The number of adults participating in sport regularly dropped to 40 per cent in 2021, showing a 6 per cent decrease on pre-pandemic levels.
Data released by Sport Ireland showed Covid-19 brought significant fluctuations in physical activity levels, with activities such as cycling, weights and running noting higher participation levels.
Although record levels of activity were seen at one point in 2020, as Covid lockdowns gripped the country, the Irish Sports Monitor showed inactivity levels returned to pre-pandemic levels by the end of last year.
Despite the wider decline in sport participation levels among adults, the proportion found to be classed as 'highly active', meeting the National Physical Activity Guidelines, has increased from 34 to 41 per cent since 2019.
The number of adults considered sedentary, not participating in any physical activity during the past week, remained broadly unchanged, falling by 1 per cent to 11 per cent in 2021.
The research also found that the socio-economic gradients in sport have widened since the last monitor in 2019, with those in employment, of higher socio-economic status, and those with high levels of education being significantly more likely to be involved in sport and physical activity.
"Those from higher socio-economic groups have benefited disproportionately from working from home arrangements, possibly providing them with more leisure time in which to be active during the pandemic than those from lower socio-economic groups," Sport Ireland added.