One of the classic myths you hear when it comes to mixing weight training and cardio is that the two simply do not mix. Whether by choice or by result, you'll only realize the results of one of them, even if you perform both of them. While it's true that powerlifters shouldn't engage in marathon endurance runs, that doesn't preclude the dedicated lifter from engaging in cardio at all. In fact, many 12-week powerlifting cycles include cardio as necessary training component. The key is to use a complementary form of cardio and blend it into your lifting schedule.
The basics of powerlifting are simple: performing a core of raw, heavy compound exercises through low-rep, high-intensity sets that use the principle of progressive overload to develop increased strength. The three classic powerlifting exercises are the squat, the deadlift and the bench press, but for a non-competitive powerlifting training regimen, you can use other compound lifts like the power clean, the high pull and the snatch. Unlike traditional body building, the purpose of powerlifting is not to directly build muscle mass to improve your physique -- the primary goal is to become stronger.
While many types of cardiovascular exercise aren't quite compatible with a powerlifting routine, there are a few types that are. Avoid any low-and-slow types of cardio. This includes fast-walking, light jogging, distance running, distance cycling or endurance swimming. The types of cardio exercise best suited to powerlifting are those that use bursts of explosive energy over a short period of time. Sprinting, especially using an interval system, is an effective cardio workout that directly fits with powerlifting, because it conditions the body for short bursts of activity and it improves fast-twitch muscle response.
When to Run
Schedule your interval cardio training for your rest days. For example, a typical powerlifting schedule will have you in the weight room three to four days each week. For a four-day lifting schedule, you'll lift on days 1 and 2, rest on day 3, lift on days 4 and 5, then rest on days 6 and 7. Perform your interval sprint training on days 3 and 6, and make sure you rest completely on day 7 to prepare for the next week's training. For a three-day lifting program, you'll lift on days 1, 3 and 5, while resting on days 2, 4, 6 and 7. In this routine, plan your sprint work for days 2 and 4.
Powerlifting by itself is an extremely taxing exercise program, and it requires sufficient rest and recovery time so that you can increase strength. Adding cardio to that program should be done carefully, with an eye to avoiding working out too much. With a full lifting program, limit your cardio sprint time to two days a week. This will reduce the frequency of many of the nagging injuries that can hamper your performance, and it will also reduce the amount of fatigue you endure through your weekly program.