The Effects of Chronic Pain Levels on Lower Extremity Energetics During Jump Landing/Cutting in Chronic Ankle Instability Patients

Up to 75% of patients with lateral ankle sprains develop chronic ankle instability (CAI). A majority of CAI patients report chronic pain and show altered jump landing/cutting patterns. Calculating joint energetics affected by chronic pain provides insight into understanding the effects of chronic pain levels on lower limbs in CAI patients. PURPOSE: To identify the effects of chronic pain levels on lower limb energetics during jump landing/cutting in CAI patients. METHODS: This study was a cross-sectional study. Fifteen CAI patients with high pain (High pain) (6males, 9females; age=22.1±2.1year; height=1.74±0.09m; mass=71.3±10.6kg, pain=66.9±9.4), matched 15 CAI patients with low pain (Low pain) (6males, 9females; age=22.3±2.1year; height=1.74±0.08m; mass=70.1±10.7kg, pain=89.3±2.6), and matched 15 healthy controls (Control) (6males, 9females; age=21.3±1.7year; height=1.73±0.08m; mass=70±10.3kg, pain=100±0). We followed the International Ankle Consortium and utilized the Foot and Ankle Outcome Scores for CAI and chronic pain levels. Ground reaction forces were collected during the jump landing/cutting, while joint power was defined by angular velocity and joint moment data. We calculated ankle, knee, and hip joint energy via the integration of negative (dissipation) or positive (generation) power curve areas. The loading phase was defined by the time from initial contact to 150 ms following, while the cutting phase extended from maximal knee flexion to 150 ms following. The Wilcoxon signed-rank test was used to assess joint energetics data. RESULTS: The high pain showed less energy dissipation and generation in the ankle during the loading and cutting phase than the low pain (p=.013 and p=.002) and control (p=.018 and p=.028). The high pain exhibited more energy generation in the hip during the cutting phase than the low pain (p=.038) and control (p=.013). CONCLUSION: The high pain showed lower energy dissipation and generation in the ankle during the loading and cutting phase than the low pain and control, possibly reflecting an effort to reduce the burden on the ankle joint. The high pain reported more energy generation in the hip during the cutting phase than the low pain and control, suggesting a proximal compensatory strategy. Therefore, chronic pain may impact motor outcomes

Examining the Acute Effects of Virtual Reality on the Star Excursion Balance Test in Chronic Ankle Instability

Chronic ankle instability (CAI) patients display mechanical and functional restrictions, along with neurocognitive dysfunction after lateral ankle sprains. Athletes need to divide their attention to effectively multitask during sports activities. Recent studies have utilized virtual reality (VR) to simulate dynamic sporting environments, aiming to enhance cognitive and postural control. However, little is known about the acute effects of VR on dynamic postural control in CAI patients. PURPOSE: To identify the acute effects of VR gear on dynamic postural control in CAI patients. METHODS: This study was a cross-over study. Twenty CAI patients (11males, 9females; age=21±3year; height=1.63±0.28m; mass=74±13.1kg). We used the Foot and Ankle Ability Measures and Ankle Instability Instrument questionnaires for CAI. VR training included 3 trials of single-leg stance; double and single-leg drop landings; and 5 trials of jump landing/cutting. Before and after VR training, participants performed 3 trials each in 3 directions: anterior (ANT), posteromedial (PM), and posterolateral (PL). The average reach distance was normalized by an individual’s leg length from the anterior superior iliac spine to the distal end of the medial malleolus. Matched paired t-tests were used to evaluate the acute effect (posttest-pretest difference) of VR training. The significance level for all analyses was set at a priori of p≤0.05. RESULTS: Acute effects were not observed in both ANT and PM directions (60.2±7.2 vs. 60.9±6.9, p=0.15 and 103.3±10.4 vs. 104.6±11.2, p=0.31). CAI patients showed an acute effect, improving PL reach distance (98.3±11.2 vs. 102.1±13.3, p=0.006) during the star excursion balance test after VR training. CONCLUSION: VR resulted in no difference in ANT direction, which is related to the dorsiflexion range of motion, suggesting that VR training had no improvement in mechanical restriction. After VR training, PL reach distance was increased, suggesting improvement in functional restriction in CAI patients. Therefore, VR training may affect functional restriction, by potentially increasing eversion strength and improving mediolateral static postural control. More data are needed to determine if VR may reduce the risk of recurrent ankle sprains in CAI patients

Effects of Anticipation on Energy Dissipation Patterns among Chronic Ankle Instability Patients

