Alzheimer disease (AD) is the most common form of dementia in humans. However, to date, the cause of sporadic AD (SAD), which is the most frequent form, is still unknown. Although it has not been possible to determine the origin of this disease, the amyloid hypothesis is one of the most accepted to explain the etiology of AD. This hypothesis proposes that the pathogenesis of AD is derived from the toxic effect produced by the amyloid-β (Aβ) peptide in the brain parenchyma, but it does not make clear how Aβ is capable of producing such damage. Furthermore, it has been observed that SAD is accompanied by disruptions in the vascular system, such as damage to the blood-brain barrier. This facilitates the transfer of some systemic proteins, such as fibrinogen, to the brain parenchyma, where Aβ is abundant. Therefore, this Aβ interacts with fibrinogen, which favors the formation of clots resistant to fibrinolysis, inducing a risk of thrombosis and neuroinflammation. Notably, Aβ is not only of neuronal origin; platelets also contribute to high Aβ production in the circulation. The Aβ present in circulation favors the activation of coagulation factor XII, which leads to the generation of thrombin and bradykinin. In addition to Aβ-induced platelet activation, all these events favor the development of inflammatory processes that cause damage to the brain vasculature. This damage represents the beginning of the toxic effects of Aβ, which supports the amyloid hypothesis. This review addresses the relationship between alterations in the vascular and hemostatic systems caused by Aβ and how both alterations contribute to the progression of SAD.

The authors assessed the cross-sectional association of physical function measures with cognition in the Kaiser Healthy Aging and Diverse Life Experiences Cohort.

Analyses included 1369 participants (24% Asian, 26% Black, 18% Latino, 32% White). Grip strength was measured using a hand-held dynamometer (kilograms) and gait speed was measured over a 4-m walk (seconds/meter). The Spanish and English Neuropsychological Assessment Scales was used to evaluate cognitive domains of executive function, semantic memory, and verbal episodic memory. Physical function measures (per SD) were associated with cognitive test z-scores in linear regression models adjusted for demographic, behavioral, and clinical factors. Racial/ethnic differences were tested using interaction terms and stratification.

Stronger grip was associated with better executive function [β=0.10 (95% confidence interval, 0.05-0.15)], semantic memory [β=0.13 (0.09-0.18)] and verbal episodic memory [β=0.07 (0.02-0.13)] with no racial/ethnic differences. Faster gait was associated with better executive function [β=0.29 (0.22-0.36)], semantic memory [β=0.23 (0.16-0.30)], and verbal episodic memory [β=0.20 (0.13-0.27)]; however, the association between gait speed and executive function varied by race/ethnicity with the strongest associations in Asians and Whites.

Across race/ethnicity, grip strength and gait speed were associated with cognition with racial/ethnic differences in the association of gait speed and executive function.

Across race/ethnicity, grip strength and gait speed were associated with cognition with racial/ethnic differences in the association of gait speed and executive function.

Nuzzo, JL. History of strength training research in man an inventory and quantitative overview of studies published in English between 1894 and 1979. J Strength Cond Res 35(5) 1425-1448, 2021-Limited scholarship exists on the history of strength training research. The current review advances existing qualitative and biographical work by inventorying all experimental studies and case reports published before 1980 on the effects of ≥1 week of strength training on human health and function. Data on authors, journals, citations, study samples, training interventions, study outcomes, and study themes were extracted and summarized. Three hundred thirty-nine strength training studies were published between 1894 and 1979. Studies included 14,575 subjects, with 10,350 undergoing strength training. Subjects were usually healthy (81.1% of articles), university students (51.0%), or aged 18-65 years (86.7%). Men comprised 70.0% of subjects. Interventions typically involved isoinertial only (64.6%) or isometric only (35.ed in the context of the results.

Montalvo, S, Gonzalez, MP, Dietze-Hermosa, M, Eggleston, JD, and Dorgo, S. Common vertical jump and reactive strength index measuring devices A validity and reliability analysis. J Strength Cond Res 35(5) 1234-1243, 2021-Several field-test devices exist to assess vertical jump, but they either lack proper validation or have been validated for the countermovement jump (CMJ) only. This study aimed to quantify the validity and reliability of metrics, including jump height and the calculated reactive strength index (RSI), obtained using the flight-time method from 4 different assessment devices with 3 different vertical jump modalities in comparison to a force platform (criterion assessment). The Optojump, Push-Band 2.0, MyJump2 mobile application, and What’sMyVert mobile application were used synchronously and together with the force platforms. Thirty subjects (17 males and 13 females; age ± SD 23.37 ± 1.87 years) performed 5 repetitions of CMJ, squat jump (SQJ), and drop jump (DJ) with a standardized 90° kneeve and reliable measurement of various vertical jumps.

0.9 and CV less then 10%. Validity was obtained through an ordinary least products regression, ICC, and CV. Significance was set at p less then 0.05. Reliability was excellent on jump height for the CMJ (ICC ≥ 0.98; CV ≤ 8.14%) for all instruments. With the exception of the Optojump, all instruments also had excellent reliability for the SQJ (ICC ≥ 0.98; CV ≤ 6.62) and DJ (ICC ≥ 0.94; CV ≤ 8.19). For the RSI metric, all instruments had excellent relative reliability (ICC ≥ 0.92), but none had excellent absolute reliability (CV ≥ 12.5%). The MyJump2 and What’sMyVert apps showed excellent validity on all jump modalities and RSI. The Optojump and Push-Band 2.0 devices both showed system and proportional bias for several jump modalities and RSI. Overall, both mobile applications may provide coaches with a cost-effective and reliable measurement of various vertical jumps.

