability in sport-related tasks. The purpose of this study was to examine the relationship between coupled gluteus maximus and medius recruitment patterns and hip-adduction variability during single-limb step-downs. Cross-sectional. Biomechanics laboratory. Forty healthy adults, including 26 women and 14 men, mean age 23.8 (1.6) years, mean body mass index 24.2 (3.1)kg/m2, participated. Lower-extremity kinematics were acquired during 20 single-limb step-downs from a 19-cm step height. Electromyography (EMG) signals were captured with surface electrodes. Isometric hip-extension strength was obtained. Hip-adduction variability, measured as the SD of peak hip adduction across 20 repetitions of the step-down task, was measured. The mean amplitudes of gluteus maximus and gluteus medius EMG recruitment were examined. Determinism and entropy of the coupled EMG signals were computed with cross-recurrence quantification analyses. Hip-adduction variability correlated inversely with determinism (r = -.453, P = .018) and positively with entropy (r = .409, P = .034) in coupled gluteus maximus/medius recruitment patterns but not with hip-extensor strength nor with magnitudes of mean gluteus maximus or medius recruitment (r = -.003, .081, and .035; P = .990, .688, and .864, respectively). Hip-adduction variability during single-limb step-downs correlated more strongly with measures of coupled gluteus maximus and medius recruitment patterns than with hip-extensor strength or magnitudes of muscle recruitment. Examining coupled recruitment patterns may provide an alternative understanding of the extent to which hip neuromuscular control modulates lower-extremity kinematics beyond examining muscle strength or EMG recruitment magnitudes.

Gait control of migraine patients with increasing light and sound levels

BackgroundUnder a typical light and sound environment context, individuals with migraine showed balance control deficits on a series of functional activities, which helps to explain why migraineurs report more falls. it isn't established, the effects of intensity light and sound in migraineurs during functional tasks. Research questionBased on the hypersensitivity to light and sound in migraineurs, not only during the attack but also in the interictal period, does the exposure to bright light and loud sound impact motor control in this population? MethodsThis cross-sectional study consisted of 51 women with migraine and 22 healthy women. They performed three walking tasks: crossing an obstacle, stepping-up and stepping-down a curb, in a control situation with ambient lighting (≅350 lux), bright light (≅1200 lux), and loud sound (≅90 dBa). For statistical analysis, a t-test, a Spearman correlation test, and a repeated measures mixed ANOVA were applied. ResultsMigraineurs presented higher discomfort induced by light (p ≤ 0.0001) and sound (p = 0.001). In the obstacle task, migraineurs had greater step width than controls in the ambient light condition (p = 0.038) and participants of both groups placed their leading foot farther away from the obstacle in the light (p = 0.033) than in the ambient light condition. For the step-up task, this distance increased for both groups and limbs in the light (leading limb: p = 0.015; trailing limb: p = 0.002) and sound (leading limb: p = 0.010; trailing limb: p ≤ 0.0001) conditions compared to the ambient light condition. Step speed increased for light and sound conditions compared to ambient light condition, except for the sound condition in the step-down task. SignificanceDespite the higher discomfort induced by light and sound in the migraineurs, the effects of these sensory manipulations were similar for both migraineurs and controls, except for step width. Light and sound manipulation induced a less conservative strategy to deal with uneven terrain in both groups.

Hip Abduction Strength: Relationship to Trunk and Lower Extremity Motion During A Single-Leg Step-Down Task in Professional Baseball Players.

BackgroundThe single-leg step down task (SLSD) is a clinical tool to assess movement and control of the lower extremity and trunk. Hip abduction weakness may impact movement quality during the SLSD, however the relationships between movement and strength are unclear.PurposeTo determine the relationship between hip abduction isometric strength and movement during the SLSD of trunk lean, pelvic drop, knee valgus, and hip flexion.Study DesignCross sectional, cohort studyMethodsOne hundred-eighteen Minor League baseball players (age=21.6 ± 2.0 years; n=68 pitchers, n=50 position players) participated. Bilateral hip abduction isometric strength was measured using a handheld dynamometer (HHD), and then multiplied by distance from the greater trochanter to the HHD and expressed as hip abduction torque. Video cameras captured the SLSD, with participants standing on one leg while lowering their contralateral heel to touchdown on the floor from a 0.203m (8in.) step. Trunk lean, trunk flexion, pelvic drop, knee valgus, and hip flexion were measured using Dartfish at heel touchdown. A value of 180° indicated no knee valgus. Pearson correlations examined the relationships between hip abduction torque and SLSD motions.ResultsThere were no significant correlations for position players. For pitchers, on the lead leg increased hip abduction torque weakly correlated with a decrease in knee valgus (r= 0.24, p=0.049). Also for pitchers on the trail leg, increased hip abduction torque weakly correlated with decreased pelvic drop (r= -0.28, p=0.021).ConclusionHip abduction strength contributes to dynamic control of the trunk and legs. Specifically in pitchers, hip abduction weakness was related to increased movement of the lower extremity and lumbopelvic regions during the dynamic SLSD task. These deficits could translate to altered pitching performance and injury.Levels of Evidence2.

