| Combat
Sports Special Issue Research article |
|
|
PHYSIOLOGICAL PROFILE OF SENIOR AND JUNIOR ENGLAND INTERNATIONAL
AMATEUR BOXERS
|
University of Chichester, Bishop Otter Campus, College Lane, Chichester,
West Sussex, England.
©
Journal of Sports Science and Medicine (2006) 5 (CSSI), 74
- 89
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| ABSTRACT |
| Despite worldwide popularity of amateur boxing, research focussed
on the physiological demands of the sport is limited. The physiological
profile of Senior and Junior England international amateur boxers
is presented. A gradual (8 to 21-days) and rapid (0 to 7-days) phase
of body weight reduction was evident with 2.2 ± 0.3 % of the
7.0 ± 0. 8 % weight loss occurring over the final 24-hours.
An increase in body weight >4% was observed following a recovery
period. High urine osmolality values (> 1000 mOsm·kg-1)
were recorded during training and competition. High post-competition
blood lactate values (>13.5 mmol·l-1) highlighted the need
for a well-developed anaerobic capacity and the importance of not
entering the ring in a glycogen depleted state. The aerobic challenge
of competition was demonstrated by maximum heart rate values being
recorded during 'Open' sparring. Mean body fat values of 9-10% were
similar to those reported for other weight classified athletes. Normal
resting values were reported for hematocrit (Senior 48 ± 2
% and Junior 45 ± 2 %), haemoglobin (Senior 14.7 ± 1.0
g·dl-1 and Junior 14.5 ± 0.8 g·dl-1), bilirubin
(Senior 15.3 ± 6.2 µmol·l-1-1) and ferritin (Senior
63.3 ± 45.7 ng·ml-1). No symptoms associated with asthma
or exercise-induced asthma was evident. A well- developed aerobic
capacity was reflected in the Senior VO2max value of 63.8
± 4.8 ml·kg-1·min-1. Senior lead hand
straight punching force (head 1722 ± 700 N and body 1682 ±
636 N) was lower than the straight rear hand (head 2643 ± 1273
N and body 2646 ± 1083 N), lead hook (head 2412 ± 813
N and body 2414 ± 718 N) and rear hook (head 2588 ±
1040 N and body 2555 ± 926 N). It was concluded that amateur
boxing performance is dependent on the interplay between anaerobic
and aerobic energy systems. Current weight making methods may lead
to impaired substrate availability, leading to reduced competitive
performance and an increased risk to a boxers health.
KEY
WORDS: Urine osmolality, blood lactate, VO2max, punching
force.
|
| INTRODUCTION |
|
Historical overview
Fundamental changes to the rules and regulations governing the sport
of boxing have taken place over the past 5000 years. Specifically,
the development of equipment (i.e., gloves and headguard), contest
format (i.e., number and duration of rounds) and the introduction
of a weight classification system (i.e., 48-91+ kg). However, despite
these changes a number of similarities still exist. For example,
significant differences in body weight between boxers immediately
prior to competing is evident, despite the introduction of weight
categories (Smith, 1998).
A historical review of the sport provides an insight into the cultural,
political and philosophical perspectives that provided the stimulus
for change. The origins of pugilism can be traced back over 5000
years to the King's Festivities in Ancient Egypt. Illustrations
indicate that pugilists fought naked before the Gods with a technique
dependent upon one arm protecting the head and the other being used
in attack (Prior, 1995).
Paintings of boys fighting in Crete during 2000 BC reveal that helmets,
the first type of head guard, were worn to protect the head and
face from punishment and a glove to protect the attacking hand.
Vase paintings from Cyprus in 1200 BC suggest the intention of the
attacking fighter was to throw punches to the head rather than the
body (Ellwanger, 1996).
At the Olympic Games of 776 BC competitors fought in a sport known
as 'pankration' that combined the techniques of wrestling and boxing
(Hickey, 1980).
There were no weight categories and fighters competed wearing a
belt and a type of leather glove called a 'cestus'. The fight was
not divided into rounds, with the winner being decided when one
of the competitors admitted defeat. The first Olympic pugilism took
place at the Olympiad of 688 BC. Pugilists wore a 3-metre narrow
thong of leather around each hand and forearm, soaked in fat, which
enabled them to make a fist. There were normally 5 to 12 pugilists
in 3 or 4 eliminatory rounds. There existed no weight classifications
and clinching was forbidden (Kluge, 1996).
In Greece, at around 400 BC attitudes towards pugilism were changing.
Society began to demand that athletes become more competitive and
contact sports, such as pugilism had a more violent nature. At this
time the basic 'stance' and 'on- guard' position of the pugilist
was developed (Prior, 1995).
In 393 AD Emperor Theodosius I banned the Olympic Games, with the
number of pugilists declining until they eventually disappeared
during the fourth century AD (Ellwanger, 1996).