Odgers, JB, Zourdos, MC, Helms, ER, Candow, DG, Dahlstrom, B, Bruno, P, and Sousa, CA. Rating of perceived exertion and velocity relationships among trained males and females in the front squat and hexagonal bar deadlift. J Strength Cond Res 35(2S) S23-S30, 2021-This study examined the accuracy of intraset rating of perceived exertion (RPE) to predict repetitions in reserve (RIR) during sets to failure at 80% of 1 repetition maximum (1RM) on the front squat and high-handle hexagonal bar deadlift (HHBD). Furthermore, the relationship between RPE and average concentric velocity (ACV) during the sets to failure was also determined. Fourteen males (29 ± 6 years, front squat relative 1RM 1.78 ± 0.2 kg·kg-1, and HHBD relative 1RM 3.0 ± 0.1 kg·kg-1) and 13 females (30 ± 5 years, front squat relative 1RM 1.60 ± 0.2 kg·kg-1, and HHBD relative 1RM 2.5 ± 0.3 kg·kg-1) visited the laboratory 3 times. The first visit tested 1RM on both exercises. During visits 2 and 3, which were performed in a counterbalanced order, subes. During each set, subjects verbally indicated when they believed they were at „6” and „9” on the RIR-based RPE scale, and ACV was assessed during every repetition. The difference between the actual and predicted repetitions performed was recorded as the RPE difference (RPEDIFF). The RPEDIFF was significantly (p less then 0.001) lower at the called 9 RPE versus the called 6 RPE in the front squat for males (9 RPE 0.09 ± 0.19 versus 6 RPE 0.71 ± 0.70) and females (9 RPE 0.19 ± 0.36 versus 6 RPE 0.86 ± 0.88) and in the HHBD for males (9 RPE 0.25 ± 0.46 versus 6 RPE 1.00 ± 1.12) and females (9 RPE 0.21 ± 0.44 versus 6 RPE 1.19 ± 1.16). Significant inverse relationships existed between RPE and ACV during both exercises (r = -0.98 to -1.00). These results indicate that well-trained males and females can gauge intraset RPE accurately during moderate repetition sets on the front squat and HHBD.

O’Brien, IT, Kozerski, AE, Gray, WD, Chen, L, Vargas, LJ, McEnroe, CB, Vanhoover, AC, King, KM, Pantalos, GM, and Caruso, JF. Use of gloves to examine intermittent palm cooling’s impact on rowing ergometry. J Strength Cond Res 35(4) 931-940, 2021-The aim of this study was to examine the use of gloves on intermittent palm cooling’s impact on rowing ergometry workouts. Our methods had subjects (n = 34) complete 3 rowing ergometer workouts of up to 8 2-minute stages separated by 45- or 60-second rests. They were randomized to one of the following treatments per workout no palm cooling (NoPC), intermittent palm cooling as they rowed (PCex), or intermittent palm cooling as they rowed and post-exercise (PCex&post). Palm cooling entailed intermittent cold (initial temperature 8.1° C) application and totaled 10 (PCex) and 20 (PCex&post) minutes, respectively. Workouts began with 8 minutes of rest after which pre-exercise data were obtained, followed by a ten-minute warm-up and the workout, and 20 minutes oflactate concentrations from intermittent cooling caused subjects to experience less fatigue during those workouts and enabled more work to be performed. Continued research should identify optimal cooling characteristics to expedite body heat removal. Practical applications suggest that intermittent palm cooling administered with gloves enhance performance by abating physiological markers of fatigue.

Maintaining physical performance the minimal dose of exercise needed to preserve endurance and strength over time, Spiering, BA, Mujika, I, Sharp, MA, and Foulis, SA. J Strength Cond Res 35(5) 1449-1458, 2021-Nearly every physically active person encounters periods in which the time available for exercise is limited (e.g., personal, family, or business conflicts). During such periods, the goal of physical training may be to simply maintain (rather than improve) physical performance. Similarly, certain special populations may desire to maintain performance for prolonged periods, namely athletes (during the competitive season and off-season) and military personnel (during deployment). The primary purpose of this brief, narrative review is to identify the minimal dose of exercise (i.e., frequency, volume, and intensity) needed to maintain physical performance over time. In general populations, endurance performance can be maintained for up to 15 weeks when training frequency is reduced to as little as 2 sessio and muscle size (at least in younger populations) can be maintained for up to 32 weeks with as little as 1 session of strength training per week and 1 set per exercise, as long as exercise intensity (relative load) is maintained; whereas, in older populations, maintaining muscle size may require up to 2 sessions per week and 2-3 sets per exercise, while maintaining exercise intensity. Insufficient data exists to make specific recommendations for athletes or military personnel. Our primary conclusion is that exercise intensity seems to be the key variable for maintaining physical performance over time, despite relatively large reductions in exercise frequency and volume.