vo2 requirements of boxing exercises, arseneau e mekary s leger l

_VO2 REQUIREMENTS OF BOXING EXERCISESERIC ARSENEAU, SAID MEKARY, AND LUC A. LEGER

Department of Kinesiology, University of Montreal, Montreal, Canada

ABSTRACT

Arseneau, E, Mekary, S, and Leger, LA. _VO2 requirements of boxing

exercises. J Strength Cond Res 25(2): 348359, 2011The

purpose of this study was to quantify the physiological require-

ments of various boxing exercises such as sparring, pad work, and

punching bag. Because it was not possible to measure the oxygen

uptake ( _VO2) of true sparring with a collecting gas valve in the

face, we developed and validated a method to measure _VO2 of

true sparring based on postexercise measurements. Nine

experienced male amateur boxers (Mean 6 SD: age = 22.0 6

3.5 years, height = 176.0 6 8.0 cm, weight = 71.4 6 10.9

kg, number of fights = 13.06 9.5) of regional and provincial level

volunteered to participate in 3 testing sessions: (a) maximal

treadmill test in the LAB, (b) standardized boxing training in the

GYM, and (c) standardized boxing exercises in the LAB.

Measures of _VO2, heart rate (HR), blood lactate concentration

[LA], rated perceived exertion level, and punching frequencies

were collected. _VO2 values of 43.4 6 5.9, 41.1 6 5.1, 24.7 6

6.1, 30.4 6 5.8, and 38.3 6 6.5 mlkg21min21 were obtained,which represent 69.7 6 8.0, 66.1 6 8.0, 39.8 6 10.4, 48.8 6

8.5, and 61.7 6 10.3% _VO2peak for sparring, pad work, and

punching bag at 60, 120, and 180 bmin21, respectively. Exceptfor lower _VO2 values for punching the bag at 60 and 120 bmin21(p , 0.05), there was no _VO2 difference between exercises.

Similar pattern was obtained for %HRmax with respective values

of 85.5 6 5.9, 83.6 6 6.3, 67.5 6 3.5, 74.8 6 5.9, and 83.0 6

6.0. Finally, sparring %HRmax and [LA] were slightly higher in the

GYM (91.76 4.3 and 9.46 2.2 mmolL21) vs. LAB (85.56 5.9and 6.1 6 2.3 mmolL21). Thus, in this study simulated LABsparring and pad work required similar _VO2 (4341 mlkg21min21,respectively), which corresponds to;70% _VO2peak. These results

underline the importance of a minimum of aerobic fitness for

boxers and draw some guidelines for the intensity of training.

KEY WORDS energy cost, physiological demand, heart rate,

sparring, pad work, punching bag

INTRODUCTION

Boxing, also known as the sweet science, hasironically very little scientific evidence concerningits physiological requirements (14). Therefore,boxers mostly rely on empirical approaches. For

a majority of boxers, training methods are established by trialand errors after numerous practices with their boxing team.Of course, this lack of tangible guidelines makes it difficult todetermine if the training methods used are optimal for thephysiological requirements of competitions. Consequently,the margin of progress and chances of success at the highestlevel become limited. As a result, it can be discouraging andpossibly lead to premature withdrawal or amplify the risk ofinjuries or failures. The few studies that were found on thephysiological requirements of boxing used various method-ologies and often reported different results. Measures such asheart rate (HR) and lactate [LA] are easy to obtain and havebeen reported several times (1,79,12,13,17,18,20,24,25). Ingeneral, HR values around 170180 bmin21 are reported forsparring (79,12,18,24,25) and ;167 bmin21 for pad work(18), whereas a wider range between 145 and 195 bmin21 isobserved for the punching bag (1,13,17,18,20,24,25). For[LA], values around 912 mmolL21 are reported after 3rounds of sparring (9,12) or punching bag (17). On the otherhand, oxygen uptake ( _VO2) during true sparring or otherboxing exercises is difficult to measure and reported valuesare controversial (see below). Reinvestigating the _VO2 cost ofboxing exercises is thus the focus of this study.

Concerning sparring, Seliger (24,25) reported higher _VO2values of 38.9 6 5.9 mlkg21min21 (Mean 6 SD) than theones obtained for the punching bag using the same subjectsand similar methodology. In their compendiums, Durnin (11)reported values of at least 21.8 and 23.1 mlkg21min21 orhigher for women and men, respectively, whereas Ainsworthet al. (2,3) reported values of 31.5 and 42.0 mlkg21min21 forsparring and in ring general [sic], respectively. In a reviewarticle, Ostyn and SJongers (21) reported a _VO2 range of26.342.0 mlkg21min21. More recently using the treadmillHR/ _VO2 regression approach, Chatterjee et al. (79)reported higher mean values from 40.3 6 7.0 to 46.6 6 6.6mlkg21min21 with peak values between 45.9 6 6.0 and50.56 7.9 mlkg21min21 from round 1 to round 3 (2-minuterounds) for women sparring.

Another typical boxing exercise is pad work, which ispunching on a partners pads or mitts. In their study, Moritaet al. (18) reported peak values of 48.2 6 3.8 mlkg21min21.

Address correspondence to Luc Leger, [email protected].

25(2)/348359

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More recently for similar exercise with Muay Thai Boxing,Crisafulli et al. (10) reported values of 42.5 6 2.2mlkg21min21 (average for 3 3-minute rounds) for pad workinvolving fists, elbows, knees, and feet to strike and block.

For the punching bag (heavy bag), Seliger (24,25) reportedvalues of 27.0 6 4.2 mlkg21min21 using meteorologicalballoons to measure _VO2. About 15 years later and usingDouglas bags, Morita et al. (18) reported very high _VO2peakvalues of 52.56 7.1 mlkg21min21, which was superior to the_VO2max of their subjects. In their compendiums (nomethodological details), Ainsworth et al. (2,3) and Moyet al. (19) reported lower values of 21.0 and 18.9mlkg21min21, respectively. Adams et al. (1) reported _VO2costs of 22.9 6 10.0 mlkg21min21 for punching at 120bmin21, whereas young adult male and female boxers (n =5 + 5) were continuously connected to a metabolic systemwithout any foot work. Two years later, ODriscoll et al. (20)did a similar study and reported higher _VO2 costs of 31.5 66.9 mlkg21min21 for a higher synchronized pace of 134bmin21 for punches and lower body movements [sic],whereas young adult male and female boxers (n = 7 + 9) werealso continuously connected to a metabolic system. Recently,Kravitz et al. (13) established the _VO2 cost of punching at 6different frequencies (60120 bmin21) with fitness boxingsubjects hitting a SLAMMAN (Fitness Quest, Canton, OH,USA), which is a type of dummy standing on the floorinstead of a regular hanging punching bag, and they reportedalmost similar _VO2 values of ;27.030.0 mlkg21min21regardless of the punching frequency.

