Purpose: To explore the feasibility of progressive strength training commenced immediately after total knee arthroplasty (TKA). Methods: A pilot study was conducted at an outpatient training facility. Fourteen patients with unilateral TKA were included from a fast-track orthopedic arthroplasty unit. They received rehabilitation including progressive strength training of the operated leg (leg press and knee-extension), using relative loads of 10 repetition maximum with three training sessions per week for 2 weeks. Rehabilitation was commenced 1 or 2 days after TKA. At each training session, knee pain, knee joint effusion and training load were recorded. Isometric knee-extension strength and maximal walking speed were measured before the first and last session. Results: The training load increased progressively (p <0.0001). Patients experienced only moderate knee pain during the strength training exercises, but knee pain at rest and knee joint effusion (p <0.0001) were unchanged or decreased over the six training sessions. Isometric knee-extension strength and maximal walking speed increased by 147 and 112%, respectively. Conclusion: Progressive strength training initiated immediately after TKA seems feasible, and increases knee-extension strength and functional performance without increasing knee joint effusion or knee pain. [Box: see text].