This study aimed to examine the sensitivity of the isometric knee extension (IKE) test to detect changes in the lower-limb strength of institutionalized older adults after exercise and inactivity periods. Thirty-four and fifteen institutionalized older adults completed the training and inactive periods, respectively. At each time point, the participants completed two testing sessions. In the first session, they performed the IKE test. As a complement to this evaluation, the second testing session was used to assess their functional capacity and handgrip strength. The sensitivity of the IKE test was examined by comparing the changes generated in this test against the repeatability of the protocol. A 4-week multicomponent Vivifrail program was implemented. After that, a subsample of the participants was re-evaluated after a 14-week inactivity period. Significant changes (p < 0.01; ES ≥ 0.27) in the IKE strength for both the dominant (+0.27 N/kg) and non-dominant legs (+0.25 N/kg) were produced after the training intervention. Likewise, significant decrements (p < 0.01; ES ≥ 0.31) were detected after the inactive period for the dominant (−0.29 N/kg) and non-dominant legs (−0.32 N/kg). All mean changes were found to be superior to the variability threshold of the IKE test for both legs, with superior sensitivity for the non-dominant leg (≥73%). Thus, the IKE test is a sensitive and practical tool for detecting changes in the lower-limb strength of institutionalized older adults after exercise and inactivity periods. Because of its applicability, it seems pertinent to implement the IKE test in a geriatric context. Full article

Workload is calculated from exercise volume and intensity. In endurance sports, intensity has been measured using heart rate or RPE, giving rise to load indexes such as sRPE or TRIMP. In cycling, the advent of power meters led to new indexes, such as TSS. All these indexes have limitations, especially for high intensity exercise. Therefore, a new index for cycling is proposed, the Power Profile Index (PPi), which includes a weighting factor obtained from the relative exercise intensity and stage type. Using power data from 67 WorldTour cyclists and fatigue records in different stage types from 102 road cyclists, weighting factors for intensity and stage type were determined. Subsequently, the PPi was computed and compared to current indexes using data from a WorldTour team during the 2018 Tour de France. The proposed index showed a strong correlation with perceived fatigue as a function of stage type (R² = 0.9996), as well as no differences in the load quantification in different types of stage profiles (p = 0.292), something that does not occur with other indexes such as TSS, RPE, or eTRIMP (p < 0.001). Therefore, PPi is a new index capable of quantifying the high intensity efforts that produce greater fatigue, as well as considering the stage type. Full article

Frailty poses a considerable risk to the performance of daily living activities, affecting the quality of life of older adults and increasing their risks of falling, disability, hospitalization, and mortality. Frailty is related to pathology with a state of negative energy balance, sarcopenia, diminished muscle strength, and low tolerance for exertion. Few intervention studies have been conducted on prefrail community-dwelling older adults. This study investigated the effects of whole-body vibration training on the biomarkers and health beliefs of prefrail community-dwelling older adults. We conducted a quasi-experimental research. Ninety participants were allocated to either an experimental or control group. This study followed the Transparent Reporting of Evaluations with Nonrandomized Designs (TREND) guidelines for quasi-experimental research design. The experimental group participated in a 12-week whole-body vibration training conducted three times per week, with 5-min continuous vibration at 12-Hz frequency and 3-mm amplitude each time. DVDs on resistance training and manuals were provided to the control group. The data were analysed through descriptive analysis, a chi-square test, an independent t test, a paired t test, and analysis of covariance. There were 42 people in the experimental group and 48 people in the control group. After the 12-week training and intervention, ANCOVA is used to analyze the experimental and control group’s results. Experimental results in 30s chair stand test (F = 98.85, p < 0.05), open-eye stand on dominant foot test (F = 26.15, p < 0.05), two–minute-step test (F = 25.89, p < 0.05), left-leg bone mineral density (F = 14.71, p < 0.05), barriers of perceived frailty (F = 39.81, p < 0.05) and cues to action (F = 92.96, p < 0.05) in health beliefs are statistically significant compared to the control group’s results. The 12-week whole-body vibration program employed in this study partly improved the biomarkers and health beliefs of prefrail community-dwelling older adults. We recommend whole-body vibration training as an exercise strategy, thereby improving community-dwelling older adults’ biomarkers and health beliefs. Full article

