The primary study that I'm going to discuss actually attached VO2max measuring equipment to world class karate athletes while they did some sparring.
The results are fairly basic and inline with my own expectations but not necessarily the expectations of many I've talked to about this topic. The study measured heart rate, %VO2max, lactic acid and energy expenditure.
Cardiovascular CapacityThe athletes aerobic capacity i.e. VO2max, was measured first using a standard treadmill test. Then the percentage of that max capacity was measured during sparring. Of note was that the athletes were only at about 40-50% of max while they were sparring. The heart rate was monitored as well and is consistent with anaerobic effort. Another study by the same lab showed that highly technical training like basic striking drills and kata had a lower %VO2max - from a cardiovascular standpoint, they were easier. While sparring drills had a higher %VO2max than actual sparring.
As such we need to include the high intensity sparring drills to get cardiovascular conditioning for fighting.
Energy ExpenditureI've heard people talk about how many calories are burned in fighting. And I've thought that the number would actually be pretty low. An assumption I'd made based on RPE and the METs Compendium. And this study does confirm my expectations. Calories were burned at rate of about 5-8 calories per minute*. so for matches that last 2-3 minutes the total calories was be only 10-15. And an entire tournament would range from 50-120 depending on the number of fights and other variables.
* One of those other variables in calorie expenditure is the athlete's weight. The measured values are really most accurate when viewed relative to bodyweight. And the above number of calories is based on 60 kg athletes. The average weight of male fighters at IGX was closer to 90 kg, so we should increase the estimate proportionally.
Lactic AcidAll kinds of karate training and sparring increased lactic acid concentrations, but not by amounts that are hard to manage. Interval training will readily adapt the body to managing the clearance of a lactate load. Well trained athletes in one study were able to clear lactic acid back to baseline levels within a few minutes after 70 minutes of training, this despite minimal cardio training as part of their regimen.
Intervals in the FightThe primary study also used video of the fights to time how much time was spent actually fighting versus not actively attacking or defending. The results don't surprise me, but they do emphasize the value of high-intensity interval training (HIIT) relative to long, slow distance (LSD) for cardiovascular conditioning.
- Average time spent on offense or defense at one time: 0.3 ± 0.1 seconds.
- Total time for the entire match
- 13.3 ± 3.3 sec. for the 2 minute matches
- 19.4 ± 5.5 sec.for the 3 minute matches
1. Iide, K., Imamura, H., Yoshimura, Y., Yamashita, A., Miyahara, K., Miyamoto, N., & Moriwaki, C. (2008). Physiological Responses of Simulated Karate Sparring Matches in Young Men and Boys. Journal of Strength & Conditioning Research (Lippincott Williams & Wilkins), 22(3), 839–844.
2. IMAMURA, H., YOSHIMURA, Y., NISHIMURA, S., NAKAZAWA, A., NISHIMURA, C., & SHIROTA, T. (1999). Oxygen uptake, heart rate, and blood lactate responses during and following karate training. [Miscellaneous Article]. Medicine & Science in Sports & Exercise February 1999, 31(2), 342–347.
3. Imamura, H., Yoshimura, Y., Nishimura, S., Nakazawa, T., Teshima, K., Nishimura, C., & Miyamoto, N. (2002). Physiological responses during and following karate training in women. / Reponses physiologiques pendant et apres un entrainement de karate chez des athletes feminines. Journal of Sports Medicine & Physical Fitness, 42(4), 431–437.