An exploration of the differences in hip strength, gluteus medius activity, and trunk, pelvis, and lower-limb biomechanics during different functional tasks

ABSTRACT The purpose of the study was to explore differences in the coronal biomechanics of the trunk, pelvis, hip, and knee joints, and gluteus medius muscle activity (GMed) during walking and step down from two riser heights. Joint kinematics and kinetics from 20 healthy participants were recorded using a 10-camera Qualisys system and force plates, and GMed EMG was recorded using a Delsys Trigno system. Hip abductor strength was measured using a hand-held dynamometer. Pelvic obliquity and lateral trunk bending excursions were significantly higher in walking than in step-down tasks. Significantly greater knee adduction moments were seen during both step-down tasks compared to level walking with significantly greater GMed activity. However, a significant interaction between side and task was seen for hip adduction moment, with step-down tasks showing lower hip moments than during walking, with greater peak hip moments being more apparent in the dominant limb. This suggests the GMed has a greater stabilizing role during the step-down tasks, although walking required a greater mechanical demand. Health professionals should expect to find less excursion of lateral trunk bending in step-down tasks compared to level walking and consider that GMed has different roles in these two tasks.

Improvements in Lower-Extremity Function Following a Rehabilitation Program With Patterned Electrical Neuromuscular Stimulation in Females With Patellofemoral Pain: A Randomized Controlled Trial.

Patellofemoral pain (PFP) is a challenging condition, with altered kinematics and muscle activity as 2 common impairments. Single applications of patterned electrical neuromuscular stimulation (PENS) have improved both kinematics and muscle activity in females with PFP; however, the use of PENS in conjunction with a rehabilitation program has not been evaluated. To determine the effects of a 4-week rehabilitation program with PENS on lower-extremity biomechanics and electromyography (EMG) during a single-leg squat (SLS) and a step-down task (SDT) in individuals with PFP. Double-blinded randomized controlled trial. Laboratory. Patients of Other Participants: Sixteen females with PFP (age 23.3 [4.9]y, mass 66.3 [13.5]kg, height 166.1 [5.9]cm). Patients completed a 4-week supervised rehabilitation program with or without PENS. Curve analyses for lower-extremity kinematics and EMG activity (gluteus maximus, gluteus medius, vastus medialis oblique, vastus lateralis, biceps femoris, and adductor longus) were constructed by plotting group means and 90% confidence intervals throughout 100% of each task, before and after the rehabilitation program. Mean differences (MDs) and SDs were calculated where statistical differences were identified. No differences at baseline in lower-extremity kinematics or EMG were found between groups. Following rehabilitation, the PENS group had significant reduction in hip adduction between 29% and 47% of the SLS (MD = 4.62° [3.85°]) and between 43% and 69% of the SDT (MD = 6.55° [0.77°]). Throughout the entire SDT, there was a decrease in trunk flexion in the PENS group (MD = 10.91° [1.73°]). A significant decrease in gluteus medius activity was seen during both the SLS (MD = 2.77 [3.58]) and SDT (MD = 4.36 [5.38]), and gluteus maximus during the SLS (MD = 1.49 [1.46]). No differences were seen in the Sham group lower-extremity kinematics for either task. Rehabilitation with PENS improved kinematics in both tasks and decreased EMG activity. This suggests that rehabilitation with PENS may improve muscle function during functional tasks.

Berberine Ameliorates Brain Inflammation in Poloxamer 407-Induced Hyperlipidemic Rats.

