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Journal of Physical Education and Sport
®
(JPES), 12(1), Art 18, pp. 111 - 116, 2012
online ISSN: 2247 - 806X; p-ISSN: 2247 – 8051; ISSN - L = 2247 - 8051 © JPES
Corresponding Author:
:
Said El-Ashker Email: dr_said24@yahoo.com
111
Original Article
Effect of boxing exercises on physiological and biochemical responses of Egyptian
elite boxers.
SAID EL-ASHKER
1,
, MOSTAFA NASR
1
1
Athletic Training Department, Faculty of Sports and Physical Education, Mansoura University, EGYPT
Published online: March 31, 2012
(Accepted for publication March 25, 2012)
Abstract:
Boxing is a combat sport characterized by High intensity movements during limited rounds, with short breaks
are insufficient for full recovery. Physiologists should be conscious of the physiological and biochemical
changes that might cause by boxing exercises. The aim of the study is to assess the effects of boxing exercises on
physiological and biochemical responses of Egyptian elite boxers. Seventeen Egyptian elite male boxers (age
range 18-23 years) registered in the Egyptian boxing federation, volunteered to participate in the study.
Physiological and biochemical measures were obtained at baseline and at the end of boxing training programme.
Student’s (T) test was followed out to examine pre- and post-test values. Data noted that boxing exercises were
associated with significant decreases (p < 0.05) in resting heart rate (HR
rest
)
,
recovery heart rate after 1 minute
(RHR
1st
)
,
recovery heart rate after 2 minutes (RHR
2nd
)
,
recovery heart rate after 3 minutes (RHR
3rd
)
,
respiratory
exchange ratio (RER) values, and blood lactate (BL) concentration, while they connected with significant
increases (p < 0.05) in peak heart rate (HR
Peak
), relative and absolute VO
2Max
, Creatine Kinase (CK) and Lactate
Dehydrogenase (LDH) values. The authors’ statistics demonstrate considerable physiological and biochemical
changes significantly affected by boxing exercises in elite boxers. Examining relationships connected with the
effects of training on physiological and biochemical aspects add new dimensions that can help in assessing,
directing and developing athletic training programmes.
Key Words: Boxing, VO2max, Heart rate, Blood lactate, Creatine kinase
Introduction
Boxing is a combat sport where two participants of the same weight battle each other with their fists in a
series of three-minute rounds (AIBA, 2010). Modification in boxing technical & competition rules especially in
the duration and number of rounds might have incorporated ascending physiological changes in boxers. Despite
the shortness of boxing match length (3 rounds x 3 min), it is distinguished that boxers should be equipped for
huge efforts on the ring (El-Ashker, 2011). Most specialists in the combat sports fields emphasized on the
importance of studying physiological changes associated with combating effort (Beneke et al., 2004; Toskovic et
al., 2002; Kravitz et al., 2003; Ghosh, 2010; Chatterjee et al., 2006). The level of performance advances
whenever such positive physiological changes occurred to achieve training adaptations lead to execute boxing
bouts efficiency, without decreasing energy production (El-Ashker, 2004).
Energy from aerobic and anaerobic metabolism relies on the intensity and length of the activity
(Kraemer et al., 2011). Boxing is characterized by High intensity movements during rounds with short breaks are
not enough for full recovery. Consequently, this results in the production of lactic acid, and elevated blood
lactate (Khanna and Manna, 2006). Boxing rounds put a heavy load on boxers who have ascending heart rate and
blood lactate concentration through bouts (Ghosh et al., 1995). Simultaneously, physiologists and athletes should
be more conscious of the biochemical changes that might caused by prolonged exercise (Warburton et al., 2002).
As a result, the best method to assess training adaptations and to prevent overtraining is examining the selected
biochemical markers (Urhausen and Kindermann, 2002; Gleeson, 2002; Umeda et al., 2008). Therefore, the
trainer should be familiar with the physiological aspects related to training.
