Are resistance and aerobic exercise training equally effective at improving knee muscle strength and balance in older women?

This study aimed to compare the magnitude of knee muscle strength and static and dynamic balance change in response to 8 months of progressive RE and AE training in healthy community-dwelling older women. A secondary aim was to assess the relationship between muscle strength and balance changes (up and go test (UGT), one-leg stance test, and center of pressure measures). This study was a secondary analysis of longitudinal data from a randomized controlled trial, a three-arm intervention study in older women (n = 71, mean age 69.0 y). The results suggest that both interventions elicited likely to almost certain improvements (using magnitude-based inference) in balance performance. Leg strength was improved after RE whereas it was unclear following AE. Improvements in strength were almost certainly moderate after RE and possibly trivial after AE, with very likely greater improvements following RE compared to AE. A large and significant negative correlation (r = -0.5; CI 90%: −0.7 to −0.2) was found between ΔUGT and change in both knee extension and knee flexion strength after 8-month RE. In conclusion, our results showed that both types of training improve balance, but RE was also effective at improving leg strength. In addition, improvements in both knee extension and flexion strength after RE appear to make an important contribution to meaningful improvements in static and dynamic balance.