This study investigated the effectiveness of recreational skiing as an intervention to improve quadriceps muscle architecture, strength, and antagonistic co‐activation in patients with unilateral total knee arthroplasty (TKA). Hence, patients with TKA were assigned to either an intervention group (IG) or control group (CG). The IG completed a 12‐week guided skiing program whereas the CG was instructed not to change their daily routines for the same period and was not allowed to ski. Before, after the intervention/after an 8‐week retention period m. rectus femoris (RF) cross‐sectional area (CSA), m. vastus lateralis muscle thickness, fascicle length, and pennation angle were measured with ultrasonography, while isometric (90° knee angle) knee extension, flexion torque and m. biceps femoris co‐activation were assessed on an isokinetic dynamometer in 26 patients. There were significant and stable increases in RF CSA for the operated (10%; P < 0.05) and non‐operated leg (12%; P < 0.01) after the training period in the IG whereas no changes were observed for the CG (all P > 0.05). There were no significant effects for other parameters (all P > 0.05). Overall, the skiing intervention was successful in increasing muscle mass in TKA older patients.