A common belief is that building strength and burning fat requires long, slow workouts. However, new research challenges this idea. High-intensity circuit training, which involves doing multiple strength exercises in shorter sessions with minimal rest, can provide similar benefits to traditional weight training.
The study was led by Sohee Carpenter, PhDc, CSCS, a Women’s Health cover star. It offers valuable insights for people who want effective workouts but have limited time or want to add variety to their routine.
Published in the European Journal of Sport Science, the study followed 14 active women in their 20s and 30s. The participants trained three times a week for eight weeks. Half of them did high-intensity circuit training, while the other half followed traditional strength training.
Both groups performed the same six exercises: leg press, dumbbell bench press, trap bar deadlift, lat pulldown, hip thrust, and standing dumbbell shoulder press. The circuit training group completed the first three exercises in a timed circuit with very little rest, then rested for five minutes before doing the last three in the same way. The traditional strength training group did each exercise one at a time, resting three minutes between sets.
Each group performed three sets of 8 to 15 repetitions, pushing themselves close to muscle failure, which means working until they almost could not do another rep with proper form.
Before and after the study, researchers measured strength, body fat, and lean muscle mass. Results showed that both groups improved their strength by increasing their three-repetition maximum—the heaviest weight lifted for three reps with good form. Both groups lost similar amounts of body fat and gained comparable muscle mass.
The researchers concluded, “Both high-intensity circuit training and traditional strength training are equally effective for increasing strength and muscle while reducing body fat in trained women. High-intensity circuit training may be preferred by those wanting to save time, as sessions were much shorter.”
Carpenter explained in an Instagram video, “Many people think circuit training is less effective for strength and body composition, but our study showed that’s not true.”
Why ‘Close to Muscular Failure’ Matters
The study emphasized that both groups trained close to muscular failure. But what does that mean?
Albert Matheny, RD, CSCS, co-founder of SoHo Strength Lab, explains that this means working your muscles until you almost cannot complete another rep with correct form. This level of effort is essential to trigger muscle adaptation and growth. “Pushing near your max signals your body to get stronger and more efficient,” he said.
You might feel muscle burning or tightness and notice your movements slowing down when you reach this point.
Which Training Method Is Better?
You don’t have to pick just one. The study shows both methods can produce similar results. If you want shorter workouts, high-intensity circuit training is effective because it reduces rest time but still builds muscle.
Matheny suggests mixing both styles. This approach helps with recovery on intense days and keeps your workouts varied. “You can’t do fast, intense moves all the time,” he notes. For those who have only done traditional strength training, adding high-intensity interval training (HIIT) can be a good, time-efficient next step.
