The comparative effects of periodized lower body strength training versus high intensity circuit programming in experienced runners.

BACKGROUND: The purpose of this study was to compare the effects of supplementing habitual run training with periodized lower body strength training versus high intensity circuit strength training on running performance and related variables in experienced runners. METHODS: Nineteen (N.=19) participants performed 8 weeks of 2 d·wk-1 periodized lower body strength training (PLB), N.=9, or high intensity circuit training (CT), N.=10. PLB sessions included 2 sets of the back squat, standing calf raise, leg press, and dumbbell lunge, with intensity linearly periodized. CT sessions simulated CrossFit-style programming and included 2-4 heavy (>10-RM) sets of a compound lift, followed by a high intensity, whole body resistance circuit. Three-km time trial (TT), V̇O2max, relative leg press 1-RM, running economy (RE) at 2 standard submaximal velocities (SV1, SV2) between 11 and 14 km∙hr-1, RPE at SV1/SV2, and peak/mean power were assessed pre and postintervention. RESULTS: Similar (P≤0.02) increases occurred in RE at 11 km∙hr-1 (36.4±3.1 to 35.4±2.4 mL·kg-1·min-1) and RPE at SV1 (12.5±1.3 to 11.4±1.6). Relative 1-RM (2.54±0.41 to 3.40±0.72) and RPE at SV2 (14.1±1.3 to 12.9±1.8) improved in both groups (P≤0.03). However, PLB showed larger improvements in 1-RM (0.43±0.18 vs. 0.2±1.9, t=2.75, P=0.015) and RPE at SV2 (-1.75±0.9 vs. -0.63±1.1, t=2.30, P=0.037). TT, V̇O2max, RE at 12-14 km∙hr-1, and power were unchanged (P≥0.27). CONCLUSIONS: PLB and CT enhanced 1-RM, RE at 11 km∙hr-1 and RPE at SV1/SV2, but neither modality improved TT performance, V̇O2max, anaerobic power, or RE at faster velocities. PLB resulted in greater improvements in 1-RM and RPE at SV2.

Polarized Versus High-Intensity Multimodal Training in Recreational Runners.

PURPOSE: This study longitudinally compared changes in running performance (5-km time trial) and fitness (maximal oxygen uptake [VO2max] and body composition [BC]) between polarized training and CrossFit Endurance (CFE) in recreational runners. METHODS: Participants (N = 21) completed 12 wk of CFE or polarized endurance training (POL). Both groups trained 5 d·wk-1. POL ran 5 d·wk-1, whereas CFE ran 3 d·wk-1 and performed CrossFit 3 d·wk-1 (run + CrossFit 1 d·wk-1). Intensity was classified as low, moderate, or high (zone 1, 2, or 3) according to ventilatory thresholds. POL was prescribed greater volume (295 [67] min·wk-1), distributed as 85%/5%/10% in Z1/Z2/Z3. CFE emphasized a lower volume (110 [18] min·wk-1) distribution of 48%/8%/44%. RESULTS: POL ran 283 (75.9) min·wk-1 and 47.3 (11.6) km·wk-1, both exceeding the 117 (32.2) min·wk-1 and 19.3 (7.17) km·wk-1 in CFE (P < .001). The POL distribution (74%/11%/15%) had greater total and percentage Z1 (P < .001) than CFE (46%/15%/39%), which featured higher percentage Z3 (P < .001). Time trial improved -93.8 (40.4) s (-6.21% [2.16%]) in POL (P < .001) and -84.2 (65.7) s (-5.49% [3.56%]) in CFE (P = .001). BC improved by -2.45% (2.59%) fat in POL (P = .02) and -2.62% (2.53%) in CFE (P = .04). The magnitude of improvement was not different between groups for time trial (P = .79) or BC (P = .88). Both groups increased VO2max (P ≤ .01), but with larger magnitude (P = .04, d = 0.85) in POL (4.3 [3.6] mL·kg·min-1) than CFE (1.78 [1.9] mL·kg·min-1). CONCLUSIONS: Recreational runners achieved similar improvement in 5-km performance and BC through polarized training or CFE, but POL yielded a greater increase in VO2max. Extrapolation to longer distances requires additional research.

Development of a Conceptual Model for Smoking Cessation: Physical Activity, Neurocognition, and Executive Functioning.

PURPOSE: Considerable research has shown adverse neurobiological effects of chronic alcohol use, including long-term and potentially permanent changes in the structure and function of the brain; however, much less is known about the neurobiological consequences of chronic smoking, as it has largely been ignored until recently. In this article, we present a conceptual model proposing the effects of smoking on neurocognition and the role that physical activity may play in this relationship as well as its role in smoking cessation. METHODS: Pertinent published peer-reviewed articles deposited in PubMed delineating the pathways in the proposed model were reviewed. RESULTS: The proposed model, which is supported by emerging research, demonstrates a bidirectional relationship between smoking and executive functioning. In support of our conceptual model, physical activity may moderate this relationship and indirectly influence smoking behavior through physical activity-induced changes in executive functioning. CONCLUSIONS: Our model may have implications for aiding smoking cessation efforts through the promotion of physical activity as a mechanism for preventing smoking-induced deficits in neurocognition and executive function.

