Endogenous Opioids and Exercise-Related Hypoalgesia: Modern Models, Measurement, and Mechanisms of Action.

This chapter will focus on the role exercise appears to have on activation and modulating factors within the central nervous system related to endogenous like opioids and its possible contribution to exercise-induced hypoalgesia. The implications for the exercise-mediated alterations of CNS activation factors related to opioids, specifically endorphins and enkephalins, will be presented. In this update, we discuss utilization of new technology and methods to monitor mechanisms of opioid involvement to suggest their contribution with exercise mediated hypoalgesia as well as their relationships to alterations of perceptions of pain and mood.

The effect of acute exercise on the cortisol awakening response.

The effects of acute exercise on the cortisol awakening response (CAR), characterized by the rapid increase in cortisol concentrations within the 30-45 min following sleep offset has yet to be fully elucidated. Thus, our study investigated the effects of late-evening acute exercise on the CAR the following morning. We hypothesized that exercise would have a significant effect on the CAR the following morning.

Plasma Apelin Unchanged With Acute Exercise Insulin Sensitization.

Blood glucose and insulin responses to aerobic exercise are well defined yet the mechanisms effecting post-exercise insulin sensitization remain incomplete. Apelin has been reported to enhance glucose uptake and insulin sensitivity , but its role as a regulator of insulin sensitivity following acute aerobic exercise has not been investigated. Therefore, the purpose of this study was to investigate apelin's response to acute bouts of maximal and submaximal aerobic exercise and to elucidate apelin's influence on insulin sensitivity.

Evaluation of a Goalkeeper-Specific Adaptation to the Yo-Yo Intermittent Recovery Test Level 1: Reliability and Variability.

Ehlert, AM, Cone, JR, Wideman, L, and Goldfarb, AH. Evaluation of a goalkeeper-specific adaptation to the Yo-Yo intermittent recovery test level 1: reliability and variability. J Strength Cond Res 33(3): 819-824, 2019-The Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) has been shown to be a reliable test with strong correlations to physical match performance in field soccer players.

Effects of partial vascular occlusion on irisin responses to loaded muscle contractions.

The purpose of the study was to determine the effects of partial vascular occlusion on irisin responses. Eight males completed trials of light (30% 1-repetition maximum (1RM)) resistance exercise (single biceps curls and calf presses) with partial vascular occlusion (LRO), moderate resistance (70% 1RM) with no occlusion (MR), and occlusion only (OO). Blood was collected before, after, and 15 min after exercise.

Effects of an individualized soccer match simulation on vertical stiffness and impedance.

An observed relationship between soccer match duration and injury has led to research examining the changes in lower extremity mechanics and performance with fatiguing exercise. Because many fatigue protocols are designed to result in substantial muscular deficits, they may not reflect the fatigue associated with sport-specific demands that have been associated with the increasing incidence of injury as the match progresses. Thus, the aim of this study was to systematically analyze the progressive changes in lower extremity mechanics and performance during an individualized exercise protocol designed to simulate a 90-minute soccer match.

Gene response of the gastrocnemius and soleus muscles to an acute aerobic run in rats.

Genes can be activated or inhibited by signals within the tissues in response to an acute bout of exercise. It is unclear how a particular aerobic exercise bout may influence two muscles with similar actions to the activity. Therefore, the purposes of this investigation was to determine the gene response of selected genes involved in the "stress" response of the gastrocnemius (fast-twitch) and soleus (slow-twitch) muscles to a single two hour aerobic exercise bout in female Sprague-Dawley Rats at the 1 hour time point after the exercise.

Effects of a fruit/berry/vegetable supplement on muscle function and oxidative stress.

Purpose: This study tested the effectiveness of a fruit, berry, and vegetable concentrate (FVC), Juice Plus+® (NSA LLC, Collierville, TN), supplement on muscle function and oxidative stress in response to an acute bout of eccentric exercise (EE).

Methods: Forty-one healthy volunteers (age = 18-35 yr) were randomly assigned to either a placebo (P) or an FVC treatment taking capsules for 28 d (6 d(-1)) before EE and for the next 4 d. All subjects completed four sets of 12 repetitions of eccentric elbow flexion with their nondominant arm.

Gender comparisons of exercise-induced oxidative stress: influence of antioxidant supplementation.

The purpose of this study was to determine the influence of gender and antioxidant supplementation on exercise-induced oxidative stress. Twenty-five men and 23 women ran for 30 min at 80% VO2 max, once before and once after 2 weeks of supplementation, and again after a 1-week wash-out period. Subjects were randomly assigned to either placebo (P), antioxidant (A: 400 IU vitamin E+1 g vitamin C), or a fruit and vegetable powder (FV) treatment.

Identifying coronary artery flow reduction and ischemia using quasistationary QT/RR-interval hysteresis measurements.

