This study examined the relationship between lower-limb muscle strength and temporal preparation in elderly adults. Time-frequency analysis of electroencephalography (EEG) was employed to investigate neural oscillations during cognitive processes over time. Forty older adults were divided into higher (HSG, 70.40 ± 5.15 years) and lower muscle strength (LSG, 71.43 ± 4.86 years) groups based on quadriceps strength estimated via a manual muscle test. Additionally, a Timed Up and Go (TUG) test was conducted to assess their risk of falls. A choice reaction time (RT) task with randomly varying foreperiods (FPs) and requiring lower-limb motor responses was used to examine the temporal preparation ability of the lower limbs. The HSG outperformed the LSG on both the TUG test and the cognitive task, and also demonstrated stronger modulation of oscillatory beta power during the late period of longer FP trials. Notably, both groups did not exhibit a significant FP effect on the task, indicating an age-related decline in the ability to utilize temporal information. In summary, the results of this study suggest that lower-limb muscle strength may play a compensatory role in mitigating age-related decline in temporal preparation and may also contribute to a reduced risk of fall.