As part of A Multidisciplinary Amazon Shelf Sediment Study (AMASSEDS), moored and shipboard current measurements made over the Amazon shelf during 1990-1991 have been analyzed to determine the dominant semidiurnal tidal constituent, the Me. These results have been combined with coastal sea level data from within the Amazon and Para Rivers, the adjacent shelf, and with satellite-derived tidal elevation data from off the shelf to provide a more complete description of the Me tide in this complex river/shelf system. Near the Amazon River mouth the Me tide propagates across the shelf and through the mouth as a damped progressive wave, with its amplitude decreasing and phase increasing upriver. Over the adjacent shelf north of Cabo Norte, the Me tide approaches a damped standing wave, with large amplitudes (greater than 1.5 m) near the coast due to near resonance within the coastal embayment formed by the Cabo Norte shoal to the south and Cabo Cassipore to the north. The observed Me tidal currents are nearly rectilinear and oriented primarily across the local isobaths. Comparisons between tidal observations in both the North Channel and the Cabo Norte-Cabo Cassipore embayment and a simple variable-width channel tidal model indicate that (1) most of the Me tidal energy dissipation occurs over the mid-and inner shelf (in water depths less than 20 m) and (2) fluid muds found there cause a significant reduction (of order 50%) in the effective bottom friction felt by the Me tide. The approximate resonant period of the Cabo Norte-Cabo Cassipore embayment is 11.9 hours, and at resonance the average energy dissipation per forcing period is roughly 2.2 times the average mechanical energy in the embayment. This damping rate is large enough that the tidal amplification is rather insensitive to forcing frequency, so that the response of the embayment to forcing over the semidiurnal band should be essentially the same. The vertical structure of the Me tidal current is examined at one outer shelf site located in 65-m water depth. The observed semimajor axis increases logarithmically with height above bottom within the lowest 1-2 m and reaches a maximum in excess of 0.5 m/s at approximately 11 m above bottom. The mean ellipticity is small (less than 0.1) and positive, indicating clockwise rotation of a nearly rectilinear current, and the semimajor axis is oriented within 10 o of the local cross-isobath direction. The Me phase increases with height above bottom, with flood at the bottom leading flood at the surface by about i hour. A simple, local homogeneous tidal model with time-and space-dependent eddy viscosity simulates the observed near-bottom velocity reasonably well, however, the model suggests that stratification above the lowest few meters may significantly affect the tidal boundary layer structure at this site. The Me energy flux onto the Amazon shelf and into the Amazon and Para Rivers has been estimated using current and surface elevation data and the best fit variable-width channel model results. The net Me energy flux ...

Pina, FLC, Nunes, JP, Schoenfeld, BJ, Nascimento, MA, Gerage, AM, Januário, RSB, Carneiro, NH, Cyrino, ES, and Oliveira, AR. Effects of different weekly sets-equated resistance training frequencies on muscular strength, muscle mass and body fat in older women. J Strength Cond Res 34(10): 2990–2995, 2020—The aim of this study was to analyze the effects of different resistance training (RT) frequencies (2 vs. 3 times per week) with an equivalent number of weekly sets performed between conditions on muscular strength and body composition in older women. Forty-seven older women (65 ± 4 years) were divided into 2 groups that performed a 12-week RT program either 2 (G2x and 3 sets) or 3 (G3x and 2 sets) times per week. The groups were evaluated before and after study on measures of body composition through dual-energy x-ray absorptiometry, and muscular strength through one repetition maximum (1RM) testing. Lean soft tissue was significantly increased in both groups (G2x = +1.7%, G3x = +1.7%), while only G3x reduced body fat after the intervention period (G2x = −0.7%, G3x = −2.9%). Similarly, significant increases were noted between conditions for 1RM scores in bench press (G2x = +11.8%, G3x = +11.9%) and knee extension (G2x = +17.4%, G3x = +10.8%). The results indicate that performing 2 or 3 RT sessions per week promotes similar improvements in muscular outcomes, while training more frequently may reduce body fat after 12 weeks of weekly sets-equated RT in untrained older women.

We analyzed the effect of an 8-week strength training (ST) program on the rate of force development (RFD) and electromyographic activity (EMG) in older women. Seventeen women (M age = 63.4 years, SD = 4.9) without previous ST experience were randomly assigned to either a control (n=7) or training (n=10) group. A leg-press isometric test was used for assessment. ST (three sessions/ week, three sets of 10-12 repetition maximum, five different exercises) induced significant increases (p < .05) on peak RPD (48.4%) and on RFD) and EMG of vastus medialis at time intervals of 0-50, 0-100, 0-150, and 0-200 ms (41.1-69.2% and 43.8-64.3%, respectively). Therefore, ST resulted in favorable changes in neuromuscular responses in older women.

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ObjectiveThe main purpose of the investigation reported here was to analyze the effect of resistance training (RT) performed at different weekly frequencies on flexibility in older women.Participants and methodsFifty-three older women (≥60 years old) were randomly assigned to perform RT either two (n=28; group “G2x”), or three (n=25; group “G3x”) times per week. The RT program comprised eight exercises in which the participants performed one set of 10–15 repetitions maximum for a period of 12 weeks. Anthropometric, body-composition, and flexibility measurements were made at baseline and post-study. The flexibility measurements were obtained by a fleximeter.ResultsA significant group-by-time interaction (P<0.01) was observed for frontal hip flexion, in which G3x showed a higher increase than G2x (+12.8% and +3.0%, respectively). Both groups increased flexibility in cervical extension (G2x=+19.1%, G3x=+20.0%), right hip flexion (G2x=+14.6%, G3x=+15.9%), and left hip flexion (G2x=+25.7%, G3x=+19.2%), with no statistical difference between groups. No statistically significant differences were noted for the increase in skeletal muscle mass between training three versus two times a week (+7.4% vs +4.4%, respectively).ConclusionTwelve weeks of RT improves the flexibility of different joint movements in older women, and the higher frequency induces greater increases for frontal hip flexion.