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Running Research News And Events
August 01, 2010
DOES CROSS-TRAINING IMPROVE RUNNERS PERFORMANCE?
Have your running times stopped improving, leaving you wondering what you can do to give it a kick-start? Are your training runs boring and you’re looking for something to make it fun again? Cross Training
Have you reached a point where you just cannot squeeze any more running into your schedule because you’ll get injured? Are you getting injured frequently?
If any of these are happening to you, consider cross training (CT). Recent research shows that supplementing, or even replacing part of your running program with other forms of exercise might be just what you need to avoid boredom, minimize injuries, and take your running to a new level.
What is cross training? The term refers to a wide variety of training activities that are not your primary focus (running), but may still have a positive crossover effect on your running. Indeed many coaches apply cross training to experienced marathoners and beginners alike. Successful athletes in most sports practice some form of cross training. Cross Training
Cross Training became a buzzword back in the 1980’s, with the advent of triathlons. Triathletes were forced to indulge in multi-sport training because of their three events. Soon afterwards, runners took up cross training and many found racing times and training performances improving, and they were injured less.
But for a long time, research proving the effectiveness of cross training lagged behind. What, then, are the purported advantages of cross training?
Running Performance Improvement
Somewhere around 50 miles per week seems to be the breakdown point for many semi-serious runners, although this self destruct point is relative to many variables in runners; years running, age, gender, experience, natural biomechanics, etc. What we do know is that when runners flirt with this much mileage, injuries soon follow.
Non-specific cross-training that uses other aerobic activities enables the runner to get more endurance training in without further compromising the running muscles and joints. It uses the same muscle groups in a different (non weight-bearing) way.
Even more exciting for the competitive runner who has reached a plateau, is the fact that these added workouts can be done at high intensity, further stimulating the aerobic (citric acid cycle) pathway for increased gains in maximal oxygen uptake.
A high intensity cycling session, for example, enables the runner to develop increased lactate tolerance, buffering capacity, and fuel resynthesis, without undergoing the high impact stress on the legs of an interval-training workout.
A runner who already performs 2-3 high intensity workouts weekly, risks injury or overtraining by adding more running workouts at this level. However, throwing in an intense stairclimber or cycling session gives the runner an extra workout each week that could help take him or her to a new level, without the added trauma of high intensity running.
It’s also possible that cross-training may activate more motor units, and thus muscle fibers, and develop much needed strength in the upper body that is generally neglected in runners although there is no direct research proving any of these claims at this time. Cross Training
However, research has shown that endurance type training does transform type IIa muscle fibers into type IIbs, meaning they’ve taken on endurance characteristics. In addition, endurance training makes many other changes to muscle tissue including increased mitochondrial density increased capillary density, increased metabolic enzyme activity, and increased glycogen storage.
Cross Training for injury prevention
By doing extra endurance work in other low impact or low weight bearing aerobic activities like cycling, stair climbing, swimming, deep-water running, or using the elliptical trainer, you get an “active rest”, with virtually no stress on your joints, and you’ll recover from those pesky lower extremity injuries or muscular soreness far faster than rest alone.
At least this is what common sense tells us about cross training. Surprisingly, a study by Murphy et al concluded that cross training might not reduce injury rate. Another study found that, “cycling can be a great choice for runners to loosen the repetitive stress of running that contributes to overuse injuries. But cycling may come with its own set of problems, particularly back pain”.
Another study (Cipriani et al) concluded that “multisport training may also contribute to a specific category of injuries, those related to the cumulative effects of cross-training”. This points to the need to know how to balance the different demands of a multi-sport training program--more about this later. Cross Training
Cross Training for Variety in Your Training Program
If you’re not enjoying your running sessions you’ll soon find yourself skipping workouts, leading to decreased training volume, and inevitably, reduced performance. Cross training enables you to take a mental break from the stress of single-sport training and gives you much needed variety by breaking your program up and adding spice to your routine.
For exercise enthusiasts using running as their primary means of developing cardio-respiratory fitness, cross training will balance the strength and endurance between muscle groups. However, this advice is written for the runner looking to improve racing and training performance, so will not dwell on general fitness benefits of cross training.
What cross-training activities are complementary to running?
