Mandy Lucinda Gault

Aging, functional capacity and eccentric exercise training

Aging is a multi-factorial process that ultimately induces a decline in our physiological functioning, causing a decreased health-span, quality of life and independence for older adults. Exercise participation is seen as a way to reduce the impact of aging through maintenance of physiological parameters. Eccentric exercise is a model that can be employed with older adults, due to the muscles ability to combine high muscle force production with a low energy cost. There may however be a risk of muscle damage before the muscle is able to adapt. The first part of this review describes the process of aging and how it reduces aerobic capacity, muscle strength and therefore functional mobility. The second part highlights eccentric exercise and the associated muscle damage, in addition to the repeated bout effect. The final section reviews eccentric exercise interventions that have been completed by older adults with a focus on the changes in functional mobility. In conclusion, eccentric endurance exercise is a potential training modality that can be applied to older adults for improving muscle strength, aerobic capacity and functional ability. However, further research is needed to assess the effects on aerobic capacity and the ideal prescription for eccentric endurance exercise.

Beneficial Physiological Effects With Blackcurrant Intake in Endurance Athletes

Blackcurrant contains anthocyanins, known to influence vasorelaxation and peripheral blood flow. We examined the effects of 7 days intake of Sujon New Zealand blackcurrant powder (6g/day) on the lactate curve, maximum oxygen uptake, and cardiovascular responses at rest and during cycling. Thirteen trained triathletes with >3 yrs experience (8 men, age: 38 ± 8 yrs, body mass: 71 ± 9 kg, BF%: 19 ± 5%, mean ± SD) performed two incremental cycling protocols with recording of physiological and cardiovascular responses (Portapres Model 2). Cardiovascular function was also measured in rest. Experimental design was double-blind, placebo-controlled, randomized and cross-over (wash-out 4 wks). Data were analyzed with two-tailed t tests and 2-way ANOVA and significance accepted at p < .05. Plasma lactate was lower at 40%, 50%, 60% and 70% of maximum power by 27%, 22%, 17% and 13%. Intensity at 4 mmol · La(-1) OBLA was 6% higher with blackcurrant without effect on heart rate and oxygen uptake. Maximum values of oxygen uptake, heart rate and power were not affected by blackcurrant, but obtained with 14% lower lactate. In rest, blackcurrant increased stroke volume and cardiac output by 25% and 26%, and decreased total peripheral resistance by 16%, with no changes in blood pressure and heart rate. Cardiovascular responses during exercise at 40%, 50%, 60%, 70% and 80% intensity were not affected. Sujon New Zealand blackcurrant powder affects lactate production and/or clearance during exercise. Sujon New Zealand blackcurrant powder affects physiological and cardiovascular responses in rest and during exercise that may have implications for exercise performance.

Effect of Wearing the Cosmed K4b2 Metabolic System on 1 Mile Walking Performance in Older Adults

Effect of Wearing the Cosmed K4b2 Metabolic System on 1 Mile Walking Performance in Older Adults This study examined in older adults the effects of wearing the Cosmed K4b2 metabolic system with face mask during the 1-mile Rockport Fitness Walking Test (RFWT). A randomised cross-over design was used (13 males, 12 females, age: 67±4 (yrs). Walking time, walking speed and final heart rate were recorded and predicted VO2max calculated. Participants had a constant walking speed during the RFWT (P = 0.24) not influenced by wearing the Cosmed K4b2. Using Bland-Altman analysis, bias for walking time, heart rate and predicted VO2max was not significant. The predicted VO2max wearing the Cosmed K4b2 was within 0.05±0.36 L·min-1. Wearing the Cosmed K4b2 metabolic system with face mask did not influence 1-mile walking performance in older adults. This observation allows the Cosmed K4b2 metabolic system to be used during walking tests in older adults to examine metabolic and physiologic adaptations by controlled exercise interventions.

Eccentric contraction-induced muscle injury does not change walking economy in older adults

Eccentric contraction-induced muscle injury does not change walking economy in older adults The aim of the study was to examine whether self-selected walking speed during downhill treadmill walking by older adults would result in muscle injury and changes in physiological responses during level walking. Twenty-six participants (age: 67 ± 4 yrs; height: 1.69 ± 0.09 m; body mass: 74.9 ± 13.1kg) were assigned to level (n = 11, 30 min, 0%) or downhill walking (n=15, 30 min, -10%) at a self-selected walking speed. Self-selected walking speed and exercise intensity were similar for both groups (level: 4.2±0.4 km·hr-1, 42±6% VO2max; downhill: 4.6±0.6 km·hr-1, 44±15% VO2max). After 48-hours, downhill walking had reduced maximal voluntary isometric force of the m. quadriceps femoris (-15%, P<0.001), indicative of muscle injury, but no changes were observed for walking economy, minute ventilation, heart rate and respiratory exchange ratio during level walking. For older adults, downhill walking at a selfselected walking speed causes muscle injury without any detrimental effect on walking economy. Regular downhill walking at a self-selected walking speed by older adults is an eccentric endurance activity that may have the potential to improve cardiovascular fitness and muscle strength.