A small number of studies have been informed in the literature concerning the physiological demands of
boxing (Khanna and Manna, 2006). The physiological requirements of boxing have been investigated on account
of heart rate, maximal oxygen uptake (VO
2Max
), blood lactate (BL) (Kravitz et al., 2003; Ghosh, 2010; Ghosh et
al., 1991). Earlier studies on Egyptian boxers focus on motor ability, aerobic and anaerobic capacities of
Egyptian Boxers (El-Ashker, 2004; Hafez, 1997; El-Hawy, 1983). Rare studies investigated the biochemical
responses of Egyptian boxers (Shehata, 2010) have been conducted. To the authors’ information, this is the first
study to analyse both physiological and biochemical responses in Egyptian boxers. Consequently, the purpose of
this study was to investigate physiological and biochemical responses of Egyptian elite boxers subsequent to
boxing exercises.
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112
Materials and methods
Participants
The study was approved by the Ethics and Research Committee of the Faculty of Sports and Physical Education,
Mansoura University, Egypt, and the guidelines of the American College of Sports Medicine (ACSM) for the
use of human subjects were accepted in the study. A total of 17 Egyptian elite male boxers (age range 18 ~ 23
yr) volunteered to participate. Subject characteristics (Mean ± SD) are located in Table 1. All of them were
registered in the Egyptian boxing federation, with a minimum of 4 years of national boxing participation. The
objective of the study was explained to the participants. Selected boxers are volunteered, and could withdraw if
they wished.
Table 1. Baseline characteristics of the study subjects (n= 17).
Variable (Mean ± SD) Range
Age (years) 19.47 ± 1.26 18.0 – 22.6
Height (m) 175.3 ± 0.02 1.71 – 1.79
Body mass (kg) 73.8 ± 5.1 68.0 – 83.2
% Body Fat 14.4 ± 1.9 11.8 – 17.54
Training age (years) 5.1 ± 1.27 3.6 – 7.5
Before acceptation as a subject, all participants were supplied with a consent form and a physical activity
willingness questionnaire. The willingness questionnaire asked about any medical troubles or situations that may
exclude participants from the study. Participants were given the type of food they are accustomed to, as well as
the training programme has been conducted in the same conditions they are familiar with.
Procedures
To evaluate the physiological and biochemical variables, Participants attended the laboratory in a comfortable
situation with at least one full rest day since their last training session. For all Participants, physiological [resting
heart rate (HR
rest
), peak heart rate (HR
Peak
), recovery heart rate after 1 minute (RHR
1st
), recovery heart rate after
2 minutes (RHR
2nd
), recovery heart rate after 3 minutes (RHR
3rd
), relative maximal oxygen uptake (VO
2Max1
),
absolute maximal oxygen uptake (VO
2Max1)
, and respiratory exchange ratio (RER)] and biochemical [Blood
Lactate (BL), Creatine Kinase (CK), and Lactate Dehydrogenase (LDH)] measures were acquired two times; at
baseline and at the end of the training programme. Data collected using a well defined data capture sheet.
Research assistants registered physiological and biochemical measures at baseline and after eight weeks.
Participants were told not to take any drugs or tobacco in the day their physiological and biochemical measures
were to be estimated. They were also informed not to execute any exercises in the 48 hours before assessing
measures.
Physiological parameters Measurement
Heart rate responses were calculated automatically by a pulse monitor (Polar Sport-tester
TM
PE 3000; Polar
Electro, Finland) and calculated at 15-second intervals. Relative and absolute VO2
max
and RER were calculated
according to standard methodology (Astrand and Rodahl, 1986). After warming-up for 15 min comprised (a
standardized 10 min routine followed by 5 min of full-body stretching routine) all participants were asked to run
on the motor-driven treadmill at a velocity of 6 km/h for 2 min. After that, the workload was augmented by 2
km/h for each 2 min unto causing volitional exhaustion. Expired gases were sampled and calculated from an
integration chamber by programmed respiratory gas analyzer device (ZAN 600™, nSpire Health GmbH,
Germany).
Biochemical parameters Measurement
Blood lactate (BL) was calculated with a portable lactate analyzer (Accusport, Boehringer Mannheim, Germany)
using adequate blood sample amount of finger pricking taken immediately after cessation of complete boxing
match. Ten millilitres of a blood sample were taken from an antecubital vein under the influence of fasting
conditions early in the morning, in complete comfort for a period of not less than 6-8 hours prior to tests under
research. Five millilitres of the blood sample were utilized to examine CK, and 5 ml were utilized to examine
LDH. Samples were cooled and stocked at -20
ᵒ
C until analyses for CK, and LDH. Specialists from the medical
laboratories at Mansoura University Hospital helped the researchers take blood samples, and carry out the
biochemical Measurements.