As we can see, the energy cost of boxing exercises variesa lot depending on the type of subjects, the methodology usedto estimate _VO2 cost and according to the type of boxingexercises. For sparring, previous studies used hinderingequipment (collecting gas valve in the face and portable_VO2 systems) or estimated _VO2from HR/ _VO2 regression, whichis not a very accurate procedure(18). In an attempt to solve theseproblems and to enable propercomparisons, we reinvestigatedthe energy cost of key boxingexercises such as sparring, padwork and punching bag witha new method to measure _VO2without hindering the boxersmovement. Furthermore, be-cause these measurements wereobtained in the LAB, we wantedto know whether the sparringintensity in the LAB and in theGYM was similar. This wasdone by comparing the HR,[LA], rated perceived exertion(RPE), and punching frequencyof sparring in the GYM and in

the LAB. A final objective was to study the effect of punchingfrequency on the _VO2 cost of the punching bag. To ourknowledge, this study is unique because it is the only one thatmeasures _VO2 of true sparring without any motionhindrance. It is also the sole study investigating the effect ofpunching frequency on the energy cost of punching the bagwith experienced boxers. Knowing accurate _VO2 requirementsis important to properly adjust the training load of boxers.

METHODS

Experimental Approach to the Problem

To fulfill our objectives, subjects participated in 3 testingsessions: (a) maximal treadmill test in the LAB, (b)standardized boxing training in the GYM, (c) and standard-ized boxing exercises in the LAB. Three 2-minute rounds ofvarious boxing exercises with 1-minute rest in between wereused as the independent variables. In the GYM, theseexercises were sparring and free punching bag, and in theLAB, they were sparring, pad work, and cadence controlledpunching bag with alternating straight punches only, withoutany foot work. The timing of dependent variables ( _VO2, HR,[LA], RPE, and video recording of punching frequency) isillustrated in Figure 1 and detailed thereafter. A minimum of1 day was required between 2 sessions, and all sessions wereconducted within a 3-month span.

Subjects

Nine experienced male amateur boxers (age = 22.0 6 3.5years, height = 176.0 6 8.0 cm, weight = 71.4 6 10.9 kg,number of fights = 13.06 9.5) of regional and provincial levelvolunteered to participate in this study (Table 1). All owneda competition passport licensed by the Canadian AmateurBoxing Association and provided written consent. The studyprotocol was approved by the Ethics Committee ofUniversity of Montreal.

Figure 1. Experimental scheme: dependent variables and their timing for each experimental session.

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Procedures

Session 1. Maximal Treadmill Test in the LAB. Before thetreadmill test, the height and weight were measured withoutshoes. For the treadmill (Q65, model 645, Quinton Instru-ments Co., Bothell, WA, USA) protocol, subjects warmed upfor 3 minutes at 8 kmh21 and 0% slope. Thereafter, the speedwas increased by 1 kmh21 every 2 minutes till exhaustion(15). The objective was to determine the _VO2peak, HRmax,[LA]max, and RPEmax of boxers. The temperature andrelative humidity were around 21 C and 35%.

Session 2. Standardized Boxing Training in the GYM. Thesecond session took place in the respective boxing GYM ofeach boxer, and the goal was to simulate a typical boxingtraining session including 3 sequences of typical exercises:shadow boxing (2 rounds), sparring (3 rounds on approxi-mately 4.9 by 4.9 m [approximately 16 3 16 ft] competitionring) and freely hitting a punching bag (3 rounds) weighingaround 34.0 kg (75.0 lb) depending on the gym. A 10-minuterest was given between each exercise, and this used to put ona head gear, a jock strap, a pair of gloves, and a mouth piece forthe sparring. Rounds were of a 2-minute duration with1-minute standing rest in between. Subjects wore hand wrapsfor the 3 exercises and 0.45-kg (16-oz) gloves for sparring andpunching the bag. Each boxer wore his customary boxinggear and was informed of the procedure beforehand. Subjectswere randomly paired and instructed to perform as theyusually would during these exercises. The RPE was measuredafter the third round of sparring and punching bag exercise,and [LA] was recorded at the end of the third round ofsparring only. For the whole GYM session, HR wascontinuously monitored. Sparring and punching bag roundswere videotaped to count the number and frequency ofpunches thrown. Temperature and relative humidity were notmeasured but subjectively were relatively constant and similarto LAB conditions.

Session 3. Standardized Boxing Exercises in the LAB. During thethird testing session, simulated boxing exercises such asshadow boxing (2 rounds), sparring (3 rounds), pad work(3 rounds), and punching bag (3 rounds) were performed inthe LAB. Boxing gear, round duration, rest period between

exercises and rounds were the same as in session 2. Exerciseswere done on a 4.3 by 4.3 m (14 3 14 ft) free space without

ropes. Sparring was a simulation of the sparring done in theGYM. For the pad work (new exercise), subjects had to hit thepartners pads in a predetermined routine of 4 different

combinations that were always repeated in the same order tillthe end of the rounds. For the right-handed boxers, thecombinations consisted of (a) jab, jab, straight right; (b) jab,

straight right, left hook, straight right; (c) jab, straight right,jab, straight right; and (d) right uppercut, left uppercut,straight right, and left hook. For the sole left-handed boxer,

left and right punches were reversed. Approximately 30seconds of the first round was needed by the subjects to getfamiliar with the combinations and afterward they would

hold a steady rate. For the punching bag rounds, subjects hadto hit a 25-kg (55-lb) bag held motionless by an assistant ina normalized way. They were asked to stand at arm length

from the punching bag with their feet stationary at the widthof their shoulders while hitting the bag alternating with jabs

and straight rights from chin to bag at the beat ofa metronome. Rounds 13 were done at 60, 120, and 180bmin21, respectively.