Ankle inversion injuries often lead to chronic ankle instability (CAI). CAI patients use altered energy dissipation patterns during jump-landing, but most studies have been limited to tasks performed under anticipated conditions. It is unclear how the anticipatory condition affects joint energetics in CAI patients. PURPOSE: To identify the effects of anticipation on energy dissipation during jump-landing among CAI, coper, and control subjects. METHODS: 60 subjects were categorized according to the Foot and Ankle Ability Measure and Ankle Instability Index. 20 CAI patients (10males, 10females, 1.74±0.1m, 69.1±10.2kg), 20 Copers (10males, 10females, 1.76±0.1m, 70.9±11.1kg), and 20 Controls (10males, 10females, 1.74±0.1m, 66.0±10.7kg) participated. Participants completed 3 trials of maximal jump-landing tasks (via arrows shown on a screen) performed under anticipated/unanticipated conditions. Energy dissipation by the ankle, knee, and hip joints was calculated by integrating regions of the joint power curve during the task. Lower extremity joint energy dissipation was calculated for the hip, knee, and ankle in the sagittal plane during 50, 100, 150, and 200 ms after initial contact with the force plate. Two-way repeated measures ANOVAs (group × condition) were used to examine the differences between condition (Anticipated, Unanticipated) and group (CAI, coper, control). RESULTS: In the unanticipated condition, copers displayed reduced ankle/hip energy dissipation and increased knee energy dissipation compared to the anticipated condition, while the CAI and Control groups demonstrated no change in energy dissipation between the two conditions. CONCLUSION: CAI patients were unable to change energy dissipation patterns between the two conditions. This finding may represent an apprehension for extra ankle strain compared to the copers. In the earliest stages of jump-landing, copers displayed the most altered energy dissipation patterns, shifting from heavily favoring the ankle during anticipated movement to dissipating much more energy into the knee while reducing the load on the ankle. These energy patterns may indicate a coping mechanism and increased knee energy dissipation in copers may be an effort to attenuate load during landing as a strategy to lessen the load absorbed by the ankle

The Effects of Chronic Pain Levels on Lower Extremity Muscle Activation During Jump Landing/Cutting in Individuals with Chronic Ankle Instability

Lateral ankle sprains (LASs) are the most common injury in sports. Up to 74% of individuals with an initial LAS develop chronic ankle instability (CAI) with chronic ankle pain being one of the residual symptoms. PURPOSE: To Identify the effects of chronic pain levels on lower extremity muscle activation during a maximal jump landing/cutting in CAI individuals. METHODS: This study was a cross-sectional study. Twenty CAI individuals with high pain (High pain) (9M, 11F; age=22±2year; height= 1.74±0.10m; mass=79.4±14.6kg, pain=67.4±7.7), 20 CAI individuals with low pain (Low pain) (9M, 11F; age=21±3year; height=1.73±0.08m; mass=74.2±12.7kg, pain=91.7±3.9), and 20 healthy controls (Control) (9M, 11F; age=22±1year; height=1.74±0.09m; mass=68.2±10.2kg, pain=100±0). We followed the International Ankle Consortium and Foot and Ankle Outcome Scores for classification of CAI and chronic pain. Electromyography (EMG) data were collected using wireless surface electrodes (2,000 Hz) during 5 trials of maximal jump landing/cutting from initial contact to toe-off (0-100% of stance). Reference EMG data were collected standing position for 3 seconds. EMG data were normalized to the reference EMG data. The electrodes were placed over the tibialis anterior (TA), peroneus longus (PL), medial gastrocnemius (MG), vastus lateralis (VL), gluteus medius (Gmed), and gluteus maximus (Gmax). Functional analyses of variance were used to evaluate between-group differences for kinematics outcomes. RESULTS: The high pain showed 3.3%, 16%, and 14% less activation in TA, PL, and MG, and 16% and 14% more activation in the VL and Gmed than the low pain. The high pain displayed 26%, 11.1%, 15%, 8.2%, 25.4%, and 11.5% less activation in the TA, PL, MG, VL, Gmed, and Gmax than the control. The low pain showed 14.9%, 18.7%, and 11.2% less activation in the TA, VL, and Gmed, and 8.7% more activation in the PL during the landing/cutting than the control. CONCLUSION: Chronic pain levels appear to impact muscle activation in CAI individuals. Both the high and low pain demonstrate altered muscle activation patterns in distal and proximal joints. The high pain prompts a hip-dominant strategy, compensating for deactivated distal muscles. The lower the level of chronic pain, the more active the PL muscles that contribute to ankle stability

The Effects of Chronic Pain Levels on Joint Angle During Jump Landing/Cutting in Individuals with Chronic Ankle Instability