In order to protect the participants and guarantee the accuracy of the values, nine participants were excluded
from the experiment because of medical conditions (high blood pressure - high blood sugar), and those whose
biochemical examinations have shown up normal values in the CK, LDH enzymes, due to their association with
certain pathogens affecting the activity of enzymes.
Training programme
The training programme was planned by the coach of Mansoura sports club. It comprised 8 weeks of total 32
sessions (≈53 hours). Researchers divided the training programme into three phases (see Table 2). 1
st
phase was
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SAID EL-ASHKER, MOSTAFA NASR
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113
aimed to overall development of physical fitness components (e.g. strength, mobility, endurance) as well as
developing fundamental motor skills; 2
nd
phase intended to develop specific physical fitness components and
enhance advanced technical skills alongside competition experience; 3
rd
phase was proposed to adjust technical
performance, train for the main competition in addition to emphasizing tactical and competition experience.
Intensity of the training programme was calculated by means of Karvonen’s formulae [Target Heart Rate =
((HR
Peak
− HR
rest
) × %Intensity) + HR
rest
] (Brown et al., 2006); HR
Peak
was estimated as 220 minus participant’s
age. HR
rest
was acquired for all participants at pre-test by asking them to recline on their own for 5 min and
wearing a pulse monitor (Polar Sport-tester
TM
PE 3000; Polar Electro, Finland), in calm area with no
distractions. HR
rest
was subsequently recorded and used to estimate target heart rate intensities. Workouts consist
of [core conditioning – running - speed work - strength training - shadow boxing - skipping rope - boxing cardio
exercises - working on heavy, double end and speed bags -boxing combinations - defensive, offensive and
counter attack skills - free sparring].
Table 2. Boxing training programme phases and variables during the training period.
phases
Variables
1
st
phase
(Basic)
2
nd
phase
(Specific)
3
rd
phase
(Taper)
Weeks 2 3 3
Workouts per week 4 4 4
Resting days per week 3 3 3
Workout duration per min 110 100 90
Intensity 70 % 80 % 90 %
Data Analysis
Data were collected from participants and then were collated and inserted in the statistical software
package, SPSS-16 (SPSS Inc, Chicago, Il). Descriptive statistics were determined for all variables. Values are
presented as Mean ± Standard deviation. Student’s (T) test was followed out to examine pre- and post-test
results. For all statistics, the level of significance was set at P < 0.05.
Results
Were the intervention boxers alike in physiological parameters at baseline and after 8 weeks boxing
exercises?
Table 3 illustrates statistical significant differences in all of the physiological parameters at p < 0.05 between pre
and post values. Boxers’ mean HR
rest
decreased (from 73.1 to 67.3 beats/min), but, in contrast, boxers’ mean
HR
Peak
increased (from 197 to 204 beats/min). During the same period, Boxers’ mean RHR
1st
, RHR
2nd
and
RHR
3rd
dropped (p < 0.05)
(from 171, 146.5 and 139 beats/min to 166.6, 141 and 128 beats/min respectively).
Simultaneously, relative and absolute VO
2Max
increased significantly (p < 0.05) (from 58.2 to 64.6 ml/kg/min;
from 4.65 to 5.23 l/min respectively). During the same period intervention boxers’ mean RER decreased
significantly (p < 0.05) (from 0.83 to 0.79).
Table 3. Pre and post-training programme physiological parameters (n=17).
95% Confidence Limits
Parameter Pre-Test
Mean (SD)
Post-Test
Mean (SD) Difference
a
Min Max P-value
HR
rest
73.1 ± 2.7 67.3 ± 1.9 - 5.8 + 3.4 + 7.1 < 0.05
HR
Peak
197 ± 5.8 204 ± 7.2 + 7.0 - 8.1 - 4.4 < 0.05
RHR
1st
171 ± 7.2 166.6 ± 5.1 - 4.4 + 3.9 + 5.1 < 0.05
RHR
2nd
146.5 ± 6.9 141 ± 6.9 - 5.5 + 4.6 + 6.1 < 0.05
RHR
3rd
139 ± 7.1 128 ± 5.1 - 11.0 + 6.6 + 8.6 < 0.05
VO
2 Max1
58.2 ± 6.9 64.6 ± 7.2 + 6.4 - 10.3 - 3.2 < 0.05
VO
2
Max2
4.65 ± 0.30 5.23 ± 0.60 + 0.6 - 0.68 - 0.36 < 0.05
RER 0.83 ± 0.02 0.79 ± 0.2 - 0.04 + 0.02 + 0.06 < 0.05
Note:
a
= post-test mean minus pre-test mean, HRrest = resting heart rate (beats/min), HR
Peak
= peak heart rate
(beats/min), RHR
1st
= recovery heart rate after 1 minute (beats/min), RHR
2nd
= recovery heart rate after 2
minutes (beats/min), RHR
3rd
= recovery heart rate after 3 minutes (beats/min),
VO
2Max1
= relative maximal
oxygen uptake (ml/kg/min), VO
2Max2
= absolute maximal oxygen uptake (l/min), RER = respiratory exchange
ratio.