As for the GYM, the whole session was videotaped, and theHR data were continuously collected. Temperature andrelative humidity were around 21 C and 37%. The RPE wasobtained at the end of sparring, pad work, and after eachpunching bag round. In addition, _VO2 was measured at theend of the third round of sparring and pad work andcontinuously during each round of punching bag. The [LA]was measured at the end of the sparring and pad work only.For sparring and pad work, boxers were connected to themouth piece of our collecting gas system immediately afterthe third round. The system was located about 2 m awayfrom the boxing ring. The whole procedure took about 35seconds, including nose-clip fixation. Once connected to themetabolic system, the subjects were asked to exertthemselves at the same intensity as before, by continuingfoot work and punching on the gloves or pads of his partnerto minimize the recovery process for 6075 seconds to givetime to the metabolic system to reach an equilibrium value.Only equilibrium values were retained as the _VO2 cost of the

TABLE 1. Biometrics and maximal treadmill values of subjects (n = 9).*

Age(y)

Weight(kg)

Height(cm)

_Vo2peak(mlkg21min21)

HRmax(bmin21)

[LA]max(mmolL21)

Experiencefight

Mean 6 SD 22.0 6 3.5 71.4 6 10.9 176.0 6 8.0 62.2 6 4.1 194.9 6 11.8 10.0 6 2.8 13.0 6 9.5Minimum 17.0 56.8 164.0 53.6 177.0 5.0 2.0Maximum 29.0 91.8 189.0 66.2 207.0 14.0 31.0

*[LA] = blood lactate concentration; HR = heart rate.


Energy Cost of Boxing


activity. The calibration of the metabolic system wascompleted about 510 minutes before the first round ofsparring.

That approach to measure postexercise _VO2 was validatedwith another group of 9 subjects using similar rounds oftreadmill exercise, to enable _VO2 measures during theexercise and postexercise phases. _VO2 obtained duringtreadmill exercise was used as our gold standard to assessthe accuracy of _VO2 measured after reconnecting the subjectsat the end of a round of running (Annex 1). In summary,_VO2 values obtained at 3 different intensities on the treadmillbetween 30 and 75 seconds after the reconnection of thesubjects were similar to the values obtained during steadystate exercise (2-way analysis of variance [ANOVA] forrepeated measures and Tukey a posteriori tests (n.s., p. 0.05)and regression analysis: r = 0.96, SEE = 1.6 mlkg21min21).

Figure 1 describes the kinetics of dependent variablesmeasured for the 3 sessions and also indicates potential directcomparisons of boxing exercises for each variable.

Measuring Apparatus and Tests

For _VO2 measures, expired gases passed through an opencircuit and were analyzed in real time by an automated andcomputerized system (Moxus Modular Metabolic System,AEI Technologies, Naperville, IL, USA) (5). Results wereaveraged every 30 seconds for the maximal treadmill test andevery 15 seconds for the simulated boxing exercises in theLAB. The HR was measured throughout every session witha Polar S810 HR monitor. Data were recorded every 5seconds and later transferred on a computer to be analyzed

(Polar Electro, Kempele, Finland). The HR measured withthe Polar S810 is very reliable (16). The RPE was recordedafter every exercise using the Borg scale (6) with scoresranging from 6 to 20 (very, very light to very, very hard).Finally, as a witness of the anaerobic solicitation, [LA] wasmeasured from a fingertip blood sample taken 4 minutes afterthe third round of the exercise. The blood sample wasanalyzed with the Lactate Pro (ARKRAY, Inc., Kyoto, Japan),which has been reported valid (22,23).

Statistical Analyses

Four 2-way (round and boxing exercise) ANOVA for repeatedmeasures with Tukey a posteriori tests were used to describeand compare %HRmax and punching frequency of eachround of sparring and punching bag in the GYM (Figure 2)and sparring and pad work in the LAB (Figure 3). Six 1-wayANOVAs were used to compare average or peak _VO2,% _VO2peak, %HR, [LA], RPE, and punching frequency valuesof the 3 rounds combined for all possible boxing exerciseswhether they were done in the GYM or in the LAB (Table 2and Figure 4). First degree Pearson correlation and SEEbetween _VO2 cost of sparring as the dependent variable andbody weight and _VO2peak as the independent variables werealso computed to see a possible effect of these 2 variables on_VO2 cost of sparring. Unless otherwise stated, all reporteddifferences are significant at the p# 0.05 level. Analyses wereperformed with or without missing data being replaced,giving exactly the same results. Thus, only results withmissing data being replaced are reported (n = 9). Mean6 SDformat is used in the text.

Figure 2. Round effects in the GYM for %HRmax (upper graph) andpunching frequency (lower graph) during sparring and punching (Mean6SD). R and E indicate round by round and exercise effects, respectively(p , 0.05). Right end bar is the mean of the 3 rounds.

Figure 3. Round effects in the LAB for %HRmax (upper graph) andpunching frequency (lower graph) during sparring and pad work (Mean6SD). R and E indicate round by round and exercise effects, respectively(p , 0.05). Right end bar is the mean of the 3 rounds.



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RESULTS

GYM Vs. LAB

Sparring was the sole exercise being studied both in the GYMand LAB in the same conditions (Table 2), and it was foundthat %HRmax and [LA] were higher (p, 0.05) in the naturalGYM environment (91.7 6 4.3 and 85.5 6 5.9 and 9.4 6 2.2and 6.1 6 2.3 mmolL21), whereas RPE and punchingfrequency were similar. Note that these %HRmax andpunching frequency values represent the average of 3 rounds,whereas RPE and [LA] were only taken at the end of last

round. _VO2, %HRmax and RPE obtained for multistagetreadmill test, sparring, pad work, and punching the bag atdifferent frequencies (60, 120, and 180 bmin21) in the LABare also illustrated in Figure 4 and %HR and RPE for sparringand free punching bag in the GYM.