It is generally agreed that the Ancient form of pugilism re-emerged
during the 17th Century as prize-fighting. Events such
as the 1634 Cotswold Games included prize-fighting where spectators
bet heavily upon the outcome of the fight. Prize-fighters were recruited
from the working classes under the patronage of the middle and upper
classes (Hickey, 1980).
As prize-fighting grew in popularity boxing 'schools' and 'academies'
were set up by prize-fighters to offer the middle and upper classes
the opportunity to learn the skills and techniques underpinning
the 'Noble Art' (Prior, 1995).
It could be argued that these individuals were the first recognised
boxing coaches. The first set of boxing rules were introduced by
Jack Broughton (1742) yet they did little to prevent the number
of serious injuries and deaths resulting from prize-fighting. In
1867 John Sholto Douglas (9th Marquis of Quennsbury),
along with close friend John Graham Chambers, constructed a new
set of rules to check the excesses of prize-fighting. One of the
major rule changes was that fighters wore gloves and there was an
attempt to match fighters according to body weight (Prior, 1995).
Development of a weight classification system
During the late 1600's to mid 1800's prize-fighting took place between
fighters not matched by body weight. In 1841 William 'Tipton Slasher'
Perry fought Charles Freeman whilst weighing 38.2 kg lighter than
his opponent (Brailsford, 1988).
The first regulated weight classification system in boxing was introduced
in 1867 and was based upon the principle of making competition fairer
by minimising differences in body weight between competitors. During
the period 1867-2002 the number of weight categories in Senior international
amateur boxing increased from 3 to 12, ranging from light-flyweight
(48 kg) to super-heavyweight (91+ kg). However, in 2003 the 63.5
kg, 67 kg, and 71 kg divisions were replaced by a 64 kg and 69 kg
category, resulting in the current 11 international Senior competition
weight classes.
Contest format
The duration of a boxing contest has undergone radical change since
the Cotswold Games in 1634. Without regulation the length of many
prize-fights lasted several hours with a time of 3-hours 15-minutes
being recorded for the fight between Simon Byrne and James 'Deaf'
Burke in 1833 (Miles, 1880).
In 1880 the Amateur Boxing Association of England was formed and
stipulated that the length of a contest would be restricted to 3
rounds. Rounds 1 and 2 were of 3-minutes duration with round 3 lasting
for 4-minutes. The recovery period between rounds was set at 1-minute.
However, if the score of the contest was level after 3 rounds a
fourth round of 2-minutes was allowed in order to determine a winner
(Hickey, 1980;
Prior, 1995).
From an energy provision perspective this change in contest format
increased the importance of energy supply from anaerobic sources.
In 1926 the contest format was changed so that all contest took
place over 3 rounds of 3-minutes duration with a 1-minute interval
between rounds. In 1997 the world governing body (Association Internationale
de Boxe Amateur, AIBA) increased the number of rounds to 5 and decreased
the duration of each round to 2-minutes. This change was not viewed
positively. Under pressure from boxers, coaches and officials, the
number of rounds was reduced by AIBA to 4 prior to the 2000 Olympic
Games.
Method of scoring
Boxing has always been scored using subjective marking. At the 1908
Olympic Games two judges and a referee awarded up to 5 points per
round for the first 2 rounds and up to 7 points for the last round
(Prior, 1995).
It was not until the 1932 Olympic Games that the referee actually
joined the boxers inside the ropes (Kluge, 1996).
Following biased judging at the 1988 Olympic Games AIBA introduced
a computer method of scoring. Five neutral judges were required
to press a red or blue button (corresponding to the boxer competing
out of the red or blue corner) when they believed a boxer had landed
a punch with sufficient force on their opponents target area. For
a punch to be registered as a scoring blow three or more of the
judges had to press the same coloured button within 1-second. The
change to computer scoring radically changed training methods with
greater emphasis placed on developing punching force and less time
devoted to developing flair (Smith, 1998).
The global appeal of amateur boxing is reflected in 196 nations
affiliated to AIBA in 2005
(AIBA, 2005).
However, given its worldwide popularity and high levels of participation
previous research related to amateur boxing is scarce. Given the
physiological demands that appear to accompany a competitive bout
and the added complication of it being a weight classified sport,
this omission is somewhat surprising. The purpose of this study
is to examine the physiological demands of amateur boxing and provide
a physiological profile of the elite amateur boxer.
|
| METHODS, RESULTS AND DISCUSSION |
|
Data
acquisition
Information presented in the following sections was recorded between
1987 and 2004. The data sets have been selected to highlight specific
issues and specifically focus on Senior England international amateur
boxers (18 to 34-years, n = 130). Where appropriate, data sets relating
to Junior England international boxers (16 to17-years, n = 26) are
presented. Section 1 examines the physiological demands of amateur
boxing from data recorded during training and competition. Section
2 presents normative physiological data from laboratory-based assessments.
