The Covid-19 outbreak forced many governments to enter a nationwide lockdown and many national and international competitions, such as the Olympic Games in Tokyo, were canceled. The lockdown determined several negative changes in the general population, such as the increase in anxiety, stress, sedentary levels and sleep problems and prevented athletes from training; therefore, the aim of this study was to evaluate, by means of a survey, changes in sleep parameters and PA characteristics of elite athletes of the Italian Track and Field Federation in three periods of the 2020: before the lockdown (T0), during the lockdown (09th March – 03rd May, T1) and the first month after the lockdown (T2). This study was conducted from May 2020 to June 2020 and data were collected using an offline survey with 89 elite track and field athletes (mean age: 24.7±5.4; mean BMI: 20.7±3.0; n=43 males [48.3%] and n=46 females [51.7%]). The survey was composed by demographic data and questions on PA and sleep behavior at T0, T1 and T2. Primary outcomes of PA were hours of training per week (Th/w), hours of training per day (Th/d) and number of training sessions per week (T/w) whereas sleep parameters included wake-up time (WT), bedtime (BT), sleep latency (SL), total sleep time (TST) and sleep quality (SQ). SQ decreased at T1 compared to T0 and T2 (p<0.0001) and athletes registered delayed BT (00:13±1:05), WT (8:41±1:20) and longer SL (28.1±29.8) at T1 compared to T0 (BT: 23:27±0:45; WT: 7:57±1:05; SL: 18.1±14.4) and T2 (BT: 23:38±0:44; WT: 8:04±0:53; SL: 19.4±15.9) whereas no changes in TST were reported. Similarly, significantly lower values of Th/w, Th/d, and T/w (p<0.0001) were registered at T1 compared to T0 and T2: the weekly training volume decreased from 16.1±5.7 hours at T0 to 10.7±5.7 hours during the lockdown. Conversely, no PA and sleep differences between male and female athletes and between short- and long-term disciplines were detected. In addition, alcohol (p=0.136) and caffeine intake (p=0.990) and the use of electronic devices (p=0.317) were similar pre-, during, and post-lockdown. The lockdown measures determined a significant decrease in training volume and frequency along with a worsening in sleep quality, sleep latency, and a delay in bedtimes and get-up times in top-level track and field athletes. With continuous spikes in Covid-19 cases around the world and associated local/regional lockdowns, these results provides important insights to better manage sleep and training in a population for whom optimal performance is essential.