Round Effects

In the GYM, only HR and punching frequency were recordedfrom round to round. %HRmax increased (p , 0.05) fromround to round for sparring and punching bag (Figure 2). For

TABLE 2. Various comparisons: sparring vs. punching bag (GYM), sparring vs. pad work (LAB), and GYM vs. LAB(sparring) for %HRmax (mean of 3 rounds), [LA], RPE, punching frequency (mean of 3 rounds), and _Vo2.*

HR(%HRmax)

[LA](mmolL21)

RPE(620 Scale)

Punching(bmin21)

_Vo2(% _Vo2peak)

_Vo2(mlkg21min21)

GYMSparring 91.7 6 4.3 9.4 6 2.2 12.9 6 1.8 35.7 6 9.9 NA NAPunching bag 86.9 6 5.7 NA 12.6 6 1.9 70.6 6 22.6 NA NASignificance 0.005 n. s. 0.003

LABSparring 85.5 6 5.9 6.1 6 2.3 12.2 6 1.3 34.9 6 7.1 69.7 6 8.0 43.4 6 5.9Pad work 83.6 6 6.3 4.0 6 1.7 13.6 6 2.1 61.4 6 7.9 66.1 6 8.0 41.1 6 5.1Significance n. s. n. s. n. s. 0.000 n. s. n. s.

GYM vs. LAB (sparring)Significance 0.006 0.018 n. s. n. s.

*RPE = rated perceived exertion; [LA] = blood lactate concentration; HR = heart rate; n.s. = not significant.Mean 6 SD (n = 9).

Figure 4. _VO2, %HRmax and RPE obtained for multistage treadmill test, sparring (SPA), pad work (PAD), and punching bag at different frequencies (BAG 60,120, and 180 bmin21) in the LAB. %HR and RPE for sparring and free punching bag in the GYM are also illustrated. Left panel: Mean and SD values covered bya same level horizontal bar are not significant (p . 0.05). Right panel: variability of individual values.




the punching frequency, however, it increased (p , 0.05)only for the punching bag (Figure 2). For each round,%HRmax was higher for sparring (vs. punching bag, p ,0.05), whereas punching frequency was higher on thepunching bag (vs. sparring, p , 0.05).

In the LAB, %HRmax increased only from round 1 toround 2 for sparring and pad work (p , 0.05), whereas thepunching frequency increased from round 1 to round 2 forpad work only (p , 0.05) (Figure 3). No pad work exercisewas performed in the GYM to allow a similar comparison. Inthe LAB, punching the bag was done at increasing imposedfrequency from round 1 to round 3 and %HRmax, andpunching frequency obviously increased (p , 0.05).%HRmax was higher for sparring (vs. pad work, p , 0.05)in round 1 only, whereas punching frequency was higher foreach round for pad work (p , 0.05).

Exercise Effects

Because GYM and LAB results were different (p , 0.05) for%HRmax and [LA] and because different exercises weredone in each location, exercise effects are reported separatelyin each location (Table 2 and Figure 4).

In the GYM, concerning %HRmax and punching fre-quency (Table 2), %HRmax was higher for sparring than forpunching bag (91.76 4.3 and 86.96 5.7, p, 0.05), but it wasthe opposite for punching frequency (35.7 6 9.9 and 70.6 622.6 bmin21, p , 0.05). The same was true for each round(Figure 2). In the LAB (Table 2), %HRmax was similar forsparring and pad work (85.56 5.9 and 83.66 6.3), except for

round 1 (Sparring . Pad, p , 0.05, Figure 3), whereaspunching frequency was higher for pad work than forsparring (61.4 6 7.9 and 34.9 6 7.1 bmin21, p , 0.05). Nofree punching bag exercise was performed in the LAB toallow similar comparisons.

In the GYM, concerning RPE and [LA], they weremeasured only after the third round and [LA] was measuredafter sparring only. Thus, only RPE exercise effects could beassessed, and no difference was found between sparring andpunching bag (12.9 6 1.8 and 12.6 6 1.9). In the LAB, RPEwas similar for sparring and pad work (12.26 1.3 and 13.662.1), but [LA] was almost higher for sparring than for padwork (6.16 2.3 and 4.06 1.7 mmol L21, respectively, p, 0.05).

Most maximal values of the treadmill test ( _VO2peak,HRmax, and RPEmax) were higher (p , 0.05) than valuesobserved while doing sparring, pad work, or punching bag inthe GYM (no % _VO2peak values in that condition) or in theLAB (Figure 4). _VO2 values of LAB sparring, pad work, andpunching bag at 180 bmin21 were similar (43.46 5.9, 41.165.1, and 38.3 6 6.5 mlkg21min21, respectively, p . 0.05).However, _VO2 increased with the punching frequency(24.7 6 6.1, 30.4 6 5.8, and 38.3 6 6.5 at 60, 120, and 180bmin21, respectively, p , 0.05). Significant increases withpunching frequency (p , 0.05) were also observed for RPEand %HRmax (Figure 4). For %HRmax, sparring, pad work,and punching bag at 180 bmin21 in the LAB and punchingbag in the GYM were all similar, whereas sparring in theGYM was higher (p, 0.05) and punching bag at 60 and 120bmin21, was lower (p , 0.05) (Figure 4). For RPE, onlypunching the bag at 60 bmin21 was lower than other boxingexercises whether they were done in the LAB or in the GYM(Figure 4).

Our regression analyses indicated that the _VO2 cost ofsparring (or its intensity) was not significantly (p . 0.05)related to body weight (r = 0.53) nor to _VO2peak (r = 0.51).However the _VO2 cost of sparring tended to be inverselyproportional to the body weight of boxers (Figure 5, uppergraph), but proportional to their _VO2peak (Figure 5, lowergraph), a trend that became significant when we duplicatedthe same results (same dispersion and twice the numbers ofsubjects).

DISCUSSION

Before discussing our results per se, it is worthwhile to discusssome methodological aspects of this study. The main purposeof this study was to quantify _VO2 requirements of variousboxing exercises such as sparring, pad work, and punchingbag. Because _VO2 could not be measured in the natural GYMenvironment, we simulated boxing exercises in the LAB anddeveloped a method to measure _VO2 for those boxingexercises by connecting subjects to the metabolic systemimmediately after 3 2-minute rounds of sparring and padwork while asking them to maintain the same level ofexertion. However, for the punching bag, subjects wereconnected to the metabolic system during the entire exercise.

Figure 5. _VO2 cost of sparring tends to decrease (n. s. at p . 0.05) asa function of body weight of boxers (upper graph) and tends to increases(n. s. at p . 0.05) as a function of _VO2peak (lower graph).