All data are expressed as group mean and standard deviation unless
specified otherwise. Although not scientifically correct the term
body weight is used in preference to body mass throughout this review
as this reflects current terminology used when discussing weight-classified
sports.
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| SECTION 1 |
|
Body
weight manipulation.
Senior England international amateur boxers have been reported to
reduce body weight prior to competing in an attempt to gain a physiological
and psychological advantage over competitors in the same weight
category (Hall and Lane, 2001,
Smith, 1993;
Smith et al., 2001).
Data contained in Table 1 supports
this statement with boxers from all weight categories (excluding
super - heavyweight) experiencing a 6.0 to 8.3 % (7.0 ± 0.8
%) decrease in body weight over a 21-day pre-contest pre-contest
period. A consistent pattern of weight loss was observed for all
weight categories, comprising of a gradual and rapid phase. A 1.7
± 0.7 % decrease in body weight occurred during the 8 to
21-day pre contest gradual phase. During the rapid phase a 5.2 ±
0.4 % reduction in body weight was observed over the final 7-days
prior to competing. Of particular interest was the need for boxers
from all categories to reduce body weight between 1.7 to 2.7 % over
the final 24-hours. The reliance of boxers to make weight by rapid
reductions in body fluid is evident. The existence of a gradual
and rapid phase of weight reduction within a weight category sport
supports the findings of Fogelholm, 1994.
The magnitude and time-scale of weight manipulation is similar to
previous research related to wrestlers (Tipton and Tcheng, 1970;
Steen and Brownell, 1990),
judo players (Umeda et al., 2004),
national hunt jockeys (Cotterill, 1992),
lightweight rowers (Koutedakis et al., 1994),
and lightweight American football players (Depalma et al., 1993).
Methods
of weight loss
It is evident from Table 2
that Senior England international amateur boxers combine both passive
and active methods of weight loss when making the competition weight.
Similar findings have been reported extensively in high school and
college wrestling (Herbert and Ribisl, 1972;
Zambraski et al., 1976;
Steen and McKinney, 1986
and Horswill, 1992).
A decrease in body weight recorded during the 8 to 21-day gradual
phase was achieved by an increase in energy expenditure leading
to a period of negative energy balance. This was primarily achieved
by increasing the amount of time spent undertaking active methods
of weight loss (gym work 100 % and running 100 %) and supported
by passive methods (energy restriction 23 %). Koutedakis et al.,
1994
reported a 6 % reduction in body mass over a 2-month period for
elite female lightweight rowers following modifications to training
and energy intake. In a case study,, Widerman and Hager (1982)
reported that modifications to a wrestlers training and diet over
a 53-day period resulted in the loss of 12.7 % body weight.
During the 7-day rapid phase immediately prior to competition a
greater interplay between active and passive methods is evident,
with the role of passive methods becoming increasingly important.
A comparison of the 3-day versus 1-day data indicates that boxers
decreased the time spent undertaking active methods (running decreased
from 94 % day-3 to 80 % day-1 and gym work from 100 % day-3 to 67
% day-1) and increased opportunities to adopt passive techniques
(energy restriction increased from 96 % day-3 to 100 % day-1 and
fluid restriction from 92 % day-3 to 95 % day-1). Steen and Brownell,
1990
reported similar findings amongst College wrestlers with 94 % and
95 % practising some degree of energy and fluid restriction, respectively.
The key role fluid manipulation plays within the weight making process
is highlighted in the sauna data whereby 13, 18 and 21 % of boxers
employed this technique 7-days, 3-days and 1-day prior to the weigh-in,
respectively. However, the use of sauna by boxers reported in Table
2 is lower than those reported for wrestlers (Steen and McKinney,
1986;
Steen and Brownell, 1990)
and national hunt jockeys (Cotterill, 1992;
Northcott, 1998).
The importance of rapid fluid loss is further highlighted by the
decision made by a significant number of boxers to wear extra layers
of clothes or plastic wet suits whilst engaged in active methods
of weight loss during the final 3-days prior to the official weigh-in.
The use of clothing induced thermal dehydration, combined with exercise,
has been well documented in high school and college wrestlers (Tipton
and Tcheng, 1970;
Boe, 1985
and Maffuli, 1992)
and national hunt jockeys (Northcott, 1998).
To highlight the magnitude of fluid and energy restriction the data
for 6 Senior England International boxers 24-hours pre and 24-hours
post weigh-in is presented in Table
3. Fluid intake during the 24-hour period prior to the official
weigh-in was 1.2 ± 0.5 l. This increased by 38 % to 3.2 ±
1.5 l during the 24-hour period post weigh-in prior to competition.