PurposeHyperlipidemia, which promotes the development of atherosclerosis, ischemic stroke, and other forms of brain injury, can be induced by poloxamer-407. Berberine is a primary pharmacological active component of Coptidis Rhizoma that has a number of therapeutic activities. This study investigated the effects of berberine on poloxamer-407-induced brain inflammation by evaluating its effects on short-term memory, cell proliferation, inflammation, and apoptosis in the hippocampus.MethodsTo induce hyperlipidemia in a rat model, 500 mg/kg of poloxamer-407 was injected intraperitoneally. Berberine was orally administered to the rats in the berberine-treated groups once a day for 4 weeks. The step-down task avoidance task was performed to measure short-term memory. An analysis of serum lipids, immunohistochemistry for 5-bromo-2′-deoxyuridine, glial fibrillary acidic protein (GFAP), and ionized calcium-binding adapter molecule 1 (Iba1) in the dentate gyrus, and western blot analysis for Bax, Bcl-2, and cytochrome c in the hippocampus were performed.ResultsIn hyperlipidemic rats, berberine reduced the levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol and increased the level of high-density lipoprotein cholesterol in hyperlipidemic rats. Berberine also increased cell proliferation and short-term memory, as well as decreasing the expression of GFAP, Iba1, Bax, and cytochrome c and increasing Bcl-2 expression.ConclusionsBerberine treatment improved short-term memory in hyperlipidemia by increasing neuronal proliferation and inhibiting neuronal apoptosis. Berberine treatment also improved lipid metabolism.

Differences in Gluteal and Quadriceps Muscle Activation During Weight-Bearing Exercises Between Female Subjects With and Without Patellofemoral Pain.

Glaviano, NR and Saliba, S. Differences in gluteal and quadriceps muscle activation during weight-bearing exercises between female subjects with and without patellofemoral pain. J Strength Cond Res 36(1): 55-62, 2022-Therapeutic exercises targeting gluteal and quadriceps muscles have been previously investigated; however, these studies have only been conducted on healthy individuals. Female subjects with patellofemoral pain (PFP) present with weakness in their gluteal and quadriceps muscles and commonly perform exercises that target these muscles. Therefore, the purpose of this study was to compare lower extremity muscle activity during 5 weight-bearing exercises between female subjects with and without PFP. Twenty female subjects with PFP and 20 healthy female subjects completed 5 weight-bearing tasks: a single-leg squat (SLS), lateral step-down, step-up task, step-down task, and lunge. Surface electromyography of the gluteus medius (GMed), gluteus maximus (GMax), vastus lateralis (VL), and vastus medialis oblique (VMO) were collected. Electromyography activity were normalized to maximal voluntary isometric contractions to represent each gluteal and quadriceps muscle as a percentage. Female subjects with PFP completed a SLS and step-up tasks with less GMed and GMax activity (p < 0.05) compared with those without PFP. Female subjects with PFP also had greater VMO activity (p < 0.05) during the step-up, step down, and lunge and VL activity (p < 0.05) during the step-up and SLS compared with healthy female subjects. Practitioners should be aware that there are differences in gluteal and quadriceps muscle activation between female subjects with and without PFP while performing weight-bearing exercises. These findings should influence both the selection of specific exercises and exercise progression when developing a treatment program that has the intended focus to address gluteal or quadriceps strength deficits in female subjects with PFP.

Dexmedetomidine ameliorates memory impairment in sleep-deprived mice

ABSTRACT The selective α2-adrenergic receptor agonist dexmedetomidine acts as an analgesic, sedative, and anesthetic adjuvant. The most common consequence of sleep deprivation is memory impairment. We investigated whether dexmedetomidine can counteract memory impairment caused by sleep deprivation and suppress the production of inflammatory factors. For inducing sleep deprivation, adult male mice were placed inside a water cage containing 15 platforms immersed in water up to 1 cm for 7 days. One day after sleep deprivation, dexmedetomidine at the respective dosage (5, 10, and 20 μg/kg) and α2-adrenoceptor antagonist atipamezole (250 μg/kg) were intraperitoneally injected into the mice, once per day for six days. The step-down avoidance task and the Morris water maze test were performed. Western blot analysis was performed to determine the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, brain-derived neurotrophic factor (BDNF), tyrosine kinase B (TrkB), nuclear transcription factor-κB (NF-κB), inhibitor of κBα (IκBα), and ionized calcium binding adapter molecule I (Iba-1) in the hippocampus. Immunohistochemistry was performed for the determination of Ki-67 and glial fibrillary acidic protein (GFAP) expression in the hippocampal dentate gyrus. Dexmedetomidine ameliorated sleep deprivation-induced deterioration of short-term memory and spatial learning ability. Dexmedetomidine inhibited production of inflammatory mediators caused by sleep deprivation. Dexmedetomidine also prevented the decrease in BDNF, TrkB expression, and cell proliferation induced by sleep deprivation. Dexmedetomidine could be used to counteract the neuropathological effects of sleep deprivation.