Background Lower limb muscle power is emerging as an important determinant of patient function after knee injury or surgery. This study tested proof of concept of a cycle sprint test for the evaluation of lower limb muscle power, as an outcome measure for patients having total knee arthroplasty (TKA). Methods Thirty-two patients were enrolled, of which 16 completed all follow-ups (3, 6, and 12 months). All patients completed the Oxford Knee Score and Knee Injury and Osteoarthritis Outcome Score questionnaires, a 10-m walk test, and 30-second sit-stand test. A trainer-mounted road cycle fitted with an instrumented crank was used for the cycle sprint test. Maximum muscle power was measured from 3, 10-second maximal efforts. Results Significant improvements in Oxford Knee Score and Knee Injury and Osteoarthritis Outcome scores relative to baseline were achieved at each follow-up ( P < .001), and functional test performance improved significantly at 6 and 12 months ( P < .001). Compared with the baseline of 268W, muscle power was significantly lower at 3 months (239W, −13%, P < .05) and significantly higher at 12 months (308W, +12%, P < .05). Conclusion The concept of muscle power measurement using a cycle sprint test before and after TKA has been demonstrated in this study. Identification of individuals with lower limb muscle power deficits after TKA may inform rehabilitation programs and enhance long-term outcomes.