The aims of this study were: to compare energy expenditure (EE) estimated from the existing GT3X accelerometer equations and EE measured with indirect calorimetry; to define new equations for EE estimation with the GT3X in youth, adults and older people; and to define GT3X vector magnitude (VM) cut points allowing to classify PA intensity in the aforementioned age-groups. The study comprised 31 youth, 31 adults and 35 older people. Participants wore the GT3X (setup: 1-s epoch) over their right hip during 6 conditions of 10-min duration each: resting, treadmill walking/running at 3,?5,?7, and 9?km???h?1, and repeated sit-stands (30?times???min?1). The GT3X proved to be a good tool to predict EE in youth and adults (able to discriminate between the aforementioned conditions), but not in the elderly. We defined the following equations: for all age-groups combined, EE (METs)=2.7406+0.00056???VM activity counts (counts???min?1)?0.008542???age (years)?0.01380??? body mass (kg); for youth, METs=1.546618+0.000658???VM activity counts (counts???min?1); for adults, METs=2.8323+0.00054???VM activity counts (counts???min?1)?0.059123???body mass (kg)+1.4410???gender (women=1, men=2); and for the elderly, METs=2.5878+0.00047???VM activity counts (counts???min?1)?0.6453???gender (women=1, men=2). Activity counts derived from the VM yielded a more accurate EE estimation than those derived from the Y-axis. The GT3X represents a step forward in triaxial technology estimating EE. However, age-specific equations must be used to ensure the correct use of this device.

Whole-body vibration (WBV) training in elderly may improve muscle strength, muscle power and postural control. However, knowledge about the effect of WBV training in elderly on measures of health as a multidimensional construct (health-related quality of life, HRQoL) is scarce. The present study aimed to determine the effects of WBV training on HRQoL in elderly women. A total of 37 women (aged 82.4 ± 5.7 years) were recruited and were assigned to either the WBV group or to the control (CON) group. After 8 months of training, the WBV group showed non-significant changes on HRQoL and additional health-related outcomes (fall risk, life satisfaction or cognitive status). Our findings are in disagreement with previous studies of shorter duration (6 weeks), which reported positive significant changes in HRQoL in elderly people. Discrepancies among studies may be partly attributed to methodological differences, but the existence of publication bias in previous studies cannot be discarded.

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Background: The SenseWear Armband (SWA) is a monitor that can be used to estimate energy expenditure (EE); however, it has not been validated in healthy adults. The objective of this paper was to study the validity of the SWA for quantifying EE levels. Results: There were significant differences between the SWA and IC, except in the group that ran at 9 km·h -1 (>9 METs). Bland-Altman analysis showed a BIAS of 1.56 METs (±1.83 METs) and limits of agreement (LOA) at 95% of −2.03 to 5.16 METs. There were indications of heteroscedasticity (R 2 =0.03; P<0.05). Analysis of the receiver operating characteristic (ROC) curves showed that the SWA seems to be not sensitive enough to estimate the level of EE at highest intensities. Conclusions:The SWA is not as precise in estimating EE as IC, but it could be a useful tool to determine levels of EE at low intensities.

The aim of this study was to investigate surface electromyographic activity (sEMG) and rate of perceived exertion (RPE) during semi-squat exercise on vibration platform compared with semi-squat exercise performed on a Smith machine. Twenty-three recreationally active students (15 males and 8 females) were exposed to six different loads in one of both exercise modes: vibration or Smith machine. The subject performed a squat in six experimental conditions; the load differed per experimental condition. For each subject the exercise mode (n=2) and the different loads per mode (n=6) were assigned in a random order to check the influence of vibration magnitude (acceleration: ms(-2)) as well as weight (kg) on sEMG and RPE. Two-way ANOVA for RPE, lumbar and lower-body sEMG revealed a significant weight main effect (P<0.01) and a significant acceleration main effect (P<0.01). The results from this study demonstrate that the training stimulus resulting from an isometric semi-squat exercise on a vibration platform (acceleration: from 12 to 89 ms(-2)) is similar to the training stimulus of an isometric semi-squat exercise on Smith machine (weight: from 20 to 70 kg) according to lower-body sEMG and RPE. However, the impact of semi-squat on vibration platform exercise for lumbar muscle is relatively small compared with semi-squat on Smith machine.

Few intervention studies have used whole-body vibration (WBV) training in the elderly, and there is inconclusive evidence about its health benefits. We examined the effect of 8 months of WBV training on muscle mass and functional capacity in elderly women. A total of 37 women (aged 82.4 ± 5.7 years) voluntarily participated in this study. Subjects were randomly assigned to a vibration group (n = 19) or a control group (n = 18). The vibration group trained on a vertical vibration platform twice a week. The control group was requested not to change their habitual lifestyle. The quadriceps femoris muscle cross-sectional area was determined by magnetic resonance imaging. All participants were evaluated by a battery of tests (Senior Fitness Test) to determine their functional capacity, as well as handgrip strength and balance/gait. General linear repeated-measure analysis of variance (group by time) was performed to examine the effect of the intervention on the outcomes variables. After 8 months, nonstatistically significant differences in the quadriceps CSA (pre-training: 8,516.16 ± 1,271.78 mm² and post-training: 8,671.63 ± 1,389.03 mm²) (p > 0.05) were found in the WBV group (Cohen's d: -0.12), whereas the CON group significantly decreased muscle mass (pre-training: 9,756.18 ± 1,420.07 mm² and post-training: 9,326.82 ± 1,577.53 mm²), with moderate effect size evident (Cohen's d: 0.29). In both groups, no changes were observed in the functional capacity, handgrip strength and balance/gait. The WBV training could prevent the loss of quadriceps CSA in elderly women.

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