Were the intervention boxers alike in biochemical parameters at baseline and after 8 weeks boxing exercises?
Table 3 illustrates statistical significant differences in all of the biochemical parameters at p < 0.05 between pre
and post values. A significant reduction in the BL concentration was reported among the intervention boxers
(from 8.7 to 7.3 mMol/L). Furthermore, intervention boxers’ mean CK increased significantly (p < 0.05) (from
205.4 to 239.4 IU/l). Additionally, intervention boxers’ mean LDH increased significantly (from 279.7 to 349.9
IU/l ).
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Table 4. Pre and post-training programme biochemical parameters (n=17).
95% Confidence Limits
Parameter Pre-Test
Mean (SD)
Post-Test
Mean (SD) Difference
a
Min Max P-value
BL
8.7 ± 1.1 7.3 ± 1.0 - 1.4 + 1.2 + 1.5 < 0.05
CK 205.4 ± 16.6 239.4 ± 9.2 + 34.1 - 42.9 - 25.3 < 0.05
LDH 279.7 ± 14.1 349.9 ± 79.5 + 70.25 - 81.1 - 58.8 < 0.05
Note:
a
= post-test mean minus pre-test mean, BL = Blood Lactate (mMol/L), CK = Creatine Kinase (IU/l), LDH
= Lactate Dehydrogenase (IU/l).
Discussion
The studied boxers executed the training programme period without any symptoms of clinical signs that
would exclude them from the study. The authors’ statistics express significant physiological and biochemical
responses to boxing exercises in elite boxers. Regarding physiological parameters, by comparing the post-
training programme values with pre-training programme values (Table 3), our results noted that boxing exercises
training programme was associated with significant decreases in HR
rest,
RHR
1st,
RHR
2nd,
RHR
3rd,
and RER values,
while it associated with significant increases in HR
Peak
, relative and absolute VO
2Max
. In connection with HR
values, a lowered resting HR has long been known as an indicator of improving aerobic capacity (Reilly et al.,
1990). It has become a fact that physical activity has a high impact on well-being enhancement in athletic
activities (Aubert et al., 2003). Our findings proposed that boxing exercises may be helpful in promoting
physiological parameters among elite boxers. This could be consequently interpreted as improved aerobic
capacity in boxers (Chatterjee et al., 2006). Thus, we can say that boxing exercises help to develop
cardiovascular fitness over time, in other words, boxing exercises are cardioprotective (serving to protect the
heart). The maximal oxygen uptake (VO
2max
) is one of the essential indicators that provides an appropriate
prediction of performance in amateur boxing (Guidetti et al., 2002), and it is considered as one of the best tests
of aerobic performance (Hale, 2003; Morris, 2010), which plays a vital role in boxing and has a main effect on
technical and tactical performance effectiveness (El-Ashker, 2004). The findings of the recent research pointed
out that boxing exercises affect significantly VO
2max
, which affirms possibility of boxing exercises’s for
enhancing aerobic performance. Pre-training relative and absolute VO
2max
values began at 58.2 ml/kg/min and
4.65 l/min respectively. Subsequent to the 8-weeks boxing training programme, relative and absolute VO
2max
values were elevated to 64.6 ml/kg/min and 5.23 l/min respectively. The average values for VO
2max
of post-
training programme were higher than the Indian elite boxers (59.5 ml/kg/min) (Ghosh, 2010); and also much
higher than levels of previous Indian boxers (54.5 ml/kg/min) (Ghosh et al., 1995); and slightly higher than
England senior national boxers (63.8 ml/kg/min) (Smith, 2006). This statistics proposes that boxing exercises
improve VO
2max
efficiently within an eight-week period.