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As indicated previously (Annex 1), this method was provenvalid without systematic error when normalized andcontrolled exercises were performed on the treadmill.Because the subjects subjectively attempted to continueexercising at the same level of exertion, it is possible thatexercise intensity may have been slightly lower or evenhigher. That is one limitation of our study, but we do notexpect a large error from that point of view.

From another point of view, we can ask ourselves ifsimulated boxing exercises in the LAB realistically corre-sponds to natural GYM boxing exercises. Based on the highersparring values of HR and [LA] observed in the GYM ascompared to the LAB (Table 2), we may expect a slightunderestimation of _VO2 values observed for sparring in theLAB. The fact that lower HRs were observed in the LAB forpunching the bag at 60 and 120 bmin21 (67.5 6 3.5 and74.86 5.9%HRmax, respectively, Figure 4) compared to freepunching bag in the GYM at a frequency of 70.6 6 22.6bmin21 (86.9 6 5.7%HRmax, Figure 4 and Table 2), alsoindicates that power of the punches or the foot work ratherthan the punching frequency may explain the higherintensity of the GYM boxing exercises compared to theLAB exercises. The same conclusions could be reached fromRPE measures. Because we do not have any LABGYMcomparison data for the pad work exercise, it is difficult to sayif the observed energy cost is also underestimated for thisactivity, but there is no reason to believe so.

We did our measurements using 2-minute rounds of boxingexercises, but actual ruling sets the round duration to 3-minute for elite amateur and professional male boxers.The 2-minute round rule is still valid for other boxers. In anyevent and at the same pace of exercise, the energy cost shouldnot be affected by the length of the round because metabolicsteady state is reached in about 2 minutes (4) as seen bycontinuous _VO2 recording. On the other hand, it is notexcluded that boxers could decrease their metabolic ratebecause of fatigue, but this would need additional study todemonstrate it. From another perspective, our measurementsonly reflect the energy cost at the end of the last or third 2-minute round. In other words, the exercises may not besteady state tasks and the values observed may not representthe average cost for those exercises, but some kind of a peakor an end value of the third round of exercise assuming that_VO2 increases from round to round and from the first tosecond minutes of each round.

Now that we better understand the methodologicallimitations, it seems easier to discuss the energy cost ofboxing exercises. From our LAB measures, we can say that atleast 43.4 6 5.9, 41.1 6 5.1 mlkg21min21 are required forsparring and pad work, respectively (Figure 4). These valuescorrespond to 69.7 6 8.0 and 66.1 6 8.0% of treadmill_VO2peak. Three months separated the _VO2peak test from _VO2measurements during the boxing exercises. A possibilityexists that these values changed during that time lapse.However, for already well trained subjects such as our boxers

(62.26 4.1 mlkg21min21), _VO2peak improvement is usually,2 mlkg21min21 over a 3-month period even with veryintense training (4). In summary, with _VO2 requirements just.40 mlkg21min21, boxing may not be a typical aerobicsport such as middle or long distance running with known_VO2max values in the 70.085.0 mlkg21min21 range, buta minimal of aerobic fitness may help to maintain first roundpace till the end of the fight.

Our sparring average _VO2 value is higher (see Introduc-tion) than the ones reported by Seliger (24,25), Durnin (11),Ainsworth et al. (2,3), and Ostyn and SJongers (21) possiblybecause of the limitations of their methodological equip-ment (24,25) or computation (2,3,11,21). However, usingtreadmill HR/ _VO2 regression, Chatterjee et al. (79)reported similar _VO2 values for women sparring with anincrease of 40.3 6 7.0 to 46.6 6 6.6 mlkg21min21 fromround 1 to round 3. That is also expected from the increased%HRmax observed from round 1 to round 3 by our ownsubjects while sparring in the GYM. It is difficult to saywhich values represent the true values. Morita et al. (18)found that treadmill HR/ _VO2 regression yielded biased _VO2estimates as compared to boxing HR/ _VO2 regression orsimply _VO2 measured during shadow, pad work, heavy bag,and punching ball exercises. The lower values reported bySeliger (24,25) may be because of hindered movement whilecarrying meteorological balloons during sparring andpunching bag. Furthermore, with a collecting gas valve inthe face, it is difficult to study true sparring as we did inour study. The studies that involved true sparring, wereestimating _VO2 from HR/ _VO2 regression, a procedure that isnot very accurate particularly if the regression was obtainedon the treadmill (18). On the other hand, measurements ofHR and [LA] were easily obtained during true sparring,and values of;180 bmin21 (79,12,18) and 910 mmolL21(9,12) were reported, which is similar to our true sparringHR and [LA] values and thus confirms the intensity ofsparring in the GYM. However, lower HR values of ;170bmin21 were reported by Seliger (24,25), but their boxerswore a mouth piece connected with tubing to meteoro-logical balloons on their back. Thus, we feel that our valuesrepresent a good estimate of the average cost of truesparring and pad work. In any event, the average values maynot be representative for all boxers. With an average around40 mlkg21min21 and an SD around 5 mlkg21min21 forsparring and pad work, it means that based on a normaldistribution, around 32% of boxers are either ,35 or .45mlkg21min21 when doing those activities. Thus, it isimportant to exercise caution before generalizing averagevalues to all individuals. Some of these differences may bebecause of the weight or the fitness level of the boxers.Typically, compared to light boxers, heavy boxers tend tomove slowly in the ring. In our study, there was a tendencyfor a lower _VO2 cost in heavier boxers (Figure 5), a tendencythat might be significant with a larger number of subjects.Similarly, the boxers with better _VO2peak tend to have




a higher _VO2 cost of sparring or to invest themselves moreduring sparring (Figure 5). Although logical and interesting,this needs to be confirmed with a larger sample.

Now let us discuss the energy cost of punching the bag. OurLAB measurements at frequencies of 60, 120, and 180bmin21, yielded _VO2 costs of 24.7 6 6.1, 30.4 6 5.8, and38.36 6.5 mlkg21min21, respectively. For free punching bagin the GYM at 70.66 22.6 bmin21, using LAB _VO2 data at 60bmin21 grossly underestimates the metabolic cost becausethe punching intensity was probably much larger. However,because %HRmax and RPE are similar to the ones observedduring punching the bag at 180 bmin21 in the LAB, the _VO2cost of free punching bag exercise in the GYM is probablycloser to the LAB cost at 180 bmin21 (38.3 6 6.5mlkg21min21, Figure 4). This value is a bit lower than thevalues we obtained for sparring and pad work, which isconsistent with the results of Seliger (24,25).

