From Charles Poliquin
Improve your athletic performance and lose fat by doing interval training instead of steady-state aerobic training. A primary error that athletes make is to do the wrong mode of conditioning for their sport. The same goes for recreational trainees who want to get leaner and feel better—the wrong mode of conditioning will keep you fat, weak, and slow.
A couple of new reviews answer the question posed in the title—only endurance athletes should do steady-state aerobics!—and provide guidance for avoiding training errors. Researchers analyzed all the previous studies that reviewed the effect of concurrent strength and aerobic training on strength, power, hypertrophy, and body fat and found the following:
• Body fat percentage decreased the most in both endurance and strength athletes when concurrent strength and near maximal interval sprints were performed.
• Repeated sprint intervals can maintain muscle mass, while increasing the metabolic rate after training. This increase corresponds to the training intensity, and leads to increased activity of an enzyme that enhances the rate of fat burning.
• Steady-state aerobic exercise leads to a very significant decrease in power output that corresponds to the length of the exercise. The lower the intensity of the aerobic exercise, the greater the loss of power.
• Strength and muscle mass are also compromised by steady-state aerobic exercise, and the effect is greatest when aerobic training is performed more than three times a week for longer than 20 minutes.
• Whereas endurance exercises compromise anaerobic performance and body composition, anaerobic training modes such as sprint intervals and weight lifting will benefit endurance athletes if programed properly. To improve endurance performance, do a strength-type resistance training program with loads of 80 percent of the 1RM or heavier. This will train the type IIA muscle fibers so they increase the rate of force development and get faster.
A second review noted that although steady-state aerobic training can produce various beneficial energy system adaptations, those same benefits can be gotten from high-intensity sprint training. Sprint training yields better or equal adaptations as steady-state aerobics in the following areas: maximal aerobic capacity, time to fatigue, and the muscle buffering capacity (the ability to remove waste products). Peak power, energy source use (substrate utilization), and stroke volume are also greater from sprints.
Steady-state aerobic training is discouraged because it can elevate cortisol, leading to an inflammatory stress response that promotes muscle loss and fat storage. It also induces muscle protein breakdown, and can directly inhibit the effectiveness of anabolic hormones like insulin-like growth factor and testosterone. Finally, slow-twitch Type I muscle fibers increase due to steady-state training, leading to decreased power.
Take away the understanding that everyone will benefit from anaerobic sprint and weight training. Only endurance athletes should do steady-state aerobic training. Anaerobic training is the only kind that should be done by strength and power athletes because, as Charles Pfeiffer writes in the review cited below, “the consequences of aerobic exercise are too detrimental to be considered an effective training modality for anaerobic athletes; let alone a necessary one.”
Anaerobic training is far preferable for achieving body composition changes in the general public. Power and functional ability are also maximized with anaerobic training and it is ideal for older individuals who need to maintain bone and muscle as they age.
Murach, K., Bagley, J., Pfeiffer, C. Is Long Duration Aerobic Exercise Necessary For Anaerobic Athletes. Strength and Conditioning Journal. April 2013. 35(2), 44-46.
Wilson, J., Marin, P., et al. Concurrent Training: a Meta-Analysis Examining Interference of Aerobic and Resistance Exercises. Journal of Strength and Conditioning Research. 2012. 26(8), 2293-2307.