BackgroundAlthough physical performance tests of the lower extremities are used to assess sarcopenia and frailty, little is known about the mechanisms by which the parameters of ground reaction force (GRF) measured during sit-to-stand motion affect the frailty status in older adults. We aimed to examine the association between GRF parameters during sit-to-stand motion and the incidence of frailty in older adults.MethodsThis longitudinal study evaluated 319 outpatients aged ≥ 65 years with cardiometabolic diseases. The GRF parameters were measured using a motor function analyzer, in which the power, speed, and balance scores were calculated. Frailty was diagnosed using the modified version of the Cardiovascular Health Study (mCHS) and the Kihon Checklist (KCL). The independent associations between scores and frailty indices were assessed using multivariate binomial logistic regression analyses. Cox regression analysis was used to examine whether power and speed scores were associated with the incidence of frailty after adjusting for covariates.ResultsLogistic regression analyses adjusted for covariates showed that the power and speed scores were associated with frailty according to the mCHS criteria (power: OR = 0.37, 95% CI = 0.22–0.63; speed: OR = 0.64, 95% CI = 0.52–0.79) and KCL criteria (power: OR = 0.40, 95% CI = 0.26–0.62; speed: OR = 0.81, 95% CI = 0.69–0.96) at baseline. Receiver operating characteristic analyses revealed that the area under the curve values of power and speed scores for discriminating mCHS-defined frailty were 0.72 and 0.73. The Cox regression analysis showed that the speed score predicted the incidence of mCHS-defined (HR = 0.45, 95% CI = 0.22–0.92,P= 0.029) and KCL-defined (HR = 0.77, 95% CI = 0.60–0.99,P= 0.039) frailty, whereas the power score was associated with the incidence of KCL-defined frailty (HR = 0.72, 95% CI = 0.55–0.95,P= 0.02) after adjusting for covariates.ConclusionsThe speed and power scores measured during sit-to-stand motion are predictive of frailty in older adults with cardiometabolic disease. Therefore, the GRF parameters measured during sit-to-stand motion could be an important indicator of frailty. Further studies are necessary to examine whether the GRF parameters can be improved by exercise or whether the changes in these parameters are associated with the improvement of frailty status.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12877-023-04011-z.