Thus, in addition to foot work, higher power of the punchesin the GYM may explain these higher RPE and HR values. Intheir study, Kravitz et al. (13) also measured the _VO2 cost ofpunching at different frequencies. Keeping in mind that theyhave used recreational fitness boxers hitting a SLAMMANinstead of a regular suspended punching bag, they havereported values around 27.030.0 mlkg21min21 for punch-ing frequencies between 60 and 120 bmin21. This is almostidentical to our values but probably underestimates the realcost of punching in the GYM with elite boxers for the reasonsmentioned above. Furthermore, ODriscoll et al. (20)reported values of 31.5 6 6.9 mlkg21min21 for a punchingfrequency of 134 bmin21, which is in between our values at120 and 180 bmin21, and Adams et al. (1) reported values of22.9 6 10.0 mlkg21min21, which is lower than our valuesobtained for the same punching frequency of 120 bmin21.However, other studies (2,3,19,24,25) reported valuesbetween 18.9 and 27.0 mlkg21min21 for free training ofboxing on the punching bag, which would be lower than ourestimate of 38.3 6 6.5 mlkg21min21 (see above).

These discrepancies in the punching bag cost may bebecause of different methodologies such as the _VO2 measures,the punching power, or frequency and the integration or notof footwork. However, Morita et al. (18) reported values of52.5 6 7.1 mlkg21min21, which this time is much largerthan our 38.36 6.5 mlkg21min21 estimate for free punchingon the bag. We do not have any explanation for this, but it isinteresting to note that their values were slightly higher thanthe _VO2max of their subjects. Thus, our 38.3 6 6.5mlkg21min21 estimate for 3 rounds of free punching bagcorresponds to 61.7 6 10.3% _VO2peak and is a much lowervalue than ;100% _VO2peak. On the other hand, it is quitefeasible to reach _VO2max on the punching bag if a boxerpunches as fast and as hard as possible and gets exhausted atthe end of a single round of punching bag. Interestingly, onestudy reports that between 2 boxers with similar HRresponse, the one with the largest punching power has thelowest punching frequency (17). The energy cost of punching

is thus related to many conditions, and it is very difficult toattribute a single value for this particular exercise.

PRACTICAL APPLICATIONS

Even though boxing requires a combination of technical,tactical, mental, and physical skills, this study indicates thataerobic fitness is certainly one of the important physicalqualities to consider as seen by a _VO2peak of 62.2 6 4.1mlkg21min21 and a relative intensity of ;70% _VO2peak forthe most demanding boxing exercises such as sparring andpad work. This also gives an indication for the minimal levelof aerobic training stimuli required for the boxers because theintensity could be higher in real competition. However,aerobic fitness is probably more important as the duration orthe number of rounds increases. From another point of view,punching frequencies of around 35 and 60 bmin21 insparring and pad work, respectively, were observed in thisstudy and gives an idea of the frequency that should be usedwhen training those abilities. To be more specific, our study isthe only one to measure the _VO2 cost of true sparring andthose values indicate (a) the importance of _VO2max in thetraining program of the boxer and (b) the minimal intensity atwhich training loads should be set for aerobic training. Thisstudy also reports punching frequency data for sparring, padwork and free training on the punching bag that could beused as training guides for boxers.

ACKNOWLEDGMENTS

The authors would like to thank Mr. Daniel Trepanier,Technical Coordinator at Boxing Canada, who facilitated ourwork and also all the boxers that participated in this study andthe subjects that participated in the validation process (Annex 1).The authors have no undisclosed professional relationshipswith companies or manufacturers that would benefit from theresults of this study. The results of this study do not constituteendorsement of the product by the authors or the NationalStrength and Conditioning Association.

REFERENCES

1. Adams, KJ, Allen, NB, Schumm, JE, and Swank, AM. Oxygen cost ofboxing exercise utilizing a heavy bag [Abstract]. Med Sci Sports Exerc29: S187, 1997.

2. Ainsworth, BE, Haskell, WL, Leon, AS, Jacobs, DR, Montoye, HJ,Sallis, JF, and Paffenbarger, RS. Compendium of physical activities:Classification of energy costs of human physical activities. Med SciSports Exerc 25: 7180, 1993.

3. Ainsworth, BE, Haskell, WL, Whitt, MC, Irwin, ML, Swartz, AM,Strath, SJ, OBrien, WL, Bassett, DR, Schmitz, KH, Emplaincourt,PO, Jacobs, DR, and Leon, AS. Compendium of physical activities:An update of activity codes and MET intensities. Med Sci Sports Exerc32: S498S504, 2000.

4. Astrand, PO and Rodahl, K. Textbook of Work Physiology (Figures 9.3and 12.13).New York, NY: McGraw-Hill, 1977.

5. Babineau, C, Leger, L, Long, A, and Bosquet, L. Variability ofmaximal oxygen consumption measurements in various metabolicsystems. J Strength Cond Res 13: 318324, 1999.

6. Borg, GA. Perceived exertion: A note on history and methods. MedSci Sports 5: 9093, 1973.



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7. Chatterjee, P. Energy expenditure of women boxers in India. NigerianJ Health Biomed Sci 5: 1720, 2006.

8. Chatterjee, P, Banerjee, AK, and Majumdar, P. Energy expenditure inwomen boxing. Kathmandu Univ Med J (KUMJ) 4: 319323, 2006.

9. Chatterjee, P, Banerjee, AK, Majumdar, P, and Chatterjee, P. Oxygenconsumption, heart rate and blood lactate response during sparringon Indian women boxers. Int J Appl Sports Sci 17: 916, 2005.

10. Crisafulli, A, Vitelli, S, Cappai, I, Milia, R, Tocco, F, Melis, F, andConcu, A. Physiological responses and energy cost duringa simulation of a Muay Thai boxing match. Appl Physiol Nutr Metab34: 143150, 2009.

11. Durnin, JV. The energy cost of exercise. Proc Nutr Soc 44: 273282,1985.

12. Ghosh, AK, Goswami, A, and Ahuja, A. Heart rate & blood lactateresponse in amateur competitive boxing. Indian J Med Res 102: 179183, 1995.