The respiratory exchange ratio (RER) refers to the ratio of carbon dioxide produced to oxygen used during
metabolism (v
co2
/ V
O2
), and it is associated with the intensity of training exercises and the major kind of energy
used (Kraemer et al., 2011; Guidetti et al., 2002). As regards RER, by comparing the pre and post-training
programme values, our findings suggested that boxing training programme was connected with decreases in
RER levels from 0.83 at baseline to 0.79 after eight-week period. This supported proposals that RER is lower
compared with before training in participants doing exercise at an sub-maximal power output (Friedlander et al.,
1997; Martin et al., 1993).
Furthermore, numerous biochemical parameters are changed by exercise. By comparing the post and
pre-training programme values (Table 4), our results showed that boxing exercises were associated with
significant decreases in BL values, and with significant increases in both CK and LDH values.
One of the main significant biochemical parameters in sport medicine is lactate (Karnincic et al., 2009), a
metabolite formed from glycolytic pathways, which is a sign for the onset of fatigue (Garrett and Kirkendall,
2000). With reference to BL, Table 4 illustrates statistical significant differences between pre and post-training
programme values in the concentration of BL, which decreased from 8.7 at baseline to 7.3 mMol/L after the
intervention training programme. Lactate constructed by muscles or other tissues can circuit in the blood and
then be used by inactive skeletal muscles, cardiac muscle, and the kidneys to produce glycogen or be altered to
pyruvate (Brooks, 2000). For instance, when blood lactate concentration increase higher than resting values,
such in anaerobic performance, inactive muscle can use lactate to create glycogen or pyruvate, consequently
reducing blood lactate concentration (Kraemer, et al., 2011). Accordingly, our result proves that the reduction of
BL concentration attributes to the development of the athletes' functional training.
Analyzing both CK and LDH at baseline illustrates that, although the participants had not started boxing training
programme yet, the average values of CK and LDH levels were 205.4 IU/l and 279.7 IU/l respectively, which
were greater than the normative values for healthy men. Normative values in healthy men ranged between 55 to
170 IU/l for CK (Pagana and Pagana, 1995; Tilkian et al., 1995), and between 100-190 IU/l for LDH
(Rosmarakis et al., 2005). We can explain that by their previous conditioned training programme they
participated in. The comparisons of baseline with post-test values suggested a positive relationship between
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115
boxing exercises and elevating CK, LDH levels. Changes in glycolytic enzymes may enhance performance in
aerobic and anaerobic actions together with rising ATP availability from glycolysis (Kraemer et al., 2011).
Increases in LDH levels have been revealed after weight training (Tesch and Alkner, 2003), speed training
(MacDougall et al., 1998; Ross and Leveritt, 2001)
and endurance training (Abernethy et al., 1990). A number of
similar researches supported our findings that significant increases in the activity of CK enzyme have been
demonstrated after physical exercises (Parra et al., 2000; Ehlers et al., 2002).
There are several potential limitations of this study. One of these limitations is the complexity in
quantifying each exercise load in the boxing training programme. The outcome results would need to be
confirmed by extra studies including a larger sample size, so as to be sufficiently powered statistically.
Prospective studies need to confirm the recent findings, examine further possible physiological and biochemical
variables and, investigate more issues (e.g., psychological – immunological – neuromuscular).
Conclusions
Within the research sample and the available possibilities, we can conclude that boxing exercises have
positive impact on the physiological and biochemical variables under research. This impact may be the result of
participating in a boxing training programme regularly, which declares that boxing exercises induce changes in
various physiological and biochemical parameters. In view of the fact that physiological and biochemical
statistics on Egyptian boxers are insufficient, the recent study might supply useful data help to promote boxing
training. The study of the physiological demands through sport activity helps in designing training programmes
on a biological foundation. Physiological and biochemical variables are considerable indicators of changes in
body systems as a result of training. In conclusion, detecting relationships associated with the effects of training
on physiological and biochemical aspects adding new dimensions that can assist in evaluating, directing and
developing athletic training programmes.