A 24 % increase in energy intake was also observed from pre weigh-in
1051 ± 901 kcal to 4411 ± 1217 kcal post weigh-in.
Steen and McKinney (1986)
reported a similar increase in energy intake from pre weigh-in 334
kcal to 4214 kcal post weigh-in for a 54 kg wrestler.
Recovery
period
The existence of a recovery period between the Official weigh-in
and competition commencing provides a window of opportunity for
the boxer to restore fluid balance and optimise carbohydrate stores.
The data contained in Table 4
shows that 2 hours prior to the weigh-in both Senior and Junior
boxers body weight was 1.6 ± 0.4 % and 1.4 ± 0.4 %
above the competition weight limit, respectively. Following a 24-hour
recovery period prior to a Dual international (competition format
that requires a boxer to weigh-in and compete only once) the Senior
boxers increased body weight by 4.4 ± 3.3 % and the Junior
boxers by 5.1 ± 2.3 %. Scott et al., 1994
recorded a similar increase in body weight (4.9 ± 2.4 %)
amongst 668 college wrestlers following a 20-hour recovery period.
Despite average values being similar between Senior and Junior boxers
it is evident that significant individual variability exists between
boxers of the same age group in relation to the amount of weight
gained during the recovery period. The two highest increases in
body weight were for the Senior 75 kg boxer (12.1 %) and Junior
60 kg boxer (9.3 %). Weight gains of this magnitude cannot occur
during multi-nation type tournaments were the boxer is required
to make the competition weight limit prior to each contest. Under
this competition format weight gains are set at ~2 to 3 % body weight.
The data contained in Table 4
clearly shows that the principle underpinning the weight classification
system, making competition fairer by minimising differences in body
weight between competitors, is not being adhered to. A similar observation
was reported by Herbert and Ribisl, 1972
in their review of wrestling, stating:
'As in many sports, the practical application of the rules does
not always measure up to the principle upon which they are founded'.
(p.416).
Integral
to the principle of matching boxers in relation to body weight is
the assumption that maximum punching force is related to body weight.
The recent development of boxing dynamometers has shown this assumption
to be correct (Karpilowski et al., 1984;
Smith, 1998).
Therefore, in the pursuit of fairness and the need to minimise the
risk to a boxer's health, large discrepancies between boxers in
terms of body weight immediately prior to competition should be
avoided. The data also highlights that Junior boxers experience
large fluctuations in body weight during a period of growth and
maturation. Only one study to date has reported an eating disorder
linked to weight making in junior boxers (Lovett, 1990).
In this case study a 15 year-old flyweight boxer was reported to
have become bulimic in his attempt to suppress his body weight in
order to continue to box domestically at 51 kg.
Hydratory
status
Urine osmolality has been shown to be a useful marker of hydratory
status (Armstrong et al., 1994;
Shirreffs and Maughan, 1998).
In amateur boxing the following urine osmolality categories have
been developed to indicate the level of dehydration: well hydrated
< 399 mOsm·kg-1; hydrated 400-799 Osm·kg-1; dehydrated
800-1199 mOsm·kg-1 and severely dehydrated > 1200 mOsm·kg-1
(osmolality scale developed as part of the ABE World Class Programme,
unpublished) (reference required) To highlight the challenge to
a boxers hydratory status a selection of osmolality values are presented
from competition and training. Table
5 shows a range of osmolality values recorded for Senior England
International amateur boxers across 12 weight categories from two
multi-nation tournaments. In Competition (A) first morning urine
osmolality samples were collected over a 10 to18-day period (number
of samples dictated by boxers level of success). The data shows
that only the 67 kg and 91 kg boxers achieved any sustained period
of fluid balance but neither boxer won a medal. The remaining 10
boxers all experienced at least 1 urine sample > 1000 mOsm·kg-1,
with 3 out of the 6 medallists recording at least 1 urine sample
> 1200 mOsm.kg-1. Indeed, the 81 kg boxer had a mean urine osmolality
value of 1177 ± 73 mOsm·kg-1 and won a gold medal.
Similar findings were recorded for Competition (B) where only the
91 kg boxer showed any prolonged period of fluid balance but again
this boxer did not win a medal. All boxers from the remaining 11
weight categories recorded at least 1 urine sample > 1000 mOsm·kg-1,
with 3 out of 7 medallists recording at least 1 urine sample >
1200 mOsm·kg-1. The high urine osmolality values recorded
in both competitions support previous data identifying the key role
rapid fluid loss strategies play in enabling a boxer to make the
weight (Table 2). The data
contained in Table 6 shows the urine osmolality values recorded for Senior
England international amateur boxers during an overseas and domestic
training camp. In relation to the overseas training camp first morning
urine osmolality samples were recorded over a 7-day period. Only
2 out of 17 boxers maintained a urine osmolality value < 1000
mOsm·kg-1, with 3 boxers recording a value > 1300 mOsm·kg-1.
