Browsing by Author "Fedewa, Michael V"

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    A Comparison of Traditional Blood Flow Restriction Versus Band Tissue Flossing for Induction of Muscular Fatigue
    (University of Alabama Libraries, 2021) Jones, Morgan Taylor; Winchester, Lee J; University of Alabama Tuscaloosa
    Resistance training with blood flow restriction (BFR) exaggerates metabolic stress and increases the number of muscle fibers recruited, resulting in greater improvements in muscular strength. An alternative method for occluding blood flow is band tissue flossing (BTF), in which an elastic band is wrapped around the limb. PURPOSE: The purpose of this study was to compare the effects of BTF to BFR on muscular fatigue. METHODS: Fifteen subjects (6 females; mean ± SD: age = 23.3 ± 0.1y, BMI = 25.7 ± 0.9kg/m2, thigh circumference = 59.9 ± 1.6cm) completed 3 sessions on separate days, each under a different condition: control (CON), BFR at 50% limb occlusion pressure, and BTF. During each session, participants performed maximal effort leg extension and flexion for 3 sets of 20 repetitions using an isokinetic dynamometer. At the start of each session, baseline heart rate (HR), lactate, glucose, and blood flow were recorded. During the BFR and BTF sessions, HR and blood flow were recorded before and 1-minute after occlusion. HR, glucose, and lactate were recorded immediately post- and 1-minute post-exercise for all sessions. Repeated measures ANOVAs were used to compare outcome measures between time points as well as between conditions. RESULTS: BFR and BTF both caused significant increases in HR compared to baseline (4.67 ± 2.14 BPM and 6.07 ± 2.56 BPM, both p < 0.01, respectively), with no significant differences between conditions. BTF significantly decreased arterial distance (-0.04 ± 0.04cm, p = 0.001), volume flow (-7.56 ± 6.88 cc/min, p = 0.001), and arterial area (-0.02 ± 0.01cm2, p < 0.001). Whereas BFR significantly decreased time-averaged mean velocity (-1.03 ± 1.65cm/s, p = 0.001). BTF caused a greater reduction in arterial distance compared to BFR (p = 0.006). However, no differences were observed in all dynamometry, electromyography, glucose, or lactate measures between occlusion conditions. CONCLUSION: BTF occluded more blood flow and yielded comparable changes in muscular fatigue when compared to BFR, providing an inexpensive training alternative when more sophisticated laboratory techniques are unavailable.
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    The Efficacy of Blood Flow Restriction During High Intensity Resistance Exercise
    (University of Alabama Libraries, 2021) Hornikel, Bjoern; Winchester, Lee J; University of Alabama Tuscaloosa
    Blood flow restriction (BFR) resistance training has demonstrated its effectiveness for inducing hypertrophic adaptations at much lower intensities (20-30% one-repetition maximum (1RM)) compared to traditional high-intensity (>65% 1RM) recommendations. Limited research has examined BFR in conjunction with high-intensity resistance training, with mixed results. The purpose of this dissertation was to expand upon this understudied area with a series of three studies to 1) better understand blood flow responses in the lower limbs with varying occlusion pressures, 2) determine the effect of high-intensity BFR (HI-BFR) resistance exercise on fatigue, ratings of perceived exertion (RPE), and pain, and 3) examine the influence of HI-BFR on metabolic stress, muscle damage, and hypoxia. Study 1 examined the effects of varying BFR occlusion pressures on blood flow volume in the legs. Results indicate a potential 50% limb occlusion pressure (LOP) threshold at which point statistically significant reductions in blood flow volume occur in the posterior tibial artery. An observed plateau in blood flow reductions between 60-80%LOP indicates the potential for reduced occlusion pressure during exercise. Study 2 examined the effects of HI-BFR on inter-set fatigue, RPE, and Pain, in addition to post-exercise neuromuscular fatigue/impairment. Significantly greater number of total repetitions and repetitions during sets 1, 2, and 4 (p < .05) were performed in the CTRL condition. Although RPE between conditions was similar across all sets (p ≥ .05), perceived pain was significantly greater in BFR across all sets (p < .05). Changes in neuromuscular performance measures were consistent across exercise conditions. Study 3 investigated the effect of HI-BFR on metabolic stress, muscle swelling, and muscle damage in response to a back-squat protocol. Significantly lower blood lactate concentrations were measured following the BFR exercise stimulus, compared to CTRL (p = .001). No significant differences in muscle swelling were observed between conditions. Post-exercise interleukin-6 was significantly greater following the BFR exercise (p = .007). The use of BFR during high-intensity resistance exercise seems to be a useful method for advanced induction of fatigue during exercise, although the reduced exercise volume due to fatigue and pain limits the overall acute hypertrophic mechanistic responses.