13. Kravitz, L, Greene, L, Burkett, Z, and Wongsathikun, J. Cardiovascularresponse to punching tempo. J Strength Cond Res 17: 104108, 2003.

14. Lane, AM.Introduction to the special issue on combat sport(Combat Sports Special Issue). J Sports Sci Med 5: iiii, 2006.

15. Leger, L and Boucher, R. An indirect continuous running multistagefield test: The Universite de Montreal Track Test. Can JAppl Sport Sci5: 7784, 1980.

16. Leger, L and Thivierge, M. Heart rate monitors: Validity, stability,and functionality. Physician Sportsmed 16: 143151, 1988.

17. Martos, E and Jako, P. Exercise physiology in boxing. Hungarian RevSports Med 39: 197220, 1998.

18. Morita, Y, Seiiti, N, and Takashi, I. Energy expenditure during boxingtraining (In Japanese). Nippon Sport Sci Univ J 13: 5966, 1984.

19. Moy, K, Scragg, R, McLean, G, and Carr, H. Metabolic equivalent(MET) intensities of culturally-specific physical activities performedby New Zealanders. N Z Med J 119: U2000, 2006.

20. ODriscoll, E, Steele, J, Perez, H, Yreys, S, Snowkroft, N, and Locasio,F. The metabolic cost of two trials of boxing exercise utilizinga heavy bag [Abstract]. Med Sci Sports Exerc 31: S158, 1999.

21. Ostyn, M, and SJongers, JJ. Cout metabolique des sports de combat(In French). Med Sport 54: 3, 1980.

22. Pyne, DB, Boston, T, Martin, DT, and Logan, A. Evaluation of theLactate Pro blood lactate analyser. Eur JAppl Physiol 82: 112116, 2000.

23. Saunders, AC, Feldman, HA, Correia, CE, and Weinstein, DA.Clinical evaluation of a portable lactate meter in type I glycogenstorage disease. J Inherit Metab Dis 28: 695701, 2005.

24. Seliger, V. Energeticky metabolismus u vybranych telesnych cviceni(In Czech). Praha, Czechoslovakia: Karlova Universita, 1967.

25. Seliger, V. Energy metabolism in selected physical exercises. Int ZAngew Physiol 25: 104120, 1968.

APPENDIX 1. VALIDATION OF POSTEXERCISEMEASUREMENTS TO ESTIMATE EXERCISE _VO2

INTRODUCTION

In some exercises such as sparring, while the boxer mayreceive punches to the head and upper body, it is notpossible to wear a collecting gas valve in the face ora portable _VO2 system on the chest to collect expired

gasses. _VO2 could be estimated from individual HR/ _VO2regression, but those estimations are not accurate, particu-larly if the regression is obtained from another type ofexercise (e.g., Treadmill vs. Sparring) (4). Because none ofthese 2 traditional methods permit proper measurements oftrue sparring _VO2, we developed a new method to do so, thatis, a method that measures _VO2 of true sparring with actualpunches to the face and chest. With this method, the subjectsare connected to the metabolic system right at the end of anexercise bout done at a relatively constant intensity that lastsat least 2 minutes to reach steady _VO2 (e.g., third 2-minuteround of sparring) and are instructed to keep moving theirlegs and arms to maintain their metabolic activity at the samelevel as it was before the connection. When the metabolicsystem reaches equilibrium ($30 seconds to wash thesystem), _VO2 is recorded as the exercise steady state oraverage value. The general purpose of this study was tovalidate this approach to measure _VO2 in field conditions.

METHODS

Subjects

Nine kinesiology students (age = 27.0 6 13.4 years, height =174.0 6 7.9 cm, and weight = 76.2 6 16.8 kg) volunteered toparticipate in this validation process.

Factors to Consider

When the method is used in the field, gases are collected only atthe end of a task done at a relatively constant intensity, forexample, after the third 2-minute round of sparring. To validatethese measures, a criterion measure was required, which was _VO2during the exercise itself. Thus, in the validation process, _VO2was measured both during the exercise and after the exercise.Furthermore, for the postexercise measures in field conditions,we asked the subjects to continue to move at the same intensityimmediately after being connected to the metabolic system toavoid the recovery process. In the validation study, treadmillexercise was used to be able to measure _VO2 both during theexercise itself and after the exercise.

One more aspect needs to be considered. When used infield conditions, the metabolic system may often bedisconnected from the subjects for 1016-minute periodsbefore reconnecting the subjects for the postexercise




measurements. Therefore, during the validation process, theexercise steady state criterion measures were taken ;1530minutes before the postexercise measures. This happenedmany times after the initial calibration to validate the methodat different intensities. We thus developed an exercise patternthat takes into consideration all these aspects including thecalibration that was made up to 85 minutes before numerousconnections and disconnections to the metabolic system.

The validation study was thus designed to answer thefollowing questions: (a) How are _VO2 values affected by many1016 minute disconnections from the metabolic systemafter initial calibration? (b) Can the gas analyzing system staycalibrated for up to 85 minutes? (c) How long does it take towash the metabolic system from zero input and to reach _VO2equilibrium? (d) Are 3 2-minuterounds of running exercise with1-minute rest in betweenenough for the subjects to reacha steady state _VO2? (e) Howdoes exercise intensity affect theaccuracy of the postexercisemeasures? (f ) Are the postexer-cise values significantly differentfrom the criterion values?

Validation Protocol

Each subject ran on the tread-mill at 3 different intensities forat least 2 minutes continuouslyto reach metabolic steady state.Intensities were chosen to coversubjects capacity and a widerange of energy costs. Eachintensity was done twice: firsttime to obtain criterion _VO2values and second time to seeif the postexercise _VO2 valueswere the same as the criterionvalues. For the postexercisemeasures of the validation pro-cess, the subjects briefly stop-ped running to connectthemselves to the gas analyzingsystem and hopped back on thetreadmill to continue running atthe same speed to avoidrecovery process for the collec-tion periods. To summarize, thesubjects (a) ran on the treadmillwhile their criterion exercise_VO2 were measured, (b) tooka 810-minute rest, (c) got backon the treadmill for 48 mi-nutes without being connectedto the system to mimic various

field conditions, (d) stopped running for 1015 seconds to puta nose clip and to connect themselves to the metabolicsystem, and (e) got back on the treadmill for 1.752 minutesto collect the postexercise measures. The protocol isillustrated in Figure 1. The black line is the predicted _VO2costs of treadmill running using Legers equation (2,3):

Vo2mlkg1 min1

2:209 3:163 speed kmh1:1

The predicted cost is thus proportional to the speed patternof the protocol and illustrates the actual exercise workloadand also enables a comparison of the _VO2 values obtainedwith our system and the values reported in the literature.