The major focus for the overseas camp was to address technical issues
with each boxer and not weight reduction. The high urine osmolality
values may be explained by a number of boxers staying within an
agreed weight limit above their competition weight by choosing to
increase energy intake at the cost of restricting fluid intake.
These urine osmolality values are higher than those reported by
Shirreffs and Maughan, 1998
who compared Senior international amateur boxers (775 ± 263
mosm·kg-1) and weight lifters (777 ± 254
mOsm·kg-1) with non-weight classified athletes
(627 ± 186 mOsm·kg-1) during an 11-day
overseas training camp. Urine osmolality data recorded during the
4-day domestic training camp are also higher than those recorded
by Shirreffs and Maughan, 1998.
Only 3 out of 17 boxers maintained a urine osmolality value <
1000 mOsm·kg-1, with 3 boxers recording values
> 1200 mOsm.kg-1. It is evident from these ese data
that the majority of Senior England international boxers do not
maintain fluid balance during training, despite often being several
weeks away from competition. Urine osmolality data for Junior England
boxers is limited. However, the data contained in Table
7 shows that during a 3-day domestic training camp 3 out of
4 boxers provided at least 1 urine osmolality value > 1000 mOsm·kg-1,
again suggesting an inability to maintain fluid balance during training.
Urine osmolality recordings were taken first thing, usually between
6.45 a.m.-7.15 a.m., following an overnight fast. Urine samples
were injected into an Osmometer and results fed back to the boxer
and coach within 10 minutes. It is important to point out that the
daily urine osmolality value does not take into account the re-hydration
strategy undertaken during the recovery period. The high osmolality
values indicate an attempt made by the boxer to enter a weight cateogory
below their natural body weight. It does not directly reflect the
hydratory status at the point of the boxer entering the ring.
Post
contest blood lactate
The effects of different methods of scoring and contest format on
post competition blood lactate values for Senior England international
boxers are shown in Table 8. High post contest blood lactate values
(> 8.0 mmol·l-1), irrespective of the method
of scoring or contest format, highlights the intense nature of competition
and identifies the critical role played by anaerobic glycolysis
in sustaining ATP resynthesis during an amateur contest. The post
bout blood lactate value of 12.8 ± 3.0 mmol·l-1
(impression scoring, 3 rounds x 3-minutes) was similar to 13.46
mmol·l-1 recorded for 5 West German Senior amateur
boxers (Kindermann and Keul, 1977).
The reduction in post contest blood lactate values from 12.8 ±
3 mmol·l-1 (impression scoring, 3 rounds x 3-minutes)
to 9.5 ± 3 mmol·l-1 (computerscoring, 3
rounds x 3- minutes) may be related to changes in training methods
and tactical strategy (Smith, 1998).
Radical changes to the contest format in 1997 (computer scoring,
5 rounds x 2- minutes) resulted in post blood lactate values decreasing
to 8.6 ± 5 mmol·l-1. In general, the contest
strategy during this period (1997 to 1999) was based upon adopting
a cautious start over the first 3 rounds with an increase in high-intensity
activities (punch rate and dynamic footwork) over the final 2 rounds
(Smith, 1998).
The current contest format (computer, 4 rounds x 2-minutes) has
resulted in further changes to training methods and tactical strategy.
Greater emphasis is now placed on the amateur boxer to perform more
frequent repeated bursts of high intensity activity (punch rate
and dynamic footwork) at an earlier stage of the contest. This change
in approach may explain the higher post contest blood lactate values
under the current contest format (13.5 ± 2 mmol·l-1)
compared to previous observations. The high post contest blood lactate
values for Junior boxers (14.1 ± 2 mmol·l-1)
highlights further the intense nature of competition and identifies
the need to integrate into an amateur boxers training programme
specific sessions aimed at increasing a boxers anaerobic capacity.
Interval pad work, such as 8 x 1-minute rounds with 1-minute recovery
between rounds, has been shown to be the most effective method of
stressing the anaerobic glycolytic energy system with lactate values
frequently > 10 mmol·l-1 (Smith, 1998).
This method of training is successful because the coach dictates
the training intensity. The need to expose the amateur boxer to
high levels of blood lactate in training (> 9.0 mmol·l-1)
was previously reported by Gosh et al., 1995.
Anaerobic glycolysis is largely dependent on the availability of
muscle glycogen (Maughan and Poole, 1981;
Guezennec et al., 1993).
However, previous data (Table 2)
has highlighted that the weight making methods adopted by Senior
England international amateur boxers may result in glycogen depletion
if the post weigh-in recovery strategy does not address the need
to consume sufficient carbohydrate. The phrase 'dead at the weight'
is commonly used by boxers and coaches to describe impaired amateur
boxing performance associated with glycogen depletion (Smith, 1994).