A brief review: the implications of iron supplementation for marathon runners on health and performance.

The marathon is considered one of the most demanding endurance events, imposing an enormous amount of physiological stress on bodily structures, the metabolic machinery, and organ systems. Scientific evidence has conclusively shown that marathoners are in need of special nutritional strategies to maintain performance and health. Indeed, among competitive athletes, marathoners are at greater risk to develop anemia, bone mineral density loss, immunosuppression, and other clinical syndromes that may affect performance. Inadequate dietary intake of the micronutrient iron has been identified as one key factor in the development of the above mentioned anomalies. In fact, iron is one of the few nutrients recommended as a supplement by the American College of Sports Medicine (ACSM), the Academy of Nutrition and Dietetics (AND), and Dietitians of Canada. Therefore, the aim of this review article is to discuss the role of iron on the marathoner's health and performance. Special emphasis will be given to the physiological mechanisms accounting for the additional iron need in this group of athletes and the nutritional strategies intended to counteract iron deficiency.

Association between flavonoid-rich fruit and vegetable consumption and total serum bilirubin.

Emerging work demonstrates that serum bilirubin is a novel biomarker implicated in cardiovascular and metabolic diseases. However, we have a limited understanding of the influence of flavonoid-rich fruit and vegetable consumption on bilirubin levels, which was the purpose of this study. Data from the 2003 to 2006 National Health and Nutrition Examination survey were used (n = 1783; 18-85 years of age), with analyses performed in 2014. Total serum bilirubin was measured from a blood sample. Using a food frequency questionnaire (FFQ), a flavonoid index variable was created summing the frequency of consumption of flavonoid-rich foods. After adjustments, greater consumption of flavonoid-rich fruits and vegetables was positively associated with bilirubin levels. Our findings suggest an association between flavonoid-rich fruit and vegetable consumption and bilirubin levels. If confirmed by prospective and experimental studies, then regular consumption of flavonoid-rich fruits and vegetables should be promoted to increase levels of bilirubin.

Influence of flavonoid-rich fruit and vegetable intake on diabetic retinopathy and diabetes-related biomarkers.

OBJECTIVE: (1) Determine the relationship between dietary flavonoid-rich fruit and vegetable consumption on diabetes-related biomarkers (e.g., HgbA1c) and diabetic retinopathy. METHODS: Data from 381 participants with diabetes from the NHANES 2003-2006 were analyzed. Blood samples were taken to measure C-reactive protein (CRP), HgbA1C, and fasting glucose and insulin. Diabetic retinopathy was assessed from a retinal imaging exam. A high-flavonoid fruit and vegetable consumption (HFVC) index variable was created from a food frequency questionnaire (FFQ). RESULTS: After adjustments, greater HFVC was associated (p<0.05) with lower levels of CRP (ß=-0.005), HgbA1C (ß=-0.005) and glucose (ß=-0.59), with greater HFVC reducing the odds of having diabetic retinopathy by 30%. CONCLUSION: Adults with diabetes consuming more flavonoid-rich fruits and vegetables had lower degrees of inflammation, better glycemic control, and reduced odds of diabetic retinopathy.

Dietary quercetin reduces chemotherapy-induced fatigue in mice.

PURPOSE: While fatigue is the most commonly reported symptom of chemotherapy, there are currently no effective treatments for chemotherapy-induced fatigue (CIF). We used a mouse model to examine the benefits of quercetin on CIF as measured by voluntary wheel running activity and sought to determine whether quercetin may be associated with a decrease in inflammation and/or anemia. METHODS: Mice were assigned to 1 of 4 groups: placebo-vehicle (Plac-PBS), placebo-5-fluorouracil (Plac-5FU), quercetin-vehicle (Quer-PBS), or quercetin-5-fluorouracil (Quer-5FU). All mice were given a daily injection of either 60 mg/kg of 5-FU or phosphate buffered saline (PBS) for 5 days. Quercetin (0.02%) treatment was administered in the food 3 days prior to 5-FU administration and for the duration of the experiment (ie, days -2 to 14). A second group of mice was sacrificed at 5 and 14 days post initial injection for assessment of monocyte chemoattractant protein-1 (MCP-1) and anemia. RESULTS: Voluntary wheel running was reduced in both the Plac-5FU and Quer-5FU groups following 5-FU injection (P < .05). However, the Quer-5FU group recovered to baseline levels by approximately day 7, whereas the Plac-5FU group remained suppressed. MCP-1 was significantly elevated at 14 days in Plac-5FU (P < .001), but no changes were seen with Quer-5FU. Treatment with 5-FU resulted in anemia at both 5 days and 14 days; however, quercetin blocked this effect at 14 days (P < .001). CONCLUSION: These results demonstrate the beneficial effect of quercetin on improving recovery of voluntary physical activity following 5-FU treatment, which may be linked to a decrease in inflammation and anemia.