Acknowledgments
The authors would like to express their gratitude to the boxers who joined in the study for their cooperation and
motivation. We also thank the Faculty of Sports and Physical Education at Mansoura University for allowing us
to use the Applied Physiology Research Lab.
References
Abernethy, P. J., Thayer, R., & Taylor, A. W. (1990). Acute and chronic responses of skeletal muscle to
endurance and sprint exercise. A review. Sports Medicine 10(6), 365-389.
AIBA, International Boxing Association. (2010). Technical & Competition Rules. 2010, Available from
http://www.aiba.org/default.aspx?pId=183#
Astrand, P, & Rodahl, K.(1986).Textbook of work physiology. New York, United States: McGraw-Hill.
Aubert, A. E., Seps, B., & Beckers, F. (2003). Heart rate variability in athletes. Sports Medicine, 33(12), 889
Beneke, R., Beyer, T., Jachner, C., Erasmus, J., & Hutler, M. (2004). Energetics of karate kumite. European
journal of applied physiology, 92(4-5), 518-523.
Brooks, G. A. (2000). Intra- and extra-cellular lactate shuttles. Medicine and science in sports and exercise,
32(4), 790-799.
Brown, S. P., Miller, W. C., & Eason, J. M. (2006). Exercise physiology : basis of human movement in health
and disease. Philadelphia, Pa. ; London: Lippincott Williams & Wilkins.
Chatterjee, P., Banerjee, A. K., Majumdar, P., & Chatterjee, P. (2006). Changes in Physiological Profile of
Indian Women Boxers During a Six Week Training Camp. International Journal of Applied Sports Sciences,
18(2), 39-49.
Ehlers, G. G., Ball, T. E., & Liston, L. (2002). Creatine Kinase Levels are Elevated During 2-A-Day Practices in
Collegiate Football Players. Journal of athletic training, 37(2), 151-156.
El-Ashker, S. (2004). Effect of developing specific endurance on some physiological responses and technical
performance effectiveness for youth boxers 'comparative study'. Mansoura University, Egypt. (In Arabic: English
abstract).
El-Ashker, S. (2011). Technical and tactical aspects that differentiate winning and losing performances in
boxing. International Journal of Performance Analysis in Sport, 11(2), 356-364.
EL-Hawy, Y. (1983). Effect of the proposed training program for young boxers on some motor skills and
functional abilities during the preparation period. Unpublished PhD thesis, Zagazig University, Egypt. (In
Arabic: English abstract).
Friedlander, A. L., Casazza, G. A., Horning, M. A., Huie, M. J., & Brooks, G. A. (1997). Training-induced
alterations of glucose flux in men. Journal of applied physiology, 82(4), 1360-1369.
Garrett, W. E., & Kirkendall, D. T. (2000). Exercise and sport science. Philadelphia ; London: Lippincott
Williams & Wilkins.
Ghosh, A. K. (2010). Heart Rate, Oxygen Consumption and Blood Lactate Responses During Specific Training
in Amateur Boxing. International Journal of Applied Sports Sciences, 22(1), 1-12.
JPES
SAID EL-ASHKER, MOSTAFA NASR
JPES
®
www.efsupit.ro
116
Ghosh, A. K., Goswami, A., & Ahuja, A. (1995). Heart rate & blood lactate response in amateur competitive
boxing. Indian Journal of Medical Research, 102, 179-183.
Ghosh, A. K., Goswami, A., Mazumdar, P., & Mathur, D. N. (1991). Heart rate & blood lactate response in field
hockey players. Indian Journal of Medical Research, 94, 351-356.
Gleeson, M. (2002). Biochemical and immunological markers of overtraining. Journal of sports science and
medicine, 1(2), 31-41.
Guidetti, L., Musulin, A., & Baldari, C. (2002). Physiological factors in middleweight boxing performance. The
Journal of Sports Medicine and Physical Fitness, 42(3), 309-314.
Hafez, S. (1997). The impact of agility developing on the level of boxing skills performance and some
physiological variables for junior (12-14 years) boxers. Suez Canal University, Port Said, Egypt. (In Arabic:
English abstract).
Hale, T. (2003). Exercise physiology : a thematic approach. Chichester: Wiley.
Karnincic, H., Tocilj, Z., Uljevic, O., & Erceg, M. (2009). Lactate profile during Greco-Roman wrestling match.
Journal of Sports Science and Medicine, 8(CSSI-3), 17 - 19.