Heart
rate analysis
Over the past 20-years technological developments in heart rate
telemetry has enabled exercise physiologists to gain a useful insight
into the physiological demands experienced by boxers during various
phases of the training programme. During the final days prior to
competition the role of 'conditioned' and 'open' sparring become
increasingly important (Hickey, 1980).
'Open' sparring is a type of training that most closely replicates
the physiological demands associated with competitive boxing. Figure
1 shows a typical heart rate response of a Senior England international
boxer to 'open' sparring. It is evident that a high heart rate response
is achieved during each 2-minute round. Recovery heart rate decreases
between rounds and in rounds 3 and 4 the heart rate response goes
above the maximum heart rate value recorded during an incremental
run to exhaustion on a motorised treadmill. Previous research has
estimated that 59 % of ATP resynthesis during a 120-second maximal
uphill run on a treadmill was provided by aerobic sources (Hermansen
and Medbo, 1984).
Therefore, in order to compete at the required intensity for all
four 2-minute rounds it is necessary for an amateur boxer to have
a well-developed aerobic capacity.
|
| SECTION
2 |
|
Estimation
of body fat
Previous data contained in Table
2 has shown that Senior England international amateur boxers
employ a variety of methods to decrease body weight. Modifications
to training and energy intake during the gradual phase of weight
cycling are aimed at reducing the amount of stored body fat. Table
9 shows the total (mm) and body fat (%) for Senior and Junior
England international boxers using the 4-site skin fold method (Durnin
and Womersley, 1974).
A body fat of 9.1 ± 2.3 % and total skin fold of 22.3 ±
4.4 mm was recorded for the Senior boxers. These values are higher
than those recorded for USA elite amateur boxers (6.9 ± 1.6
%) and wrestlers (7.9 ± 2.8 %) in Fleck, 1983.
A higher body fat (10.1 ± 2.6 %) and total skin fold (23.8
± 5.9 mm) was recorded for the Junior boxers. This difference
may be related to the maturation process and or the fact that Junior
boxers will have spent less time practising their weight reduction
strategies. Whilst the reasons for the differences between Senior
and Junior boxers remain unclear what is apparent is the attempt
made by Junior boxers to alter their body fat stores.
Blood
profile
The continuous supply of oxygen to maintain aerobic ATP resynthesis
during amateur boxing
competition is vital and is dependent on a number of factors (Smith,
1998).
An increase in blood hematocrit is observed when amateur boxers
become dehydrated or undertake altitude training (Friedmann et al.,
1999).
Data contained in Table 10
shows that for both Senior (48 ± 2 %) and Junior (45 ±
2 %) England international boxers hematocrit values were within
the normal range but slightly higher than those reported for Senior
international German amateur boxers (Friedmann et al., 1999).
Normal values were also recorded for haemoglobin (Senior 14.7 ±
1.0 g·dl-1 and Junior 14.5 ± 0.8 g·dl-1).
However, a review of the range of haemoglobin values shows several
boxers with values below the normal range. Possible reasons for
the low values may be related to inappropriate weight making methods.
Normal bilirubin (15.3 ± 6.2 µmol·l-1-1)
and ferritin (63.3 ± 45.7 ng·ml-1) values
were recorded for the Senior group. However, Child et al., 2000
reported that following intense amateur boxing training Senior England
boxers experienced a significant increase in red blood cell destruction
that was not matched by a parallel increase in red blood cell formation,
with 2 boxers ferritin levels below 20 ng.ml-1.
Lung
function
Prior to the 2004 Olympic Games the International Olympic Committee-Medical
Commission (IOC-MC) required athletes using 2 agonists to provide
clinical evidence to support their claims that they had asthma (Dickinson
et al., 2005).
Asthma and exercise-induced asthma are two conditions that may impair
oxygen kinetics. Table 11 shows the lung function profile of
Senior and Junior International amateur boxers pre and 10 minutes
post an incremental run to exhaustion. Figures 2, 3, 4 and 5 show
that both Senior and Junior boxers had no sign of asthma or exercise-induced
asthma. Failure to identify any boxers exhibiting asthmatic symptoms
agrees with the findings of Dickinson et al., 2005
who reported no incidences of asthma or exercise-induced asthma
amongst elite Senior boxers prior to the 2000 or 2004 Olympic Games.
Aerobic
capacity
The requirement for an amateur boxer to have a well-developed aerobic
capacity has been identified (Section 1). The absolute and relative
VO2max values for Senior and Junior international amateur
boxers of a similar body mass are shown in Table
12. A relative VO2max value of 63.8 4.8 ml.kg-1.
min-1 for the Senior boxers is similar to that reported
for two groups of national Senior German amateur boxers prior to
altitude training (Group 1 [n = 9]: 61.0 ± 4.9 ml·kg-1·min-1
and Group 2 [n = 7]: 62.1 ± 3.6 ml·kg-1·min-1)
Friedmann et al. (1999).
