Chronic effects of different intensities of power training on neuromuscular parameters in older people: a systematic review with meta-analysis

Background Power training (PT) has been shown to be an efective method for improving muscle function, includ‑ ing maximal strength, measured by one-repetition maximum (1RM), and power output in older adults. However, it is not clear how PT intensity, expressed as a percentage of 1RM, afects the magnitude of these changes. The aim of this systematic review (International prospective register of systematic reviews—PROSPERO—registration: CRD42022369874) was to summarize the evidence from randomized clinical trials (RCT) assessing the efects of lowintensity (≤49% of 1RM) and moderate-intensity (50–69% of 1RM) versus high-intensity (≥70% of 1RM) PT on maximal power output and maximal strength in older adults. Methods We included RCTs that examined the efects of diferent intensities of power training on maximum strength and power output in older people. The search was performed using PubMed, LILACS, Embase, and Scopus. Methodological quality was assessed using the preferred reporting items for systematic reviews and meta-analyses (PRISMA 2020 statement checklist), and the quality of evidence was determined using the PEDro scale. Data were analyzed using standardized mean diferences (SMD) with a 95% confdence interval (CI), and random efects models were used for calculations. A signifcance level of p≤0.05 was accepted. Results Three RCTs assessing 179 participants, all of high methodological quality, were included. There were no sig‑ nifcant diferences between diferent PT intensities in terms of power output gains for leg press [SMD=0.130 (95% CI −0.19, 0.45), p=0.425] and knee extension exercises [SMD: 0.016 (95% CI −0.362, 0.395), p=0.932], as well as leg press 1RM increases [SMD: 0.296 (95% CI −0.03, 0.62); p=0.072]. However, high-intensity PT (70–80% of 1RM) was sig‑ nifcantly more efective than low-intensity PT in increasing 1RM for knee extension exercise [SMD: 0.523 (95% CI 0.14, 1.91), p=0.008]. Conclusions PT performed at low-to-moderate intensities induces similar power gains compared to high-inten‑ sity PT (70–80% of 1RM) in older adults. Nonetheless, the infuence of PT intensity on lower-limb strength gains seems to be dependent on the assessed exercise. Cautious interpretation is warranted considering the inclusion of only three studies

Assessing the impact of physical exercise on cognitive function in older medical patients during acute hospitalization: secondary analysis of a randomized trial

Background: Acute illness requiring hospitalization frequently is a sentinel event leading to long-term disability in older people. Prolonged bed rest increases the risk of developing cognitive impairment and dementia in acutely hospitalized older adults. Exercise protocols applied during acute hospitalization can prevent functional decline in older patients, but exercise benefits on specific cognitive domains have not been previously investigated. We aimed to assess the effects of a multicomponent exercise intervention for cognitive function in older adults during acute hospitalization. Methods and findings: We performed a secondary analysis of a single-blind randomized clinical trial (RCT) conducted from February 1, 2015, to August 30, 2017 in an Acute Care of the Elderly (ACE) unit in a tertiary public hospital in Navarre (Spain). 370 hospitalized patients (aged ≥75 years) were randomly allocated to an exercise intervention (n = 185) or a control (n = 185) group (usual care). The intervention consisted of a multicomponent exercise training program performed during 5–7 consecutive days (2 sessions/day). The usual care group received habitual hospital care, which included physical rehabilitation when needed. The main outcomes were change in executive function from baseline to discharge, assessed with the dual-task (i.e., verbal and arithmetic) Gait Velocity Test (GVT) and the Trail Making Test Part A (TMT-A). Changes in the Mini Mental State Examination (MMSE) test and verbal fluency ability were also measured after the intervention period. The physical exercise program provided significant benefits over usual care. At discharge, the exercise group showed a mean increase of 0.1 m/s (95% confidence interval [CI], 0.07, 0.13; p < 0.001) in the verbal GVT and 0.1 m/s (95% CI, 0.08, 0.13; p < 0.001) in the arithmetic GVT over usual care group. There was an apparent improvement in the intervention group also in the TMT-A score (−31.1 seconds; 95% CI, −49.5, −12.7 versus −3.13 seconds; 95% CI, −16.3, 10.2 in the control group; p < 0.001) and the MMSE score (2.10 points; 95% CI, 1.75, 2.46 versus 0.27 points; 95% CI, −0.08, 0.63; p < 0.001). Significant benefits were also observed in the exercise group for the verbal fluency test (mean 2.16 words; 95% CI, 1.56, 2.74; p < 0.001) over the usual care group. The main limitations of the study were patients’ difficulty in completing all the tasks at both hospital admission and discharge (e.g., 25% of older patients were unable to complete the arithmetic GVT, and 47% could not complete the TMT-A), and only old patients with relatively good functional capacity at preadmission (i.e., Barthel Index score ≥60 points) were included in the study. Conclusions: An individualized, multicomponent exercise training program may be an effective therapy for improving cognitive function (i.e., executive function and verbal fluency domains) in very old patients during acute hospitalization. These findings support the need for a shift from the traditional (bedrest-based) hospitalization to one that recognizes the important role of maintaining functional capacity and cognitive function in older adults, key components of intrinsic capacity.This study was funded by a Gobierno de Navarra project Resolución grant 2186/2014 and acknowledged with the 'Beca Ortiz de Landazuri' as the best research clinical project in 2014, as well as by a research grant PI17/01814 of the Ministerio de Economía, Industria y Competitividad (ISCIII, FEDER)

