Sports Special Issue Research article
COMPARISON OF NORMALIZED MAXIMUM AEROBIC CAPACITY AND BODY COMPOSITION
OF SUMO WRESTLERS TO ATHLETES IN COMBAT AND OTHER SPORTS
1United States Military Academy, West Point, Department of Physical Education,
West Point, NY, USA
2Tokyo Metropolitan University, Department of Exercise and Sport Science,
3Nihon University, Department of Exercise Physiology, Tokyo, Japan
4The University of Tokyo, Department of Human Ecology, Tokyo, Japan
Journal of Sports Science and Medicine (2006) 5 (CSSI), 13
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wrestling is unique in combat sport, and in all of sport. We examined
the maximum aerobic capacity and body composition of sumo wrestlers
and compared them to untrained controls. We also compared "aerobic
muscle quality", meaning VO2max normalized to predicted
skeletal muscle mass (SMM) (VO2max /SMM), between sumo
wrestlers and controls and among previously published data for male
athletes from combat, aerobic, and power sports. Sumo wrestlers, compared
to untrained controls, had greater (p < 0.05) body mass (mean ±
SD; 117.0 ± 4.9 vs. 56.1 ± 9.8 kg), percent fat (24.0 ± 1.4 vs. 13.3
± 4.5), fat-free mass (88.9 ± 4.2 vs. 48.4 ± 6.8 kg), predicted SMM
(48.2 ± 2.9 vs. 20.6 ± 4.7 kg) and absolute VO2max (3.6
± 1.3 vs. 2.5 ± 0.7 L·min-1). Mean VO2max /SMM
(ml·kg SMM-1·min-1) was significantly different (p <
0.05) among aerobic athletes (164.8 ± 18.3), combat athletes (which
was not different from untrained controls; 131.4 ± 9.3 and 128.6 ±
13.6, respectively), power athletes (96.5 ± 5.3), and sumo wrestlers
(71.4 ± 5.3). There was a strong negative correlation (r = - 0.75)
between percent body fat and VO2max /SMM (p < 0.05).
We conclude that sumo wrestlers have some of the largest percent body
fat and fat-free mass and the lowest "aerobic muscle quality"
(VO2max /SMM), both in combat sport and compared to aerobic
and power sport athletes. Additionally, it appears from analysis of
the relationship between SMM and absolute VO2max for all
sports that there is a "ceiling" at which increases in SMM
do not result in additional increases in absolute VO2max.
WORDS: Oxygen uptake, skeletal muscle mass, fat-free mass, fat
|Combat sports arguably contain unique characteristics in comparison
to other sports: one must directly attack and conquer an opponent.
Most combat sports require (in the physical realm) a mix of technique,
strength, aerobic fitness, power, and speed. Thus, usually no one
performance characteristic dominates in combat sports, like in (for
instance) the shot put, where size, strength and power dominate, or
marathon running, where ability to maintain continuous aerobic output
dominates (Bassett and Howley, 2000).
One of the most unique combat sports is that of Sumo wrestling. To
win in sumo, one must push one's opponent out of the ring, or cause
the opponent to touch the ground with any part of the body except
the soles of the feet. Although this sounds deceptively simple, sumo
is an extremely complex sport requiring a combination of strength
(Kanehisa, et al., 1997; 1998), massive size (very large fat free
and fat mass; Hattori, et al., 1999; Kondo, et al., 1994), and probably
some combination of anaerobic and aerobic capacity. The characteristics
needed to participate at an elite level in this sport are held only
by a select group of athletes. Interestingly, we could find no published
study on the anaerobic or aerobic characteristics of sumo wrestlers.
The purpose of this study is to compare and contrast the maximum aerobic
capacity and body composition of sumo wrestlers with untrained controls,
and to previously published data from participants in other combative,
aerobic, and power sports. Untrained controls were used to indicate
where on the aerobic capacity continuum that sumo wrestlers fall.
Eight untrained college undergraduates (22.2 ± 1.0 yrs; all data
presented as mean ± SD) and eight highly trained, championship-level
college sumo wrestlers (21.1 ± 1.0 yrs) volunteered to participate
in this study. The sumo wrestlers were members of Japan's number
one collegiate team, and included a champion of the Japan Amateur
Championship. Sumo wrestlers had been competitively training for
a minimum of four years (5.5 ± 2.6 years). Controls had not participated
in recreational sports for at least two years prior to testing.
