Women who pump iron in the gym cut their risk of developing diabetes, say researchers.
The findings come from a study that tracked the health of nearly 100,000 US nurses over a period of eight years.
Lifting weights, doing press-ups or similar resistance exercises to give the muscles a workout was linked with a lower risk of diabetes, the work in PLoS Medicine shows.
Adults are already advised to do such exercise at least twice a week.
The benefit seen in the study was on top of any gained from doing aerobic workouts that exercise the heart and lungs - something which adults are meant to do for at least 150 minutes a week.
Women who engaged in at least 150 minutes a week of aerobic activity and at least an hour a week of muscle-strengthening activities had the most substantial risk reduction compared with inactive women. They cut their odds of developing type 2 diabetes by a third.
Experts already know that regular aerobic exercise, such as jogging, brisk walking or swimming, can help stave off type 2 diabetes.
The latest work suggests adding resistance training to exercise regimes - something already recommended by the NHS - will give further protection.
The Harvard Medical School researchers point out that their work is not perfect - it looked at only nurses who were mostly Caucasian and relied on the study participants reporting how much exercise they did rather than directly measuring it.
But they say their findings chime with similar results they already have for men.
They believe the explanation may be partly down to maintaining a greater muscle mass to act as a buffer against diabetes.
Type 2 diabetes develops when the insulin-producing cells in the body are unable to produce enough insulin, or when the insulin that is produced does not work properly.
Insulin enables the body to use sugar as energy and store any excess in the liver and muscle.
Our genes and lifestyles influence our chances of developing type 2 diabetes. Carrying excess weight increases a person's risk.
If you are overweight, every kilogram you lose could reduce your risk by up to 15%, according to Diabetes UK.
Dr Richard Elliott, spokesman for the charity, said: "Despite limitations to which this research can be applied to women in general, it underlines the message that leading an active, healthy lifestyle can help to reduce the risk of type 2 diabetes.
"We know for certain that the best way to reduce your risk of type 2 diabetes is to maintain a healthy weight by eating a healthy, balanced diet and by taking regular physical activity. At this time of year, many people are looking for an easy way to lose weight and be more physically active. We recommend finding an activity you enjoy as you are more likely to stick with it and stay motivated."