Karen M. Keane

Effects of Montmorency tart cherry (Prunus Cerasus L.) consumption on vascular function in men with early hypertension

BACKGROUND Tart cherries contain numerous polyphenolic compounds that could potentially improve endothelial function and reduce cardiovascular disease risk. OBJECTIVE We sought to examine the acute effects of Montmorency tart cherry (MC) juice on vascular function in subjects with early hypertension. DESIGN A placebo-controlled, blinded, crossover, randomized Latin square design study with a washout period of ≥14 d was conducted. Fifteen men with early hypertension [systolic blood pressure (SBP) ≥130 mm Hg, diastolic blood pressure ≥80 mm Hg, or both] received either a 60-mL dose of MC concentrate or placebo. Microvascular reactivity (laser Doppler imaging with iontophoresis), arterial stiffness (pulse wave velocity and analysis), blood pressure, and phenolic acid absorption were assessed at baseline and at 1, 2, 3, 5, and 8 h postconsumption. RESULTS MC consumption significantly lowered SBP (P < 0.05) over a period of 3 h, with peak reductions of mean ± SEM 7 ± 3 mm Hg 2 h after MC consumption relative to the placebo. Improvements in cardiovascular disease risk factors were closely linked to increases in circulating protocatechuic and vanillic acid at 1-2 h. CONCLUSIONS MC intake acutely reduces SBP in men with early hypertension. These benefits may be mechanistically linked to the actions of circulating phenolic acids. This study provides information on a new application of MCs in health maintenance, particularly in positively modulating SBP. This trial was registered at clinicaltrials.gov as NCT02234648.

Muscle Damage Response in Female Collegiate Athletes After Repeated Sprint Activity.

Abstract Keane, KM, Salicki, R, Goodall, S, Thomas, K, and Howatson, G. Muscle damage response in female collegiate athletes after repeated sprint activity. J Strength Cond Res 29(10): 2802–2807, 2015—Exercise-induced muscle damage (EIMD) is a well-investigated area, however there is a paucity of data surrounding the damage response in females. The aim of this study was to examine the damage responses from a sport-specific bout of repeated sprints in female athletes. Eleven well-trained females (mean ± SD; age: 22 ± 3 years; height: 166.6 ± 5.7 cm; mass: 62.7 ± 4.5 kg) in the luteal phase of the menstrual cycle completed a repeated sprint protocol designed to induce EIMD (15 × 30 m sprints). Creatine kinase, countermovement jump height, knee extensor maximal voluntary isometric contraction (MVIC) force, delayed onset muscle soreness (DOMS), 30-m sprint time, and limb girth were recorded before, after, 24, 48, and 72 hours after exercise. Creatine kinase was elevated at 24, 48, and 72 hours (p ⩽ 0.05), peaking at 24 hours (+418%) and returning toward baseline at 72 hours. Countermovement jump height was reduced immediately after, 24, and 48 hours (p ⩽ 0.05). Sprint performance was also negatively affected immediately after, 24, 48, and 72 hours after exercise. Muscle soreness peaked at 48 hours (p < 0.01) and remained significantly elevated at 72 hours after exercise (p < 0.01). Limb girth and MVIC did not alter over time. This study provides new information on the EIMD response in trained females after a sport-specific bout of repeated sprints. Importantly, this damage response has the potential to negatively affect performance for several days after exercise.

Minimal muscle damage after a marathon and no influence of beetroot juice on inflammation and recovery

This study examined whether beetroot juice (BTJ) would attenuate inflammation and muscle damage following a marathon. Using a double blind, independent group design, 34 runners (each having completed ca. ∼16 previous marathons) consumed either BTJ or an isocaloric placebo (PLA) for 3 days following a marathon. Maximal isometric voluntary contractions (MIVC), countermovement jumps (CMJ), muscle soreness, serum cytokines, leucocytosis, creatine kinase (CK), high sensitivity C-reactive protein (hs-CRP), and aspartate aminotransferase (AST) were measured pre, post, and 2 days after the marathon. CMJ and MIVC were reduced after the marathon (P < 0.05), but no group differences were observed (P > 0.05). Muscle soreness was increased in the day after the marathon (BTJ; 45 ± 48 vs. PLA; 46 ± 39 mm) and had returned to baseline by day 2, irrespective of supplementation (P = 0.694). Cytokines (interleukin-6; IL-6, interleukin-8, tumour necrosis factor-α) were increased immediately post-marathon but apart from IL-6 had returned to baseline values by day 1 post. No interaction effects were evident for IL-6 (P = 0.213). Leucocytes increased 1.7-fold after the race and remained elevated 2 days post, irrespective of supplement (P < 0.0001). CK peaked at 1 day post marathon (BTJ: 965 ± 967, and PLA: 1141 ± 979 IU·L-1) and like AST and hs-CRP, was still elevated 2 days after the marathon (P < 0.05); however, no group differences were present for these variables. Beetroot juice did not attenuate inflammation or reduce muscle damage following a marathon, possibly because most of these indices were not markedly different from baseline values in the days after the marathon.