About 60% of chronic ankle instability (CAI) individuals report ankle pain persisting for longer than 3 months. They have the risk of recurrent ankle sprains while performing multiplanar tasks such as jumping with landing/cutting. However, little is known about the effects of chronic pain levels on joint kinematics differences and how chronic pain levels contribute to motor outcomes when performing multiplanar motions. PURPOSE: To identify the effects of pain levels on kinematics during jump landing/cutting in CAI individuals. METHODS: This study was a cross-sectional study. Twenty CAI patients with high pain (high pain) (9 males, 11 females; age=22±2year; height=1.74±0.10m; mass=79.4±14.6kg, pain=67.4±7.7), 20 CAI patients with low pain (low pain) (9 males, 11 females; age=21±3year; height=1.73±0.08m; mass=74.2±12.7kg, pain=91.7±3.9), and 20 healthy controls (9 males, 11 females; age=22±1year; height=1.74±0.09m; mass=68.2±10.2kg, pain=100±0). We followed the International Ankle Consortium criteria for classifying CAI and utilized the Foot and Ankle Outcome Scores for chronic pain levels. We used 44 reflective markers to calculate joint angles collected during the jump landing/cutting task from initial contact to toe-off (0-100% of stance). Functional analyses of variance were used to evaluate between-group differences for kinematics outcomes. RESULTS: The high pain showed 4.8° less plantarflexion from 0-12% than the low pain from 0-8% and 4.9° less plantarflexion than the healthy control. The high pain exhibited 1.4° less inversion from 8-12% than the low pain. The knee joint presented 1.5° less flexion from 0-5% and then 4.4° more flexion at 10-24% than healthy controls, showing a greater knee joint angle variability. The high pain showed 5.3°, 3.6°, and 3.5° higher hip flexion from 2-24%, 50-61%, and 75-82%, respectively than the healthy control. CONCLUSION: The high pain demonstrated less plantarflexion and inversion in the ankle while exhibiting more kinematics variance in the knee joint and hip during multiplanar tasks. These findings may result in a stiffer landing in the ankle and proximal landing strategy during jump landing/cutting tasks. Thus, chronic pain levels affect joint kinematics during multiplanar tasks

Submaximal Force Steadiness and Accuracy in Patients With Chronic Ankle Instability

Context: Patients with chronic ankle instability (CAI) have demonstrated sensorimotor impairments. Submaximal force steadiness and accuracy measure sensory, motor, and visual function via a feedback mechanism, which helps researchers and clinicians comprehend the sensorimotor deficits associated with CAI. Objective: To determine if participants with CAI experienced deficits in hip and ankle submaximal force steadiness and accuracy compared with healthy control participants. Design: Case-control study. Setting: Research laboratory. Patients or Other Participants: Twenty-one patients with CAI and 21 uninjured individuals. Main Outcome Measure(s): Maximal voluntary isometric contraction (MVIC) and force steadiness and accuracy (10% and 30% of MVIC) of the ankle evertors and invertors and hip abductors were assessed using the central 10 seconds (20%– 87% of the total time) of the 3 trials. Results: Relative to the control group, the CAI group demonstrated less accuracy of the invertors (P , .001). Across all motions, the CAI group showed less steadiness (P , .001) and less accuracy (P , .01) than the control group at 10% of MVIC. For MVIC, the CAI group displayed less force output in hip abduction than the uninjured group (P , .0001). Conclusions: Patients with CAI were unable to control ongoing fine force (10% and 30% of MVIC) through a feedback mechanism during an active test. These findings suggested that deficits in sensorimotor control predisposed patients with CAI to injury positions because they had difficulty integrating the peripheral information and correcting their movements in relation to visual information

Bioactivity-guided Identification and Cell Signaling Technology to Delineate the Lactate Dehydrogenase a Inhibition Effects of Spatholobus Suberectus on Breast Cancer

