Chronic exercise training increases the functional capacity of the heart perhaps by increased myocyte contractile function, as has been observed in rodent exercise models. We examined whether cardiac myocyte function is enhanced following chronic exercise training in Yucatan miniature swine, whose heart characteristics are similar to humans. Animals were designated as either sedentary (SED), i.e., cage confined, or exercise trained (EX), i.e., underwent 16 to 20 weeks of progressive treadmill training. Exercise training efficacy was shown with significantly increased heart weight to body weight ratios, skeletal muscle citrate synthase activity, and exercise tolerance. Force-velocity properties were measured by attaching skinned cardiac myocytes between a force transducer and position motor and shortening velocities were measured over a range of loads during maximal Ca²⁺ activation. Myocytes (n = 9) from nine EX pigs had comparable force production but a ~30% increase in peak power output compared to myocytes (n = 8) from eight SED. Interestingly, EX myofibrillar samples also had higher baseline PKA-induced phosphorylation levels of cardiac troponin I (cTnI), which may contribute to the increase in power. Overall, these results suggest that enhanced power generating capacity of porcine cardiac myofibrils contributes to improved cardiac function following chronic exercise training.