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    The Efficacy of Performance Tests and Testing Instruments within Elite Female Volleyball Players
    (University of Alabama Libraries, 2023) Wright, Will C; Esco, Michael R
    With the plethora of available tests and testing devices for both the vertical jump and change of direction ability, evaluating the efficacy of these methods and systems is a valuable pursuit for researchers and practitioners alike. Specifically, evaluating the efficacy of these methods within a highly trained population that emphasizes vertical jump and COD ability like volleyball would highlight changes that occur with high levels of specific training. Therefore, the purpose of this dissertation is to evaluate the agreement of common COD ability test, jump testing devices, and explore the utility of new technology for collecting data more effectively. The specific aims are as follows:Study 1: To evaluate the relationships of commonly used COD test (T-test, L-drill, and 5-10-5 shuttle) in Division I female volleyball players.Study 2: To determine the agreement of three devices assessing vertical jump performance with the criterion reference force plate system.Study 3: To compare the agreement between a motorized sprint resistance device, timing gates, and a global positioning system for total time to complete and peak velocity achieved during a commonly used change of direction drill in elite female volleyball players.
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    Health-Related Disparities Between Young Adult Sexual Minority and Heterosexual Women
    (University of Alabama Libraries, 2023) Sullivan, Katherine; Fedewa, Michael V
    The negative physical and psychological health outcomes which disproportionately affect sexual minority women (SMW), when compared to heterosexual women (HSW), may be attributed to community-wide perceptual differences in self-evaluation and/or the chronic exposure of sexual orientation-related psychosocial stressors (i.e., discrimination, stigma, prejudice, etc.). The limited research which has examined the potential effect of sexual orientation on negative health outcomes has yielded inconsistent results. Furthermore, there is a paucity of research specifically focusing on young adult women, who represent a unique subgroup of the population. The general purpose of this dissertation was to expand upon this understudied area with three separate research studies. Study 1 examined potential differences in relative adiposity (%Fat) and body dissatisfaction (BD) between young adult SMW and HSW. When comparing a combined group of SMW to HSW, SMW had moderately higher %Fat than HSW (p=.046, ES=.53); however, these results were not statistically significant when SMW were split into two groups, lesbian/gay and bisexual/plurisexual, and compared to HSW (V=0.064, F(4, 162)=1.33, p=.263). No differences in BD were observed regardless of SMW groupings (?=0.90, F(8, 156)=1.05, p=.404). Linear correlations were observed between %Fat, BD, and sexual orientation, such that higher %Fat was associated with greater BD and that sexual minority status was associated with lower body dissatisfaction; however, lesbian/gay sexual orientation seemed to intensify the association between %Fat and BD. Study 2 examined potential differences in cumulative allostatic load and physical activity (PA) between young adult SMW and HSW. Results indicated no differences in cumulative allostatic load (F(1, 38)=0.206, p=.652) or PA parameters (p<.05 for all) between young adult SMW and HSW. Study 3 examined potential differences in PA behaviors between SMW and HSW through a systematic review and meta-analysis. Although the results indicated that there were no significant differences in PA between SMW and HSW (ES=-0.038, 95%CI -0.179 to 0.102, p=0.576), differences in PA were associated with age (?=-0.018, 95%CI -0.034 to -0.003, p=0.022) and body mass index (?=-0.145, 95%CI -0.228 to -0.061, p=0.002). The results of this dissertation highlight the need for additional research in order to better understand the complex association between sexual orientation and health-related behaviors and outcomes among women.
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    Monitoring the Effects of Resistance Exercise on Heart Rate Variability
    (University of Alabama Libraries, 2020) Holmes, Clifton John Nicolas; Esco, Michael R.; Winchester, Lee J; University of Alabama Tuscaloosa
    Heart rate variability (HRV) has become a popular tool for monitoring autonomic stress responses, however, the efficacy of HRV as a valid internal training load marker for resistance exercise has not been well-established. We conducted three studies to address this gap. Study 1 compared the effects of low, moderate, and high set volumes in acute resistance exercise sessions on post-exercise parasympathetic reactivation. Three full-body resistance exercise sessions of varying set volumes were performed with HRV being measured pre- and for 30 minutes post-exercise. Statistically significant differences were observed across sessions and recording times (p?.05), but not with the session × time interaction. When comparing pre-post exercise HRV, significant differences were found across all sessions. The low volume session was significantly different from both the moderate and high volume sessions, but no differences were found between moderate and high volume sessions. Study 2 determined the relationship between pre-post changes in HRV, neuromuscular performance, and biochemical fatigue markers in response to resistance exercise. A bout of high set volume resistance exercise was performed with HRV, neuromuscular performance, and biochemical fatigue markers being measured pre- and post-exercise. Statistically significant correlations were observed with ?HRV Post5-10 and ?Lactate immediate post-exercise (r = -0.440, p = .036), and ?HRV Post5-10 and ?Lactate Post30 (r = -0.549, p <.001). Study 3 examined the validity and reliability of HRV derived from smartphone photoplethysmography (PPG) under resting and post-resistance exercise conditions. Participants completed four resting, simultaneous ECG and PPG measurements on separate days and one measure post-resistance exercise. Significant, yet small (ES=0.2-0.6) to moderate (ES=1.14) differences were found between simultaneous measures with moderate-to-very large correlations (r=0.41-0.76) and good agreement at rest. For the intraday reliability of PPG, ICC was “nearly perfect” (ICC=0.91) and interday reliability ICC was “very large” (ICC=0.88). The use of smartphone PPG seems to be an appropriate surrogate for ECG. However, HRV may not be a sensitive enough method for detecting all differences in set volumes. Practitioners should use an integrative approach to assess an individual’s recovery status and readiness to perform.
