e-ISSN 1734-2260 from 2005

ISSN 1429-0022 from 1997 till 2004
Indexed in: SportDiscus; EMBASE/Excerpta Medica; Index Copernicus

Medicina Sportiva 2005 vol. 9 Issue 1
Copyright ® 2005 Medicina Sportiva

Muscle weakness in the elderly: mechanism and benefits of exercise
Walter R. Frontera


The relationship between circulating sex hormones and plasma CK-MM and LDH activity in physically active regularly menstruating females
Grażyna Lutosławska, Marlena Żołnowska, Marzena Niedbalska, Elżbieta Skierska, Anna Kęska



Discriminatory analysis of anthropometric characteristics in young swimmers
Bożena Ostrowska, Jarosław Domaradzki, Krystyna Rożek-Mróz



The dangers of overhydration: lessons from the Houston Marathon
Tamara D. Hew



Controlled breathing and heart rate variability
Eva Vlčková, Pavel Stejskal, Aleš Jakubec, Iva Řehová, Filip Pavlík, Michal Botek



Effect of strength exercise and N-acetylocysteine on metabolism of glutathione, oxidative damage and erythropoietin production
Zembroń–Łacny Agnieszka, Szyszka Kazimierz, Sobańska Barbara






MUSCLE WEAKNESS IN THE ELDERLY: MECHANISM AND BENEFITS OF EXERCISE

Walter R. Frontera

Professor and Chairman in the Department of Physical Medicine and Rehabilitation, Harvard Medical School,
Chief of Service in the Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Massachusetts General Hospital,
Brigham and Women’s Hospital, Boston, Massachusetts, USA

The 20^th century was characterized by a dramatic increase in the number and percentage of people joining the group of men and women older than 60 years. Life expectancy has increased around the world. Aging, as a biological process, impacts all physiological systems in the human body. One of the most typical findings in the elderly is the loss of functional capacity including significant losses in muscle mass, strength, and power. As a result, simple daily tasks, such as rising from a chair and climbing stairs, require a larger percentage of the voluntary strength and lead to early fatigue. Longitudinal studies show that muscle strength is lost at a rate of approximately 1% per year but women appear to maintain the strength of the muscles of the upper limbs. Muscle power is lost at a faster rate. Muscle atrophy contributes to these losses but there is scientific evidence suggesting that muscle quality (strength adjusted for size) is also affected. The molecular mechanism underlying these losses is unknown but it could include changes in the biochemistry and function of the motor protein myosin. Exercise has been shown to significantly enhance muscle strength and mass in the elderly. Typical exercise programs require progressive resistance, 3-4 sets for various muscle groups, 8-10 repetitions per set, and a training intensity of 60-80% of the maximal capacity. Free weights as well as special weight training devices can be used. Strength training increases muscle strength, cross-sectional area, and muscle fiber specific force. Muscle protein synthesis is activated. Strength training also enhances cardiovascular function and joint flexibility and restores functional capacity in frail elderly.
Key words: sarcopenia, aging, muscle strength, exercise training
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THE RELATIONSHIP BETWEEN CIRCULATING SEX HORMONES AND PLASMA CK-MM AND LDH ACTIVITY IN PHYSICALLY ACTIVE REGULARLY MENSTRUATING FEMALES

Grażyna Lutosławska¹, Marlena Żołnowska¹, Marzena Niedbalska¹, Elżbieta Skierska², Anna Kęska²