Mapping the sites of latency and reactivation by bovine herpesvirus 5 (BoHV-5) and a thymidine kinase-deleted BoHV-5 in lambs

A thymidine kinase (tk)-deleted bovine herpesvirus 5 (BoHV-5tkΔ) was previously shown to establish latent infection and reactivate - even poorly - in a sheep model (Cadore et al. 2013). As TK-negative alphaherpesviruses are unlike to reactivate in neural tissue, this study investigated the sites of latency and reactivation by this recombinant in lambs. For this, groups of lambs were inoculated intranasally with the parental BoHV-5 strain (SV-507/99) or with the recombinant BoHV-5tkΔ. During latent infection (40 days post-inoculation, pi), the distribution of recombinant virus DNA in neural and non-neural tissues was similar to that of the parental virus. Parental and recombinant virus DNA was consistently detected by PCR in trigeminal ganglia (TGs); frequently in palatine and pharyngeal tonsils and, less frequently in the retropharyngeal lymph nodes. In addition, latent DNA of both viruses was detected in several areas of the brain. After dexamethasone (Dx) administration (day 40pi), the recombinant virus was barely detected in nasal secretions contrasting with marked shedding of the parental virus. In tissues of lambs euthanized at day 3 post-Dx treatment (pDx), reverse-transcription-PCR (RT-PCR) for a late viral mRNA (glycoprotein D gene) demonstrated reactivation of parental virus in neural (TGs) and lymphoid tissues (tonsils, lymph node). In contrast, recombinant virus mRNA was detected only in lymphoid tissues. These results demonstrate that BoHV-5 and the recombinant BoHV-5tkΔ do establish latent infection in neural and non-neural sites. Reactivation of the recombinant BoHV-5tkΔ, however, appeared to occur only in non-neural sites. In anyway, the ability of a tk-deleted strain to reactivate latent infection deserves attention in the context of vaccine safety

Reativação e distribuição do DNA latente do herpesvírus bovino tipo 5 no encéfalo de ovinos infectados experimentalmente

A biologia da infecção latente pelo herpesvírus bovino tipo 5 (BoHV-5) tem sido estudada em bovinos e coelhos, mas vários aspectos permanecem desconhecidos. Este artigo relata uma avaliação de ovinos jovens como modelo para o estudo da infecção latente pelo BoHV-5. Treze cordeiros com idade entre seis e sete meses, inoculados pela via intranasal (IN) com a cepa SV-507/99 do BoHV5 (título de 10(6,8) DICC50/mL) excretaram o vírus em secreções nasais em títulos de até 10(5,5) DICC50/mL, com duração de até 11 dias, desenvolvendo anticorpos neutralizantes em títulos de 16 a 128 no dia 30 pós-inoculação (pi). Os ovinos inoculados apresentaram apenas secreção nasal serosa leve e hipertermia transitória. O PCR de secções do encéfalo de cinco animais inoculados no dia 30 pi revelou a presença de DNA viral latente nos gânglios trigêmeos (TG, 5 de 5 animais), bulbo olfatório (BO, 5/5), ponte (2/5), cerebelo (2/5), córtex cerebral (1/5). Administração de dexametasona (Dx, n=4) ou flumetasona (FluM, n=4) a oito ovinos no dia 65 pi resultou em reativação e excreção viral por 3 de 4 animais de cada grupo. A excreção viral nas secreções nasais iniciou no dia 3 pós-tratamento e durou entre 1 e 5 dias nos ovinos tratados com Dx (títulos até 10(2,8)TCID50/mL) e foi mais tardia, durando entre 1 e 3 dias nos animais tratados com FluM (títulos de 10(2,1) TCID50/mL). Uma análise por PCR do encéfalo dos animais submetidos à reativação, no dia 65 pós-infecção, revelou uma distribuição do DNA latente semelhante àquela observada nos animais não submetidos à reativação. Em resumo, a capacidade do BoHV-5 estabelecer infecção latente, a colonização dos TGs a BOs com DNA viral latente e a reativação induzida por corticoides são achados promissores para o uso de cordeiros como modelo para a infecção latente pelo BoHV-5