Saturday, January 22, 2011

Endurance Training and Strength Training: A Powerful Combo

Many exercise physiology texts suggest that adding a weight lifting program to endurance training can diminish the cardiovascular and muscle adaptations needed to achieve a high level of fitness. Likewise, adding aerobic exercises to a weight-training program are thought limit gains in strength and power. Several research studies conducted in the mid-1980s showed this to be the case. As a result, athletes whose sport depends on endurance typically shy away from rigorous strength training. When strength training is used, it generally involves relatively light weights and large numbers of repetitions. The idea is to use weight training as a way to improve short-term endurance and avoid gains in muscle mass that might hinder long-term endurance performance. However, new research suggests that we need to re-think the idea of combining strength and endurance training. It appears that high-intensity weight training combined with endurance training may actually benefit endurance performance as well as improve strength and power without significant muscle hypertrophy.

The studies generally focused on endurance athletes and supplemented their endurance training with a program of high-intensity weight lifting. For the weight training, subjects trained 2-3 times per week using a progressive approach. The program started with lifts of 50-60% of the subjects’ 1 repetition maximum (1RM, the maximal amount of weight the athlete can lift one time). The subjects progressed over several weeks until they were performing sets of 4-6 repetitions with ≥ 85% of 1RM (or using the subject’s 4-6 RM). Some studies also used plyometric or explosive types of exercises. Training typically lasted for 10-12 weeks or longer.

The research showed the benefits of adding strength training to an endurance training program incuded: 1) increased VO2max, 2) increased strength and explosive power, 3) improved cycling time trial performance, 4) improved 5K running performance, and 4) improved sprint performance at the end of a 3 hour exercise bout. At the level of the muscle, little or no muscle hypertrophy was observed and not increase in body mass (especially when compared to strength training alone). However, there were important biochemical changes within the muscle that benefit both short- and long-term endurance. Thus, adding high-intensity strength training to an endurance program clearly improved performance in endurance sports.

Why such a difference between these studies and earlier research? The key seems to lie in the intensity of the weight-training program. Older studies supplemented endurance training with a low-intensity lifting routine including lifts requiring ≤ 60% of the 1RM. This is also the approached used with endurance athletes add weight lifting to their training routine. The new studies, on the other and used heavier weights (≥ 85% of 1RM), fewer repetitions per set (≤ 10) as well as explosive types of exercise (plyometrics). Thus the key seems to be combining endurance training with high-intensity resistance exercise rather than low intensity.

Will this type of training work for soccer? That’s a good question. So far, the research has focused on endurance athletes, mainly runners, cyclists and cross-country skiers. However, soccer players can run up to 7 km per match so there is an important endurance component to performance. The match also requires high-intensity sprints interspersed with lower intensity running as well as starting, stopping, cutting and turning. Based on these new research studies, it seems very likely that high intensity weight training could benefit performance. Also, improved strength through resistance exercise can reduce the risk of injury, especially ankle and knee sprains. Given all of this, it seems reasonable to suggest that including high-intensity weight training, as part of a soccer fitness program would aid the soccer player.

What about the young athlete and weight training? Caution should be exercised when considering high-intensity strength training for younger players. While weight lifting is considered safe and effective for children and young adolescents, most experts recommend against using heavy weights as well as free-weight exercises with this group. In fact, several studies show that low resistance, high repetition exercises are more effective for developing strength in pre-pubertal athletes. Also, caution should be exercised with beginning and novice athletes regardless of their age, especially those who have limited experience with weight training. Too much to soon or overloading the young athlete can raise the potential for injury. For more information on the safety and benefits of resistance exercise for young athletes as well as program design recommendations, click HERE and HERE.

The bottom line, in contrast to some exercise physiology texts, combining endurance and resistance training can be beneficial for the endurance athlete, as long as the training is high-intensity. Gains in strength, power and fitness can lead to improved performance compared to endurance training alone. As for the soccer player, high-intensity weight training has the potential to benefit performance on the pitch. However, coaches and athletes should exercise caution when using this sort of program young or inexperienced players and should avoid using it with very young, pre-pubescent players.

References:

Andersen JL, Aagaard P (2010) Effects of strength training on muscle fiber types and size; consequences for athletes training for high intensity sport. Scandinavian Journal of Medicine and Science in Sports, 20:32-38.

Aagaard P, Andersen JL (2010) Effects of strength training on endurance capacity in top-level endurance athletes. Scandinavian Journal of Medicine and Science in Sports, 20:39-47.

Losnegard T, Mikkelsen K, Rønnestad BR, Hallén J, Rud B, Raastad T (2010) The effect of heavy strength training on muscle mass and physical performance in elite cross country skiers. Scandinavian Journal of Medicine and Science in Sports, DOI: 10.1111/j.1600-0838.2009.01074.x

Rønnestad BR, Hansen EA, Raastad T (2009) Strength training improves 5-min all-out performance following 185 min of cycling. Scandinavian Journal of Medicine and Science in Sports, OI: 10.1111/j.1600-0838.2009.01035.x

Rønnestad BR, Hansen EA, Raastad T (2010) Effect of heavy strength training on thigh muscle cross-sectional area, performance determinants, and performance in well-trained cyclists. European Journal of Applied Physiology, 108:965-975.