The department's ethical commission approved the study. All participants
received a verbal and written description of the study and gave
informed consent prior to testing. We also compared the results
from the sumo wrestlers and untrained controls with previously published
data from combative (including Judo, karate, boxing, wrestling,
and Kendo), aerobic (including marathon, long and middle distance
running, rowers, and cross country skiing), and power sports (including
U.S. football, discus throw, shot put, and basketball; see Table
1). Weighted means of these groups from previously published
results were calculated for comparison purposes.
Measurement of VO2 max
Maximal oxygen uptake (VO2max) was assessed by graded
work on a cycle ergometer (Aerobike 400, COMBI Co., Ltd.). The participants
started to exercise at 30 W for 2 min, and the load was increased
by 15 W every minute until exhaustion. The exercise was terminated
when the participants failed to maintain the prescribed pedaling
frequency of 60 rpm. Respiratory gas was collected with an automated
breath-by-breath mass spectrometry system (Aeromonitor AE-280S,
Minato Medical Science Co., Ltd.) and gas exchange was computed
every 60 s. Heart rate was monitored by a Polar Heart Rate Monitor
(Vantage XL, Polar, USA). The following criteria were used to establish
maximum effort: oxygen consumption appearing to plateau with increasing
workload (< 150 ml·min-1), maximum heart rate within
± 11 bpm of the age-predicted maximum (220-age), and a maximum respiratory
exchange ratio above 1.15.
of body composition
Fat-free mass (FFM) was estimated from body density using the subcutaneous
fat measurements from ultrasound (Body density = 1.090 - 0.00050
[sum 9 sites of AT thickness]; Abe, et al., 1994).
We have previously reported that the standard error of the estimate
(SEE) of body density using ultrasound equations is approximately
0.006 g·ml-1 (~ 2.5% body fat) in the normal Japanese
population (Abe, et al., 1994).
However, extracellular fluid content tends to increase in obese
participants (Waki, et al., 1991) and may be higher in sumo wrestlers.
If so, this could affect the estimation of body composition in sumo,
but to what extent is unclear. Our unpublished observations show
a significant strong correlation between under water weighing-measured
body density and ultrasound estimated body density for sumo wrestlers
(n = 45, r = 0.919, p < 0.001). However, after calculation of
body fat percentage, these unpublished results suggested an overestimation
of body fat by ~ 4%. Thus, our present results may overestimate
body fat percentage in sumo wrestlers by ~ 4%. Body fat percentage
was calculated from body density using the equation of Brozek, et
al. (1963). FFM was derived by subtracting fat mass from total body
of skeletal muscle mass
For all Participants and previously collected data, skeletal muscle
mass (SMM) was predicted from FFM using the equation SMM = 1.47
x FFM + 18.1 (Abe et al., 2003).
Comparisons of body mass, FFM, percent body fat, and
VO2max were made between sumo and controls using a t-test.
Comparisons of the means of VO2max /SMM were made between
sumo wrestlers, untrained controls, combat athletes, aerobic athletes,
athletes via an ANOVA with Tukey's post-hoc test. Linear regression
was used to assess relationships between FFM and VO2max,
and percent body fat and VO2max /SMM. Statistical significance
was set at p< 0.05.
presented as means ± SD unless otherwise noted. Results of data
collected in this study (sumo wrestlers and untrained controls)
are shown at the top of Table 1, and are compared with previous results collected
from combat, aerobic, and power sport participants. Sumo wrestlers,
compared to untrained controls, were taller (1.77 ± 0. 03 vs. 1.72
± 0.03 m; p < 0.05), and had larger (p < 0.05) body mass (117.0
± 4.9 vs. 56.1 ± 9.8 kg), percent fat (24.0 ± 1.4 vs. 13.3 ± 4.5),
fat-free mass (88.9 ± 4.2 vs. 48.4 ± 6.8 kg), predicted SMM (48.2
± 2.9 vs. 20.6 ± 4.7 kg) and VO2max (3.6 ± 1.3 vs. 2.5
± 0.7 L·min-1). Heart rate at maximum was not different
between sumo wrestlers and controls (189 ± 8 vs. 192 ± 7 bpm, respectively;
p > 0.05). Relative VO2max to body mass, however,
was significantly lower in sumo wrestlers compared to untrained
controls (31.1 ± 1.3 vs. 44.6 ± 9.1 ml·kg-1·min-1, respectively;
p < 0.05).
