Source notes

Can one resistance circuit improve both aerobic fitness and strength? Combining studies in healthy adults, the authors found improvements in maximum oxygen use and the heaviest bench press completed once. They reported average increases of about 9.7% and 13.2%, respectively, across the included training results. Separate pooled comparisons also favoured circuits over control conditions. Each outcome drew on eight papers, with 118 circuit-training participants assessed for oxygen use and 237 for bench-press strength. These averages describe the studies analysed, not guaranteed gains or the results of one standardised circuit.

A circuit combines successive resistance exercises with relatively little rest, but the included programmes differed widely in loads, session length and duration. That variety supports the possibility of improving both outcomes through this format. It also makes an exact best programme difficult to identify. Greater improvements in a subgroup do not establish that one programme feature caused the difference, because participants and other training details also varied.

How Does This Show Up in Real Life?

For a healthy adult considering circuit training, this paper supports viewing it as more than a way to make a resistance workout feel breathless. Repeated programmes improved measured aerobic capacity as well as a specific strength test. However, feeling exhausted in one session is not evidence that the same adaptations will follow. The authors examined programmes lasting weeks, with planned exercise selection and progression. Their subgroup findings should also not be turned into simple rules such as lighter weights always producing more strength or shorter programmes always working better. Lower starting fitness could explain some larger gains with lighter loads. The analysis does not show that circuits outperform a well-designed strength-only or aerobic-only programme, and bench-press improvements cannot establish equivalent gains in every movement or muscle group.

Study results were highly variable, and methodological quality was moderate overall. Women and some training-experience groups were sparsely represented. Several apparent dose differences depended on very few studies, with cutoffs chosen for comparison rather than demonstrated physiological thresholds. The analysis did not establish persistence after training stopped. Direct comparisons with separate strength and aerobic programmes were identified as a further research need.

This is useful support for resistance circuits as one training option, with the strongest claim limited to the measured outcomes in healthy adults. The average improvements show potential. Choosing a precise routine still requires more information than the largest effect reported in a subgroup.