Path Integration: Effect of Curved Path Complexity and Sensory System on Blindfolded Walking

Path integration refers to the ability to integrate continuous information of the direction and distance traveled by the system relative to the origin. Previous studies have investigated path integration through blindfolded walking along simple paths such as straight line and triangles. However, limited knowledge exists regarding the role of path complexity in path integration. Moreover, little is known about how information from different sensory input systems (like vision and proprioception) contributes to accurate path integration. The purpose of the current study was to investigate how sensory information and curved path complexity affect path integration. Forty blindfolded participants had to accurately reproduce a curved path and return to the origin. They were divided into four groups that differed in the curved path, circle (simple) or figure-eight (complex), and received either visual (previously seen) or proprioceptive (previously guided) information about the path before they reproduced it. The dependent variables used were average trajectory error, walking speed, and distance traveled. The results indicated that (a) both groups that walked on a circular path and both groups that received visual information produced greater accuracy in reproducing the path. Moreover, the performance of the group that received proprioceptive information and later walked on a figure-eight path was less accurate than their corresponding circular group. The groups that had the visual information also walked faster compared to the group that had proprioceptive information. Results of the current study highlight the roles of different sensory inputs while performing blindfolded walking for path integration

Comparison of Ultrastructural Alterations in Peripheral Artery Disease Skeletal Muscle

Peripheral artery disease (PAD) is characterized by obstructed hemodynamics and claudication reducing quality of life and muscle function. A myopathy has been shown to develop in PAD patients and characterization of changes in skeletal muscle needs further elucidation. PURPOSE: To assess myofibrillar ultrastructural changes between control and stage IV PAD patients. METHODS: Twenty-six participants (13 control:13 stage IV) were recruited to take part in this cross-sectional study. The mean(±SD) age, mass, height, and BMI were 53(±11) years, 81(±22) kg, 165(±15) cm, and 30(±1.5) kg/m2. Muscle samples were collected from the gastrocnemius and prepared for transmission electron microscopy. Relative mitochondria area, average mitochondrial size, number of mitochondria/250μm2, relative myofibril area, average m-line length, number of z-discs/250μm2, mitochondria/z-disc, relative lipid droplet area, average lipid droplet size, and number of lipid droplets/250μm2 were measured and averaged for each participant using two-individual micrographs. All variables were statistically assessed using an independent t-test or Mann-Whitney U at a significance value of pRESULTS:Relative mitochondrial area (U=11.534, p2 (t=5.343, p2 (t=-1.902, p=.07) was observed. M-line lengths were shorter for stage IV PAD patients than controls (U=11.543, p2 (U=.037, p=.848). Average mitochondria/z-disc was significantly greater in controls than in stage IV PAD patients (t=5.737, pCONCLUSION:The largest changes seen in PAD skeletal muscle ultrastructure are in the mitochondria number and total mitochondria area. This decrease in mitochondria may explain altered muscle function not accounted for by hemodynamic obstructions

Patients with peripheral arterial disease exhibit reduced joint powers compared to velocity-matched controls

Previous studies have shown major deficits in gait for individuals with peripheral arterial disease before and after the onset of pain. However, these studies did not have subjects ambulate at similar velocities and potential exists that the differences in joint powers may have been due to differences in walking velocity. The purpose of this study was to examine the joint moments and powers of peripheral arterial disease limbs for subjects walking at similar self-selected walking velocities as healthy controls prior to onset of any symptoms. Results revealed peripheral arterial disease patients have reduced peak hip power absorption in midstance (p = 0.017), reduced peak knee power absorption in early and late stance (p = 0.037 and p = 0.020 respectively), and reduced peak ankle power generation in late stance (p = 0.021). This study reveals that the gait of patients with peripheral arterial disease walking prior to the onset of any leg symptoms is characterized by failure of specific and identifiable muscle groups needed to perform normal walking and that these gait deficits are independent of reduced gait velocity

Patients with peripheral arterial disease exhibit reduced joint powers compared to velocity-matched controls

Previous studies have shown major deficits in gait for individuals with peripheral arterial disease before and after the onset of pain. However, these studies did not have subjects ambulate at similar velocities and potential exists that the differences in joint powers may have been due to differences in walking velocity. The purpose of this study was to examine the joint moments and powers of peripheral arterial disease limbs for subjects walking at similar self-selected walking velocities as healthy controls prior to onset of any symptoms. Results revealed peripheral arterial disease patients have reduced peak hip power absorption in midstance (p = 0.017), reduced peak knee power absorption in early and late stance (p = 0.037 and p = 0.020 respectively), and reduced peak ankle power generation in late stance (p = 0.021). This study reveals that the gait of patients with peripheral arterial disease walking prior to the onset of any leg symptoms is characterized by failure of specific and identifiable muscle groups needed to perform normal walking and that these gait deficits are independent of reduced gait velocity

The Usage of Skeletal Muscle Oxygenation and Heart Rate Variability as Predictors of Aerobic Fitness.

