Impact of concurrent training versus aerobic or resistance training on cardiorespiratory fitness and muscular strength in middle-aged to older adults: A systematic review and meta-analysis.

ABSTRACT

The effects of aerobic training (AT) on cardiorespiratory fitness (CRF), and resistance training (RT) on muscular strength, are well known in older adults. However, less is known about the potential additive benefits of concurrent training (CT) versus AT or RT alone in this population. We conducted a systematic review and meta-analysis to investigate the effects of CT, versus AT or RT, on CRF and muscular strength in middle-aged to older adults. PubMed and Web of Science were searched through October 2021 to identify randomized trials evaluating CT versus AT and/or RT in middle-aged and older adults (>50 yrs). Studies were included that measured CRF, using maximal or peak oxygen uptake (VO2max/peak); and/or lower- and upper-body muscular strength measured using 1-repetition maximum (1RM) to 10RM tests during isoinertial contractions, or peak torque during isometric dynamometry or isokinetic dynamometry at 30 to 60°/s. Standardized mean differences (SMD) and 95% confidence intervals (95% CIs) were determined using random or fixed effects models. Forty-nine studies involving 2,587 middle-aged to older participants with mean ages ranging from 55 to 88 years, were included in the meta-analysis. Results indicated that CT effectively increased VO2max/peak (SMD 0.77, p = 0.005, 12 intervention arms) when compared to RT. In addition, CT effectively increased lower- (SMD 0.60, p = 0.001, 43 intervention arms) and upper-body (SMD 0.57, p = 0.001, 28 intervention arms) muscular strength when compared to AT. However, there were no differences in VO2max/peak (SMD 0.09, p = 0.09, 33 intervention arms) between CT and AT, or in lower-body (SMD 0.07, p = 0.48, 21 intervention arms) and upper-body (SMD -0.07, p = 0.38, 17 intervention arms) muscular strength between CT and RT. Overall, CT was shown to be effective for increasing CRF and muscular strength in middle-aged to older adults and there was no negative effect on the magnitude of changes in these outcomes compared to either AT or RT alone. These results suggested that CT should be considered a viable strategy to improvement of CRF and muscular strength with aging.