A lower VO2max value of 57.5 ± 6.9 ml·kg-1·min-1
was reported for 8 Senior Italian middleweight (75kg) amateur boxers
(Guidetti et al., 2002).
Differences in VO2max between groups may be related to
the type of training undertaken and the mean body weight of boxers
included in each study. This suggestion is supported by the work
of Gosh et al. (1995)
who reported lower VO2max values in Indian Senior international
amateur boxers from the heavier weight categories. A significantly
lower relative VO2max value of 49.8 ± 3.29 ml·kg-1·min-1
was recorded for the Junior boxers. Such differences may be related
to age, level of maturation or length of time engaged in aerobic
training. Indeed, Bunc et al., 1996
reported a VO2max value of 67.9 ± 5.9 ml·kg-1·min-1
following extensive aerobic training for Junior elite triathletes.
The importance of having a high aerobic capacity is supported by
the data from a recent British Olympic medallist who had a relative
VO2max value of 69.1 ml·kg-1·min-1.
A
number of aerobic and anaerobic threshold measurements have been
used to monitor training adaptations and set training intensities.
The information contained in Table
13 shows the running velocity (km·hr-1), heart
rate (b·min-1) and VO2 (l·min-1)
response for Senior England international boxers at a blood lactate
value of 2 mmol·l-1 and 4 mmol·l-1.
In relation to running velocity a speed of 10.43 ± 1.48 km·hr-1
and 13.38 ± 1.13 km·hr-1 was recorded at
2 mmol·l-1 and 4 mmol·l-1 respectively.
A value at 2 mmol·l-1 of 2.7 ± 0.43 l·min-1
and 3.42 ± 0.52 l·min-1 at 4 mmol·l-1
for VO2 was recorded with the 4 mmol·l-1
VO2 as a percentage of VO2max being 86 ±
6 %. Heart rate values were 151 ± 10 b·min-1
and 174 ± 8 b·min-1 for 2 mmol·l-1
and 4 mmol·l-1, respectively. The 4 mmol·l-1
reference point has been used to identify the maximum exercise intensity
whereby a plateau in blood lactate can be achieved (Heck et al.,
1985).
This method of determining individual training thresholds has been
successfully applied to the training programmes of Senior and Junior
England international amateur boxers (Smith, 1998).
The peak running velocity is identical to the value reported by
Friedman et al. (1999)
for German national amateur boxers (16.7 ± 1.0 km·hr-1).
Punch
profile
The recent development of sport-specific dynamometers is an important
step towards ecological validity in analysing amateur boxing performance
(Smith et al., 2000).
The data contained in Table 14
shows the maximum punching force for straight and hook punches,
to head and body, of Senior international amateur boxers. From the
data it is evident that in relation to straight punching at the
head a higher punching force was recorded for the straight rear
hand compared to the lead hand (lead hand 1722 ± 700 N vs
rear hand 2643 ± 1273 N). A similar finding was recorded
for straight punches thrown at the body (lead hand 1682 ±
636 N vs rear hand 2646 ± 1083 N). In relation to straight
punching the observed differences in punching force between
lead and rear hand may be related to an increase in the force generated
by the legs (Fritsche, 1978;
Filimonov et al., 1983),
degree of body rotation and the distance over which the long-range
straight punch is thrown (Hickey, 1980).
Also, the introduction of computer scoring has resulted in greater
emphasis in training being placed on developing rear hand punching
force (Smith, 1998).
However, for the hook punches similar punching force values were
recorded for lead and rear hand to the head (lead hand 2412 ±
813 N vs rear hand 2588 ± 1040 N) and body (lead hand 2414
± 718 N vs rear hand 2555 ± 926 N). The increase in
lead hand hook punching force compared to the straight lead hand
may be attributed to the increase in body rotation associated with
the technique of throwing a lead hand hook punch (Hickey, 1980).
In comparison to previous data collected on elite England Senior
international amateur boxers, the straight punching values are lower
(Smith et al., 2000).
The reason for this is somewhat unclear but may reflect a greater
number of boxers included in the data presented in Table
14. A higher average rear hand straight peak punching force
of 3427 ± 811 N for Australian Senior international amateur
boxers was reported (Walilko et al., 2005).
However, this comparison should be treated with caution as Walilko
et al., 2005
study had a low number of subjects (n = 7) with 2 boxers being super
heavyweights (classified as > 91 kg).
The ability to throw repeated punches of sufficient force is a key
component of success in amateur boxing (Smith, 1998).