Figure 1. Typical individual kinetic of predicted and measured _VO2 during and after exercise at 3 differentintensities.

Figure 2. Comparison between predicted _VO2 (equation 1) and _VO2 measured during and after exercise for 9subjects at 3 intensities (Differences between type of _VO2 estimates: n.s., p . 0.05; intensity effect: p , 0.05).



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Each subject had a different set of speeds. The individualkinetic of _VO2 measured during and after exercise at 3different speeds for 1 subject is also illustrated in Figure 1(gray line) and enables comparison between exercise andpostexercise measures and between literature predicted costsfor 3 different intensities. Similar curves were obtained for allthe subjects.

Statistical Analyses

Postexercise _VO2 measures, criterion exercise _VO2 meas-ures, and literature predicted _VO2 values (equation 1) werecompared for each running intensity using a 2-way ANOVAfor repeated measures and Tukey a posteriori tests. A linearregression and a scatterplot were also done to compare

postexercise _VO2 measures and criterion exercise _VO2measures. Unless otherwise stated, all reported differencesare significant at the p # 0.05 level.

RESULTS

Figure 1 is a typical representation of _VO2 predictions and_VO2 measurements during and after exercise at 3 differentintensities during the exercise protocol for 1 subject. Similarpatterns were obtained for all the subjects. Figure 2summarizes the results of the whole group and illustratessimilar values between criterion exercise, postexercise, andliterature predicted _VO2 values. This is observed for the wholerange of investigated metabolic levels. Not only were thevalues obtained immediately after reconnecting the subjectsto the metabolic system similar to the criterion exercisevalues, but these 2 values were also similar to reported valuesin the literature indicating no important systematic differ-ences between these _VO2 values. Furthermore, randomvariation between _VO2 measured during running or imme-diately after reconnecting the subjects to the metabolicsystem were very small as seen by the high correlation andthe small SEE (r = 0.96, SEE = 1.6 mlkg21min21, Figure 3)between these 2 variables.

A closer look at the individual curves with extendedabscissas (Figure 4) illustrates that the system equilibrium isreached between 30 and 75 seconds (second to fifth15-second sample) after reconnection. Similar results weresystematically obtained for all the subjects, indicating that onlya short delay or a short time-sampling collection is required toobtain proper _VO2 values after reconnecting the subject.

DISCUSSION

Our metabolic system yields similar exercise and post-exercise _VO2 values for the same workload after beingdisconnected many times for 1016 minute periods. Thus,it is not a problem to measure _VO2 many times after

different tasks of various in-tensities between 8 and 13kmh21 or ;25 to 45mlkg21min21 while the met-abolic system is disconnectedin between and calibrated upto 85 minutes before. Further-more, we can see that themetabolic system adjusts itselfwithin 3045 seconds afterreconnecting the subjects. Fi-nally, we can see that 3 2-minute periods of exercise areenough to achieve metabolicsteady state and that attained_VO2 values truly reflect theenergy cost of the activitybeing measured, which is inconformity with the classical

Figure 4. Typical enlarged individual and superposed _VO2 kinetic after reconnecting the subject to the metabolicsystem at 3 different intensities. The system reaches equilibrium from the second 15-second sample or 30 secondsafter reconnecting the subjects.

Figure 3. Regression and Pearson correlation between _VO2 measuredduring and after exercise for 9 subjects at 3 intensities.




work of Astrand and Rodahl (1). Of course, we used wellcontrolled treadmill running instead of subjective arm andleg exercise during the postexercise period of thevalidation process. Although we cannot be totally sure,the error should not be much different when the level ofactivity is subjectively maintained after reconnecting thesubject to the metabolic system when the method is usedwith other types of activities where it is not possible towear a respiratory face mask (e.g., sparring). Therefore, itis difficult to say if the limitations of the present approachare smaller or larger than the limitations of approachesused in previous sparring studies. However, the resultswe obtained with this new approach certainly bringnew insight in the _VO2 cost of true sparring. Thus, theresults of this validation process confirm the potential ofthis new approach in field conditions for our metabolicsystem at least.

These results were obtained with the same metabolicsystem used with the boxers in the experimental study. Withother models or brands of metabolic system, however, werecommend to check as we did the stability of the _VO2measures for many disconnections and connections after theinitial calibration and to check the time required by themetabolic system to reach equilibrium values after recon-necting the subjects from a zero input signal. Furthermore,

before measuring the energy cost of a new activity with thisapproach, it is also recommended to check if the metabolicsystem used yields treadmill or cycling _VO2 values that aresimilar to accepted literature values.

CONCLUSION AND PRACTICAL APPLICATIONS

That method was developed to determine the _VO2 cost ofrelatively steady-state 2-minute rounds of sparring and padwork in boxing but could also be useful in other field situations(a) where the use of a portable _VO2 system seriously hindersthe motion pattern or (b) where such a portable system is notavailable. It is however important to make sure that thesubjects are relatively in a steady state before connecting thesubjects to the metabolic system and that the subjects continueto exercise at the same level during the measurement phase.

REFERENCES

1. Astrand, PO and Rodahl, K. Textbook of Work Physiology (Figure 9.3,p. 296). New York, NY: McGraw-Hill, 1977.

2. Hall, C, Figueroa, A, Fernhall, B, and Kanaley, JA. Energy expenditureof walking and running: Comparison with prediction equations. MedSci Sports Exerc 36: 21282134, 2004.

3. Leger, L and Mercier, D. Gross energy cost of horizontal treadmilland track running. Sports Med 1: 270277, 1984.

4. Morita, Y, Seiiti, N, and Takashi, I. Energy expenditure during boxingtraining (in Japanese). Nippon Sport Sci Univ J 13: 5966, 1984.



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vo2 requirements of boxing exercises, arseneau e mekary s leger l

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