Wednesday, June 17, 2009

Getting a Bigger Bang for Your Training Buck?

Coaches and athletes are constantly searching for ways to improve fitness. Endurance and interval training are the most often used. However, these programs usually require a time commitment of 30-00 minutes per day. This time commitment makes it difficult, if not impossible, to incorporate endurance training into a typical practice session. Researchers at McMaster University have found that a program brief, high intensity exercise might actually improve fitness more than a traditional endurance training program. This program requires only 2-3 minutes of exercise per session – a much bigger bang for the training buck. But, can this type of training be effectively used by soccer players?

In a series of studies headed by Dr. Kirsten Burgomaster, the researchers asked their subjects to perform a very small number of very high-intensity bouts of exercise. The high-intensity training groups used a stationary bicycle and performed 30 seconds of all-out, supra-maximal exercise - they pedaled as hard as they could for 30 seconds. They then rested for 4 minutes and repeated the bout 4 to 6 times. This was done 3 times per week for either 2 or 6 weeks. For comparison, an endurance training group cycled continuously for 40-60min per session, 5 times per week.

After only two weeks of training (only 6 sessions), the high-intensity group, doubled endurance time. That is, they exercise for nearly twice as long before reaching exhaustion. They also improved time-trial performance by 10%. The endurance group showed little to no improvement. After 6 weeks the high-intensity group showed several important biochemical changes within the muscle, such as glycogen, phosphocreatine levels and metabolic enzyme activities. Interestingly, laboratory measures of “fitness” such as VO2max and exercise heart rates were not improved.

A key difference in the two training groups was the amount of time spent training and the total amount of work performed. Training for high-intensity group required about 2-3 minutes of actual exercise compared to 60 minute for the endurance group. Including recovery, the high-intensity session lasted ~20 minutes. Also, the high-intensity group performed about half as much total work as the endurance group. The bottom line is that high-intensity training resulted in greater improvements with less time and work.

As a coach, it’s easy to see how this type of high-intensity training would be a tremendous benefit for improving fitness when practice time is limited. The big question is, should coaches consider using this type of training with their players? Instead of using an exercise bike, players could do repeated 30 second sprints (or 200-300 meter sprints) with a 4 minute recovery. However, there are a few things to consider before abandoning traditional training. First, the researchers are quick to point out that they don’t know for sure if high-intensity training provides all of the cardiovascular, metabolic and muscular benefits that traditional endurance training does. It’s also not known if the improvements are long lasting. Second, it’s not known if the improvements found in these studies will translate into improved fitness over the course of a 70-90 minute match. This is particularly important when one considers the stop-start, run-sprint nature of soccer. Third, and most importantly, cycling is much different than running when it comes to impact forces on the knee, ankle and hip. Using high-intensity running during training might increase the risk of orthopedic, over-use injuries, especially in young athletes. At the very least, players should be allowed a day or two to recover from each training session.

For now, this series of studies raises some very interesting ideas regarding training. They may ultimately cause us to re-think how we go about fitness development. However, much more work needs to be done to determine of high-intensity training is appropriate and effective for young footballers.

Note: Many thanks to Dr. Don Kirkendall of the FIFA Medical Assessment and Research Centre for suggesting this topic.

References:

Gibala MJ, McGee SL (2008) Metabolic adaptations to short-term high-intensity interval training: A little pain for a lot of gain? Exercise and Sports Sciences Reviews, 36:58-63.

Burgomaster KA, Howarth KR, Phillips SM, Rakobowchuk, MacDonald MJ, McGee SL, Gibala MJ (2008) Similar metabolic adaptation during exercise after low volume sprint interval and traditional endurance training in humans. Journal of Physiology, 586:151-160.

Gibala MJ, Little JP, van Essen M, Wilkin GP, Burgomaster KA, Safdar A, Raha S, Tarnopolsky MA (2006) Short-term spring interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance. Journal of Physiology, 575:901-911.

Burgomaster KA, Heigenhauser GJF, Gibala MJ (2005) Effect of short-term sprint interval traiig on human skeletal muscle carbohydrate metabolism during exercise and time-trial performance. Journal of Applied Physiology, 100:2041-2047.

Burgomaster KS, Hughes SC, Heigenhauser GJF, Bradwell SN, Gibalb MJ (2004) Six sessions of sprint interval training increases muscle oxidative potential and cycle endurance capacity in humans. Journal of Applied Physiology, 98:1985-1990.