The number of punches thrown per round is dependent on a boxer's
style and the tactics employed throughout a contest. From video
analysis of competitive bouts a punching sequence was developed
that required the boxer to throw 76 straight punches, incorporating
single, 2-punch and 3-punch combinations with lead and rear hands,
over 4 x 2-minute rounds on a boxing dynamometer (Smith et al.,
2000).
These data are contained in Table
15 and shows a total punching force of 388113 ± 102020
N per 4 x 2-minute simulated contest. The punch force data per round
shows a similar value for each of the first three rounds (Round
1 96144 ± 26798 N, Round 2 96173 ± 25098 N and Round
3 95935 ± 24661 N) with an increase evident in the final
round (Round 4 99861 ± 26898 N).
|
| CONCLUSION |
|
Energy
supply during a 4 x 2-minute amateur boxing contest is provided
through the inter-play between anaerobic and aerobic energy systems.
The important role of anaerobic metabolism is reflected in a peak
mean punching force of 2646 ± 1083 N for a single punch,
delivered in < 60 milliseconds (Smith and Dyson, 1996),
and high post contest blood lactate value (Seniors: 13.5 ±
2 mmol·l-1 and Juniors 14.1 ± 2 mmol·l-1).
A high relative VO2max value of 63.8 ± 4.8 ml·kg-1.min-1
reflects the aerobic challenge to the amateur boxer competing over
four 2-minute rounds. Impaired oxygen carriage was not evident from
the tests for asthma and exercise-induced asthma or abnormalities
within the blood haematological profile. However, following several
months of intense training, ferritin stores were shown to decrease
below the normal range in a limited number of boxers. In most cases,
except for the super heavyweight category, England international
amateur boxers select a competition weight below their natural body
weight and reduced body weight accordingly. A gradual and rapid
phase of weight reduction was identified during a 21-day period
prior to the weigh-in. A variety of active and passive methods of
weight loss were identified, with the crucial role of rapid fluid
loss highlighted over the final 3-days. The implications on hydratory
status of employing this method of weight loss were reflected in
the high urine osmolality values (> 1000 mOsm·kg-1)
recorded during training and competition. The existence of a recovery
period between the official weigh-in and competition commencing
provides the amateur boxer with a window of opportunity to re-address
any fluid or energy deficiencies. However, insufficient time or
the adoption of an inappropriate strategy could result in an amateur
boxer entering the ring in a dehydrated and glycogen-depleted state,
leading to impaired performance and an increased risk to health.
Practical
guidelines
- Prior
to the start of each competitive season a boxer's competition
weight class must be identified. In most cases the weight class
remains the same for domestic and international contests. However,
for certain boxers there may be the requirement to compete at
a lower weight category for internationally championships. Major
domestic and international competitions must be identified and
an appropriate training programme established. A programme of
laboratory testing and field support
- work,
both in training and at competition, also needs to be established.
The need for role clarification between athlete, coach and service
provider is vital (Collins et al., 1999).
In relation to body weight specific training weight bands need
to
be established for the 'gradual' and 'rapid' phases of weight
loss. The time scale for weight reduction needs to be identified,
along with the active and passive methods of weight loss. A post
weigh-in fluid and energy replacement strategy must be developed
to re-address any imbalances caused by the weight making process.
This strategy of replenishment must be practised in training.
Finally, time must be set aside following each competition cycle
for reflection. What worked? What did not work? What needs to
change in the future?
|
| ACKNOWLEDGMENTS |
| The author
is pleased to acknowledge the support of the England Amateur Boxing
Association. In particular, Mr Ian Irwin, ABE Coaches, members of
the ABE World Class Support Programme and boxers. In addition, the
author also wishes to acknowledge the intellectual contribution of
Professor Tudor Hale from the University of Chichester and Mr. Simon
Northcott in the preparation of the manuscript. |
| KEY
POINTS |
- Senior
England international amateur boxers decrease 6.0-8.3 % (7.0 ±
0.8 %) body weight over a 21-day pre-contest period by employing
passive and active weight making methods.
- Urine
osmolality values >1000 mOsm·kg-1 are recorded during
training and competition.
- Senior
and Junior England international amateur boxers experience high
post contest blood lactate values (Seniors 13.5 ± 2 mmol·l-1
and Juniors 14.1 ± 2 mmol·l-1 under the current
4 rounds x 2-minute contest format.
- Senior
England international amateur boxers have a high relative VO2max
of 63.8 ± 4.8 ml·kg-1·min-1
- Senior
England international amateur boxers have a straight and hook
punch force >2400 N, except for the straight lead hand to the
head and body.
|
| AUTHOR
BIOGRAPHY |
Marcus
S. SMITH
Employment: Principal
Lecturer and current Field Leader in Exercise Physiology at
the University of Chichester., UK.
Degrees: BA, PhD
Research interests: The role of body weight manipulation
on sports performance
E-mail: m.smith@ucc.ac.uk |
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