In an effort to improve performance, serious distance runners tend to keep their ears close to the beat of the latest in exercise physiology research. Most recently, running economy and muscle recruitment have become buzz phrases in the research world. The inextricable link between the two provides an important key for those who want to run faster and more efficiently. The good news is that running economy can be achieved through optimal muscle recruitment, which can be trained through plyometric exercises. The studies have shown that even less than two months of this type of training will translate into tangible improvements in the efficiency of a runner. With that fact in mind, it seems worth putting in that little bit of extra work.
Muscle recruitment program
"We recruit muscle fibers in every activity that we do," explains Dr. Jason Karp, a coach and exercise physiologist. Depending on the nature and intensity of whatever it is that you're doing, you recruit a certain amount of fibers. Distance runners tend to recruit the aerobic slow-twitch fibers the majority of the time. However, when a runner engages in speed work or plyometrics, more of the fast-twitch muscle fibers are recruited.
"Part of improving your ability to run is maximizing muscle recruitment because the more muscles you recruit, the more ability you have to produce force against the ground and the faster you'll go," explains Dr. Karp. However, he says, you also want to recruit as few muscle fibers for the task as possible. Simply put, the more muscles you recruit, the more oxygen that is required - and this translates into decreased running economy.
Running economy is all about using oxygen efficiently. For instance, two runners could be running at 8:00 per mile pace, but the one that is recruiting fewer muscle fibers will have better running economy. Additionally, either runner's economy can decrease throughout a run as they fatigue. "Initially at 8:00 per mile pace, you'll be recruiting just slow-twitch fibers, but if you are to hold that pace for 2-plus hours, as you fatigue, the fast-twitch muscles will be recruited, even though you're still going 8:00 pace," says Dr. Karp.
Regardless of your pace, you have an arsenal of muscle fibers. You get at the fast-twitch fibers either by running long and first expending the slow-twitch fibers, like in the aforementioned example, or by running fast. As can be expected, at some point you'll completely run out of ammo as your running economy simultaneously plummets.
Plyometrics and economy
Plyometric training has been shown to be an important part of training a distance runner to recruit muscle fibers most efficiently. Dr. Karp explains this, saying, "Increasing the rate at which muscles can produce force helps improve how oxygen is used to maintain any given speed. It's really about exploiting the elastic properties of muscles and tendons and how they utilize elastic energy." The better the muscles are at producing force against the ground quickly, the less time you spend on the ground. Think of a 4:00 miler compared to an 8:00 miler; the faster runner pops with each step, spending very little time on earth.
An article published just this summer in the Journal of Strength and Conditioning highlighted the importance of plyometrics for improving running economy. In this study, researchers had 35 distance runners, all running the same mileage, subscribe to either a dynamic weight training program or a plyometric exercise regimen. After eight weeks, it was found that the plyos were more effective in improving "energy cost of running," or running economy, than the weight lifters. Another study showed that just six weeks of plymometrics led to improved running economy. Other research has identified a significant link between anaerobic power and 10K running performance and 5K running performance.
David Jankowski of ZAP Fitness has seen plyometric training help elicit better performances as he has transitioned into a professional career. Finishing fourth in his marathon debut at the 2010 Medtronic Twin Cities Marathon's hosting of this year's national championships (2:16:15), Jankowski says that doing anaerobic work in the mountains of North Carolina is a vital part of his training. "I'm much smoother than I used to be. That efficiency translates into faster times and being able to hold a pace longer," he explains.
Jankowski and the ZAP crew do everything from hurdle drills to uphill strides to quick-start drills. "We do these exercises to train ourselves to recruit those fast-twitch muscles that we don't always use on our regular runs," he says.
Jankowski has subsequently gone from a loping and bouncy stride to a more efficient gait since his time at ZAP, where he first began engaging in these drills. This makes sense because plyometrics help the muscles transition from the eccentric to concentric contraction more quickly, thus producing more force against the ground.
Putting plyos into practice
Since joining ZAP, Jankowski has surprised even himself with the raw speed he's been able to achieve, a gear he didn't have in college. "I think this can be partially attributed to doing some of the more explosive stuff, like the quick starts and hurdle drills. It definitely helped train my muscles to recruit those fast-twitch fibers," he says. Dropping 14 seconds in the 1500m (3:45:34) this past spring was proof enough of his improvement.
"If you run 60 miles a week, but it's all slow, it's not going to do much for your muscle power. Plyometrics will improve muscle power, which will mean faster race times," says Dr. Karp. He suggests having a coach watch you perform the drills to ensure that you are doing them properly. Begin with lower-level plyos, like hopping in place, or running bleachers two steps at a time, before graduating to more difficult exercises. That progression will help you avoid injury and ease into the new training.
While Jankowski says he is one of those runners who has always responded best to aerobic training, he concedes that the sprint drills and plyometrics have helped bring him to the next level. Coming off his 2:16 debut marathon, he says, "The drills added into my training have clearly had an impact."
Dr. Jason Karp's Sample Plyometric Training
Try this program to increase muscle power. Spend as little time on the ground as possible between hops/bounds/jumps. Do exercises on a soft surface, like grass, track or a gymnastics mat. Begin with two sessions per week of two sets of 10 repetitions (2 x 10) with full recovery between sets.
|Weeks||Single Leg Hops||Bleacher Hops||Double Leg Bounds||Alternate Leg Bounds||Squat Jumps||Depth Jumps||Box Jumps|
Single leg hops: 1) On one leg, hop up and down; 2) hop forward and back; 3) hop side to side.
Bleacher hops: Standing at the bottom of the bleacher steps on one leg, hop up the steps. Walk back down and hop up again on the other leg.
Double leg bound: From a squat position with both legs, jump forward as far as you can.
Alternate leg bound: In an exaggerated running motion, bound (which looks like a combination of running and jumping) forward from one leg to the other.
Squat jumps: With hands on hips in a squat position, jump straight up as high as you can. Upon landing, lower back into a squat position in one smooth motion and immediately jump up again.
Depth jumps: From a standing position on a 1-foot tall box, jump onto the ground and land in a squat position. From this squat position, jump straight up as high as you can.
Box jumps: From the ground, jump with two feet onto a 1-foot tall box, and then immediately jump into the air and back down to the ground. As you get experienced with the exercise, try jumping with one foot at a time.
Written by Mackenzie Lobby
Mackenzie Lobby is a freelance journalist, coach and runner based in Minneapolis, Minn.
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