The predicted SMM and VO2max/SMM results are in reasonable
agreement with previous results using MRI to quantify SMM (Sanada
et al., 2005).
Mean VO2max/SMM was significantly different (p < 0.05)
among aerobic athletes (164.8 ± 18.3 ml·kgSMM-1·min-1),
combat athletes (which was not different from untrained controls;
131.4 ± 9.3 and 128.6 ± 13.6 ml·kgSMM-1·min-1, respectively),
power athletes (96.5 ± 5.3 ml·kgSMM-1·min-1), and sumo
wrestlers (71.4 ± 5.3 ml·kgSMM-1·min- 1).
Figure 1 was created by using
previous data (weighted mean results) from combat, aerobic, and
power sport participants (from Table 1), and data collected from sumo wrestlers and untrained
controls in the current study, and shows the relationship between
SMM and absolute VO2max for these participants. There
appears to be an overall positive relationship between SMM and absolute
VO2max until ~ 45 kg of predicted SMM; the relationship
appears to weaken after this point.
Figure 2 is a plot of the relationship
between percent fat and VO2max/SMM from sumo and untrained
controls, and previously collected data (weighted mean results)
from combat, aerobic, and power athletes. There is a strong negative
correlation between these variables (r = - 0.75; p < 0.05).
our knowledge, this is the first time that VO2max results
have been reported for sumo wrestlers. However, in order to make
better comparisons of VO2max among participants of varying
fat and body mass, we divided VO2max by the amount of
skeletal muscle mass (SMM) - SMM being the functional tissue for
oxygen uptake during strenuous physical work. The calculation of
VO2max /SMM should provide an indication of the "aerobic
muscle quality" of the athlete's skeletal muscle. We use the
term "aerobic muscle quality" to refer to the amount of
oxygen consumed per skeletal muscle mass. The higher this value,
the higher the aerobic muscle quality. We found that sumo wrestlers
have a low "aerobic muscle quality" (low VO2max
/SMM), compared to untrained controls and other combat sports, and
aerobic and power sports (Table
1). Why might the aerobic muscle quality, i.e. VO2max
/SMM, be low in sumo wrestlers?
Maximum oxygen uptake is equal to the product of cardiac output
(itself a function of heart rate and stroke volume) and the arterial-venous
oxygen differences in the blood. Clearly one or more of these factors
must be affected in sumo wrestlers to account for the low VO2max
/SMM. It is possible that the massive skeletal muscle hypertrophy
in sumo wrestlers is not matched by increases in heart size and/or
stroke volume; that is, cardiac output may be low per unit of SMM
for sumo wrestlers, resulting in abnormally low VO2max
/SMM values. However, a recent study of professional Japanese sumo
wrestlers suggests that left ventricular dilation is indeed very
large in these athletes (median left ventricular [LV] end-diastolic
volume ~ 60 mm), although it should be noted that LV function is
normal, and LV dimensions were significantly correlated with body
size, which would lead one to assume that sumo wrestlers have normal
LV sizes and stroke volumes for their amount of skeletal muscle
mass (Kinoshita, et al., 2003).
Additionally, we noted normal (within ± 5 % of predicted) maximal
heart rates (see Results) in sumo wrestlers at VO2max.
This suggests cardiac output of these athletes is not compromised.
The low VO2max /SMM results for sumo wrestlers should
therefore be the cause of alterations in arterial-venous oxygen
content differences, indicating a "peripheral" limitation.
It is possible that the massive skeletal muscle hypertrophy in sumo
wrestlers could decrease the capillary density, or mitochondrial
density, of skeletal muscle, resulting in less oxygen delivered
or utilized per volume of myofibrillar tissue and thus a lower VO2max
/SMM. Another possibility could be that the high fat, high calorie
diet and/or high fat storage mass in sumo wrestlers results in higher
than normal intramuscular stores of lipid (obesity has been shown
to increase intramuscular triglyceride stores; Gray et al., 2003;
Goodpaster et al., 2000).
This could result in a "diluting" of myofibrillar content
and a decrease in VO2max /SMM, although the amounts of
triglycerides stored would have to be substantial.