Because myocardial ischemia induces QT/RR hysteresis, a correlation was hypothesized to exist between the extent of myocardial flow reduction and the magnitude of QT/RR hysteresis. Graded reductions in regional myocardial perfusion in the distribution of the left anterior descending coronary artery in open-chest pigs were used to model 1-vessel coronary artery disease. At each reduced level of left anterior descending coronary artery flow, the heart was electrically paced at progressively higher and lower rates between an initial control and maximum heart rate values.

Aerobic exercise bout effects on gene transcription in the rat soleus.

Purpose: This study was designed to identify changes in gene transcription that occur in the soleus muscle of untrained, 10-wk-old rats after a single aerobic exercise bout, and to identify which families of genes are most likely affected.

Methods: Rats were either run for 2 h and killed 1 h after exercise, or they remained sedentary and were killed at a matched time. Soleus muscles from each animal were examined using DNA microarrays, four genes related to RONS were analyzed by PCR, and two proteins were checked by Western blot analysis.

Oxidative stress response to aerobic exercise: comparison of antioxidant supplements.

Purpose: To compare the effects of two antioxidant formulas on biomarkers of oxidative stress before and after aerobic exercise.

Methods: Aerobically trained men (N=25) and women (N=23) were assigned to one of three treatments: 400 IU of vitamin E+1 g of vitamin C (V; N=15), a fruit and vegetable juice powder concentrate (FV; N=16), or a placebo (P; N=17). Subjects ran for 30 min at 80% VO(2 max) before, after 2 wk of supplementation, and after a 1-wk washout period.

Oxidative stress response in normal and antioxidant supplemented rats to a downhill run: changes in blood and skeletal muscles.

The purpose of this study was to determine if changes in oxidative stress biomarkers in blood and skeletal muscles are similar in normal and antioxidant supplemented rats after a downhill run. Sixty-six male Sprague-Dawley rats were pretreated with a normal rat diet or diet + antioxidants (2,000 mg vitamin C + 1,000 IU vitamin E/kg diet) for 2 weeks. Exercised rats ran 90 min on a rodent treadmill at a speed of 16 m/min at -16 degrees grade.

Vitamin C supplementation affects oxidative-stress blood markers in response to a 30-minute run at 75% VO2max.

Vitamin C supplementation (VC) (either 500 or 1000 mg/d for 2 wk) was compared to a placebo treatment (P) to ascertain if VC could influence oxidative stress. Twelve healthy males (25 +/- 1.4 y) were randomly assigned in a counter-balanced design with a 2-wk period between treatments.

Effects of acute aerobic and anaerobic exercise on blood markers of oxidative stress.

The purpose of this study was to compare oxidative modification of blood proteins, lipids, DNA, and glutathione in the 24 hours following aerobic and anaerobic exercise using similar muscle groups. Ten cross-trained men (24.3 +/- 3.

Combined antioxidant treatment effects on blood oxidative stress after eccentric exercise.

Purpose: This study was designed to ascertain the effects of a combination antioxidant therapy on plasma protein carbonyls (PC), malondialdehyde (MDA), and whole blood total (TGSH), oxidized (GSSG), and reduced (GSH) glutathione in non-resistance trained females after eccentric resistance exercise.

Methods: Eighteen women (aged 19-31 yr) were randomized in a double-blind manner to either an antioxidant supplement (N = 9; 400 IU vitamin E, 1 g vitamin C, and 90 mug selenium per day) or a lactose placebo (N = 9) for 14 d before and for 2 d after eccentric elbow flexor exercise. Blood samples taken before and immediately, 2, 6, 24, and 48 h postexercise were analyzed for PC, MDA, TGSH, and GSSG.

Effect of microhydrin on blood lactate, protein carbonyls, and glutathione status in rats before and after aerobic exercise.

To examine the effects of an antioxidant treatment on blood lactate, protein carbonyls (PC), and glutathione status, 42 male rats were assigned to either a control treatment (water, C) or one of two Microhydrin treatments (added to water, MH I or MH II). Rats from each treatment were assigned to either exercise (60 min of running) or rest. A treatment-by-time interaction was noted for blood lactate, with elevations only in the C and MH I treatments post-exercise (approximately 2.

Eccentric exercise effect on blood oxidative-stress markers and delayed onset of muscle soreness.

Purpose: This study examined the effects of a single bout of high-intensity eccentric exercise (EE) on blood protein carbonyls, glutathione status, and muscle damage indicators to ascertain whether blood markers of oxidative stress are elevated at the time delayed onset of muscle soreness (DOMS) occurs.

Methods: Eight healthy men (26.5 +/- 1.

Age-associated changes of responses to acetylsalicylic acid.

Aspirin can be an effective antipyretic, analgesic and anti-inflammatory agent, but unfortunately, its use in the elderly is often excessive [43]. In a survey by Gillies and Skyring, the overall prevalence of daily aspirin intake was greater in middle-age and older-age groups than for those of less than 40 years of age [16]. The elderly are susceptible to the advertising of non-prescription drugs and aspirin is frequently self-prescribed [8,31].