The benefits of aerobic exercise (AE) training on blood pressure (BP) and arterial stiffness are well established, but the effects of resistance training are less well delineated. The purpose of this study was to determine the impact of resistance vs aerobic training on haemodynamics and arterial stiffness. Thirty pre-or stage-1 essential hypertensives (20 men and 10 women), not on any medications, were recruited (age: 48.2 ± 1.3 years) and randomly assigned to 4 weeks of either resistance (RE) or AE training. Before and after training, BP, arterial stiffness (pulse wave velocity (PWV)) and vasodilatory capacity (VC) were measured. Resting systolic BP (SBP) decreased following both training modes (SBP: RE, pre 136±2.9 vs post 132±3.4; AE, pre 141±3.8 vs post 136 ± 3.4 mm Hg, P ¼ 0.005; diastolic BP: RE, pre 78 ± 1.3 vs post 74 ± 1.6; AE, pre 80 ± 1.6 vs post 77 ± 1.7 mm Hg, P ¼ 0.001). Central PWV increased (P ¼ 0.0001) following RE (11 ± 0.9-12.7 ± 0.9 m s À1 ) but decreased after AE (12.1 ± 0.8-11.1 ± 0.8 m s À1 ). Peripheral PWV also increased (P ¼ 0.013) following RE (RE, pre 11.5±0.8 vs post 12.5 ± 0.7 m s À1 ) and decreased after AE (AE, pre 12.6 ± 0.8 vs post 11.6 ± 0.7 m s À1 ). The VC area under the curve (VC AUC ) increased more with RE than that with AE (RE, pre 76±8.0 vs post 131.1±11.6; AE, pre 82.7±8.0 vs post 110.1 ± 11.6 ml per min per s per 100 ml, P ¼ 0.001). Further, peak VC (VC peak ) increased more following resistance training compared to aerobic training (RE, pre 17±1.9 vs post 25.8±2.1; AE, pre 19.2±8.4 vs post 22.9 ± 8.4 ml per min per s per 100 ml, P ¼ 0.005). Although both RE and AE training decreased BP, the change in pressure may be due to different mechanisms.

We examined arterial stiffness, baroreflex sensitivity (BRS), and systolic arterial pressure (SAP) variability after an acute bout of aerobic exercise compared to resistance exercise. We hypothesized that arterial stiffness would be reduced after aerobic exercise, while it would be increased after resistance exercise, and these alterations would be associated with differential changes in BRS and SAP variability. Arterial stiffness, BRS, and SAP variability were assessed before and 20 min after a bout of aerobic exercise and resistance exercise in 13 male participants. Pulse wave velocity (PWV) was used to measure central (carotid-femoral) and peripheral (femoral-dorsalis pedis) arterial stiffness. BRS was derived via the sequence technique. Spectral decomposition of beat-to-beat SAP variability was used as an estimate of sympathetic vasomotor tone. A mode-by-time interaction (p < 0.001) was detected for central PWV, due to an increase in PWV (p < 0.05) following resistance exercise and a decrease in PWV following aerobic exercise (p < 0.05). A mode-by-time interaction was also detected for peripheral PWV (p < 0.05), due to a decrease in peripheral PWV following aerobic exercise (p < 0.05) with no change following resistance exercise. BRS was significantly lower following resistance compared with aerobic exercise (p < 0.004). SAP variability increased following resistance exercise (p < 0.05) but there was no interaction. In conclusion, aerobic exercise decreased both central and peripheral arterial stiffness, while resistance exercise significantly increased central arterial stiffness only. BRS was reduced after both bouts of exercise, but significantly greater reductions were seen following resistance exercise.

A sedentary lifestyle and lack of physical activity are well-established risk factors for chronic disease and adverse health outcomes. Thus, there is enormous interest in measuring physical activity in biomedical research. Many consumer physical activity monitors, including Basis Health Tracker, BodyMedia Fit, DirectLife, Fitbit Flex, Fitbit One, Fitbit Zip, Garmin Vivofit, Jawbone UP, MisFit Shine, Nike FuelBand, Polar Loop, Withings Pulse O, and others have accuracies similar to that of research-grade physical activity monitors for measuring steps. This review focuses on the unprecedented opportunities that consumer physical activity monitors offer for human physiology and pathophysiology research because of their ability to measure activity continuously under real-life conditions and because they are already widely used by consumers. We examine current and potential uses of consumer physical activity monitors as a measuring or monitoring device, or as an intervention in strategies to change behavior and predict health outcomes. The accuracy, reliability, reproducibility, and validity of consumer physical activity monitors are reviewed, as are limitations and challenges associated with using these devices in research. Other topics covered include how smartphone apps and platforms, such as the Apple ResearchKit, can be used in conjunction with consumer physical activity monitors for research. Lastly, the future of consumer physical activity monitors and related technology is considered: pattern recognition, integration of sleep monitors, and other biosensors in combination with new forms of information processing.

The purposes of this study were to determine if the fatigability of the quadriceps femoris varies by biological sex under conditions of normal muscle blood flow and ischemia, and if differences in neuromuscular activation patterns exist. Young men and women (n = 11/group; age 20-39 years) performed a sustained knee extension contraction at 25% of maximal force under conditions of occluded (OCC) and normal muscle blood flow (NON-OCC). Electromyographic (EMG) activity was recorded from the vastus lateralis (VL), rectus femoris (RF), vastus medialis (VM) and biceps femoris (BF) muscles, and analyzed for fatigue-induced changes in the amplitude and burst rate and duration (transient changes in motor unit recruitment) of the signal. Additionally, force fluctuations during the sustained contraction were quantified. Women had a longer time to task failure during the NON-OCC task [214.9 +/- 20.5 vs. 169.1 +/- 20.5 (SE) s] (P = 0.02), but not during the OCC task (179.6 + 19.6 vs. 165.2 +/- 19.6 s). EMG data demonstrated sex differences in the neuromuscular activation pattern of the RF muscle and the collectively averaged QF muscles. During the NON-OCC and OCC tasks women achieved a higher relative activation of the RF at task failure than men (NON-OCC: 40.68 +/- 4.57 vs. 24.49 +/- 4.19%; OCC: 36.80 +/- 5.45 vs. 24.41 +/- 2.12%) (P = 0.02 and 0.05, respectively). Also, during both tasks, they demonstrated a greater relative activation at task failure than men when an average of the VL, VM and RF was considered. Additionally, women exhibited a greater coefficient of variation in force fluctuations during the last-third of the fatiguing NON-OCC task (6.21 +/- 0.567 vs. 4.56 +/- 0.56%) (P = 0.001). No sex differences in EMG burst rate or duration were observed, although there was a trend towards greater EMG burst rate of the RF in association with muscle fatigue in the women (P = 0.09). Interestingly, the only neuromuscular activation variable that displayed a significant relationship with the time to task failure was the average relative EMG of the QF at task failure, and this relationship was observed under both experimental blood flow conditions (NON-OCC: r = 0.47, P = 0.03; OCC: r = 0.44, P = 0.04). These results indicate that sex differences in muscle blood flow and/or muscle metabolism are in part responsible for the female advantage in fatigue-resistance. Additionally, these findings suggest that men synergistically recruit the RF compartment to a lesser extent than women in association with muscle fatigue, and that women achieve an overall greater relative activation of the QF at task failure than men. However, the implications of these sex differences in neuromuscular activation patterns during fatiguing muscular contractions on the ability to withstand muscle fatigue (prolonged time to task failure) does not appear to be causally related.