People with strong legs are less likely to develop heart failure after a heart attack, according to research.

Myocardial infarction is the most common cause of heart failure, with around 6-9 per cent of heart attack patients going on to develop the condition. Previous research has shown that having strong quadriceps is associated with a lower risk of death in patients with coronary artery disease.

The new study, presented at the Heart Failure 2023, a scientific congress of the European Society of Cardiology (ESC) in Prague tested the hypothesis that leg strength is associated with a lower risk of developing heart failure after acute myocardial infarction.

"Quadriceps strength is easy and simple to measure accurately in clinical practice. Our study indicates that quadriceps strength could help to identify patients at a higher risk of developing heart failure after myocardial infarction who could then receive more intense surveillance," said Kensuke Ueno, a physical therapist at Kitasato University's Graduate School of Medical Sciences in Japan.

The researchers included 932 patients hospitalised from 2007 to 2020 with acute myocardial infarction who did not have heart failure prior to the admission and did not develop heart failure complications during their hospital stay. The median age was 66 years and 753 participants (81 per cent) were men.

Maximal quadriceps strength was measured as an indicator of leg strength. Patients sat on a chair and contracted the quadriceps muscles as hard as possible for five seconds.

A handheld dynamometer attached to the ankle recorded the maximum value in kg. The measurement was performed on each leg and the researchers used the average of both values.

During an average follow-up of 4.5 years, 67 patients (7.2 per cent) developed heart failure. The incidence of heart failure was 10.2 per 1,000 person-years in patients with high quadriceps strength and 22.9 per 1,000 person-years in those with low strength.

Compared with low quadriceps strength, a high strength level was associated with a 41 per cent lower risk of developing heart failure. The investigators also analysed the association between quadriceps strength as a continuous variable and the risk of developing heart failure.

Each 5 per cent body weight increment in quadriceps strength was associated with an 11 per cent lower likelihood of heart failure.

While the findings need to be replicated in other studies, "they do suggest that strength training involving the quadriceps muscles should be recommended for patients who have experienced a heart attack to prevent heart failure," Ueno said.