Blackcurrant Alters Physiological Responses and Femoral Artery Diameter during Sustained Isometric Contraction

Blackcurrant is rich in anthocyanins that may affect exercise-induced physiological responses. We examined tissue oxygen saturation, muscle activity, cardiovascular responses and femoral artery diameter during a submaximal sustained isometric contraction. In a randomised, double-blind, crossover design, healthy men (n = 13, age: 25 ± 4 years, BMI: 25 ± 3 kg·m−2, mean ± SD) ingested New Zealand blackcurrant (NZBC) extract (600 mg∙day−1 CurraNZ™) or placebo (PL) for 7-days separated by 14-days washout. Participants produced isometric maximal voluntary contractions (iMVC) and a 120-s 30%iMVC of the quadriceps with electromyography (EMG), near-infrared spectroscopy, hemodynamic and ultrasound recordings. There was no effect of NZBC extract on iMVC (NZBC: 654 ± 73, PL: 650 ± 78 N). During the 30%iMVC with NZBC extract, total peripheral resistance, systolic, diastolic, and mean arterial pressure were lower with increased cardiac output and stroke volume. With NZBC extract, EMG root mean square of the vastus medialis and muscle oxygen saturation were lower with higher total haemoglobin. During the 30%iMVC, femoral artery diameter was increased with NZBC extract at 30 (6.9%), 60 (8.2%), 90 (7.7%) and 120 s (6.0%). Intake of NZBC extract for 7-days altered cardiovascular responses, muscle oxygen saturation, muscle activity and femoral artery diameter during a 120-s 30%iMVC of the quadriceps. The present study provides insight into the potential mechanisms for enhanced exercise performance with intake of blackcurrant.

New Zealand Sujon blackcurrant lowers lactate accumulation during cycling in triathletes

Background Blackcurrant intake has been reported to increase peripheral blood flow in humans (Matsumoto, et al., 2005), potentially by anthocyanin-induced vasorelaxation and vasodilation (Ziberna, et al., 2013). Increased peripheral blood flow may affect the exercise intensity at lactate indicators (e.g. onset of blood lactate accumulation (OBLA) at 4 mmol∙L-1) and maximum oxygen uptake. We examined the effect of 1-week Sujon blackcurrant powder supplementation on the blood lactate curve and aerobic capacity of trained triathletes. Methods Healthy male (n=8) and female (n=5) triathletes with >3 yrs experience (age: 38±8 yrs, height: 174±5 cm, body mass: 71±9 kg, BMI: 23±2, BF%: 19±5%, mean±SD) performed cycling tests for lactate responses (4 min stages with 2 min recovery, start power 50 W with 30 W increments) and maximum oxygen uptake (start power 50 W for 4 min with 30 W∙min-1 increments) at self-selected pedal cadence (SRM ergometer, SRM International, Germany). Familiarized participants were tested following 7 days of Sujon blackcurrant powder (S, 6g/day) or placebo (P) intake. Experimental design was double-blind and randomized with a wash-out period of 4 weeks. Oxygen consumption (Douglas bag technique) and heart rate were recorded during the cycling tests. Intensity, oxygen uptake and heart rate at 4 mmol∙L-1 OBLA were calculated using lactate analysis software (Newell et al., 2007). Lactate responses were calculated at relative intensities with individual lactate curves. Paired t-tests were used for analysis with significance accepted at p<.05. Results The intensity at 4 mmol∙L-1 OBLA was 6% higher with Sujon (P: 223±57, S: 236±60 W, range -5 to 22%, 11 participants showed an increase and 1 no change) (p<.01). In both conditions at 4 mmol∙L-1 OBLA, there were no differences in heart rate (P: 159±7, S: 164±10 b∙min-1, p=.13) or oxygen uptake (P: 2.91±0.73, S: 2.96±0.71 L∙min-1, p=.31). Blood lactate was lower at 40% (P: 1.24±0.52, S: 0.91±0.46 mmol∙L-1), 50% (P: 1.58±0.78, S: 1.23±0.64 mmol∙L-1), 60% (P: 2.29±0.96, S: 1.91±0.87 mmol∙L-1) and 70% (P: 3.52±1.10, S: 3.08±1.21 mmol∙L-1) of maximum power, decreases of 27%, 22%, 17% and 13%, respectively (all p<.01). There was no effect on maximum values of oxygen uptake (P: 49.1±6.2, S: 49.7±6.1 mL∙kg-1∙min-1, p=.16), power (P: 305±68, S: 307±62 W, p=.66) or heart rate (P: 172±10, S: 172±11 b∙min-1, p=.68). However, maximum oxygen uptake with Sujon was obtained with 14% lower lactate values (measured 3-min after exhaustion; P: 7.85±1.69, S: 6.79±1.51 mmol∙L-1, range -27 to 48%, 10 participants showed a decrease and 1 no change) (p=0.02). Conclusions Intake of New Zealand Sujon blackcurrant powder is associated with 1) a substantial downward and rightward shift of the lactate curve during cycling over a wide range of intensities, and 2) lower lactate accumulation at aerobic capacity suggesting increased lactate clearance or altered substrate oxidation. These findings may have implications for training practice and aerobic performance of endurance athletes. Acknowledgement Funding for this study and conference attendance was provided by the University of Chichester, Health Currancy Ltd (UK) and Gibb Holdings (Nelson) Ltd (NZ).