Khanna, G. L., & Manna, I. (2006). Study of physiological profile of Indian boxers. Journal of sports science
and medicine, 5(CSSI), 90-98.
Kraemer, W. J., Fleck, S. J., & Deschenes, M. R. (2011). Exercise physiology : integrating theory and
application. Philadelphia, United States: Lippincott Williams & Wilkins.
Kravitz, L., Greene, L., Burkett, Z., & Wongsathikun, J. (2003). Cardiovascular response to punching tempo.
Journal of Strength and Conditioning Research, 17(1), 104-108.
MacDougall, J. D., Hicks, A. L., MacDonald, J. R., McKelvie, R. S., Green, H. J., & Smith, K. M. (1998).
Muscle performance and enzymatic adaptations to sprint interval training. Journal of applied physiology, 84(6),
2138-2142.
Martin, W. H., Dalsky, G. P., Hurley, B. F., Matthews, D. E., Bier, D. M., Hagberg, J. M., et al. (1993). Effect of
endurance training on plasma free fatty acid turnover and oxidation during exercise. American journal of
physiology, 265(5 Pt 1), E708-714.
Morris, M., Lamb, K. L., Hayton, J., Cotterrell, D., & Buckley, J. (2010). The validity and reliability of
predicting maximal oxygen uptake from a treadmill-based sub-maximal perceptually regulated exercise test.
European journal of applied physiology, 109(5), 983-988.
Pagana, K. D., & Pagana, T. J. (1995). Mosby's diagnostic and laboratory test reference (2
nd
edition). St. Louis ;
London: Mosby.
Parra, J., Cadefau, J. A., Rodas, G., Amigo, N., & Cusso, R. (2000). The distribution of rest periods affects
performance and adaptations of energy metabolism induced by high-intensity training in human muscle. Acta
Physiologica Scandinavica, 169(2), 157-165.
Reilly, T., Secher, N., Snell, P., & Williams, C. (1990). Physiology of sports. London: Taylor & Francis . N.
Spon.
Rosmarakis, E. S., Kapaskelis, A. M., Rafailidis, P. I., & Falagas, M. E. (2005). Association between Wegener's
granulomatosis and increased antithyroid antibodies: report of two cases and review of the literature.
International Journal of Clinical Practice, 59(3), 373-375.
Ross, A., & Leveritt, M. (2001). Long-term metabolic and skeletal muscle adaptations to short-sprint training:
implications for sprint training and tapering. Sports Medicine, 31(15), 1063-1082.
Shehata, A. (2010). Impact of the using ozone on cardio-respiratory fitness and some biochemical variables in
boxers. Unpublished Master's thesis, Mansoura University, Egypt. (In Arabic: English abstract).
Smith, M. S. (2006). Physiological Profile of Senior and Junior England International Amateur Boxers. Journal
of sports science and medicine, 5(CSSI), 74-89.
Tesch, P. A., & Alkner, B. A. (2003). Acute and Chronic Muscle Metabolic Adaptations to Strength Training. In
P. V. Komi (Ed.), Strength and Power in Sport, (2
nd
edition). Oxford, UK.: Blackwell Science Ltd.
Tilkian, S. M., Conover, M. B., Tilkian, A. G., & Tilkian, S. M. C. i. o. l. t. (1995). Clinical & nursing
implications of laboratory tests (5
th
edition). St. Louis ; London: Mosby.
Toskovic, N. N., Blessing, D., & Williford, H. N. (2002). The effect of experience and gender on cardiovascular
and metabolic responses with dynamic Tae Kwon Do exercise. Journal of Strength and Conditioning Research,
16(2), 278-285.
Umeda, T., Suzukawa, K., Takahashi, I., Yamamoto, Y., Tanabe, M., Kojima, A., et al. (2008). Effects of intense
exercise on the physiological and mental condition of female university judoists during a training camp. Journal
of sports sciences, 26(9), 897-904.
Urhausen, A., & Kindermann, W. (2002). Diagnosis of overtraining: what tools do we have? Sports Medicine,
32(2), 95-102.
Warburton, D. E., Welsh, R. C., Haykowsky, M. J., Taylor, D. A., & Humen, D. P. (2002). Biochemical changes
as a result of prolonged strenuous exercise. British journal of sports medicine, 36(4), 301-303.
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