1. Department of Biochemistry,
2. Department of Biology, Academy of Physical Education, Warsaw, Poland

Abstract
Introduction: It has been noted that CK-MM response to physical stress is much less pronounced in females than in males probably due to lower striated muscle mass and protective estrogen action in the muscle. However, data concerning possible contribution of physiological fluctuation in ovarian hormones to enzyme leakage into blood are not available.
Aim of the study: This study aimed at evaluation of resting plasma CK-MM and total LDH activity in females in follicular and luteal phases of the menstrual cycle and comparison of data with these found in males.
Methods: A total of 46 subjects (25 males and 21 females) volunteered to participate in the study. Basal body temperature measurements 3 months before the study and assay of 17ß-estradiol and progesterone plasma levels between days 5-8 and again between days 19-22 of the menstrual cycle allow to classify female subjects as ovulating. Male participants were tested twice, 2 week apart. Plasma CK-MM and LDH activities were determined at 340 nm using commercial kits (Alpha Diagnostics and Randox Laboratories, respectively). Ovarian hormones were determined using a standard radioimmunoassay using commercial kits (POLATOM, Swierk).
Results: In females plasma CK-MM activity did not differ with respect to the menstrual cycle phase and there were no difference in enzyme activities between male and female subjects. In contrast, plasma LDH activity in the luteal phase was significantly higher than in the follicular phase of the menstrual cycle. Both in males in females weak, but significant correlations were found between plasma CK-MM and LDH activity indicating that only a minor part of LDH in plasma was muscle-originated. Multivariate regression analysis revealed that in females plasma LDH activity was more strongly associated with plasma 17ß-estradiol levels than with plasma CK-MM activity.
Conclusion: Circulating ovarian hormones have no effect on plasma CK-MM activity in regularly menstruating women. On the contrary, physiological fluctuations in sex hormones due to menstrual cycle significantly contribute to the variability in plasma LDH activity.
Key words: females, menstrual cycle, creatine kinase MM, lactate dehydrogenase
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DISCRIMINATORY ANALYSIS OF ANTHROPOMETRIC CHARACTERISTICS IN YOUNG SWIMMERS

Bożena Ostrowska¹, Jarosław Domaradzki², Krystyna Rożek-Mróz³

1. Department of Kinesitherapy, University of Physical Education in Wrocław,
2. Department of Anthropomotor Activity, University of Physical Education in Wrocław,
3. Department of Physiotherapy in Internal Diseases, University of Physical Education in Wrocław

Abstract
The aim of this study was to describe the set of somatic characteristics, which significantly discriminate young swimmers.
Methods: 160 pupils (11 and 12-year-old) from primary schools in Wrocław were recruited for the study. The research group (Group I) consisted of swimmers and the comparative group (Group II), the non-swimmers. The participants selected for the study had been involved in swimming for 2 - 3 years. On average their training time per week was 12 to 18 hours. The following parameters were established: body height and weight, upper and lower extremities length, circumferences of: thighs, shanks, arms, forearms, chest at rest, chest after inspiration, chest after expiration, waist, hips, shoulder width, hip width, chest width, chest depth, and Rohrer index. In order to accomplish the aim of the study, a discrimination analysis method was employed.
Results: Analysis of the results indicated that the model for boys significantly appeared to discriminate the studied groups. The parameters, which distinguish the groups to the largest degree, include circumferences of the body, length parameters, and hip width. Those parameters indicate formation of the body figure typical for swimmers, characterized by specific proportions of the chest and hips, and usually by longer limbs. The difference in muscles circumferences is a direct result of training. This diversity between the groups of girls is less significant. This indicates that physical training influences the female body figure to a smaller degree than that of males. The parameters which discriminate girls the most, are the circumference of the thigh and shank, the hip width and the chest depth.
Conclusions: Sport training decreases dysmorphic differences and increases similarities in the constitution of boys and girls.
Key words: young swimmers, somatic features
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THE DANGERS OF OVERHYDRATION:
LESSONS FROM THE HOUSTON MARATHON

Tamara D. Hew
MRC/UCT Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, The University of Cape Town, Sports Science Institute, South Africa

Abstract
Aim: To provide a narrative overview of the pathogenesis of exercise associated hyponatremia from the singular perspective of the Houston Marathon. This is a summary paper of singular studies that have been published elsewhere.
Methods: Data on all symptomatic and asymptomatic cases of hyponatremia (N = 60) recorded from the Houston Marathon were analyzed from 1999–2003. Cumulative data from 117 research volunteers who participated in separate trials from 2000–2003 were summarized by trial and as a whole. The appropriate scientific methodology is detailed in separate published abstracts and manuscripts.
Results: The results from all data collected from 1999–2003 Houston Marathon are summarized by the following statements:
1. Hyponatremia is not a “rare” occurrence in the Houston Marathon
2. Overdrinking is the causative factor in the development of hyponatremia in marathon runners
3. Sodium supplementation does not protect against the development of hyponatremia
4. Women are at increased risk for fluid retention
5. Weight loss does not equate to dehydration in this cohort of recreational runners
Conclusion: Over hydration is the primary causative factor in the development of hyponatremia in Houston Marathon Runners participating in the event between the years 1999–2003. Marathon runners must therefore be warned about the dangers of excessive fluid intake during endurance events.
Key words: hyponartemia, sodium, marathon, runners, overdinking
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CONTROLLED BREATHING AND HEART RATE VARIABILITY