Aerobic glycolysis is an important feature of cancer cells. In recent years, lactate dehydrogenase A (LDH-A) is emerging as a novel therapeutic target for cancer treatment. Seeking LDH-A inhibitors from natural resources has been paid much attention for drug discovery. Spatholobus suberectus (SS) is a common herbal medicine used in China for treating blood-stasis related diseases such as cancer. This study aims to explore the potential medicinal application of SS for LDH-A inhibition on breast cancer and to determine its bioactive compounds. We found that SS manifested apoptosis-inducing, cell cycle arresting and anti-LDH-A activities in both estrogen-dependent human MCF-7 cells and estrogen-independent MDA-MB-231 cell. Oral herbal extracts (1 g/kg/d) administration attenuated tumor growth and LDH-A expression in both breast cancer xenografts. Bioactivity-guided fractionation finally identified epigallocatechin as a key compound in SS inhibiting LDH-A activity. Further studies revealed that LDH-A plays a critical role in mediating the apoptosis-induction effects of epigallocatechin. The inhibited LDH-A activities by epigallocatechin is attributed to disassociation of Hsp90 from HIF-1alpha and subsequent accelerated HIF-1alpha proteasome degradation. In vivo study also demonstrated that epigallocatechin could significantly inhibit breast cancer growth, HIF-1alpha/LDH-A expression and trigger apoptosis without bringing toxic effects. The preclinical study thus suggests that the potential medicinal application of SS for inhibiting cancer LDH-A activity and the possibility to consider epigallocatechin as a lead compound to develop LDH-A inhibitors. Future studies of SS for chemoprevention or chemosensitization against breast cancer are thus warranted.published_or_final_versio

Immunolocalization of KATP channel subunits in mouse and rat cardiac myocytes and the coronary vasculature.

BACKGROUND: Electrophysiological data suggest that cardiac KATP channels consist of Kir6.2 and SUR2A subunits, but the distribution of these (and other KATP channel subunits) is poorly defined. We examined the localization of each of the KATP channel subunits in the mouse and rat heart. RESULTS: Immunohistochemistry of cardiac cryosections demonstrate Kir6.1 protein to be expressed in ventricular myocytes, as well as in the smooth muscle and endothelial cells of coronary resistance vessels. Endothelial capillaries also stained positive for Kir6.1 protein. Kir6.2 protein expression was found predominantly in ventricular myocytes and also in endothelial cells, but not in smooth muscle cells. SUR1 subunits are strongly expressed at the sarcolemmal surface of ventricular myocytes (but not in the coronary vasculature), whereas SUR2 protein was found to be localized predominantly in cardiac myocytes and coronary vessels (mostly in smaller vessels). Immunocytochemistry of isolated ventricular myocytes shows co-localization of Kir6.2 and SUR2 proteins in a striated sarcomeric pattern, suggesting t-tubular expression of these proteins. Both Kir6.1 and SUR1 subunits were found to express strongly at the sarcolemma. The role(s) of these subunits in cardiomyocytes remain to be defined and may require a reassessment of the molecular nature of ventricular KATP channels. CONCLUSIONS: Collectively, our data demonstrate unique cellular and subcellular KATP channel subunit expression patterns in the heart. These results suggest distinct roles for KATP channel subunits in diverse cardiac structures

Effects of Running on Femoral Articular Cartilage Thickness for Anterior Cruciate Ligament Reconstruction Patients and Non-ACLR Control Subjects

Anterior cruciate ligament reconstruction (ACLR) patients are more likely to develop posttraumatic knee osteoarthritis than non-ACLR counterparts. The effect of running on femoral articular cartilage thickness is unclear. PURPOSE: The purpose of this study was to compare how 30 minutes of running influences femoral articular cartilage thickness for ACLR patients and non-ACLR control subjects. We hypothesized that running would deform the femoral articular cartilage more for the ACLR patients than for the control subjects. METHODS: We recruited 20 individuals with primary unilateral ACLR and 20 matched non-ACLR controls. ACLR patients and control subjects were matched based upon age, gender, BMI, and weekly running mileage. The present procedures were approved by the appropriate institutional board and all subjects provided informed consent before data collection. We used ultrasound imaging to measure femoral articular cartilage thickness before and after 30 minutes of running. The ultrasound images were manually analyzed using ImageJ software by the same investigator. Total femoral articular cartilage cross-sectional area of each image was segmented into three regions: medial, lateral, and intercondylar. Deformation due to the run was compared between the ACLR patients and control subjects for each region using independent t tests (P \u3c 0.05, adjusted for multiple comparisons). RESULTS: The 30-minute run resulted in more deformation for the ACLR patients (0.03 ± 0.01 cm) than the matched controls (0.01 ± 0.01 cm) for the medial region (p \u3c 0.01) of the femoral articular cartilage. Identically, the 30-minute run resulted in more deformation for the ACLR patients (0.03 ± 0.01 cm) than the matched controls (0.01 ± 0.01 cm; p \u3c 0.01) for an average of the entire articular cartilage area (medial, lateral, and intercondylar). No significant differences existed between groups for the lateral or intercondylar regions. CONCLUSION: Thirty minutes of running deformed medial and overall femoral articular cartilage more for ACLR patients than non-ACLR control subjects