This study aimed to analyze the validity and sensitivity of two time-shortened Wingate anaerobic tests (WAnTs), by means of three phases. In Phase A, 40 participants performed a traditional 30 s WAnT, whereas the first 15 s (WAnT₁₅) and 20 s (WAnT₂₀) were used to elaborate two predictive models. In Phase B, another 30 s WAnT was performed by 15 different volunteers to examine the error of these models (cross-validation). Finally, in Phase C, a 30 s WAnT was registered before and after a 10-week velocity-based training conducted by 22 different participants (training group, TRAIN = 11; control group that fully refrained from any type of training, CONTROL = 11). Power changes (in Watts, W) after this training intervention were used to interpret the sensitivity of the time-shortened WAnT. Adjusted coefficient of determination (R²) was reported for each regression model, whereas the cross-validation analysis included the smallest detectable change (SDC) and bias. Close relationships were found between the traditional 30 s WAnT and both the WAnT₁₅ (R² = 0.98) and WAnT₂₀ (R² = 0.99). Cross-validation analysis showed a lower error and bias for WAnT₂₀ (SDC = 9.3 W, bias = −0.1 W) compared to WAnT₁₅ (SDC = 22.2 W, bias = 1.8 W). Lastly, sensitivity to identify individual changes was higher for WAnT₂₀ (TRAIN = 11/11 subjects, CONTROL = 9/11 subjects) than for WAnT₁₅ (TRAIN = 4/11 subjects, CONTROL = 2/11 subjects). These findings suggest that the WAnT₂₀ could become a valid and sensitive protocol to replace the traditional 30 s WAnT. Full article

This study aimed to systematically review the effects of the different velocity loss (VL) thresholds during resistance training (RT) on strength and athletic adaptations. The VL was analyzed as both a categorical and continuous variable. For the categorical analysis, individual VL thresholds were divided into Low-Mod_VL (≤ 25% VL) or Mod-High_VL (> 25% VL). The efficacy of these VL thresholds was examined using between-group (Low-Mod_VL vs. Mod-High_VL) and within-group (pre–post effects in each group) analyses. For the continuous analysis, the relationship (R²) between each individual VL threshold and its respective effect size (ES) in each outcome was examined. Ten studies (308 resistance-trained young men) were finally included. The Low-Mod_VL group trained using a significantly (p ≤ 0.001) lower VL (16.1 ± 6.2 vs. 39.8 ± 9.0%) and volume (212.0 ± 102.3 vs. 384.0 ± 95.0 repetitions) compared with Mod-High_VL. Between-group analyses yielded higher efficacy of Low-Mod_VL over Mod-High_VL to increase performance against low (ES = 0.31, p = 0.01) and moderate/high loads (ES = 0.21, p = 0.07). Within-group analyses revealed superior effects after training using Low-Mod_VL thresholds in all strength (Low-Mod_VL, ES = 0.79–2.39 vs. Mod-High_VL, ES = 0.59–1.91) and athletic (Low-Mod_VL, ES = 0.35–0.59 vs. Mod-High_VL, ES = 0.05–0.36) parameters. Relationship analyses showed that the adaptations produced decreased as the VL threshold increased, especially for the low loads (R² = 0.73, p = 0.01), local endurance (R² = 0.93, p = 0.04), and sprint ability (R² = 0.61, p = 0.06). These findings prove that low–moderate levels of intra-set fatigue (≤25% VL) are more effective and efficient stimuli than moderate–high levels (> 25% VL) to promote strength and athletic adaptations. Full article

Introduction: This study describes the theoretical foundations of the development of an equation that allows for the estimation of the mobilized load when training with suspension devices (type TRX^®) and presents a mobile application as a means for its use. Methods: Systems of equations are proposed of which the terms depend on the angulation of the device with respect to the vertical (angle α), the relationship between the height of grip, the height of the center of mass and the weight of the subject, which are recorded from a photo. Results: Based on the photo and the subject’s standing height, the application allows the user to measure the angle α, providing the values of applied force (in N) and mobilized load in relation to the percentage of body mass, applying the calculations described in our equations. The equation also provides the estimated value of the load mobilized during a push up on the floor (68% of the subject’s body mass) and the equation for the calculation of the mobilized load when the suspension device is fixed to the feet. Conclusions: It is possible to use equations to estimate the load mobilized in each repetition during training using suspension devices and to implement this algorithm in a mobile application. Full article