Sometimes the schedule gets slammed. On such days, Dr. Brian Hickey, PhD, an exercise scientist and assistant professor at Florida A&M University, has to shoehorn a workout into 10 minutes or less, or skip it altogether.

But skipping is not really an option. An accomplished runner and duathlete, honored in 2004 as Florida Track and Field Athlete of the Year, Hickey abides by a “No Days Off” policy. He says, “You miss one day, and it becomes easier to discover reasons why you might miss two days or three.”

Plenty of research suggests that you can get a productive workout in ten minutes, he avers. But he adds, there are reasons why a runner wanting to achieve high performance and longevity should avoid the high-mileage regimens recommended in most conventional running programs—in which a runner accumulates as much volume as possible, running upwards of 60, 80 or 100 miles per week, month after month.

“I want to make every step count,” Hickey says, reacting to Runner’s World survey data from 2009 showing that at least 65 percent of runners suffer an injury each year.

For dedicated marathoners, the situation is even worse. A 2007 conference paper prepared at Stanford University and published in Sports Medicine revealed that when preparing for the marathon, 90 percent of runners incur an injury of some sort—mostly involving the knees. According to the Stanford researchers, things become especially perilous when a runner averages more than 5 miles per day. “There is a particularly high risk for injury when crossing a threshold of 40 miles per week,” the study asserts.

With more than 25 years of experience competing and coaching, Hickey has special clarity on the issue of smart training. With his own field-testing, he has compared scientific research to what works and what doesn’t work.

Make every step count

Hickey spends his miles like a miser—running no more than 20 miles per week—and targets specific training effects he wants from each mile. “If you don’t know the purpose of a workout, you are not only throwing away potential performance gains, you’re opening the door to unnecessary injury risk,” he says.

Whereas traditional training programs often include easy runs of 30 to 60 minutes and easy long runs of two hours or more—both to build cardiovascular fitness— Hickey believes the cost of the pounding outweighs the benefits. Instead, he uses the high-intensity, low-duration model in CrossFit Endurance, in which the body’s energy systems are trained with a mixture of interval workouts, time trials and racing, combined with CrossFit-style high-intensity metabolic conditioning workouts, which build stamina and endurance.

Studies supporting the crossover from circuit training to running go back to a National Athletic Health Institute study performed in the 1970s. Participants improved their running endurance by 5 to 6 percent over 10 weeks without running a single step. Hickey says that CrossFit workouts—without the joint-wearing effects of logging many miles—produce bonus effects of increased mobility, stamina, elasticity and core strength. He also hedges his bets by riding his bike to boost his oxidative system like easy running does, but with zero impact.

Minimize ground contact time

Hickey uses the core strength be builds with CrossFit to facilitate a style of running that further reduces musculoskeletal punishment. “Think about inertia,” he says, referring to Newton’s First Law of Motion: an object moving at a constant velocity stays at that velocity unless acted upon by another force. “You want to minimize those forces out to slow you down.”

Hickey works to maintain a stride rate of 180 steps per minute to minimize ground contact time. “If I minimize ground contact time, I’ll maximize rotation at the hip,” he says.

In this scenario, the hip acts like a second foot. Also, the less time the foot spends on the ground, the fewer twisting forces are transmitted to the knees.

“The problem when you slow down to 80 strides per minute or less is that you lumber along,” Hickey says. “What happens then? The hip comes through and plop, your foot just stays there.” It becomes a constant start and stop, and the accumulation of countering forces will—on each and every landing of the foot—have a leaden effect on inertia. “With a fast stride rate, my lower leg is just along for the ride,” Hickey says. “I run more with my heart and lungs.”

Lift heavy

On days when Hickey is exceptionally busy and has only a brief window in which to train, he uses his time to stimulate the natural hormones in his body, namely testosterone and human growth hormone, which produce lean muscle mass, a boost in VO2 max and a host of other positive biochemical effects. He says, “If you only have five minutes, go swing a heavy kettlebell. Or do three sets of five Deadlifts.”

One of Hickey’s favorite workouts in a pinch is to grab a 24-kg kettlebell and rip through 100 swings as fast as possible. A 2010 study at Truman State University found that kettlebell work triggers a high heart rate and delivers considerable endurance benefits. In just a few minutes, Hickey performs a workout that boosts his core strength and endurance while stimulating a powerful hormonal response.

As a Masters athlete in his mid-40s, Hickey says that strength/power work is crucial. Among the effects of aging are a decline in power, muscle mass and flexibility. These declines can be mitigated, if not countered, by lifting heavy weights as part of a weekly schedule.