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    Resistance Trained Women's Response to Blood Flow Restriction Training
    (University of Alabama Libraries, 2023) Fleming, Abby; Winchester, Lee J
    Low-load resistance training (20-30% one-repetition max (1RM)) with blood flow restriction (LI-BFR) is able to induce similar strength, hypertrophic, and vascular adaptations to traditional high-load resistance training (>65% 1RM) (HIRT). Minimal research has been conducted examining the combination of HIRT and BFR (HIRT+BFR). Of the available research, the results are inconsistent, and none have looked at an exclusively female sample. With the lack of female participants in this specific area of research and training research in general, the need for further research in female subjects is necessary, as there are potential physiological adaptations from what is observed in males. The three studies of this dissertation were conducted to understand the physiological, vascular, and hormonal adaptations to HIRT+BFR training in resistance trained women. In study 1, 4-weeks of a lower-body HIRT+BFR training was implemented to determine changes in strength, muscle activation, movement velocity, and peak power. Results indicate similar adaptations between HIRT+BFR and HIRT alone for all measurements (all p > 0.05) except bar velocity during deadlift 1RM, where HIRT+BFR presented a decrease post-training (p < 0.05). Study 2 examined changes to vascular reactivity after the same 4-weeks of HIRT+BFR training. HIRT+BFR and HIRT produced similar changes to femoral and tibial arterial measurements (all p > 0.05). Acutely, during the initial 1RM testing session, the HIRT+BFR group significantly increased femoral artery time-averaged mean velocity (TAMV) from pre- to post- exercise (p = 0.007). During the final 1RM testing session there was also a time effect for femoral artery TAMV (p = 0.005), though only the HIRT group was significantly increased (p = 0.023). Study 3 examined the hormonal response to an acute bout of lower-body HIRT+BFR. There were no significant changes to dehydroepiandrosterone sulfate (DHEA-S) in either group (all p > 0.05). Insulin-like growth factor 1 (IGF-1), however, did trend towards a time effect (p = 0.051), where the HIRT+BFR group significantly increased post-exercise (p = 0.025). The combination of HIRT and BFR does not seem to enhance performance or vascular adaptations but may promote greater hormonal responses over HIRT alone.
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    Resisted Propulsion Power in Wheelchair Athletes
    (University of Alabama Libraries, 2022) Aldrich, Elizabeth; Richardson, Mark; University of Alabama Tuscaloosa
    Resisted propulsion has been recommended to train propulsion power in wheelchair athletes. However, prescription for such training is not provided and is most often adopted from able-bodied sports training. Wheelchair athletes have unique considerations as their level of impairment will affect their performance ability. This study examined findings and recommendations from able-bodied training, sought maximal propulsion power producing loads in wheelchair athletes and examined the relationship between maximal propulsion power and other trainable exercises. A review of able-bodied resisted sprint training revealed resisted sprint training did not significantly improve sprint performance over short distances from rest (Hedges' d ES = 0.11, p = 0.09). More recent studies however have indicated that heavier loads are likely to produce more favorable results. Seventeen competitive wheelchair athletes participated in trials to measure maximal power, its related parameters, and to test the repeatability of power output. Maximal propulsion power was found to be [mean (SD)] 371.60 (134.09)W and was very repeatable (ICC = 0.93, p < 0.001). The percent of maximal velocity the maximal power load induced was 50.16% (7.51) which matches values found in able-bodied athletes. Maximal wheelchair propulsion power was significantly related to class (r = 0.62, p = 0.009) and field-tests of medicine ball throw (r = 0.55, p = 0.02) and 20-m sprint velocity (r = 0.65, p = 0.005). With a better understanding of maximal propulsion power, practitioners and researchers can explore the dosage and training outcomes. KEY WORDS: resisted sprinting, wheelchair propulsion, wheelchair sport, power