Energy cost and cardiorespiratory demands of nunchaku exercise

The purpose was to examine the energy cost and cardiorespiratory demands of nunchaku exercise, one of the martial arts performed with an instrument.

Nine male martial art practitioners (age 26.4 (+/-SD) 3.4 years, VO2max 54.1+/-9.0 ml x kg(-1)x min(-1)) completed three nunchaku exercise trials, lasting 20 sec, 1 min and 5 min. Cardiorespiratory response was followed by the Cosmed K4 portable respiratory analysis system.

Oxygen consumption (VO2) was determined during pre-exercise rest, the exercise period and the recovery phase (10-15 min), and energy release from lactate (La) production was calculated assuming that an increase of 1 mmol x l(-1) corresponds to aVO2 of 3 ml O2 (di Prampero 1981).

The overall energy cost of nunchaku exercise attained 76+/-16 kJ (229+/-48 kJ x min(-1)), 98+/-23 kJ and 271+/-72 kJ (54+/-14 kJ x min(-1)) for the 20 sec, 1 min and 5 min nunchaku exercise, respectively. From the point of view of the energy sources (alactic, lactic and oxidative), 20-sec performance was essentially "anaerobic alactic" (69:15:16%), 1 min exercise "alactic-oxidative" (49:16:35%) and 5-min performance an "oxidative" exercise workload (17% alactic: 6% lactic: 77% oxidative, respectively). The intensity of the exercise, on the average, corresponded to 43, 49 and 56% of VO2max and 69, 72 and 76% of HRmax, for the 20 sec, 1 min and 5 min exercises, respectively.

Nunchaku exercise elicits high alactic and oxidative energy sources, but its demand for anaerobic glycolytic pathway seem to be relatively low, regardless the duration of the exercise. The energy cost (EC) for 20-sec to 5-min lasting exercise may be described by power function EC=10.84.t(-0.522) (n=24, r2=0.95), where EC is in kJ x min(-1) x kg(-1) and t in seconds.