Minutes 1878

https://place.asburyseminary.edu/freemethodistminutesyearbooks/1016/thumbnail.jp

TORQUE VARIABILITY AND COMPLEXITY DURING A FATIGUING TASK IN INDIVIDUALS WITH MULTIPLE SCLEROSIS

Grant Chesbro1, David Lantis2, Brian Pribble1, Christopher Black1, Daniel Larson1 and Rebecca Larson1 1University of Oklahoma, Norman, OK 2Valparaiso University, Valparaiso, IN Multiple Sclerosis (MS) is an autoimmune disorder that affects the central nervous system (CNS) resulting in fatigue, impaired mobility, and reduced quality of life. Bilateral differences in lower limb strength and function have been observed in patients with MS making assessment and treatment difficult. Previous research suggests that CNS disorders can reduce the complexity of a variety of physiological systems. However, it is unknown whether complexity is affected in a similar bilateral manner in MS. Purpose: The purpose of this study was to assess bilateral differences in torque variability and complexity during a fatiguing task in MS. Methods: Thirteen MS (5 Male and 8 Female, Age: 49.4±8.9yrs) performed isometric dorsiflexion contractions (30% of MVC) until task failure. Based on MVCs, limbs were classified as either the stronger or weaker leg. Five sec. of data from the start (Fresh) and the end (End-Task) of the contractions were analyzed for variability (SD: Standard Deviation, CV: Coefficient of Variation) and complexity (DFA: Detrended Fluctuation Analysis, SE: Sample Entropy). Results: Torque variability was increased from Fresh to End Task in the strong (SD: 2.67±0.78 to 5.63±1.80, p\u3c0.001; CV: 3.10±1.10 to 7.09±2.33, p\u3c0.001) and weak legs (SD: 4.32±0.79 to 9.36±3.24, p\u3c0.001; CV: 4.49±1.81 to 9.49±1.92, p\u3c0.001). There was between leg difference in torque variability at Fresh (SD: 2.67±0.78 to 4.32±0.79, p\u3c0.001; CV: 3.10±2.33 to 4.49±1.81, p=0.26) and End Task (SD: 5.63±1.80 to 9.36±3.24, p=0.001; CV: 7.09±2.33 to 9.49±1.92, p\u3c0.001). The complexity of the torque signals decreased from Fresh to End Task in the strong (SE: 0.47±0.08 to 0.32±0.05, p\u3c0.001) and weak (SE: 0.35±0.03 to 0.22±0.05, p\u3c0.001) legs. There were between leg differences in torque signal complexity at both the Fresh (SE: 0.47±0.08 to 0.35±0.03, p\u3c0.001) and End Task (SE: 0.32±0.05 to 0.22±0.05, p\u3c0.001) time points. There were no changes in DFA. Conclusion: Reductions in complexity are thought to reduce the adaptable states for a system to deal with stressors. Significant differences in complexity and variability were seen between limbs and between time points in MS suggesting that measures of variability and complexity could be useful for assessing the effects of bilateral asymmetry caused by MS

EFFECTS OF MENSTRUAL CYCLE PHASE ON SUBJECTIVE PARAMETERS DURING A GRADED-EXERCISE TEST

Bianca Alvarenga Rambo Galletti1, Morgan Delp1, Grant Chesbro1, Brian Pribble1, Ryan Miller2, Christopher Black1 and Rebecca Larson1 1University of Oklahoma, Norman, OK 2Wake Forest University, Winston-Salem, NC Intro: Regular hormonal fluctuations in women can potentially influence subjective parameters such as discomfort ratings and sensitivity to exercise. Purpose: To evaluate subjective parameters at the end of a maximal aerobic exercise testing across three different menstrual cycle phases: early follicular (day 0-3 EF]), ovulation (within 24h from peak basal body temperature [O]), and mid-luteal (7 days following ovulation [L]). Methods: Three maximal graded exercise tests (GXT) on cycle ergometer were administered to 12 females and 9 (control) males (mean age 21.4 ± 1.3 yr-old) at three defined phases of the menstrual cycle. All females were required to have a trackable eumenorrheic menstrual cycle and not take any hormonal oral contraceptives, intrauterine devices, implants, injections, or any other hormonal birth control method. Males completed 3 GXTs at intervals corresponding to menstrual cycle phases. Overall ratings of perceived exertion (RPE) using the modified Borg scale were recorded at the end of each 60-second exercise stage till exhaustion. In addition, the Perceived Recovery Status (PRS) scale was recorded by each individual 24 hours after each GXT. Results: Male subjects showed no significant differences in RPE or PRS across visits, but females reported significantly higher RPE and significantly lower PRS during EF visit (RPE 8.92 ± 0.79 and PRS 6.83 ± 0.94), when compared to the O (RPE 7.67 ± 1.23 and PRS 8.83 ± 1.12) and L visits (RPE 7.75 ± 1.06 and PRS 8.67 ± 0.65). Discussion/Conclusion: Findings from this study suggests that women perceive higher levels of exertion at the end of a GXT (maximal exercise) and feel less recovered 24h later during EF. Early follicular phase occurs when the levels of progesterone and estradiol are low, which can affect inhibitory mechanisms of pain, increase pain sensitivity, and increase kinesthetic awareness of discomforts. Therefore, controlling for the menstrual cycle phase can potentially help decrease a female\u27s discomfort during exercise and improve performance

THE EFFECTS OF THE MENSTRUAL CYCLE ON BODY COMPOSITION AND LOWER BODY FLEXIBILITY

Bianca A. R. Galletti1, Ashley N. Fox1, Brian Pribble1, Ryan Miller1, Grant Chesbro1, Christopher D. Black, FACSM1, Daniel J. Larson1, & Rebecca D. Larson1 1The University of Oklahoma, Norman, Oklahoma Regular menstrual cycle phases are known for their hormonal fluctuations during a month, which could influence body composition and muscle connective tissue laxity. Purpose: To investigate differences in lower body flexibility and total body composition across three different menstrual cycle phases: early follicular (EF), ovulation (O), and mid-luteal (L). Methods: 27 participants were separated into 3 groups: 8 female non-contraceptive users (NC), 10 female oral-contraceptive users (OC) and 9 males in the control group (CON). Each visit included flexibility assessments of hip extension/flexion and knee extension/flexion via goniometer of the dominant leg and a Dual-Energy X-Ray Absorptiometry (DXA) scan. Results: CON had significantly less body fat (25.45±4.86%, 32.98±8.97% and 32.5±6.05%, respectively) and higher lean mass (62.79± 7.12kg, 41.16±6.32kg and 40.44±5kg, respectively) than the NC and OC groups across all menstrual cycle phases. There was no significant differences in body composition across different phases, demonstrating an excellent reliability in males and females (ICC \u3e 95%). Hip extension flexibility was significantly higher for NC (22.37±4.34°) compared to OC (14.2±5°) and CON (15.22±5.93°) in the luteal phase as well as significantly higher for NC (16.88±7.53°) in the ovulation phase when compared to OC (12.7±8.37°) and CON (14.78±10.84°). Knee extension flexibility was significantly higher for OC (7.9±3.57°) when compared to CON (4.22±2.95°) in the luteal phase, while knee flexion did not demonstrate significant differences between groups or across phases. Conclusion: This study suggests that assessments of body composition via DXA are remarkably reliable across different phases of the menstrual cycle. The higher hip mobility in NC during ovulation and luteal phases could be due to fluctuations in estrogen concentration, which is thought to have a laxative effect on tendons and ligaments in females by decreasing sinew stiffness