Perhaps the low VO2max /SMM in sumo wrestlers is related
to the content of aerobic enzymes in their skeletal muscle. The
training and competition style of sumo is very brief and anaerobic
- most competitions are over in < 1 minute. Thus, the aerobic
energetic system probably receives little stress during sumo training
and competition. On the other hand, grappling style sports (i.e.
wrestling, Judo) probably require a combination of aerobic and repeated
anaerobic types of energy (Amtmann and Cotton, 2005).
This is because they typically last for > 2 minutes, with times
of very high intensity interspersed throughout the competition.
Likewise, striking combat sports (i.e. karate, boxing, Kendo) also
require a combination of aerobic and repeated anaerobic types of
energy. Therefore increases in skeletal muscle aerobic enzymes (and
thus increases in VO2max /SMM) should occur in other
combat sports and aerobic sports, but not in sumo wrestlers. Perplexing,
however, is the fact that sumo wrestlers appear to have a lower
VO2max /SMM than other power athletes, and untrained
controls (Table 1). More research
examining the intracellular content and structure of sumo wrestler's
skeletal muscle is needed.
Sumo wrestlers have a higher fat-free mass (FFM), fat mass, and
predicted skeletal muscle mass (SMM) compared to other combative
sports (Table 1). Indeed, sumo wrestlers have some of the largest
absolute FFM (and thus, SMM) measured in humans (Hattori, et a.,
Kanehisa, et al., 1997, 1998, Kondo, et al., 1994, Yamauchi, et
al., 2004). Why might these attributes be helpful in the sport of
sumo wrestling? These attributes make the wrestler difficult to
push off his feet or move. The large fat mass of sumo wrestlers
plays a part in lowering the center of gravity of the body, providing
stability to the wrestler. The large muscle mass allows the sumo
wrestlers to create enormous absolute force and power to move their
opponent, and also provides stability.
The large SMM and fat mass (FM) in sumo wrestlers may also play
a role in the shape of results in Figure 1: the relationship between SMM and absolute
VO2max is generally linear until about 45 kg of SMM;
then the relationship begins to disappear (right hand side of Figure
1) for the athletes with large SMM, i.e. power athletes and
sumo wrestlers. This may indicate that athletes with a very large
SMM incur a "penalty" in the form of an aerobic plateau.
It is well known that energy cost per distance increases with increases
in body mass in humans (McArdle et al., 2001).
The results of Figure 2 support
this concept: VO2max /SMM is negatively related to percent
body fat, indicating that excess fat is detrimental to work because
it increases the carried load, which increases oxygen costs. Although
the data analyzed are limited in scope, the ceiling of increasing
SMM in human athletes without incurring a "penalty" in
the guise of plateaued or decreasing aerobic performance seems to
be ~ 45 kg of SMM based on the data analyzed (Figure
sumo wrestlers have a low VO2max /skeletal muscle mass
compared to untrained controls and combat, aerobic, and power sport
athletes, which is currently unexplainable, but may be related to
the lack of aerobic training particular to sumo wrestling practice/competition,
and/or the large fat mass in these athletes. The enormous fat and
skeletal muscle mass in sumo wrestlers is unique in the combat sports,
and in all of sport. Further investigation into sumo wrestler aerobic
skeletal muscle function is warranted.
wrestlers have a high absolute VO2max compared to untrained controls.
sumo wrestlers have a low VO2max /kg of skeletal muscle mass compared
to other combat sports, other strength/power sports, and untrained
reason for this is unknown, but is probably related to alterations
in sumo skeletal muscle compared to other sports.
on the present and previous data, there appears to be a "ceiling"
at which increases in skeletal muscle mass do not result in additional
increases in absolute VO2max
Prof., United States Military Academy, Department of Physical
Education, West Point, NY, USA.
Research interests: Neurophysiological responses to hydrogen
ions, sport nutrition
Tokyo Metropolitan University, Department of Exercise and Sport
Science, Tokyo, Japan.
Research interests: Muscle physiology and training.
Nihon University, Department of Exercise Physiology, Tokyo,
Research interests: Body composition and physiology of
student, Tokyo Metropolitan University, Depart. of Exercise
and Sport Science, Tokyo, Japan
Associate, The University of Tokyo, Department of Human Ecology,