HOW important is aerobic training for fighters? Opinions vary, and I’ll give you mine shortly. Speed bags and jumping rope have been integral aspects of the conditioning programs of boxers for many years; so has roadwork. Many of the greats of the sport agree, one being Sugar Ray Leonard.

In his POWER (Prepare, Overcome and Win Every Round) speech, Leonard discussed the importance of roadwork in preparing for his fight, and eventual victory, against Marvin Hagler on April 6, 1987, for the WBC Middleweight Championships. “I did the roadwork to defeat Hagler,” says Leonard. “It was organized…and specific…and it worked.”

Many other great champions have been vocal about the benefits of roadwork. Muhammad Ali reportedly hit the pavement for 4 to 6 miles in the morning before breakfast. Said Ali, “The fight is won or lost far away from witnesses ̶ behind the lines, in the gym, and out there on the road, long before I dance under those lights.” As for Floyd Mayweather, check out YouTube for a video of him doing a long run at midnight.

Although I believe some cardio training is necessary for boxers, I see many fighters overdoing aerobic training. I will even go so far as to say that some boxing champions are champions despite their extensive emphasis on roadwork, not because of it. The research I have found on this subject points to several reasons that boxers should take a more conservative approach to long-distance, steady-state roadwork. Here are five of the most important:

  1. Aerobic training can make you slow. Here’s why: Aerobic training makes powerful fast-twitch muscle fibers behave like weaker slow-twitch muscle fibers. A decade-long Canadian study published in 1994 in the Journal of Sports Medicine and Physical Fitness found that subjects who performed regular distance running had 70.9 percent type I fibers in contrast to 37.7 percent found in subjects in a control group. The researchers concluded, “The results revealed that endurance training may promote a transition from type II to type I muscle fiber types and occurs at the expense of the type II fiber population.” This situation is the last thing a fighter needs.
    What’s more, the effects of aerobic training are not localized but create an overall decrease in power. A study published in 2003 in the European Journal of Applied Physiology examined the short-term effects of aerobic training on the rate of force development (ROFD). ROFD is the speed at which force can be produced – it’s the difference between being strong and being powerful.
    In this three-week study of two groups of men who strength-trained, one group performed an additional aerobic training session 30 to 60 minutes in length. Only in the strength training group did the subjects increase their rate of force development, leading the researchers to conclude that “…low-frequency concurrent strength and endurance training leads to interference in explosive strength development.” In practical terms this means aerobic training can reduce punching power. A fighter who can end fights early by punching hard has a serious advantage, so an activity that is apt to reduce punching power is not a wise use of training time.
  1. Aerobic training can make you sick. Excessive aerobic training compromises the immune system, making athletes more susceptible to illness. Studies show that continuous exercise sessions of about 90 minutes each cause greater immune dysfunction than moderate to high-intensity exercise.
  1. Aerobic training can make you fat. Seriously! While in the short-term, aerobic training can help you lose fat, when overdone it can actually make you fatter. One study of women aerobics instructors found that those who taught the most classes had the highest body fat levels. A larger-scale study of 8,080 male and 4,871 female distance runners confirmed those findings. Specifically, in this nine-year study that appeared in the International Journal of Obesity in 2006 researchers found that runners who increased their mileage during the course of this study had larger waistlines.
  1. Aerobic training may lower your testosterone. In a study published in 1995 in the Journal of Applied Physiology, researchers split 35 US Army soldiers into four groups. One group did strength training for the entire body, the second did only upper body strength training, the third did only aerobic training, and the fourth group did both strength and aerobic training. The key point is that only the subjects in the strength-training group increased their testosterone levels and reduced levels of a stress hormone called cortisol. In contrast, the group that combined strength and aerobic training experienced an increase in cortisol, thereby creating a catabolic environment that would reduce gains in strength. The catabolic state could cause a reduction in muscle mass, thus reducing the number of calories the body burns at rest and contributing to fat gain.
  1. Aerobic training increases your risk of overuse injuries. Roadwork can place considerable stress on the joints, especially for heavier fighters. A study on amateur boxers training at the United States Olympic Training Center, which was published in 1990 in The Physician and Sportsmedicine, cites evidence of the connection between aerobic training and overuse injuries in boxers.

Aerobic training does have some merit, especially for fighters who have the defensive skills to stretch their fights into the later rounds. In those rounds there would be a greater contribution of the aerobic system. This is why I have my fighters do a minimal amount of aerobic training – more so as a recovery method – in addition to high-intensity interval training. I also use strongman training as a form of energy system training for my fighters, including world champion Yuriorkis Gamboa who excelled at the farmer’s walk. By including sufficient variety in their training fighters will have the reserve they need in those later rounds without significantly compromising their striking power.

The point is that aerobic training has its place but overdoing it can lead to undesirable consequences. While endurance is important, it’s only one of many qualities a talented fighter must develop to become great.

Mortiz Klatten’s book about strength and conditioning for fighters, The Klatten Power Boxing System, is available now from Amazon.

As a strength coach for boxing, Moritz Klatten has trained three Olympic champions, four amateur world champions, and five professional world champions, including Yuriorikis Gamboa, Juan Carlos Gómezs, Herbie Hide, and Jack Culcay. Among the boxing coaches he has worked with are Ismael Salas, Orlando Cuellar, Fritz Sdunek, Michael Timm, Freddie Roach, Joey Gamache and Jimmy Montoya. Coach Klatten is also an accomplished strength coach for football and has attracted an international clientele that includes Zlatko Junuzović, Werder Bremen; Tolgay Arslan, Beşiktaş; and Piotr Trochowski, Augsburg. Coach Klatten works primarily out of Champ Performance, his own gym in Hamburg, Germany, where he offers strength coaching internships and operates a satellite training service to work with athletes worldwide. He can be reached at klatten@champperformance.de