Identification of the force-velocity curve on dynamic resistance exercise for rats.

The aim of this study was to identify force-velocity and power-velocity curves in climbing activity protocols, used as dynamic resistance exercise in rats. Eighteen 45-day-old male Wistar rats (weight = 211.9 ± 5.2 g) were evaluated. After familiarization to the climbing procedure, the animals performed an incremental climbing test (load relative to 75% of the body mass at first stage, followed by 30 g increments with and 120 s recovery between climbs) to determine the maximum carrying capacity (MCC). After this, the animals climbed with different loads (without load, 10%, 20%, 30%, 40%, 50%, 75%, 90%, and 100% of MCC) with 120 s recovery between climbs. Time for each climb was recorded to calculate the mechanical power. The peak power was reached at 30% of MCC. For the force-velocity curve, an inversely proportional relation was observed between force and velocity, as expected, greater forces were expressed in lower velocities. Therefore, our results suggest that training at 30% of MCC should be encouraged aiming the target for greater power output and 90%-100% of MCC should be the load aiming for strength training in climbing activities for rats.

Effect of Body Position on Force Production During the Isometric Midthigh Pull.

Beckham, GK, Sato, K, Santana, HAP, Mizuguchi, S, Haff, GG, and Stone, MH. Effect of body position on force production during the isometric midthigh pull. J Strength Cond Res 32(1): 48-56, 2018-Various body positions have been used in the scientific literature when performing the isometric midthigh pull resulting in divergent results. We evaluated force production in the isometric midthigh pull in bent (125° knee and 125° hip angles) and upright (125° knee, 145° hip angle) positions in subjects with (>6 months) and without (<6 months) substantial experience using weightlifting derivatives. A mixed-design ANOVA was used to evaluate the effect of pull position and weightlifting experience on peak force, force at 50, 90, 200, and 250 ms. There were statistically significant main effects for weightlifting experience and pull position for all variables tested, and statistically significant interaction effects for peak force, allometrically scaled peak force, force at 200 ms, and force at 250 ms. Calculated effect sizes were small to large for all variables in subjects with weightlifting experience, and were small to moderate between positions for all variables in subjects without weightlifting experience. A central finding of the study is that the upright body position (125° knee and 145° hip) should be used given that forces generated are highest in that position. Actual joint angles during maximum effort pulling should be measured to ensure body position is close to the position intended.

Exercise intensity modulates nitric oxide and blood pressure responses in hypertensive older women.

BACKGROUND AND AIMS: Whether intensity or other characteristics of physical activity can better promote the release of nitric oxide (NO) and reduction of blood pressure in hypertensive older-adults is still unknown. In this study, the post-exercise blood pressure (BP) response and NO release after different intensities of aerobic exercise in elderly women were analyzed. METHODS: Blood pressure response and NO were analyzed in 23 elderly mildly hypertensive women. Participants underwent (1) high-intensity incremental exercise (IT); (2) moderate-intensity 20 min exercise at 90% of the anaerobic threshold (AT), and (3) control (CONT) session. BP was measured before and after interventions; volunteers remained seated for 1 h. NO estimates were made through NO2- analyses. RESULTS: After CONT session, both diastolic BP and mean arterial pressure (MAP) were significantly higher than during pre-exercise resting. Post-exercise hypotension (PEH) was observed after exercise at IT and 90% of AT. Although exercise in both sessions lowered SBP and MAP compared with CONT, exercise at the highest intensity (IT) was more effective on lowering systolic BP after exercise. In comparison with pre-exercise resting, NO2- increased significantly only after IT, but both exercise sessions caused NO2- to increase compared with CONT. CONCLUSION: Exercise intensity and NO release may exert a role in eliciting PEH in mildly hypertensive elderly women.

The higher exercise intensity and the presence of allele I of ACE gene elicit a higher post-exercise blood pressure reduction and nitric oxide release in elderly women: an experimental study.

BACKGROUND: The absence of the I allele of the angiotensin converting enzyme (ACE) gene has been associated with higher levels of circulating ACE, lower nitric oxide (NO) release and hypertension. The purposes of this study were to analyze the post-exercise salivary nitrite (NO2-) and blood pressure (BP) responses to different exercise intensities in elderly women divided according to their ACE genotype. METHODS: Participants (n = 30; II/ID = 20 and DD = 10) underwent three experimental sessions: incremental test - IT (15 watts workload increase/3 min) until exhaustion; 20 min exercise 90% anaerobic threshold (90% AT); and 20 min control session without exercise. Volunteers had their BP and NO2- measured before and after experimental sessions. RESULTS: Despite both intensities showed protective effect on preventing the increase of BP during post-exercise recovery compared to control, post-exercise hypotension and increased NO2- release was observed only for carriers of the I allele (p < 0.05). CONCLUSION: Genotypes of the ACE gene may exert a role in post-exercise NO release and BP response.

An analysis of Bundesliga matches before and after social distancing by COVID-19.

Methods: Variables from 305 matches from 2019/2020 Bundesliga season were analyzed. Normality, mean comparisons, analysis of variance and effect sizes were performed. Results: After SD, lower values were observed for goals attempt and distance covered, while higher values were found for passes accuracy and fouls committed (p < 0.05). Home teams before SD presented higher number of goals scored at 2nd half and less fouls committed than visiting opponents, after SD away teams had higher number of goals scored at the same half (p = 0.043) and a similar number of fouls (p = 0.035). Home teams performed more sprints than visiting opponents before SD, but after SD no difference was observed between home and away teams (p = 0.042). Total distance covered for both home and away teams were lower after SD (p = 0.041). Home teams presented higher values of goal attempts to the target, but changing from small to trivial effects sizes (ES) after SD. However, home advantage was 50.32 ± 19.06% before SD, after SD comeback the home advantage was 40.37 ± 26.08% (ES = 0.45). Conclusions: The return to football pitch without stadium supporters, affected some game and physical variables, as well as home advantage.