The metabolic equivalents of one-mile walking by older adults; implications for health promotion

Background: Instructions for older adults regarding the intensity of walking may not elicit an intensity to infer health gains. We recorded the metabolic equivalents (METs) during a 1-mile walk using constant and predicted values of resting MET in older adults to establish walking guidelines for health promotion and participation. Methods: In a cross-sectional design study, participants (15 men, 10 women) walked 1-mile overground, in a wooden floored gymnasium, wearing the Cosmed K4b2 for measurement of energy expenditure. Constant or predicted values for resting MET were used to calculate the number of 1-mile walks to meet 450-750 MET∙min∙wk-1. Results: Participants had MET values higher than 3 for both methods, with 29% and 64% of the participants higher than 6 for a constant and predicted MET value, respectively. The METs of the1-mile walk were (mean ± SD) 6 ± 1 and 7 ± 1 METs using constant and predicted resting MET,and similar for men (constant: 6 ± 1 METs; predicted: 7 ± 1 METs) and women (constant: 5±1METs; predicted: 6 ± 1 METs) (P > 0.05). Conclusion: Older adults that are instructed to walk 1-mile at a fast and constant pace meet the minimum required intensity for physical activity, and public health guidelines. Health professionals, that administer exercise, could encourage older adults to accumulate between six and nine 1-mile walks per week for health gains.

Effect of New Zealand Sujon blackcurrant on resting cardiovascular function in triathletes.

Background Blackcurrant contains anthocyanin, a component known to induce vasorelaxation and vasodilation in rat aortic rings (Ziberna et al., 2013). In humans, blackcurrant intake has been reported to increase peripheral blood flow (Matsumoto et al., 2005), with higher anthocyanin intake having beneficial effects on cardiovascular function in women (Jennings et al., 2012). However, the effect of blackcurrant intake on cardiovascular function in endurance-trained athletes is unknown. We examined the effect of 1-week Sujon blackcurrant powder supplementation on resting cardiovascular function of trained triathletes. Methods Thirteen healthy triathletes with >3 years experience (8 men; mean±SD: age: 38±8 years, height: 174±5 cm, body mass: 71±9 kg, BMI: 23±2, BF%: 19±5%, VO2max: 49.1±6.2 mL∙kg-1∙min-1, maximum power: 305±68 W) volunteered. Participants were tested following 7 days of Sujon blackcurrant powder (S, 6g/day) or placebo (P) intake, administered following a double-blind, crossover, randomized design with a wash-out period of 4 weeks. Cardiovascular function was recorded for 20 min in supine participants using a beat-to-beat blood pressure monitoring system (Portapres® Model 2, Finapres Medical Systems BV, Amsterdam, The Netherlands). Cardiovascular measures were averaged over 10 consecutive beats, with the lowest systolic blood pressure (BP) and associated measures analysed. Paired two-tailed t-tests were used for analysis with significance accepted at p≤.05. Results There were no differences in systolic BP (P: 121±23, S: 120±23 mmHg, p=.92), diastolic BP (P: 69±16, S: 63±14 mmHg, p=.12), mean arterial BP (P: 86±18, S: 82±18 mmHg, p=.33), and heart rate (P: 58±9, S: 59±10 beats∙min-1, p=.95). Stroke volume (P: 82±23, S: 99±25 mL, p<.01) and cardiac output (P: 4.8±1.6, S: 5.8±1.7 L, p<.05) were increased by 25% and 26%, respectively. There was a 16% lower total peripheral resistance (P: 20.2±8.9, S: 15.2±5.3 mmHg∙L-1∙min-1, p=.05). The changes in resting cardiovascular function were observed in 10 participants. Conclusions Resting cardiovascular function of trained endurance athletes responds positively to 1-week intake of New Zealand Sujon blackcurrant powder. Intake of New Zealand Sujon blackcurrant powder is associated with 1) an increase in stroke volume and cardiac output, and 2) a decrease in total peripheral resistance. For resting skeletal muscles, these observations may influence the delivery of nutrients and clearance of metabolites. The effect on New Zealand Sujon blackcurrant on resting cardiovascular function may support the recovery of endurance athletes. Acknowledgement Funding for this study and conference attendance was provided by the University of Chichester, Health Currancy Ltd (UK) and Gibb Holdings (Nelson) Ltd (NZ).