Heart rate variability (HRV) is used to assess the autonomic nervous system’s (ANS) activity on the heart, while skeletal muscle oxygenation (SmO2) measures how well muscles uptake oxygen from the blood. Both measurements have demonstrated strong associations with cardiorespiratory fitness and are altered with increased exercise workloads. Both have been used to assess athletic performance. While the gold standard for assessing cardiorespiratory fitness is VO2 max testing, several situations preclude the usage of a true VO2 max. Purpose: To determine if HRV and SmO2 possess predictive qualities to accurately assess cardiorespiratory fitness levels. Methods: Thirty-six healthy fit individuals (n = 22 men; n = 14 women; age 37.6 + 12.4 yr; BF% 19.2 + 7.1%; VO2max 41.8 + 7.4 ml/kg/min) completed a single VO2 max ramp protocol treadmill test while wearing an infrared oxyhemoglobin (MOXY) Sensor to assess SmO2 while HRV was assessed via Polar (Bluetooth monitor (Polar H7)) heart rate (HR) monitor. The MOXY Sensor was placed on the lateral-posterior belly of the gastrocnemius while the Polar HR monitor was placed on the distal third of the sternum using an elastic belt. The data was analyzed using a Pearson Correlation to compare SmO2, HRV indices, and VO2max associations. In addition, a multiple linear regression analysis was performed to examine the relationship between HRV indices and SmO2 to VO2 max. All analyses were performed using SPSS (v. 28.0.1.1). Results: There was a significant correlation between VO2 max, mean of RR intervals (mRR) (r = 0.440, p = 0.007), and THb Max (r = 0.509, p = 0.002). mRR and THb Max were able to significantly predictive (r2 = 0.365, p = 0.001) VO2 max outcomes. Conclusion: The combination of SmO2 measurements and HRV can assist in predicting VO2 max levels, but further research is needed to determine the accuracy at which it will predict. This can be a useful and simple method for predicting cardiorespiratory fitness when a VO2 max test is unavailable, or an individual is unfit to perform one. This can aid in better exercise prescription for chronic diseased individuals

Stroke Survivors Control the Temporal Structure of Variability During Reaching in Dynamic Environments

Learning to control forces is known to reduce the amount of movement variability (e.g., standard deviation; SD) while also altering the temporal structure of movement variability (e.g., approximate entropy; ApEn). Such variability control has not been explored in stroke survivors during reaching movements in dynamic environments. Whether augmented feedback affects such variability control, is also unknown. Chronic stroke survivors, assigned randomly to a control/experimental group, learned reaching movements in a dynamically changing environment while receiving either true feedback of their movement (control) or augmented visual feedback (experimental). Hand movement variability was analyzed using SD and ApEn. A significant change in variability was determined for both SD and ApEn. Post hoc tests revealed that the significant decrease in SD was not retained after a week. However, the significant increase in ApEn, determined on both days of training, showed significant retention effects. In dynamically changing environments, chronic stroke survivors reduced the amount of movement variability and made their movement patterns less repeatable and possibly more flexible. These changes were not affected by augmented visual feedback. Moreover, the learning patterns characteristically involved the control of the nonlinear dynamics rather than the amount of hand movement variability. The absence of transfer effects demonstrated that variability control of hand movement after a stroke is specific to the task and the environment

The Influence of Age and Cardiorespiratory Fitness on Cardiac Autonomic Modulation. A Pilot Study.

Maximal rate of oxygen consumption (VO2max) is traditionally viewed as the gold standard of determining cardiorespiratory fitness (CF) in healthy and diseased populations. CF has a significant influence on the improvement of cardiac autonomic modulation (CAM) and the risk of morbidity and mortality rates. Heart rate variability (HRV) is a non-invasive way to assess CAM. Age is another factor that influences CAM and CF in healthy and diseased populations. However, what is not fully elucidated, is if CF is maintained at a high level throughout adulthood, will CAM remain relatively unchanged. PURPOSE: To determine if age and CF are significantly correlated to variables of HRV to determine CAM in healthy fit individuals. METHODS: Twenty-two healthy individuals (n = 14 male; n = 8 female, Age 33.2 ± 11.8 years, %BF 18.3 ± 6.0, VO2max 42.0 ± 6.2 ml/ /kg/min) completed a single health assessment to quantify CF and HRV. HRV was measured for 5 mins in the supine position and during a standard VO2max test using an elastic belt and Bluetooth monitor (Polar H7). CardioMood software was used to process HRV variables high frequency (HF), low frequency (LF), total power (TP) were assessed for frequency domain, and standard deviation of all NN intervals (SDNN) and the square root of the mean of the squares of successive R-R interval differences (RMSSD) for the time domain. Pearson correlation was used to check associations between age and CF, and CAM. Multiple regression was implemented to determine if there were any differences in HRV variables in relation to age and VO2max. A paired sample t-test was used to determine changes in HRV variables from rest to VO2max. All analyses were performed using SAS (v.9.3). RESULTS: HRV variables were significantly altered from rest to VO2max (p \u3c 0.05). HRV time and frequency domain variables were not significantly correlated to age and CF level (p \u3e 0.05). The multiple regression analysis indicated that the only significance was max heart rate is 0.642 bpm lower during exercise for each 1-year increase in age (p = 0.035). CONCLUSION: The analysis of pilot data focused on determining the impact of CF and age on CAM appears not to be significantly correlated when utilizing HRV. However, due to the project\u27s continuation and further data collection, significant outcomes may still be observed

