The S77 treadmill has the power of a club-quality treadmill. No need to join a club, the S77 treadmill gives you everything in the comfort of your own home. The S77 treadmill has all the same great features as the F85 treadmill and adds a 4.0 HP motor and also incorporates the largest deck that Sole offers, comfortable for any runner. These powerful additions make the S77 treadmill quite a fitness package.