Effects of montmorency tart cherry (L. Prunus Cerasus ) consumption on nitric oxide biomarkers and exercise performance

The purpose of this study was to investigate the effects of Montmorency tart cherry juice (MC) on nitric oxide (NO) biomarkers, vascular function, and exercise performance. In a randomized, double‐blind, placebo (PLA)‐controlled, crossover study, 10 trained cyclists (mean ± SD; V˙ O2peak 59.0 ± 7.0 mL/kg/min) acutely ingested 30 mL of either MC or PLA following dietary restrictions of polyphenol‐rich compounds and completed 6‐minutes moderate‐ and severe‐intensity cycling bouts 1.5 hour post‐ingestion on 2 occasions for each experimental condition. The severe‐intensity cycling test was continued to exhaustion on 1 occasion and immediately followed by a 60‐seconds all‐out sprint on the other occasion. Blood pressure, pulse wave measures, tissue oxygenation index, and plasma nitrite concentration were assessed pre‐ and 1.5 hour post‐ingestion. Time to exhaustion was not different between conditions (P > .05), but peak power over the first 20 seconds (363 ± 42 vs 330 ± 26 W) and total work completed during the 60‐seconds all‐out sprint (21 ± 3 vs 19 ± 3 kJ) were 10% higher in the MC trial compared to the PLA trial (P < .05). Systolic blood pressure was 5 ± 2 mm Hg lower 1.5 hour post‐MC supplementation compared to PLA supplementation (P < .05). There were no differences in pulse wave measures, plasma nitrite concentration, or tissue oxygenation between the MC and PLA trials (P > .05). These results suggest that acute supplementation with MC can lower blood pressure and improve some aspects of exercise performance, specifically end‐sprint performance, in trained cyclists.

Adaptation to Damaging Dance and Repeated-sprint Activity in Women

Abstract Brown, MA, Howatson, G, Keane, KM, and Stevenson, EJ. Adaptation to damaging dance and repeated-sprint activity in women. J Strength Cond Res 30(9): 2574–2581, 2016—The repeated bout effect (RBE) refers to the prophylactic effect from damaging exercise after a single previous bout of exercise. There is a paucity of data examining the RBE in women, and investigations using exercise paradigms beyond isolated eccentric contractions are scarce. In light of the limited literature, this investigation aimed to determine whether 2 different sport-specific exercise bouts would elicit a RBE in women. Twenty-one female dancers (19 ± 1 years) completed either a dance-specific protocol (n = 10) or sport-specific repeated-sprint protocol (n = 11). Delayed-onset muscle soreness (DOMS), limb girths, creatine kinase (CK), countermovement jump height, reactive strength index, maximal voluntary contraction, and 30-meter sprint time were recorded before and 0, 24, 48, and 72 hours after exercise. An identical exercise bout was conducted approximately 4 weeks after the initial bout, during which time the subjects maintained habitual training and dietary behaviors. DOMS and 30-meter sprint time decreased after a second bout of both activities (p = 0.003; = 0.38 and p = 0.008; and = 0.31, respectively). Circulating CK was also lower at 24, 48, and 72 hours after the second bout, independent of group (p = 0.010 and = 0.23). Compared with the repeated-sprint protocol, the magnitude of change in DOMS was greater after a subsequent bout of the dance protocol (p = 0.010 and = 0.19). These data are the first to demonstrate that dance and repeated-sprint activity resulting in muscle damage in women confers a protective effect against muscle damage after a subsequent bout.