Effect of New Zealand Sujon blackcurrant on cardiovascular responses during cycling in triathletes

Background Anthocyanin is a component known to induce vasorelaxation and vasodilation in rat aortic rings (Ziberna et al., 2013) and is present in high amounts in New Zealand Sujon blackcurrant. During typing work in humans, an activity of low intensity, peripheral blood flow was increased by blackcurrant intake (Matsumoto et al., 2005). It is not known whether anthocyanin would affect the cardiovascular responses at different exercise intensities. We examined the effect of 1-week Sujon blackcurrant powder supplementation on cardiovascular responses at low, moderate and high intensities of trained triathletes. Methods Ten healthy triathletes with >3 years experience (5 men and 5 women; mean±SD: age: 40±5 years, height: 173±6 cm, body mass: 69±9 kg, BMI: 23±2, BF%: 19±4%, VO2max: 49±7 mL∙kg-1∙min-1, maximum power: 293±68 W) volunteered. Participants were tested following 7 days of Sujon blackcurrant powder (S, 6g/day) or placebo (P) intake, administered following a double-blind, crossover, randomized design with a wash-out period of 4 weeks. Cardiovascular function (Portapres® Model 2, Finapres Medical Systems BV, Amsterdam, The Netherlands) was recorded during an incremental cycling protocol (4 min stages with 2 min recovery, start power 50 W with 30 W increments). Stages representing low (i.e. 40% VO2max), moderate (i.e. 60%) and high (i.e. 80%) intensity were analysed for responses averaged for the last minute. Paired two-tailed t-tests were used for analysis with significance accepted at p<.05. Results At each intensity, there were no differences in systolic BP (40% - P: 183±29, S: 195±31, p=.13; 60% - P: 196±35, S: 195±31, p=.40; 80% - P: 215±33, S: 220±33 mmHg, p=.50), diastolic BP (40% - P: 82±14, S: 88±17, p=.09; 60% - P: 87±14, S: 88±17, p=.39; 80% - P: 97±14, S: 101±19 mmHg, p=.36), heart rate (40% - P: 100±9, S: 101±10, p=.62; 60% - P: 126±12, S: 125±11, p=.85; 80% - P: 152±13, S: 154±11 beats∙min-1, p=.56), stroke volume (40% - P: 100±17, S: 96±24, p=.47; 60% - P: 94±20, S: 88±26, p=.53; 80% - P: 88±18, S: 88±28 mL, p=.98), cardiac output (40% - P: 10.0±1.8, S: 9.8±2.4, p=.78; 60% - P: 11.8±2.8, S: 11.6±3.1, p=.90; 80% - P: 13.3±2.6, S: 13.4±4.1 L∙min-1, p=.93), and total peripheral resistance (40% - P: 11.6±4.3, S: 13.2±5.6, p=.28; 60% - P: 10.7±4.3, S: 11.7±6.3, p=.60; 80% - P: 10.2±3.3, S: 11.3±5.5 mmHg∙L-1∙min-1, p=.34). Conclusion Previous studies indicated that anthocyanin intake may have performance-enhancing effects resulting from high-intensity training (Braakhuis et al., 2014) and increases peripheral blood flow at very low intensity (Matsumoto et al., 2005). The cardiovascular responses at low, moderate and high intensity cycling in trained triathletes athletes were unaffected by one week intake of New Zealand Sujon blackcurrant powder. It is concluded that New Zealand Sujon blackcurrant does not have adverse cardiovascular effects during exercise in trained triathletes. Acknowledgement Funding for this study and conference attendance was provided by the University of Chichester, Health Currancy Ltd (UK) and Gibb Holdings (Nelson) Ltd (NZ).