Acute Renal Responses to Moderate-Intensity Aerobic Exercise with Non-traditional markers of Renal Health and Function in Healthy Individuals: A Pilot Study

Aerobic exercise elicits a multitude of physiological improvements in both healthy and diseased populations. However, acute changes in renal function with aerobic exercise remain difficult to quantify by traditional marker serum creatinine (sCr) to estimate glomerular filtration rate (eGFR). Recently, novel biomarkers cystatin C (CyC) and urine epidermal growth factor (uEGF) have been introduced as more reliable markers of renal health and function to be used in conjunction with sCr to assess changes in renal health and function in mid-spectrum CKD. Potentially, greater changes in novel markers of renal health and function similar to mid-spectrum CKD can be observed in healthy individuals. PURPOSE: To determine if an acute bout of moderate-intensity aerobic exercise can transiently alter novel markers of renal health and function in healthy individuals. METHODS: Thirty-nine participants (n = 18 men; n = 21 women; age 32.5 + 12.6 yr; height 171.1 + 11.4 cm; weight 78.7 + 15.6 kg; BMI 27.1 + 5.8) completed a single acute bout of moderate-intensity (50-65% HRR) aerobic exercise. Blood and urine samples were collected pre-exercise and 15 minutes post-exercise by the same technician under standardized conditions and stored at -60 ºC until project completion. Serum creatinine (sCR), urine creatinine (uCr), urine epidermal growth factor (uEGF), uEGF/uCr ratio (uEGFR), cystatin C (CyC) and eGFR - modification of diet in renal disease (MDRD) and the CKD-EPI- responses were analyzed using a paired sample t-test. RESULTS: Relative to pre-exercise measures: sCR (p = 0.38), uEGF (p = 0.35), and uEGFR (p = 0.09) remained unchanged, whereas, uCr (p = 0.045) and CyC (p = 0.00) significantly changed post-exercise. There was a difference in uEGF pre- to post-exercise, but the standard deviation was large, likely preventing this from being significant. In contrasts MDRD (p = 0.04) significantly increased while CKD-EPI (p = 0.22) had no significant changes. CONCLUSION: Acute changes in traditional and novel biomarkers of renal health and function in healthy individuals remain unclear after an acute bout of moderate-intensity aerobic exercise. Further investigation focused on sampling time and exercise intensity is needed to solidify the current understanding of renal health and function

Can athletes be tough yet compassionate to themselves? Practical implications for NCAA mental health best practice no. 4

Recent tragic events and data from official NCAA reports suggest student-athletes’ wellbeing is compromised by symptoms of mental health (MH) disorders. Self-compassion (SC) and mental toughness (MT) are two psychological constructs that have been shown effective against stressors associated with sports. The purpose of this study was to investigate SC, MT, and MH in a NCAA environment for the first time and provide practical suggestions for MH best practice No.4. In total, 542 student-athletes participated across Divisions (Mage = 19.84, SD = 1.7). Data were collected through Mental Toughness Index, Self-Compassion Scale, and Mental Health Continuum–Short Form. MT, SC (including mindfulness), and MH were positively correlated. Males scored higher than females on all three scales. No differences were found between divisions. SC partially mediated the MT-MH relationship, but moderation was not significant. Working towards NCAA MH best practice should include training athletes in both MT and SC skills (via mindfulness)

Surface-enhanced Raman spectral biomarkers correlate with Ankle Brachial Index and characterize leg muscle biochemical composition of patients with peripheral arterial disease

Peripheral arterial disease (PAD) is characterized by atherosclerotic blockages of the arteries supplying the lower extremities, which cause a progressive accumulation of ischemic injury to the skeletal muscles of the lower limbs. This injury includes altered metabolic processes, damaged organelles, and compromised bioenergetics in the affected muscles. The objective of this study was to explore the association of Raman spectral signatures of muscle biochemistry with the severity of atherosclerosis in the legs as determined by the Ankle Brachial Index (ABI) and clinical presentation. We collected muscle biopsies from the gastrocnemius (calf muscle) of five patients with clinically diagnosed claudication, five patients with clinically diagnosed critical limb ischemia (CLI), and five control patients who did not have PAD. A partial least squares regression (PLSR) model was able to predict patient ABI with a correlation coefficient of 0.99 during training and a correlation coefficient of 0.85 using a full cross-validation. When using the first three PLS factor scores in combination with linear discriminant analysis, the discriminant model was able to correctly classify the control, claudicating, and CLI patients with 100% accuracy, using a full cross-validation procedure. Raman spectroscopy is capable of detecting and measuring unique biochemical signatures of skeletal muscle. These signatures can discriminate control muscles from PAD muscles and correlate with the ABI and clinical presentation of the PAD patient. Raman spectroscopy provides novel spectral biomarkers that may complement existing methods for diagnosis and monitoring treatment of PAD patients