Which anthropometric and lower body power variables are predictive of professional and amateur playing status in male rugby union players

The purpose of this study was to compare anthropometric and lower body power measurements between current professional and amateur male rugby union players. The present study also sought to determine which anthropometric and physical performance variables were predictive of playing standard. Thirty professional and 30 amateur RU players performed Wattbike 6 s maximal effort (WB6S) and countermovement (CMJ) and squat jump (SJ) assessments, anthropometric measures were also taken. Dependant variables recorded and analysed including: body mass, stature, Σ8 site skinfolds, WB6S absolute and relative peak power, CMJ and SJ average concentric force, jump height, peak velocity, time to peak force, rate of force development (RFD) and absolute and relative peak force and power. Professional players were heavier, taller and leaner than their amateur counterparts (p < 0.05). Professional players performed significantly better in all physical performance measures except CMJ and SJ time to peak force, CMJ RFD and SJ relative peak force. Variables which were predictive of playing standard were: Σ8 skinfolds, CMJ peak velocity and WB6S absolute and relative peak power (p < 0.05). These findings indicate that the current body of male professional RU players is anthropometrically and physically superior to their amateur counterparts, although not all variables assessed here were predictive of playing standard. Data presented here indicate that Σ8 skinfolds, WB6S absolute and relative power and CMJ peak velocity are predictive of playing standard, whereas other anthropometric and strength and power variables are not.

Dietary intake of anthocyanins and risk of cardiovascular disease: a systematic review and meta-analysis of prospective cohort studies

Abstract Accumulating evidence suggests flavonoid intake is associated with reduced risk of non-communicable diseases. We aimed to systematically determine and quantify the potential association between dietary anthocyanin intake and risk of cardiovascular diseases (CVD). A systematic literature search of studies reporting anthocyanin intake and risk of fatal or nonfatal CVD was performed using SCOPUS, MEDLINE, CINAHL and Cochrane Library. The relative risk (RR) or hazard ratio (HR) of highest category of anthocyanin foods were pooled in a random-effects meta-analysis. Subgroup analysis were conducted to determine possible sources of heterogeneity. The meta-analysis suggested intake of dietary anthocyanins and reduced risk of CHD (RR = 0.91, 95% CI: 0.83, 0.99; I2 = 12.0, Ph = 0.337) and CVD mortality (RR = 0.92, 95% CI: 0.87, 0.97; I2 = 0.0, Ph = 0.584). However, there was no relationship between the intake of these compounds and reduced risk of MI, stroke or total CVD. Subgroup analysis determined reduced risk of CHD and CVD mortality was more prominent for anthocyanidin intake, as opposed to anthocyanin or berries. Our systematic review and meta-analysis provides evidence that anthocyanins, specifically anthocyanidins, reduce the risk of CHD and CVD mortality. Further randomized controlled trials on anthocyanin intake and CVD risk factors are needed to support these findings.

Student use and perception of technology enhanced learning in a mass lecture knowledge-rich domain first year undergraduate module

The purpose of this study was to examine student use and perceptions of technology enhanced learning tools (TELTs), including their value for learning. Students enrolled onto a 12-week undergraduate science module had access to four TELTs each week, (i) a recording of the lecture (Panopto™), (ii) an animated mini review of the lecture (ShowMe), (iii) a multiple choice quiz hosted on Blackboard® (MCQ), and (iv) a module Twitter feed. Ninety-five students completed a survey at the end of the module, which included quantitative and qualitative questions, to examine whether they perceived the TELT to be useful for their learning. Analysis of the quantitative data suggest that Twitter was used significantly less than the other three TELTs (p < 0.001) with less people agreeing that it helped their learning (p < 0.001), whilst ShowMe and MCQ had a greater occurrence of an ‘agree’ rating compared to Twitter and Panopto (p ≤ 0.002). A thematic analysis of the qualitative responses identified assessment as a common theme across all four TELTs, being a positive factor for Panopto, ShowMe and MCQ, but negative for Twitter. Students highlighted ShowMe as being particularly useful for simplifying information. Based on this study TELTs similar to ShowMe (i.e. animations) are most recommended as this was one of the two highly rated TELTs (alongside MCQ), but may have more potential for crossover with other subjects, and students found it useful for more than just assessment.

The Contribution of the Neuromuscular System in the Repeated Bout Effect

Maximal eccentric contractions induce an immediate strength loss that results from skeletal muscle damage, the symptoms of which can persist for several days after the exercise insult. The repeated bout effect (RBE) refers to the acute adaptive response precipitated from a single bout of eccentric contractions that result in an attenuated damage response on subsequent, potentially damaging, bouts of exercise. The mechanisms for this adaptive response are thought to be, at least in part, from neural adaptations.

The Contribution of the Neuromuscular System in the Repeated Bout Effect: 1514 Board #167 June 2, 8: 00 AM - 9: 30 AM.

Maximal eccentric contractions induce an immediate strength loss that results from skeletal muscle damage, the symptoms of which can persist for several days after the exercise insult. The repeated bout effect (RBE) refers to the acute adaptive response precipitated from a single bout of eccentric contractions that result in an attenuated damage response on subsequent, potentially damaging, bouts of exercise. The mechanisms for this adaptive response are thought to be, at least in part, from neural adaptations.