Alter-G G-Trainer Treadmill for Weightless Running

The "Alter-G G-Trainer," a treadmill which uses a compressed air chamber to lift and reduce the effective weight of its user, has been approved by the FDA for use in rehabilitation for injuries to the lower extremities. The G-Trainer can reduce up to 80% of lower body weight. Prices are probably somewhat extravagant, but unless you keep a rehabilitation chamber in your mad scientist fortress you'll likely only see the trainer when you send henchmen off to be restored to service.