Eva Vlčková, Pavel Stejskal, Aleš Jakubec, Iva Řehová, Filip Pavlík, Michal Botek
Faculty of Physical Culture, Palacký University, Olomouc, Czech Republic

Abstract
The aim of this study was to compare SA HRV under conditions of spontaneous and controlled breathing with the use of a new SA HRV evaluation method.
Methods: The results of the short-term recording of spectral analysis (SA) of heart rate variability (HRV) in 21 healthy volunteers with additional vagal stimulation by means of controlled breathing are presented in this article. To a standard orthoclinostatic test (supine-standing-supine) three supine positions with controlled breathing (12, 9, 6 breaths/min) were added.
Results: Controlled breathing did not influence heart rate. With gradually decreasing breathing frequency (BF) and increasing breathing volume, a step by step increase in the average value of total spectral power (PT) started. The highest value of PT was found during the slowest BF (6/min). Also, the frequency of dominant fluctuations slowed down and a shift of spectral power from the HF zone towards the LF zone took place.
Conclussions: Because of these shifts, we were not able to use the usual interpretation of individual indexes as well as complex indexes of SA HRV.
Key words: heart rate variability, autonomic nervous system, spontaneous respiration, controlled respiration
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EFFECT OF STRENGTH EXERCISE AND N-ACETYLOCYSTEINE ON METABOLISM OF GLUTATHIONE, OXIDATIVE DAMAGE AND ERYTHROPOIETIN PRODUCTION

Zembroń–Łacny Agnieszka¹, Szyszka Kazimierz², Sobańska Barbara¹

1. Department of Biochemistry,
2. Department of Sport Medicine, Faculty of Physical Culture in Gorzów Wlkp., Poland

Abstract

Introduction/Purpose: Glutathione is a ubiquitous thiol playing important role in cellular defense against oxidative stress. Earlier studies have shown, that glutathione metabolism and production of erythropoietin (EPO) may be modulated by N-acetylcysteine. The aim of this study was to determine whether a strength exercise induces oxidative stress and whether intensification of glutathione metabolism by oral treatment with N-acetylcysteine reduces plasma protein and lipid damage and results in changes of EPO level.
Methods: Ten healthy male volunteers participated twice in this study. Subjects performed an intensity resistance exercise (shoulder press, bench press, straightening up with weights). Subjects were given oral dose of 3 x 600 mg N-acetylcysteine (NAC) daily for three days before the second study. Venous blood samples were collected 5min before exercise, immediately post exercise and after 24 h rest. Protein carbonyls (PC), lipid peroxidation products (TBARS), erythropoietin (EPO) and glutathione (GSH) levels as well as γ-glutamyl transpeptidase (GGT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities were evaluated.
Results: The applied exercise at maximal intensity (post-exercise lactate: 7.71 ± 2.13 and 8.00 ± 2.18 mmol . l-1) caused significant changes in the tested parameters. The pre- and post-exercise levels of oxidative damage (PC, TBARS) were lower after NAC administration. The glutathione metabolism (GSH, GGT, GPx, GR) was enhanced by NAC. No effect of NAC on EPO activity was observed.
Conclusions: Our study has shown that a strength exercise increases in oxidative damage level and initiates changes in glutathione metabolism whereas the N-acetylcysteine administration enhances antioxidative glutathione system and attenuates oxidative stress without any effect on erythropoietin level in subjects’ blood.
Key words: thiols, oxidative stress, erythropoietin, strength test
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