Acute Blood Pressure Response to High- and Moderate-Speed Resistance Exercise in Older Adults With Hypertension

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 effective method for improving muscle function, including 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, affects 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 effects of low-intensity (≤ 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 effects of different 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 differences (SMD) with a 95% confidence interval (CI), and random effects models were used for calculations. A significance level of p ≤ 0.05 was accepted.

RESULTS

Three RCTs assessing 179 participants, all of high methodological quality, were included. There were no significant differences between different 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 significantly more effective 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-intensity PT (70-80% of 1RM) in older adults. Nonetheless, the influence 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.

Power Training Prescription in Older Individuals: Is It Safe and Effective to Promote Neuromuscular Functional Improvements?

Muscle power has been reported to be critical in counteracting age-related declines in functional performance. Muscle power output in functional performance exercises can be greatly improved in a short period of time (i.e., ≤ 12 weeks) using specific exercise interventions such as power training (i.e., exercises attempting to move loads ranging from 20 to 70% of 1-repetition maximum as fast as possible during the concentric muscle action, followed by a controlled, slower eccentric muscle action). Despite the widespread evidence on the effectiveness of power training in older adults (~ 300 scientific articles published on this topic in the past 10 years), some scientists do not recommend the use of explosive-type muscular contractions during resistance training (i.e., power training) for the older population; indeed, some international guidelines do not mention this type of exercise for older people. The reasons underlying this absence of mention and recommendation for the use of power training as a fundamental exercise strategy for older people are still not well known. Therefore, we attempted to point out the main issues about safety, feasibility, and effectiveness of muscle power training to promote neuromuscular functional improvements in older people.