Mandy Lucinda Gault

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 over ground, 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.

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.

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 muscle's 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.

An ageing related decline in muscle strength and steadiness decreases quality of life and increases the risk for falls. Downhill treadmill walking (DTW) may enhance muscle strength and steadiness in older adults. Eighteen healthy older adults (age: 67 ± 4, body mass: 75 ± 14 kg) completed 12-weeks of level treadmill walking (LTW, 0 %, n = 8) or DTW (−10 %, n = 10) (30 min, 3 days per week) at a self-selected walking speed (re-adjusted in week 4 and 8). Maximal voluntary isometric force (MVIF) and electromyography (EMG) of the m. quadriceps femoris (QF) were measured at baseline, 4, 8 and 12 weeks. Steadiness of submaximal (5, 10 and 20 % MVIF) isometric contractions (i.e. coefficient of variation of the force signal) and EMG of QF were measured at baseline and 12 weeks. Baseline MVIF of LTW (340 ± 112 N) and DTW (368 ± 128 N) increased equally by 14 ± 6 and 5 ± 6 % (p < 0.05). Steadiness at 5 %MVIF improved following 12 weeks of LTW (baseline: 0.04 ± 0.01; 12 weeks: 0.03 ± 0.01) and DTW (baseline: 0.04 ± 0.02; 12 weeks: 0.03 ± 0.01 (p < 0.05). EMG root mean square of m. vastus lateralis during MVIF increased by 38 % following 12 weeks of LTW only (p < 0.05). The potential implications for an exercise modality, such as DTW, with a lower oxygen demand, to improve muscle strength could serve as a rehabilitative countermeasure for older adults.