The Principle of Specificity
This aged principle states that if you are to improve in a specific sport, you should practice that activity solely, and by throwing other similar activities into the mix you confuse your neuromuscular system, thus actually retarding your running progress.
One study (Foster et al) more or less confirmed this principle. Well-trained men and women added either running or swimming to their baseline running schedules, versus a group that continued their baseline running. The training period was for 8 weeks. Cross Training
After the post-tests were done, the extra running group improved in a test that measured lactate build up at a set velocity, while the other groups did not. And the researchers had the sense to put in a field test that actually measured running times over 2 miles. Again the extra running group improved the most, by 26.4 seconds, with the cycling group improving its times by 13.2 seconds. The running baseline group did not improve its time significantly. So, according to this study, cross training may improve running performance, but not as much as a running only program.
You see, you’re supposed to use the same type, speed, duration, and range of motion of an activity to improve your desired sport, in this case running. Because of their differing emphasis on various muscle groups, the nervous and muscular systems work in contrasting ways during different activities. This explains why world-class athletes like Tour de France cyclists, for example, are not world-class marathoners.
These elite cyclists exercise most of the muscle groups used in running, but in a very different way. Thus they are extremely efficient at cycling, but would be only average in distance running because their neuromuscular system is not efficient in the mechanics of running.
Lance Armstrong recently ran the Boston Marathon (April, 2008), recording a time of 2:50:58. Certainly this time is not to be sneezed at, but a thousand Boston marathoners can boast that they beat the 7-time winner of Le Tour.
But, like many age-old tenets of exercise science, there is contradicting research showing that indeed some activities can help improve other sports.
But what effect do aerobic activities have on running? Certainly coaches will tell you the best way to training for running is by running, yet some recent studies appear to contradict this principle. And for a long time no published study had linked cross training with actually improving running performances, until recently. . . .
Then a study by Ruby et al., had three groups of exercisers do a ten-week training program of running, or cycling, or a mixture of both. Their results found that all groups improved VO2 max. (The oxygen processing ability of the body) similarly. So, this study showed that at least a combined cross-training program achieves similar fitness to sports specific training. Cross Training
Another study (Millet et al), looked at cross-training effects in elite triathletes. It concluded that a certain amount of cross-transfer training occurs between cycling and running, but not with swimming.
One of the most promising studies to validate cross-training, conducted by Mutton et al., looked at the effects of running four days/week compared with a combined cycling (2 days/week) and running (2 days/week) schedule, for a total of four days/week, over a five week training program.
The results for both groups were almost identical, both groups improving VO2 max significantly, and reducing their 5 km run times by 7% (running only) and 8% (running/cycling). This showed that augmenting a running program with cycling showed no decrease in performance over a running only program.
Another cycling/running study at the university of Toledo found similar results, when 10 well-trained runners (who averaged 30-35 miles/week), added 3 cycling workouts per week to their existing training schedules, for 6 weeks. The workouts were all high intensity, such as 5-minute interval efforts, 150-second and 75-second high intensity bursts, and a longer duration workout of 50 minutes at 80% of maximal heart rate. Another group of runners added three similar running workouts to their training schedule.
After 6 weeks the running/cycling group times came down by almost 30 seconds, from 18:16 to 17:48, or 3%, which was almost the same as the running only group’s average. The conclusions were that adding extra running sessions was no better than adding extra cycling sessions.
A California State University study also used two groups of runners for a study on cross training. A running only group and a cycling only group performed a 9-week training program. At the end of the training both groups performed the same in running tests. Cross Training
An interesting study in 2003 found triathletes who cycled at a fast cadence reduced their 2-mile times by 7% on average. The implications are that cycling at a faster speed cadence similar to running improves running performance. The researchers theorize that the neuromuscular effects of fast cycling transfer to running, if done at a similar cadence.
A review by Tanaka concluded that there is clearly some transfer of training effects, (VO2 max.), from cycling to running. This is most noticeable when running is the main cross-training method. Swimming however, has minimal effects on running or cycling. Perhaps, after all, the specificity principle isn’t as significant as many coaches and exercise scientists have long believed.
At the very least, it appears that certain activities preserve and maintain running fitness while the runner is doing less, or even no, running. This in itself could be a reason for the runner to cross-train. Cross Training